U.S. patent application number 16/248493 was filed with the patent office on 2019-07-18 for implantable nasal stimulator systems and methods.
The applicant listed for this patent is Oculeve, Inc.. Invention is credited to Douglas Michael Ackermann, Manfred Franke, Janusz Kuzma, James Donald Loudin, Paul Taehyun Yu.
Application Number | 20190217095 16/248493 |
Document ID | / |
Family ID | 55761601 |
Filed Date | 2019-07-18 |
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United States Patent
Application |
20190217095 |
Kind Code |
A1 |
Franke; Manfred ; et
al. |
July 18, 2019 |
IMPLANTABLE NASAL STIMULATOR SYSTEMS AND METHODS
Abstract
Described here are systems, devices, and methods for implanting
a nasal stimulator into nasal tissue and electrically stimulating
nasal tissue. In some variations, a nasal microstimulator
implantation system may comprise an implantation tool and an
implantable microstimulator. An implantation tool may comprise a
shaft and features to releasably attach a microstimulator. A
microstimulator may comprise a passive stimulation circuit and one
or more electrodes. In other variations, a nasal implantation
system may additionally comprise one or more additional devices,
such as a controller, an electrical probe, and/or a dissection
tool.
Inventors: |
Franke; Manfred; (Valencia,
CA) ; Loudin; James Donald; (Houston, TX) ;
Kuzma; Janusz; (Bayview, AU) ; Yu; Paul Taehyun;
(Los Altos, CA) ; Ackermann; Douglas Michael; (San
Francisco, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Oculeve, Inc. |
South San Francisco |
CA |
US |
|
|
Family ID: |
55761601 |
Appl. No.: |
16/248493 |
Filed: |
January 15, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14920852 |
Oct 22, 2015 |
10207108 |
|
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16248493 |
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62067391 |
Oct 22, 2014 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61N 1/3606 20130101;
A61N 1/37205 20130101; A61N 1/36046 20130101; A61N 1/3756 20130101;
A61N 2001/37294 20130101 |
International
Class: |
A61N 1/36 20060101
A61N001/36; A61N 1/375 20060101 A61N001/375; A61N 1/372 20060101
A61N001/372 |
Claims
1.-20. (canceled)
21. A system, comprising: a microstimulator configured to be
implanted into nasal tissue of a nasal cavity of a patient, the
microstimulator including at least one electrode for delivering an
electrical stimulus to nasal tissue to thereby increase tear
production in the patient; and an implantation device comprising an
elongate shaft having a distal end configured to releasably couple
to the microstimulator.
22. The system of claim 21, wherein the electrical stimulus is
pulsed.
23. The system of claim 21, wherein the electrical stimulus
comprises a biphasic symmetric pulse waveform.
24. The system of claim 23, wherein the frequency of the biphasic
pulse waveform is between 20 Hz and 80 Hz.
25. The system of claim 21, wherein the electrical stimulus has a
waveform with a varying pulse width.
26. The system of claim 21, wherein the electrical stimulus has a
waveform with a varying frequency.
27. The system of claim 221, wherein the electrical stimulus has a
waveform with a varying amplitude.
28. The system of claim 21, wherein the microstimulator includes a
dissipation circuit configured to receive an output signal from a
controller and, based on the received output signal, deliver an
electrical current to nasal tissue.
29. The system of claim 21, wherein the microstimulator includes
one or more fixation elements that promote tissue ingrowth.
30. The system of claim 21, wherein the distal end of the
implantation device includes a friction holder including one or
more friction elements configured to contact at least a portion of
the microstimulator and frictionally resist movement of the
microstimulator relative to the implantation device.
31. The system of claim 30, wherein the implantation device
includes a pusher slidably disposed within a lumen of the elongate
shaft and movable between a proximal position and a distal
position, the pusher configured to release the microstimulator from
the friction holder when in the distal position.
32. The system of claim 21, wherein the implantation device
includes a retractable cover that extends over the microstimulator
in an extended position and exposes at least a part of the
microstimulator in a retracted position.
33. The system of claim 32, wherein the retractable cover includes
a distal end having a sharp edge for making an incision in nasal
tissue.
34. The system of claim 33, wherein the distal end of the
retractable cover is curved and wraps at least partially around the
distal end of the microstimulator when the retractable cover is in
the extended position.
35. The system of claim 34, wherein the retractable cover is
flexible thereby allowing the curved distal end of the retractable
cover to straighten when the retractable cover is retracted to
expose at least a part of the microstimulator.
36. The system of claim 21, wherein the implantation device
includes a tension system for releasably coupling the
microstimulator to a distal end of the implantation tool, the
tension system comprising a tensioning element that, when under
tension, secures the microstimulator against the distal end of the
implantation device.
37. The system of claim 21, further comprising an electrical probe
comprising an electrode coupled to an endoscope, the electrode
configured to electrically stimulate nasal tissue for determining
an implantation site along the nasal cavity.
38. The system of claim 21, further comprising a dissection tool
configured to form an implantation site in the nasal cavity for
implanting the microstimulator, the dissection tool comprising a
blade positioned at a distal end of a dissection shaft and a
suction opening extending through a portion of the blade.
39. A system, comprising: a microstimulator configured to be
implanted into nasal tissue of a nasal cavity of a patient, the
microstimulator including at least one electrode for delivering an
electrical stimulus to nasal tissue to thereby increase tear
production in the patient; an implantation device comprising an
elongate shaft having a distal end configured to releasably couple
to the microstimulator; an electrical probe comprising an electrode
coupled to an endoscope, the electrode configured to electrically
stimulate nasal tissue for determining an implantation site along
the nasal cavity; and a dissection tool configured to form the
implantation site in the nasal cavity for implanting the
microstimulator, the dissection tool comprising a blade positioned
at a distal end of a dissection shaft and a suction opening
extending through a portion of the blade.
40. The system of claim 39, wherein the microstimulator includes a
dissipation circuit configured to receive an output signal from a
controller and, based on the received output signal, deliver an
electrical current to nasal tissue.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation and claims priority to
U.S. patent application Ser. No. 14/920,852 filed on Oct. 22, 2015,
which claims priority to U.S. Provisional Application No.
62/067,391, filed on Oct. 22, 2014, and titled "IMPLANTABLE NASAL
STIMULATOR SYSTEMS AND METHODS," which is hereby incorporated by
reference in its entirety.
FIELD
[0002] The present invention relates generally to systems, devices,
and methods for implanting a nasal stimulator into nasal tissue and
electrically stimulating nasal tissue for the treatment of
indications such as dry eye.
BACKGROUND
[0003] Dry Eye Disease ("DED") is a condition that affects millions
of people worldwide. More than 40 million people in North America
have some form of dry eye, and many millions more suffer worldwide.
DED results from the disruption of the natural tear film on the
surface of the eye, and can result in ocular discomfort, visual
disturbance and a reduction in vision-related quality of life.
Activities of daily living such as driving, computer use, housework
and reading have also been shown to be negatively impacted by DED.
Patients with severe cases of DED are at risk for serious ocular
health deficiencies such as corneal ulceration, and can experience
a quality of life deficiency comparable to that of moderate-severe
angina.
[0004] DED is progressive in nature, and fundamentally results from
insufficient tear coverage on the surface of the eye. This poor
tear coverage prevents healthy gas exchange and nutrient transport
for the ocular surface, promotes cellular desiccation and creates a
poor refractive surface for vision. Poor tear coverage typically
results from: 1) insufficient aqueous tear production from the
lacrimal glands (e.g. secondary to post-menopausal hormonal
deficiency, auto-immune disease, LASIK surgery, etc.), and/or 2)
excessive evaporation of aqueous tear resulting from dysfunction of
the meibomian glands. Low tear volume causes a hyperosmolar
environment that induces an inflamed state of the ocular surface.
This inflammatory response induces apoptosis of the surface cells
which in turn prevents proper distribution of the tear film on the
ocular surface so that any given tear volume is rendered less
effective. This initiates a vicious cycle where more inflammation
can ensue causing more surface cell damage, etc. Additionally, the
neural control loop, which controls reflex tear activation, is
disrupted because the sensory neurons in the surface of the eye are
damaged. As a result, fewer tears are secreted and a second vicious
cycle develops that results in further progression of the disease
(fewer tears cause nerve cell loss, which results in fewer tears,
etc.).
[0005] There is a wide spectrum of treatments for DED, although
without substantial efficacy for treatment of the condition.
Treatment options include: artificial tear substitutes, ointments,
gels, warm compresses, environmental modification, topical
cyclosporine, omega-3 fatty acid supplements, punctal plugs and
moisture chamber goggles. Patients with severe disease may further
be treated with punctal cautery, systemic cholinergic agonists,
systemic anti-inflammatory agents, mucolytic agents, autologous
serum tears, PROSE scleral contact lenses and tarsorrhaphy. Despite
these treatment options, DED continues to be considered one of the
most poorly treated diseases in ophthalmology. Accordingly, it
would be desirable to have a more effective treatment for dry
eye.
[0006] Strategies described herein for treatment of DED take
advantage of the nasolacrimal reflex. The nasolacrimal reflex is a
well-established pathway by which nasal stimuli promote tear
production. Electrical stimulation applied to sensory neurons in
the nasal cavity may activate the nasolacrimal reflex and thereby
increase tear production. Devices and methods to deliver electrical
stimuli to areas of the nasal cavity are therefore promising
alternatives to the current treatment options for DED.
BRIEF SUMMARY
[0007] Described here are systems, devices, and methods for
implanting a nasal stimulator into nasal tissue and electrically
stimulating nasal tissue. In some variations, the methods described
here comprise methods of tear production in a patient. In some
variations, the methods comprise implanting a microstimulator into
nasal tissue and delivering an electrical stimulus via the
microstimulator to produce tears. In some variations, the
electrical stimulus is pulsed. In some variations, the electrical
stimulus comprises a biphasic symmetric pulse waveform. In some
variations, the frequency of the biphasic pulse waveform is between
20 Hz and 80 Hz. In some variations, the electrical stimulus has a
waveform with a varying pulse width. In some variations, the
electrical stimulus has a waveform with a varying frequency. In
some variations, the electrical stimulus has a waveform with a
varying amplitude.
[0008] In some variations, the methods described here comprise
methods for delivering a microstimulator into nasal tissue of a
patient. In some variations, the methods comprise identifying an
implantation site in the nasal tissue, forming a pocket in the
nasal tissue at the implantation site, and inserting a
microstimulator into the pocket. In some variations, at least a
portion of the pocket is located adjacent to the anterior ethmoidal
nerve. In some variations, identifying the implantation site
comprises electrically stimulating the nasal tissue at at least one
location, and observing or recording a response to electrically
stimulating the nasal tissue at the at least one location. In some
variations, an electrical probe is used to electrically stimulate
the nasal tissue. In some variations, the electrical probe
comprises an endoscope and an electrode coupled to the endoscope.
In some variations, the response comprises one or more of tearing,
sneezing, and paresthesia. In some variations, the pocket is
substantially between the mucosal layer and the nasal septum. In
some variations, forming the pocket comprises incising the nasal
tissue to create a pocket opening and extending the pocket from the
pocket opening. In some of these variations, the pocket is extended
using a dissection tool comprising a shaft, a blade at a first end
of the shaft, and a suction opening extending through a portion of
the blade. In some variations, the pocket is extended using a
dissection tool comprising a shaft with a distal end and a proximal
end, a blade positioned at the distal end of the shaft, and a
lumen, where the lumen extends distally from an opening at the
proximal end of the shaft, and where the lumen is configured to
receive an endoscope shaft therewithin. In some of these
variations, the dissection tool further comprises a compressible
section configured to change a diameter of the lumen in order to
releasably attach the dissection tool to the endoscope shaft. In
some variations, an implantation tool is used to insert the
microstimulator into the pocket. In some variations the
implantation tool comprises a retractable cover, and the
retractable cover enters the pocket before the microstimulator. In
some variations, a device used to perform the method comprises a
depth stop to indicate a distance relative to a distal end of the
device. In some variations, the microstimulator is tested before it
is inserted into the pocket. In some variations, the methods
further comprise repositioning or removing the microstimulator
after it has been inserted into the pocket. In some variations the
implantation site is marked with a dye before the pocket is
formed.
[0009] In some variations, the methods described here comprise
methods of improving ocular surface health in a patient. In some
variations, the methods comprise implanting a microstimulator into
nasal tissue and delivering an electrical stimulus via the
microstimulator to produce tears.
[0010] In some variations, the systems described here comprise
systems for implanting a microstimulator into nasal tissue. In some
variations, the systems comprise a microstimulator configured to be
implanted into nasal tissue and an implantation tool. In some
variations, the microstimulator is releasably attached to the
implantation tool. In some variations, the microstimulator is
releasably attached to the implantation tool with static friction,
and the microstimulator is released from the implantation tool by
overcoming the static friction. In some variations, the
microstimulator is releasably attached to the implantation tool via
tension, and the microstimulator is released from the implantation
tool by releasing the tension. In some variations, the implantation
tool comprises a retractable cover. In some variations, the
retractable cover is movable relative the microstimulator between a
first position and a second position, where at least a portion of
the retractable cover covers a portion of the microstimulator in
the first position. In some variations, the systems further
comprise an electrical probe, and the electrical probe comprises an
endoscope coupled to at least one electrode. In some variations,
the systems further comprise a dissection tool, and the dissection
tool comprises a curved blade, a suction lumen, and an opening in
the curved blade in fluid communication with the suction lumen. In
some variations, the implantation tool comprises a depth stop to
mechanically prevent advancement of the implantation tool into a
nasal cavity past the depth stop. In some variations, the
dissection tool comprises a depth stop to mechanically prevent
advancement of the dissection tool into a nasal cavity past the
depth stop. In some variations, the implantation tool comprises a
depth marking to visually indicate a distance the implantation tool
has been advanced into a tissue pocket or a nasal cavity. In some
variations, the dissection tool comprises a depth marking to
visually indicate a distance the dissection tool has been advanced
into a tissue pocket or a nasal cavity.
[0011] In some variations, the devices described here comprise
devices for atraumatically electrically stimulating nerve tissue in
a cavity. In some variations, devices comprise at least one
electrode and a visualization tool, where the at least one
electrode is coupled to the visualization tool. In some variations,
the visualization tool is an endoscope. In some variations, the
device further comprises a conductive shaft that is attached to the
at least one electrode, and the visualization tool is coupled to
the conductive shaft.
[0012] In some variations, the devices described here comprise
devices for dissecting tissue. In some variations, the devices
comprise a shaft, a blade at a first end of the shaft, a suction
opening extending through a portion of the blade, and a tube
extending from the suction opening to a port. In some variations,
the tube is coupled to an exterior surface of the shaft. In some
variations, the shaft comprises a lumen and the tube is at least
partially disposed in the shaft lumen. In some variations, the
blade comprises a curve.
[0013] In some variations, the devices described here comprise
devices for dissecting tissue. Some of these devices comprise a
shaft comprising a distal end and a proximal end, a blade
positioned at the distal end of the shaft, and a lumen, where the
lumen extends distally from an opening at the proximal end of the
shaft, and the lumen is configured to receive an endoscope shaft
therewithin. In some variations, at least a portion of the blade is
transparent. In some variations, the blade comprises an edge and a
face, and the face is an area at least partially enclosed by the
edge. In some variations, the face of the blade is an opening, and
in some of these variations, the blade further comprises a window
that at least partially covers the face. In some variations where
the face is an opening, the device further comprises a barrier
positioned at least partially within a distal portion of the lumen,
and the barrier is configured to prevent obstruction of a view from
the endoscope shaft. In some of these variations, the barrier
comprises a liquid polymer configured to solidify after delivery
into the device. In some variations, the face is a solid surface
that is integral with the edge, and the blade does not comprise any
external openings. In some variations, the device comprises a
sleeve configured to cover at least a portion of the blade. In some
variations, the device comprises a least one tube configured to
provide irrigation or suction. In some variations, the device
comprises an attachment mechanism configured to releasably attach
the device to the endoscope shaft. In some of these variations, the
attachment mechanism comprises a compressible section configured to
change a diameter of the lumen. In some of these variations, the
attachment mechanism comprises a screw portion and a nut portion,
and the screw portion and the nut portion comprise mating threads.
In some of these variations, the attachment mechanism is configured
to compress the compressible section and decrease the diameter of
the lumen when the screw portion and the nut portion are screwed
together. In some variations, the compressible section comprises
deflectable wings. In some variations, the screw portion comprises
the compressible section. In some of these variations, a proximal
section of the shaft comprises the screw portion and the nut
portion.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1A shows a perspective view of a variation of an
implantation tool and a microstimulator described here. FIG. 1B
shows a magnified view of a distal portion of the implantation tool
and microstimulator of FIG. 1A.
[0015] FIG. 2A shows a perspective view of a first side of a
variation of a microstimulator described here. FIG. 2B shows a
perspective view of a distal portion of a variation of an
implantation tool described here and a second side of the
microstimulator of FIG. 2A. FIG. 2C shows a perspective view of a
variation of a microstimulator described here. FIG. 2D shows a
perspective view of another variation of a microstimulator
described here.
[0016] FIGS. 3A-3C show perspective views of a variation of a
microstimulator described here.
[0017] FIGS. 4A and 4B show perspective views of portions of a
variation of an implantation tool and a microstimulator described
here. FIG. 4C shows a perspective view of a proximal portion of a
variation of an implantation tool described here.
[0018] FIGS. 5A-5C show perspective views of a distal portion of a
variation of an implantation tool and a microstimulator described
here.
[0019] FIGS. 6A-6C show perspective views of a variation of an
implantation tool and a microstimulator described here.
[0020] FIGS. 7A and 7B show perspective views of a distal portion
of the implantation tool and microstimulator of FIGS. 6A-6C.
[0021] FIGS. 8A-8C show perspective views of a cross-section of the
implantation tool and microstimulator of FIGS. 6A-6C.
[0022] FIG. 9 shows a perspective view of a distal portion of the
implantation tool and microstimulator of FIGS. 6A-6C.
[0023] FIG. 10 shows an illustrative side view of a variation of a
retrieval tool described here.
[0024] FIG. 11 shows a perspective view of a variation of an
electrical probe described here.
[0025] FIGS. 12A and 12B show perspective views of variations of
dissection tools described here.
[0026] FIGS. 13A and 13B show perspective views of a variation of a
dissection tool described here.
[0027] FIGS. 14A and 14B show perspective views of variations of a
dissection tool and a distal portion of an implantation tool,
respectively, comprising depth stops described here.
[0028] FIG. 15 shows a cutaway view of a nasal cavity.
[0029] FIG. 16 shows a cutaway view of a nasal cavity and a
variation of a tissue pocket described here.
[0030] FIG. 17 shows a cutaway view of a nasal cavity and
variations of tissue pockets and a microstimulator described
here.
[0031] FIG. 18 shows a cutaway view of a nasal cavity and cut-away
views of variations of tissue pockets described here.
[0032] FIG. 19 shows a cutaway view of a nasal cavity and a
variation of a tissue pocket opening and microstimulator described
here.
[0033] FIG. 20 shows a cutaway view of a nasal cavity and a
variation of an implanted microstimulator.
[0034] FIG. 21 shows a fluoroscopic image of a portion of a goat
skull and a variation of a microstimulator described here.
[0035] FIG. 22 shows a bar graph depicting tear production in goats
implanted with a variation of a microstimulator described here.
[0036] FIG. 23 shows a variation of a passive stimulation circuit
suitable for a microstimulator described here.
[0037] FIG. 24 shows a variation of a controller described
here.
[0038] FIG. 25 shows a block diagram of a variation of a controller
circuit suitable for a controller described here.
[0039] FIG. 26 shows a block diagram of another variation of a
controller circuit suitable for a controller described here.
[0040] FIGS. 27A-27E show perspective views of a variation of an
implantation tool and microstimulator described here.
[0041] FIGS. 28A and 28B show fluoroscopic images of a portion of a
goat skull with a variation of a microstimulator and an
implantation tool described here, releasably attached and detached,
respectively.
[0042] FIGS. 29A-29C show fluoroscopic images of a procedure to
implant a variation of a microstimulator described here into a
human cadaver.
[0043] FIGS. 30A-30C show a variation of a dissection tool
described here configured for use with an endoscope.
[0044] FIG. 31 shows a distal portion of a variation of a
dissection tool described here configured for use with an
endoscope.
[0045] FIGS. 32A and 32B show a distal portion of a variation of a
dissection tool described here with an attachable blade.
[0046] FIG. 33 shows a distal portion of a variation of a
dissection tool described here configured for use with an
endoscope.
[0047] FIG. 34 shows a distal portion of a variation of a
dissection tool described here configured for use with an
endoscope.
[0048] FIGS. 35A and 35B show a variation of a dissection tool
described here configured for use with an endoscope, and FIG. 35C
shows a magnified view of an attachment mechanism of the dissection
tool of FIGS. 35A and 35B.
DETAILED DESCRIPTION
[0049] The devices, systems, and methods described herein may be
used to increase tear production by electrically stimulating nasal
tissue with a microstimulator that is surgically implanted into a
nasal cavity. The microstimulator may comprise a passive
stimulation circuit configured to receive power wirelessly, such as
from an external controller, and one or more electrodes to deliver
an electrical stimulus to surrounding tissue. Devices and methods
are described for implanting the microstimulator in a desired
location in the nasal cavity, which in some variations is within a
surgically-created tissue pocket adjacent to the nasal septum. For
example, an electrical probe for identifying the desired
implantation site and dissection tools for creating the nasal
tissue pocket are described. Also described are implantation tools
configured to deliver the microstimulator through a nostril and
into the tissue pocket. In addition, devices and methods are
described for increasing tear production after the microstimulator
is implanted, which in some variations may be used to treat Dry Eye
Disease (DED).
Devices and Systems
[0050] FIGS. 1A and 1B show perspective views of one variation of a
nasal implant stimulation system (100) described here comprising a
microstimulator (101) and an implantation tool (102). FIG. 1A
depicts the microstimulator (101) releasably attached to a distal
end of the implantation tool (102), and FIG. 1B shows a magnified
view of the microstimulator (101) and a distal portion of the
implantation tool (102). The microstimulator may be configured to
be implanted into nasal tissue, where it may generate and deliver
an electrical stimulus. As shown in FIG. 1B, the microstimulator
(101) may comprise a housing (103) and an extension (104). The
housing may comprise a stimulation circuit (not pictured), and the
extension may comprise one or more electrodes (105).
[0051] The implantation tool (102) may be configured to position
the microstimulator (101) in a nasal cavity and release the
microstimulator into a tissue pocket. The implantation tool may
comprise a shaft (106), a handle (108), and one or more features
for releasably attaching the microstimulator (101). For example,
the implantation tool (102) shown in FIGS. 1A and 1B comprises a
tension system to releasably attach the microstimulator. The
tension system may comprise a tensioning element (111) (e.g., a
string, suture, wire, or the like) that may attach to the
microstimulator and hold it against a contact surface (107) at a
distal end of the implantation tool shaft (106). The tensioning
element may extend through a lumen of the implantation tool shaft
to its proximal end, where the tensioning element may be secured by
a connector, such as a knob (112). This may allow tension to be
maintained in the tensioning element to hold the microstimulator in
place. In order to detach the microstimulator from the implantation
tool, tension in the tensioning element may be released, such as by
cutting the tensioning element.
[0052] The implantation tool (102) may comprise one or more
features to protect the microstimulator (101) during implantation
and/or facilitate the formation of a pocket in tissue for the
implant. For example, the implantation tool (102) may comprise a
retractable cover (109) that may be slidable relative to the shaft
(106). The retractable cover may be slidable between a retracted,
proximal position, which is shown in FIGS. 1A and 1B, and an
advanced, distal position (not shown). When the retractable cover
is in the retracted position, an electrode (105) of the
microstimulator may be exposed, and the microstimulator may be
detached from the implantation tool. When the retractable cover is
in the advanced position, the electrode may be covered and
protected, and the microstimulator may be advanced into a nostril
and positioned at an implantation site. In some variations, when
the retractable cover is in the advanced position, a portion of the
retractable cover may extend distal to the microstimulator. This
may, for example, protect the microstimulator and/or allow the
retractable cover to be used for creating and/or opening a tissue
pocket.
[0053] A nasal microstimulator implantation system may additionally
or alternatively comprise other tools, which are described in more
detail herein. For example, tools are described that may help to
select an implantation site for a microstimulator, such as an
electrical probe. The electrical probe may comprise a conductive
shaft to electrically stimulate areas of the nasal cavity in order
to locate a specific site that produces tearing when stimulated.
The electrical probe may also comprise an endoscope to visualize
the areas that are stimulated. In some variations, the system may
comprise one or more devices to dissect (incise, separate, elevate,
and/or the like) nasal tissue in order to form a tissue pocket to
receive the microstimulator. For example, a dissection tool may
comprise a sharp blade for incising tissue to make an opening for
the tissue pocket and/or a blunt blade for extending the tissue
pocket. The dissection tool may be configured to provide suction
and/or configured to be used with an endoscope to improve
visualization around the blade.
Microstimulator
[0054] FIG. 2A and FIG. 2B show perspective views of opposite first
and second sides of a microstimulator (200), respectively. In FIG.
2A, the microstimulator is depicted alone, and in FIG. 2B, it is
depicted attached to an implantation tool (201). As shown, the
microstimulator (200) may comprise a housing (202) and an extension
(204) connected to the housing, although in other variations the
housing may be partially or completely contained within the
extension.
[0055] The shape and size of the microstimulator may aid in
atraumatic insertion of the device into nasal tissue. Generally,
the shape of a microstimulator may be flat and thin. As will be
discussed in more detail herein, during implantation, the
microstimulator may be inserted into a tissue pocket within the
nasal submucosal layer. A flat, thin shape may decrease the risk of
catching, stretching, or otherwise traumatizing nasal tissue (e.g.,
nasal septum, submucosa) during implantation. As seen in FIGS. 2A,
2B, and 3A-3C, the microstimulator may comprise one or more rounded
edges which may also reduce the risk of tissue damage as the
microstimulator is advanced into or past tissue. One or more
portions of the microstimulator (e.g., an extension) may be formed
from a flexible material such as silicone and/or may be a molded
component, such as a molded silicone. The materials may allow the
microstimulator to conform to one or more portions of the anatomy
(e.g., the nasal septum) and/or prevent trauma during
implantation.
[0056] The microstimulator may be small enough to be inserted
through a nostril and implanted within a layer of submucosa
adjacent to the nasal septum or a turbinate without significantly
interfering with the passage of air or fluid through the nasal
cavity. In some variations the dimensions may be less than about 30
mm by about 10 mm by about 5 mm (L.times.W.times.H). In some of
these variations, the dimensions may be about 15 mm-25 mm by about
3 mm-7 mm by about 1 mm-3 mm (L.times.W.times.H). In some of these
variations, the dimensions may be about 17 mm by about 5 mm by
about 2 mm (L.times.W.times.H). In variations of the
microstimulator comprising a housing adjacent to an extension, such
as shown in FIGS. 2A-2C, the thickness of the extension (203) may
be less than that of the housing (202) and may gradually increase
to the thickness of the housing. The width of the extension may be
greater than the width of the housing and may taper to the width of
the housing, as seen in FIGS. 2A and 2B. In some variations, the
housing may have the same width as the extension, or the housing
may be wider than the extension. In some variations, the
microstimulator may be encapsulated in a coating. A coating, such
as silicone, provides electrical insulation, waterproofing,
biocompatibility, and/or safety (e.g., rounded edges, lubricious
surface that slides easily over the nasal septum). FIG. 2C shows a
variation of a microstimulator (210) encapsulated in a coating
(212).
[0057] The microstimulator may comprise one or more connectors,
which may facilitate attachment of the microstimulator to another
device. For example, one or more connectors may attach the
microstimulator to an implantation tool and/or a tool for
minimally-invasive retrieval or repositioning. As shown in FIG. 2A,
one variation of the connector comprises an eyelet (204) at the
proximal end of the housing. This eyelet may attach to an
implantation tool and/or a tool for retrieval or repositioning. In
some variations, an eyelet may be recessed into a portion of the
housing or extension such that the eyelet does not extend beyond
the dimensions of the microstimulator. It should be appreciated
that in some variations, the connector or connectors may be located
in other positions on the microstimulator (e.g., other positions on
the housing or on the extension) or have other forms (e.g., hook,
slot, or magnet). In some variations, different connectors may be
used to attach the microstimulator to different devices, whereas in
other variations, the same one or more connectors may be used with
different devices.
[0058] The housing (202) of the microstimulator (200) may comprise
a housing case containing some or all of a stimulation circuit,
described in more detail herein. The housing case may be
hermetically sealed and may be formed from one or more metals
(e.g., titanium) or other biocompatible materials.
[0059] In some variations, the stimulation circuit may comprise one
or more passive stimulation circuits in which the device does not
include any internal logic or intelligence (e.g., ASICs,
microcontrollers or the like). In some of these variations, the
microstimulator does not have an internal battery. In these
variations, the microstimulator may include only a dissipation
circuit that receives an output signal from a controller, generates
a current based on the received signal, and delivers the generated
current. The dissipation circuit may contain one or more signal
conditioning units which may shape or otherwise modify the signal
received from a controller. In some variations, the circuit may be
configured to receive energy from an external source, rectify the
energy into a stimulation pulse, and allow for passive charge
balancing. In some variations the stimulation circuit may comprise
one or more current rectifiers, one or more amplitude limiting
units, and one or more ramping control units, combinations thereof,
or the like. In some variations, the dissipation circuit may
comprise one or more adjustable/tunable components.
[0060] In other variations, a microstimulator may include internal
logic which may be used to shape or modify a signal received from a
controller. In some of these variations, the microstimulator may
not include an internal battery, such that operating power is
received by the output signal of a controller. In still other
variations, the microstimulator may comprise an implantable pulse
generator, which may include all of the circuitry necessary to
generate and deliver electrical pulses to tissue. The stimulation
circuits described here may contain elements which allow a
controller to detect one or more operating parameters of the
stimulation circuit.
[0061] FIG. 23 depicts a variation of a stimulator circuit (4320)
which may be configured to passively ramp a stimulation signal
provided by the stimulation circuit. As shown there, stimulator
circuit (4320) may comprise a receiving unit (4322), a signal
conditioning unit (4324), a ramping control unit (4326), and an
output unit (4328). The receiving unit (4322) may be configured to
receive an output signal from a controller (not shown), and may
transmit the received signal to the signal conditioning unit (4324)
and the ramping control unit (4326). In the variation shown in FIG.
23, the receiving unit (4322) may comprise a resonant circuit
comprising a coil (4330) connected in parallel with a tuning
capacitor (4332). This resonant circuit may be tuned or otherwise
configured to receive an output signal that is transmitted at a
certain frequency or range of frequencies. It should be
appreciated, however, that the receiving unit (4322) may comprise
any suitable components that receive an output signal (e.g., a
magnetic field, RF signal, optical signal, ultrasound signal, or
the like) and generate a current or voltage therefrom.
[0062] The signal received by the receiving unit (4322) may be
passed to the signal conditioning unit (4324) and the ramping
control unit (4326). In the variation shown in FIG. 23, the signal
conditioning unit (4324) may comprise a rectification unit (4334),
an amplitude control unit (4336), and a current source unit (4338).
It should be appreciated that the signal conditioning unit (4324)
may include only some of these individual components and/or may
contain additional components as desired. In variations that
include a rectification unit (4334), the rectification unit (4334)
may be configured to convert any alternating current signals to
direct current signals. The rectifying unit may be a half-wave
rectifier or a full-wave rectifier, and in some instances may be
configured to smooth the rectified signal. For example, the
variation of rectification unit (4334) shown in FIG. 23 may
comprise a half-wave rectifier comprising a diode (4340) and a
smoothing capacitor (4342) placed at the output of the half-wave
rectifier.
[0063] In variations that include an amplitude control unit (4336),
the amplitude control unit (4336) may be configured to limit the
maximum amplitude of the signal delivered by the output stage
(4328). For example, the amplitude control unit (4336) shown in
FIG. 23 may comprise a zener diode (4344), which may shunt current
away from the signal conditioning unit (4324) when the voltage
across the zener diode (4344) exceeds a threshold voltage. It
should be appreciated that the amplitude control unit (4336) may
comprise any suitable current or voltage limiting elements, which
may be positioned in any suitable portion of the stimulator circuit
(4300) (e.g., as part of the receiving unit (4322), the signal
conditioning unit (4324), the ramping control unit (4326), the
output unit (4328), combinations thereof, and the like). In some
variations, a stimulation circuit may comprise a plurality of
amplitude control units, each of which may limit a different aspect
of the generated stimulation signal, or may limit aspects of the
generated control signal at different locations.
[0064] In variations where the signal conditioning unit (4324)
comprises a current source unit (4338), the current source unit
(4338) may be configured to act as a voltage-controlled current
source which may output a current based on a voltage input received
by the current source unit (4338). For example, in some variations
(such as that shown in FIG. 23), the current source unit (4338) may
comprise a transistor (4346) (e.g., a JFET, MOSFET, BJT) where the
gate and the source of the transistor (4340) are connected (e.g.,
via a resistor (4348) or the like). In some variations, the current
source unit (4338) may act as a constant-current source that may
provide a constant current when any voltage above a certain
threshold is applied to an input of the current source unit (4338).
In some variations, a current source unit may comprise one or more
current-limiting diodes or the like. In some variations the current
source unit (4338) may comprise a current mirror circuit. The
current mirror circuit may be symmetric or asymmetric.
[0065] Once the received output signal has been conditioned by the
signal conditioning unit (4324), the signal may be passed to the
output unit (4328). The output unit (4328) may thus deliver the
processed signal as an output signal to tissue (4350) via
electrodes (4352). In some variations, the output unit (4328) may
be configured to allow for passive charge balancing. For example,
output unit (4328) may comprise a capacitor (4354) and resistor
(4356). The capacitor (4354) may charge when the signal
conditioning unit (4324) is delivering current to the output unit
(4328) and tissue (4350), and may discharge when the signal
conditioning unit (4324) is not delivering current to the output
unit (4328), which may allow the output unit (4328) to provide a
biphasic, charge-balanced, stimulation signal to tissue (4350). In
some variations, the output unit (4328) may comprise a
current-limiting device (not shown) or the like, which may limit
the magnitude of the balancing current produced by the capacitor
(4354).
[0066] As mentioned above, the ramping control unit (4326) may be
configured to ramp the signal provided from the signal processing
unit (4324) to the output unit (4326). As shown in FIG. 23, the
ramping control unit (4326) may comprise a charging unit (4358) and
a field-effect transistor (4360). The field-effect transistor
(4360) may be any suitable transistor (e.g., a MOSFET, BJT, or the
like). The signal conditioning unit (4324) and the output unit
(4328) may be connected to the source and drain terminals of the
field-effect transistor (4360), and the charging unit (4326) may be
connected to the gate terminal of the field-effect transistor
(4360). As mentioned above, the current that passes between the
signal conditioning unit (4324) and the output unit (4328) through
the field-effect transistor (4360) may be dependent on a voltage
provided by the charging unit (4326) to the gate terminal of the
field-effect transistor (4360). As such, the ramping control unit
(4326) may be configured to increase the amplitude of the
stimulation signal as the charging unit (4326) charges.
[0067] The charging unit (4326) may be configured to increase the
voltage provided to the field-effect transistor (4360) as the
receiving unit (4322) receives an output signal generated by a
controller. For example, as shown in FIG. 23, the charging unit
(4326) may comprise a capacitor (4362) which may be charged as
receiving unit (4322) receives the output signal. As the capacitor
(4362) charges, the voltage applied to the field-effect transistor
(4360) may increase, which may thereby increase the current that
may pass from the signal conditioning unit (4324) to the output
unit (4328). This may result in a ramped stimulation signal
produced by the microstimulator. In some instances, the charging
unit (4326) may comprise a rectifying diode (4364) or other
rectification circuit which may rectify the signal received from
the receiving unit (4322). Additionally, the charging unit (4326)
may comprise one or more additional components (e.g., resistors
(4366) and (4377), diode (4368) and transistor (4370), which may
control the rate at which the capacitor (4362) charges and
discharges. While the stimulator circuits described above with
respect to FIG. 23 is a passive circuit that passively ramp a
stimulation signal without the use of internal logic or
intelligence, it should be appreciated that in some variations a
stimulation circuit as described here may comprise a
microcontroller or other internal logic that may control the
ramping of a stimulation signal.
[0068] Other variations of circuits that may be suitable for use in
a nasal microstimulator are described in U.S. patent application
Ser. No. 13/441,806, filed Apr. 6, 2012, and titled "Stimulation
Devices and Methods," which is hereby incorporated by reference in
its entirety.
[0069] In a microstimulator that comprises a passive stimulation
circuit without an internal power source, the microstimulator may
comprise one or more elements to receive power from an external
source. For example, a controller may generate and transmit power
wirelessly via an output signal (e.g., magnetic field). The
microstimulator may comprise one or more energy-receiving units
that receive the output signal from the controller to power the
microstimulator. In some variations, the energy-receiving unit may
be located in the extension of the microstimulator. The
energy-receiving unit may be a coil, which may be formed from a
wire having a length turned into a plurality of windings. In
variations where the extension comprises more than one coil (e.g.,
two, three), each coil may be configured to receive the same signal
or different signals. It may be advantageous for more than one coil
to receive different signals, as this may allow more than one
component (e.g., more than one electrode) of the microstimulator to
be controlled separately.
[0070] The extension of the microstimulator may comprise one or
more electrodes, which may deliver an electrical stimulus to
tissue. In FIG. 2B, the extension (203) comprises one electrode
(205). However, it should be appreciated that the extension may
comprise any suitable number of electrodes (e.g., one, two, three,
or four or more electrodes) positioned on any suitable portion or
portions of the extension. In some variations, it may be
advantageous for a microstimulator to comprise more than one
electrode, as this may allow more than one area of tissue to be
stimulated separately or simultaneously. That is, current may be
directed via two or more different pathways between active and
return electrodes at the same time, and/or current may be directed
via two or more different pathways over time. This may be
desirable, for example, to reduce accommodation to a stimulus. For
example, FIG. 2D shows another variation of a microstimulator (250)
comprising a first electrode (258) and a second electrode (260),
each located on a first side of an extension (256). In some
instances, the housing (252) may also comprise a conductive
material (e.g., titanium), such that all or a portion of the
housing may function as a return. In variations of the
microstimulator that comprise more than one electrode, the
electrodes may be positioned on one or more sides of the extension,
and/or may be positioned near the housing. For example, FIGS. 3A-3C
depict a microstimulator (300) comprising an extension (302) and a
housing (301), where a first electrode (304) is located adjacent to
a first side of the housing a second electrode (305) is located
adjacent to a second side of the housing. One or more of the
electrodes may be recessed, which may provide for more uniform
charge density on the electrode surface, but need not be. The
composition of the electrode may include, but is not limited to,
platinum, iridium, platinum iridium, iridium oxide, sputtered
iridium oxide, titanium nitride, tantalum, and combinations
thereof.
[0071] As shown in FIGS. 3A and 3B, the microstimulator may
comprise one or more feedthroughs (306) that extend between and
electrically connect the housing (301) and the extension (302). One
or more elements, such as an electrode (304, 305) or a coil (303),
may be electrically connected to hermetically-sealed stimulation
circuitry within the housing case by the feedthroughs.
Additionally, one or more of the feedthroughs may comprise an
insulating member which may electrically isolate the feedthrough
from the housing. FIG. 2C also illustrates another variations of
feedthroughs (222), which extend between the housing case (214) and
the extension (216), which may electrically connect the circuitry
within the housing to the coil (218) and/or electrode (220) on the
extension (216).
[0072] The microstimulator may comprise other components or
materials that may affect functionality. For example, to help keep
the microstimulator in an implanted position, the microstimulator
may comprise one or more fixation elements (e.g., one or more
hooks, barbs, or anchors) or one or more materials (e.g., a Dacron
covering) or structures that may promote tissue ingrowth. The
microstimulator may have one or more coatings which may be adhesive
and/or bioabsorbable. In some variations, the microstimulator may
comprise one or more coatings that have electrically conductive
and/or electrically insulative properties (e.g., silicone).
[0073] In some variations, the microstimulator described here may
be configured to be compatible with magnetic resonance imaging
scanners. In some of these variations, the microstimulator may be
configured to minimize its movement that may result from magnetic
forces created during magnetic resonance imaging or minimize
heating that may occur in the components of the microstimulator.
For example, in some variations, the microstimulator may be made
from non-ferromagnetic or reduced-ferromagnetic materials. In other
variations, the microstimulator may comprise ferromagnetic
materials, but the relative amount of these components may be small
enough such that forces provided on these components during
magnetic resonance imaging do not substantially move the
microstimulator. In other variations, the microstimulator may be
configured such that magnetic resonance imaging does not cause
inadvertent stimulation or other activation of the microstimulator.
For example, when the microstimulator comprises a receiving circuit
having a resonant frequency, the microstimulator may be configured
such that the resonant frequency is outside of the frequency ranges
produced during magnetic resonance imaging (e.g., the frequencies
produced by the main field gradient field, and/or radio frequency
fields of a magnetic resonance imaging scanner).
[0074] An electrical stimulus delivered by the microstimulators
described here may include a waveform or waveforms, which may be
tailored for specific treatment regimens and/or specific patients.
Waveforms that may be delivered by one or more variations of the
microstimulators described herein are described in more detail in
U.S. patent application Ser. No. 14/809,109, filed Jul. 24, 2015,
and titled "Stimulation Patterns for Treating Dry Eye," which is
hereby incorporated by reference in its entirely. In variations in
which the microstimulator is configured to deliver a stimulus via
two or more different pathways, the same or different waveforms may
be delivered for each pathway, and the waveform delivered via each
pathway may be changed over time. The waveforms may be pulse-based
or continuous. It should be appreciated that the waveforms
described here may be delivered via a multipolar (e.g., bipolar,
tripolar) configuration or a monopolar configuration. When the
microstimulator is configured to deliver a continuous waveform, the
waveform may be a sinusoidal, quasi-sinusoidal, square-wave,
sawtooth/ramped, or triangular waveform, truncated-versions thereof
(e.g., where the waveform plateaus when a certain amplitude is
reached), or the like. Generally, the frequency and peak-to-peak
amplitude of the waveforms may be constant, but in some variations
the microstimulator may be configured to vary the frequency and/or
amplitude of the waveform. This variation may occur according to a
pre-determined plan, or may be configured to occur randomly within
given parameters. For example, in some variations the continuous
waveform may be configured such that the peak-to-peak amplitude of
the waveform varies over time (e.g., according to a sinusoidal
function having a beat frequency). In some instances, varying the
amplitude and/or frequency of a stimulation waveform over time, or
pulsing the stimulus on and off (e.g., 1 second on/1 second off, 5
seconds on/5 seconds off), may help reduce patient habituation (in
which the subject response to the stimulation decreases during
stimulation). Additionally or alternatively, ramping the amplitude
of the stimulation waveform at the beginning of stimulation may
increase comfort.
[0075] When the microstimulator is configured to create a
pulse-based electrical waveform, the pulses may be any suitable
pulses (e.g., a square pulse, a haversine pulse, or the like). The
pulses delivered by these waveforms may by biphasic, alternating
monophasic, or monophasic, or the like. When a pulse is biphasic,
the pulse may include a pair of single phase portions having
opposite polarities (e.g., a first phase and a charge-balancing
phase having an opposite polarity of the first phase). In some
variations, it may be desirable to configure the biphasic pulse to
be charge-balanced, so that the net charge delivered by the
biphasic pulse is approximately zero. In some variations, a
biphasic pulse may be symmetric, such that the first phase and the
charge-balancing phase have the same pulse width and amplitude. In
other variations, a biphasic pulse may be asymmetric, where the
amplitude and/or pulse width of the first pulse may differ from
that of the charge-balancing phase. In some variations, the aspect
ratio between the amplitude and duration may change over time,
either abruptly or gradually. Additionally, each phase of the
biphasic pulse may be either voltage-controlled or
current-controlled. In some variations, both the first phase and
the charge-balancing phase of the biphasic pulse may be
current-controlled. In other variations, both the first phase and
the charge-balancing phase of the biphasic pulse may be
voltage-controlled. In still other variations, the first phase of
the biphasic pulse may be current-controlled, and the second phase
of the biphasic pulse may be voltage-controlled, or vice-versa.
[0076] When an electrical pulse waveform is an alternating
monophasic pulsed waveform, each pulse delivered by the
microstimulator may have a single phase, and successive pulses may
have alternating polarities. Generally, the alternating monophasic
pulses are delivered in pairs at a given frequency (such as one or
more of the frequencies listed above, such as between 30 Hz and 50
Hz), and may have an inter-pulse interval between the first and
second pulse of the pair (e.g., about 1000 .mu.s, between 500 .mu.s
and 1500 .mu.s, between 50 .mu.s and 150 .mu.s or the like). Each
pulse may be current-controlled or voltage-controlled, and
consecutive pulses need not be both current-controlled or both
voltage-controlled. In some variations where the pulse waveform is
charged-balanced, the waveform may comprise a passive
charge-balancing phase after delivery of a pair of monophasic
pulses, which may allow the waveform to compensate for charge
differences between the pulses.
[0077] When a microstimulator is configured to deliver a
pulse-based waveform, the stimulation amplitude, pulse width, and
frequency may be the same from pulse to pulse, or may vary over
time. For example, in some variations, the amplitude of the pulses
may vary over time. In some variations, the amplitude of pulses may
vary according to a sinusoidal profile. In some variations, the
stimulation waveform may be a modulated high frequency signal
(e.g., sinusoidal), which may be modulated at a beat frequency of
the ranges described above. In such variations, the carrier
frequency may be between about 100 Hz and about 100 kHz. In other
variations, the amplitude of pulses may increase (linearly,
exponentially, etc.) from a minimum value to a maximum value, drop
to the minimum value, and repeat as necessary. In some variations,
the user may be able to control the stimulus during its delivery.
For example, using a controller the user may increase the intensity
of the stimulus. It may be desirable for the patient to increase
the intensity of the stimulus until the stimulus causes paresthesia
(e.g., tingling, tickling, prickling). As such, the patient may be
able to self-determine the proper stimulation intensity and
self-adjust the stimulus to a level effective to achieve the
desired result (e.g., tear production). It may be desirable for the
user to increase the intensity of the stimulus slowly in order to
minimize discomfort.
[0078] In some instances, it may be desirable to configure the
stimulation waveform to minimize side effects. In some instances,
it may be desirable to promote stimulation of larger-diameter
nerves (e.g., afferent fibers of the anterior ethmoidal nerve),
which may promote a therapeutic effect, while reducing the
stimulation of smaller nerves (e.g., a-delta fibers, c fibers,
sympathetic and parasympathetic fibers), which may result in
discomfort or mucus production. Generally, for smaller
pulse-widths, the activation threshold for larger-diameter nerves
may be lower than the activation threshold for the smaller nerve
fibers. Conversely, for larger pulse-widths, the activation
threshold for larger-diameter nerves may be higher than the
activation threshold for the smaller nerve fibers. Accordingly, in
some instances, it may be desirable to select a pulse width that
preferably activates the larger-diameter nerves. In some
variations, the pulse width may be between 30 .mu.s and about 70
.mu.s, or may be between about 30 .mu.s and about 150 .mu.s.
[0079] More specifically, the microstimulator may be configured to
deliver a waveform at a frequency between about 0.1 Hz and about
200 Hz. In some of these variations, the frequency is preferably
between about 10 Hz and about 60 Hz. In some of these variations,
the frequency is preferably between about 25 Hz and about 35 Hz. In
others of these variations, the frequency is preferably between
about 50 Hz and about 90 Hz. In some of these variations, the
frequency is preferably between about 65 Hz and about 75 Hz. In
other variations, the frequency is preferably between about 130 Hz
and about 170 Hz. between about 0.1 Hz and about 200 Hz. In some of
these variations, the frequency is preferably between about 10 Hz
and about 200 Hz. In some of these variations, the frequency is
preferably between about 30 Hz and about 150 Hz. In others of these
variations, the frequency is preferably between about 50 Hz and
about 80 Hz. In others of these variations, the frequency is
preferably between about 30 Hz and about 60 Hz. In some variations,
the frequency may be about 1.5 Hz, about 10.25 Hz, about 70 Hz,
about 150 Hz, about 25 Hz, about 27.5 Hz, about 30 Hz, about 32.5
Hz, about 35 Hz, about 37.5 Hz, about 40 Hz, about 42.5 Hz, about
45 Hz, about 47.5 Hz, about 50 Hz, about 52.5 Hz, about 55 Hz,
about 57.5 Hz, about 60 Hz, about 62.5 Hz, or about 65 Hz. In some
of these variations, the frequency is preferably between about 145
Hz and about 155 Hz. In some variations, high frequencies, such as
those between about 145 Hz and about 155 Hz may be too high for
each pulse to stimulate/activate the target nerve. As a result, the
stimulation may be interpreted by the patient to have an element of
randomness, which in turn may help to reduce subject
habituation.
[0080] Similarly, for the treatment of dry eye, when the first
phase of the biphasic pulse is current-controlled, the first phase
may preferably have an amplitude between about 10 .mu.A and 100 mA.
In some of these variations, the amplitude may be preferably
between about 0.1 mA and about 10 mA. In yet others of these
variations, the amplitude may preferably be between about 1.0 mA
and about 10 mA. Amplitudes within these ranges may be high enough
to stimulate targeted tissue, but sufficiently low as to avoid any
significant heating of tissue, ablation of tissue, or the like. In
some variations the amplitude may be between about 1.0 mA and about
5.0 mA. In other variations, the first phase may have an amplitude
of about 0.1 mA, about 0.2 mA, about 0.3 mA, about 0.4 mA, about
0.5 mA, about 0.6 mA, about 0.7 mA, about 0.8 mA, about 0.9 mA, or
about 1.0 mA. In some variations, the amplitude may be variable.
For example, the amplitude may vary between about 1.3 mA and about
1.5 mA, about 2.2 mA and about 2.5 mA, about 3.2 mA and about 3.7
mA, about 4.3 mA and about 5.0 mA. When the first phase of the
biphasic pulse is voltage-controlled, the first phase may
preferably have an amplitude between about 10 mV and about 100
V.
[0081] In some variations, the amplitude may vary over time. This
may reduce patient accommodation. In some variations, the amplitude
of pulses may increase (linearly, exponentially, etc.) from a
minimum value to a maximum value, drop to the minimum value, and
repeat as necessary. In some variations, the amplitude of the
pulses may vary according to a sinusoidal profile. In some
variations in which the amplitude varies over time, the amplitude
may vary at a frequency suitable for reducing patient accommodation
or increasing patient comfort such as between about 0.1 Hz and
about 5 Hz, between about 1 Hz and about 5 Hz, between about 1 Hz
and 2 Hz, between about 2 Hz and 3Hz, between about 3 Hz and 4 Hz,
or about 4 Hz and about 5 Hz. In some variation, the amplitude may
vary at a frequency of about 1.0 Hz, about 1.1 Hz, about 1.2 Hz,
about 1.3 Hz, about 1.4 Hz, about 1.5 Hz, about 1.6 Hz, about 1.7
Hz, about 1.8 Hz, about 1.9 Hz, about 2.0 Hz, about 2.1 Hz, about
2.2 Hz, about 2.3 Hz, about 2.4 Hz, about 2.5 Hz, about 2.6 Hz,
about 2.7 Hz, about 2.8 Hz, about 2.9 Hz, about 3.0 Hz, about 3.1
Hz, about 3.2 Hz, about 3.3 Hz about 3.4 Hz, about 3.5 Hz, about
3.6 Hz, about 3.7 Hz, about 3.8 Hz, about 3.9 Hz, or about 4.0
Hz.
[0082] Additionally, the first phase may preferably have a pulse
width between about 1 .mu.s and about 10 ms. In some of these
variations, the pulse width may preferably be between about 10
.mu.s and about 100 .mu.s. In other variations, the pulse width may
preferably be between about 100 .mu.s and about 1 ms. In yet other
variations, the pulse width may be between about 0 .mu.s and about
300 .mu.s. In yet other variations, the pulse width may be between
about 0 .mu.s and 500 .mu.s.
[0083] In some variations, the pulse width may be constant over
time. In other variations, the pulse width may vary over time.
Pulse width modulation over time may increase the efficacy and/or
comfort of the stimulation. In some variations, the pulse width may
increase (linearly, exponentially, etc.) from a minimum value to a
maximum value, drop to the minimum value, and repeat as necessary.
In some variations, the pulse width may vary according to a
sinusoidal profile. In another variation, the pulse width may
periodically increase from a baseline pulse width to a longer pulse
width for a certain number (e.g., one, two) of pulses. In any form
of pulse width modulation, the pulse width may vary at any suitable
frequency. In some variations the pulse width may vary at about 0.1
Hz, about 0.2 Hz, about 0.3 Hz, about 0.4 Hz, about 0.5 Hz, about
0.6 Hz, about 0.7 Hz, about 0.8 Hz, about 0.9 Hz, about 1 Hz, about
1.1 Hz, about 1.2 Hz, about 1.3 Hz, about 1.4 Hz, or about 1.5 Hz.
In some variations, modulation of the pulse width at a rate between
about 0.5 Hz and 1 Hz may be desirable to increase patient comfort
during stimulation. In some variations, the increase and decrease
of pulse width may be defined by a function implemented by the
microstimulator. For example, the pulse width may be defined by a
function such that the pulse width varies exponentially. In one
variation, the function defining pulse width may comprise two
phases--a first phase during which the pulse width of the leading
pulse increases over time according to an exponential function, and
a second phase during which the pulse width of the leading pulse
exponentially decays over time.
[0084] In some instances, the waveforms described herein may be
delivered in a continuous fashion, while in other instances, the
waveforms may be delivered in a non-continuous fashion having on
periods and off periods, which may reduce patient accommodation.
Exemplary on/off durations include without limitation, 1 second
on/1 second off, 1 second on/2 seconds off, 2 seconds on/1 seconds
off, 5 seconds on/5 seconds off, 0.2 seconds on/0.8 seconds off,
less than 1 second on/less than 10 seconds off.
Implantation Tool
[0085] Generally, an implantation tool as described herein may be
used to deliver a microstimulator through a nostril of a subject to
a desired implantation site. The implantation tool may comprise a
shaft, features that may allow the microstimulator to be releasably
attached to the implantation tool, and a handle that may improve a
user's control of the system. The shaft may facilitate maneuvering
the microstimulator into and within a confined space, such as a
portion of the nasal cavity or tissue. The shaft may have any
suitable, elongate shape (e.g., cylinder, rectangular prism), such
that at least a distal end of the shaft may be inserted through a
nostril and into a nasal cavity of a patient. In some variations,
the shaft may be shaped to reduce the risk of trauma to the nostril
and nasal tissue during implantation. For example, the shaft may
have a flat and thin shape, comprise rounded edges, and/or comprise
a lubricious coating. In some variations, the shaft may be
straight, whereas in other variations the shaft may comprise one or
more curves, which may facilitate manipulation of the distal end of
the implantation tool at an implantation site. In some variations,
the shaft may be steerable with one or more controls. The
implantation tool may have a length that is at least long enough
for a proximal portion of the tool to be held and maneuvered by a
user outside of a patient's nasal cavity while a distal portion of
the tool is within the nasal cavity. For example, in some
variations, the length of the implantation tool may be between
about 15 cm and about 25 cm. In some of these variations the length
may be about 17 cm. The length of the portion of the implantation
tool that may be inserted into a nostril during the implantation
procedure may be different for different patients, and may be less
than about 7 cm (e.g., between about 2 cm and about 6 cm, about 4
cm).
[0086] In variations of the implantation tool described herein, the
microstimulator may be releasably attached to a distal end of the
shaft. It should be appreciated, however, that the microstimulator
may be releasably attached at any suitable location on the
implantation tool. The system may be configured such that the
microstimulator is irreversibly detachable from the implantation
tool (i.e., once the microstimulator is detached from the
implantation tool, it may not be able to be reattached), or the
system may be configured such that the microstimulator is
reversibly detachable from the implantation tool (i.e., the
microstimulator may be reattached to the implantation tool after
being detached). When the microstimulator is reversibly detachable,
this may facilitate, for example, repositioning or removal of the
microstimulator after delivery. For example, an implantation tool
may comprise a hook that releasably attaches to an eyelet on a
microstimulator. To release the microstimulator, the hook may be
unhooked from the eyelet. To reposition or remove the
microstimulator, the hook may rehook the eyelet.
[0087] The implantation tool may hold the microstimulator in an
orientation that facilitates implantation (e.g., implantation into
a tissue pocket). For example, when the implantation tool is
inserted in a nasal cavity, it may be advantageous for the
microstimulator to be held in the correct orientation for
implantation. This may minimize any repositioning that may be
needed after the microstimulator is deposited, which may minimize
tissue trauma and the time of the implantation procedure. In some
variations, it may be advantageous for the implantation tool to
have minimum contact with the microstimulator, which may in turn
minimize the portion of the implantation tool that may enter tissue
when the microstimulator is deposited and minimize the size of
tissue pocket that may be formed.
[0088] A variation of the implantation tool (102) is illustrated in
FIGS. 1A and 1B, releasably attached to a microstimulator. This
implantation tool comprises a shaft (106), a handle (108), and a
tension system to facilitate the releasable attachment of a
microstimulator to the implantation tool. The tension system
comprises a contact surface or cup (107) at a distal end of the
shaft that is complimentary to the shape of the microstimulator, a
tensioning element (111) that is connected to the microstimulator,
and a knob (112) that secures the tensioning element to a proximal
end of the implantation tool. The tensioning element may be any
suitable flexible, string-like structure, such as a suture, a wire,
or a chain. This embodiment comprises a retractable cover (109)
that may be advanced and retracted relative to the shaft. The
retractable cover may facilitate one or a number of functions
during the implantation process. For example, in one position the
retractable cover may cover and protect the microstimulator
electrode. In some variations, the retractable cover may comprise a
curved distal tip, which may facilitate tissue pocket formation or
opening.
[0089] The implantation tool (102) shown in FIGS. 1A and 1B
comprises a shaft (106) that may allow a user to maneuver the
microstimulator into and within a confined space, such as a portion
of the nasal cavity or tissue. As shown in FIG. 1A, the
implantation tool may comprise a handle (108) at a proximal end of
the implantation tool that may allow a user to manipulate and
control the implantation tool. Generally, the handle may be sized
and configured to be held by a user. In some variations, a handle
may have a length between about 10 cm and about 20 cm (e.g.,
between about 12 cm and 15 cm). While shown in FIG. 1A as having a
circular cross-sectional shape, the handle may have a cross-section
having any suitable shape (e.g., rectangular, oval, irregular
shape). In some variations, the handle may comprise one or more
grooves and/or finger indentations that may allow a user to more
easily grasp or hold the implantation tool. The handle may be
integrally formed the shaft or formed separately and attached in
any suitable manner.
[0090] The implantation tool may comprise features that facilitate
the releasable attachment of the microstimulator to the
implantation tool. The microstimulator may be attached to the
implantation tool while the microstimulator is inserted through a
nostril and positioned for implantation. When positioned at a
desired implantation location, the microstimulator may be released
from the implantation tool. A tension system is one variation that
may facilitate this process, an example of which is shown in FIGS.
4A-4C. FIGS. 4A and 4B depict perspective views of a distal portion
of an implantation tool, and FIG. 4C depicts a perspective view of
a proximal portion of the implantation tool. The tension system may
comprise a contact surface (402) at a distal end of the shaft
(404), a tensioning element (406) that may be at least partially
disposed in a lumen of the shaft, and a knob (408) at a proximal
end of the shaft. The contact surface shape may be complimentary to
the shape of a portion of the microstimulator (410), which may
maintain the microstimulator in a desired orientation. The
tensioning element may attach to the microstimulator (e.g., attach
to a connector on the microstimulator, such as an eyelet (412), as
was described in more detail with respect to FIG. 2A), and may
extend within the shaft lumen between a distal opening (414) at the
cup and a proximal opening (416) at the proximal end of the shaft.
A knob may secure the tensioning element at the proximal opening.
FIG. 4A depicts the microstimulator at a distance from the contact
surface, but tension may be applied to the tensioning element, such
that the microstimulator is pulled into contact with the holder, as
is shown in FIG. 4B. The knob may hold the tensioning element in
tension to maintain contact between the contact surface and
microstimulator during portions of the implantation procedure.
[0091] The contact surface (402) may comprise any suitable shape
that is complementary to a portion of the microstimulator (410). It
may in some instances be desirable for the cross-sectional
dimensions of the contact surface to be less than or equal to those
of the microstimulator when the contact surface and microstimulator
are coupled. This may reduce tissue trauma during implantation, and
may limit the size of tissue pocket formation during implantation.
For example, as illustrated in FIG. 4B, the contact surface (402)
may have a concave shape complementary to an outer convex surface
of the distal end of the microstimulator (410), allowing the
contact surface to stabilize the microstimulator while having a
height (411) and width (413) smaller than or equal to the
dimensions of the microstimulator (410).
[0092] The contact surface may be shaped to hold the
microstimulator in a desired orientation (e.g., the correct
orientation for implantation). For example, in FIGS. 4A and 4B, the
orientation of the contact surface holds the microstimulator such
that the longitudinal axes of the microstimulator and the
implantation tool shaft are parallel. In some variations, however,
the contact surface may be shaped in such a way as to hold the
microstimulator at an angle relative to the shaft. In FIGS. 4A and
4B, the longitudinal axis of the shaft is aligned with the
longitudinal axis of the microstimulator. However, in other
variations, the contact surface may hold the microstimulator in an
orientation such that the longitudinal axis of the microstimulator
is parallel to but displaced relative to the longitudinal axis of
the shaft. In some variations, this may be advantageous because it
may allow the microstimulator to be advanced along a tissue surface
while the shaft is at a distance from the tissue surface.
[0093] The contact surface may be shaped to securely hold the
microstimulator in a fixed orientation relative to the shaft to
reduce the risk of the microstimulator being inadvertently moved or
dislodged from its desired orientation during the implantation
procedure. In some variations, the contact surface may contact
portions of one or more sides of the microstimulator, which may
reduce the risk of dislodgement. The materials of the contact
surface may have stiffness and/or strength that may reduce the risk
that a force applied to the microstimulator and/or contact surface
may deform the contact surface and/or reposition the
microstimulator. The contact surface may be integrally formed with
the shaft or formed separately and attached to the shaft in any
suitable manner (e.g., welded, screwed).
[0094] The tension system may comprise a tensioning element (406)
to attach the microstimulator to the implantation tool. In the
variation shown in FIG. 4A, the tensioning element forms a loop
through an eyelet (412) on the microstimulator (410), but the
tensioning element may connect to a portion of the microstimulator
in any suitable way (e.g., tied, clamped). The tensioning element
may extend from the connection on the microstimulator, through the
distal opening (414) of the contact surface (402), and into the
lumen of the implantation tool shaft (404). In some variations, a
contact surface may not comprise an opening and/or the shaft may
not comprise a lumen, and the tensioning element may instead be
positioned outside of the shaft. While FIG. 4C shows the tensioning
element exiting the shaft lumen through the proximal opening (416)
at the proximal end of the shaft, it should be appreciated that the
tensioning element may exit the shaft lumen at any suitable
location.
[0095] The tensioning element (e.g., string, suture, wire, or the
like) may comprise any suitable material or materials, one or more
of which may be biocompatible. A tensioning element comprised of
one or more biocompatible materials may be particularly
advantageous in variations of the implantation procedure where at
least a portion of the tensioning element may be implanted with the
microstimulator. The tensioning element may comprise one more
bioabsorbable materials (e.g. polydioxanone, polyglycolide) and/or
one or more nonabsorbable materials (e.g., nylon, polypropylene).
The tensioning element may optionally comprise one or more
radiopaque materials in order for the tensioning element to be
visible with x-ray and fluoroscopy. In some variations, the
tensioning element may be elastic. In some variations, the
implantation system may comprise more than one tensioning
element.
[0096] The tensioning element may be releasably attached to the
implantation tool in order to hold the microstimulator against the
contact surface during portions of the implantation procedure. In
the variation shown in FIG. 4C, the tensioning element (406) is
attached to the implantation tool with a knob (408). The knob may
have a spherical shape with a radius greater than the radius of the
proximal opening (416) of the lumen of the implantation tool shaft
(404), which may prevent the knob from entering the lumen. It
should be appreciated that the knob may comprise any shape that has
at least one cross-sectional dimension larger than the
cross-sectional dimensions of the proximal opening. The knob may be
secured to the tensioning element to hold the tensioning element
taut, which may in turn secure the microstimulator to the
implantation tool as described herein.
[0097] In some variations, for example, the knob may comprise a
lumen (424) extending between a distal inlet and proximal outlet
(422). The tensioning element may extend proximally from the
proximal opening (416) of the implantation tool lumen, enter the
distal inlet of the knob (408), and exit from the proximal outlet
(422) of the knob. A portion of the tensioning element extending
proximally from the proximal outlet (422) may be secured to
maintain tension in the tensioning element. For example, a knot may
be tied in the tensioning element that abuts against the proximal
outlet. A cross-sectional dimension of the knot may be larger than
the cross-sectional dimensions of the proximal outlet, which may
reduce the risk of the knot entering the knob lumen and releasing
the tension in the tensioning element. As another example, a clip
having larger cross-sectional dimensions than the proximal outlet
of the knob (422) may be attached to the tensioning element at the
proximal outlet. Alternatively, the tension system may not comprise
a knob, and a clip having larger cross-sectional dimensions than
the proximal opening of the implantation tool lumen may be attached
to the tensioning element at the proximal opening.
[0098] In other variations, friction may hold the tensioning
element in place within the knob lumen (424). Friction between the
tensioning element and knob lumen may be increased by materials of
the tensioning element, materials of the knob lumen, and/or an
element within the knob lumen (e.g., one-way valve). While not
shown, in some variations the tensioning element may be secured
between an internal surface of the knob and an external surface of
the implantation tool shaft. For example, the implantation tool
shaft may comprise a male component that may be inserted into the
knob lumen, which may function as a female component. The
tensioning element may exit through the proximal opening of the
implantation tool shaft and then be positioned around the external
surface of the male component. The male component and the
tensioning element may be inserted into the lumen of the knob, such
that the tensioning element is held between an external surface of
the male component and an internal surface of the knob. In some
variations, in order to attach the knob to the male component, the
knob may comprise internal threads, and the male component may
comprise mating external threads. In other variations, the knob may
be secured to the male component with a press fit.
[0099] In variations of the implantation tool that comprise a
tension system to releasably attach the microstimulator to the
implantation tool, the microstimulator may be released by removing
the tension. In the example described comprising a tensioning
element and knob, removing the tension may comprise releasing the
tensioning element from the knob. In some variations, releasing the
tensioning element from the knob may comprise cutting or otherwise
severing the tensioning element. In variations where the tensioning
element is tied into a knot at the proximal outlet of the knob, the
tensioning element may be severed at any position distal to the
knot with a blade or scissors. In some variations, a knot may be
untied to release the tensioning element. In variations of the knob
that comprise a clip positioned on the tensioning element at the
proximal outlet of the knob, the tensioning element may be released
by removing the clip. In variations where the knob screws onto a
portion of the shaft, the tensioning element may be released by
unscrewing the knob. When the tension in the tensioning element is
released, the microstimulator may no longer be held against the
contact surface at the distal end of the implantation tool.
Releasing the tensioning element while the microstimulator is in a
tissue pocket may release the microstimulator into the tissue
pocket. The implantation tool may then be withdrawn from the
implantation site while the microstimulator is left in place.
[0100] In some variations, the implantation tool may comprise a
retractable cover (e.g., retractable cover 109 in FIGS. 1A-1B).
FIGS. 5A-5C are perspective views of a distal portion of an
implantation tool (500) comprising a retractable cover (501) and an
attached microstimulator (502). The retractable cover may comprise
a proximal portion (504) that is at least partially disposed around
the implantation tool shaft (506) and slidable relative to the
shaft. The retractable cover may be slidable relative to the shaft
between an advanced, distal position for implantation and a
retracted, proximal position for release within a tissue pocket.
FIGS. 5A and 5B show the retractable cover in an advanced, distal
position, and FIG. 5C shows the retractable cover in a retracted,
proximal position. Moving the retractable cover from the advanced,
distal position to the retracted, proximal position may expose or
uncover more of the microstimulator. While FIG. 5C shows the
microstimulator still partially covered by the retractable cover,
it should be appreciated that in some variations, when the
retractable cover is in the retracted, proximal position, it may
not cover any of the microstimulator.
[0101] The retractable cover may slidably move along the
implantation tool into one or more positions in any suitable way.
For example, the proximal portion of the retractable cover may be
disposed around at least a portion of the shaft such that a user
may advance or retract the proximal portion of the retractable
cover to a desired position. In some variations, the shaft and/or
retractable cover may comprise one or more locks that may indicate
and/or hold the retractable cover in a desired position. For
example, a lock may hold the retractable cover in an advanced
position during implantation. The lock may be unlocked by a user
(e.g., by applying sufficient force to the retractable cover) in
order to change the position of the retractable cover.
[0102] FIG. 5A shows a first side of the retractable cover and FIG.
5B shows an opposite, second side of the retractable cover. The
retractable cover may comprise a distal portion (508) that covers
at least a portion of an attached microstimulator when the
retractable cover is in an advanced, distal position, as will be
discussed in more detail herein. The distal portion of the
retractable cover may comprise a distal tip (510) that extends
distal to a distal end (512) of an attached microstimulator when
the retractable cover is in an advanced, distal position. In some
variations, the distal tip (510) may be curved such that it wraps
at least partially around the distal end of an attached
microstimulator when the retractable cover is in an advanced
position. In some variations, the retractable cover may comprise a
channel or port for suction, irrigation, or fluid delivery (e.g.,
to administer a conductive fluid to an implantation site that may
improve stimulation by a microstimulator).
[0103] In the advanced, distal position, the retractable cover may
facilitate one or a more steps of the implantation procedure. For
example, in variations of the retractable cover that comprise a
distal tip that extends distal to the microstimulator, the
retractable cover may facilitate tissue pocket opening and/or
formation. The distal tip may apply force to tissue to open a
pocket and/or to extend a pocket as it is advanced though tissue. A
distal tip may be used to open a pre-formed tissue pocket (e.g.,
pre-formed by a dissection tool) that may be the implantation site
for the microstimulator. The thickness of the distal tip may be
less than the thickness of the microstimulator, which may make it
easier to insert the distal tip into an opening than it may be to
insert the microstimulator without a distal tip into an opening. In
some variations, one or more portions of the retractable cover
(e.g., the distal tip) may comprise one or more sharp edges and/or
one or more blunt edges. For example, the retractable cover may
comprise a sharp edge to make an incision in tissue to start tissue
pocket formation and/or one or more blunt edges to extend a tissue
pocket. In some variations, as is shown in FIGS. 5A-5C, the width
of the retractable cover distal tip may be tapered such that the
width decreases from a proximal end of the tip to the distal end of
the tip. When the tip is advanced through an opening in tissue, the
increasing width of the tip may dilate the opening as the tip
passes therethrough. Additionally or alternatively, a retractable
cover may shield a microstimulator during insertion.
[0104] In some variations in which the retractable cover comprises
a curved distal tip, the curved distal tip may be flexible, such
that it may be biased to a curved configuration when unconstrained
(e.g., when the distal tip is distal to the microstimulator as in
FIGS. 5A and 5B), but may be straightened when a force is applied
to an inner curvature of the distal tip (e.g., when the retractable
cover is retracted relative to the microstimulator). FIG. 5C
depicts the distal tip in a straightened configuration. When
retracted, the contact between the cover and the inner curvature of
the distal tip may exert a force that straightens the distal tip of
the retractable cover.
[0105] In an advanced, distal position, a portion of the
retractable cover may cover at least a portion of one or more
electrodes. The microstimulator shown in FIGS. 5A-5C comprises one
electrode (514) on a first side that is partially covered by the
retractable cover when the retractable cover is in the advanced
position. Coverage of an electrode by the retractable cover may
protect the electrode during the implantation procedure.
[0106] The retractable cover may also facilitate testing of the
microstimulator. Testing may prevent a malfunctioning implant from
being implanted. As compared to testing the microstimulator with a
separate device, testing with the implantation tool may decrease
the operating room time required for the implantation procedure,
simplify tasks and equipment that may be needed for the
implantation procedure, and/or reduce the infectious risk of
touching an electrode before insertion. In some variations, testing
of a microstimulator's electrical stimulus is facilitated by one or
more electrodes positioned on a distal portion of the implantation
tool (e.g., on the retractable cover). When a microstimulator is
attached to the implantation tool and the retractable cover is in
an advanced position, the one or more electrodes of the
implantation tool may longitudinally align with and face towards
the one or more electrodes of the microstimulator. In this
position, the microstimulator may be activated by a controller to
generate an electrical stimulus, and the electrical stimulus may be
detected by electrodes on the retractable cover. The implantation
tool may comprise an indicator (e.g., a light, an audible sound) to
indicate if a satisfactory stimulus has been delivered. If the
microstimulator is stimulating as desired, the microstimulator may
be implanted. If the microstimulator is not functioning as desired,
one or more changes may be made (e.g., the microstimulator may be
replaced).
[0107] In some variations, when the retractable cover is an
advanced position, there may be an air gap between the one or more
electrodes of the microstimulator and the one or more electrodes of
the retractable cover. Before implantation, the retractable cover
and microstimulator may be submerged in a conductive solution
(e.g., saline), which may fill the air gap and allow the
implantation tool to detect a signal produced by the
microstimulator. The microstimulator may also be tested after
insertion into a tissue pocket while still connected to the
implantation tool. In this case, blood, other nasal fluid, and/or
an injected conductive solution (e.g., saline) may fill the air gap
between the microstimulator and the retractable cover to conduct a
signal produced by the microstimulator to the implantation
tool.
[0108] In some variations, a distal portion of the implantation
tool (e.g., retractable cover) may comprise one or more electric
connectors that protrude from the device towards the electrodes of
an attached microstimulator. For example, a retractable cover may
comprise one or more springs that may contact one or more
electrodes of an attached microstimulator when the retractable
cover is in an advanced position. The one or more springs may be
gently biased towards the one or more electrodes of the
microstimulator, such that contact is made but the electrodes are
not scratched or otherwise damaged. This configuration may
facilitate testing of the microstimulator's electrical stimulus
without introducing a conductive fluid. For example, a
microstimulator may be packaged pre-attached to an implantation
tool with a retractable cover in an advanced position, and the
packaging and devices may be sterile. A controller may activate the
microstimulator while still packaged, and an indicator on the
implantation tool may be visualized through the packaging, such
that testing of the microstimulator may be performed without
breaking the sterile field.
[0109] The implantation tool may comprise an indicator (e.g., a
light, an audible sound) that indicates if the microstimulator is
delivering an appropriate stimulus. In some variations, the
indicator may comprise an LED, which may be connected to support
electronics. The LED may be positioned at any suitable location on
the implantation tool (e.g., the handle, the retractable cover). In
some variations, an implantation tool may comprise a different
indicator for each electrode on the microstimulator. In other
variations, the implantation tool may comprise one or more
electrodes, but may not comprise an indicator. In these variations,
the implantation tool may comprise one or more leads that may be
connected to another device (e.g., an oscilloscope) that may
indicate if a desired electrical signal is produced by the
microstimulator. In still other variations, the implantation tool
may not comprise features to test the microstimulator, but the
retractable cover may comprise one or more openings that may allow
a device (e.g., an oscilloscope) to directly contact and test the
electrodes of the microstimulator while it is attached to the
implantation tool.
[0110] In some variations, the implantation tool may comprise a
light (e.g., LED) that is separate from an indicator light. The
light may be located at a distal end of the implantation tool and
may be turned on while positioned in the nasal cavity. The light
may have a sufficient power (e.g., a 3W LED) to be seen from
outside the nasal cavity through nasal tissue while it is within
the nasal cavity. In some variations, an LED may be positioned on
the implantation tool at a location that corresponds to the
position of an attached microstimulator (e.g., at the same
longitudinal position as a distal end of a microstimulator). When
the implantation tool and attached microstimulator are inserted
into a nasal cavity, light from the LED may be seen from outside
the nasal cavity to give a visual indication of the position of the
microstimulator. In some variations, this may reduce the risk of
advancing the implantation tool and microstimulator too deep into
the nasal cavity. In some variations, the light may illuminate the
nasal septum in order to visualize the transition point between
cartilage and bone. This may facilitate implantation of the
microstimulator adjacent to a desired part of the nasal septum
(e.g., over the bony part).
[0111] Another variation of an implantation tool (600) is depicted
in FIGS. 6A-6C. FIG. 6A shows the implantation tool (600) detached
from a microstimulator (602), FIG. 6B shows the microstimulator
releasably attached to the implantation tool, and FIG. 6C shows the
implantation tool releasing the microstimulator. This variation of
implantation tool comprises a shaft (604), a handle (606), and a
friction system that may facilitate the releasable attachment of a
microstimulator to the implantation tool with. The friction system
may comprise a holder (608), a pusher (610), and a control slider
(612). These features will be described in more detail herein.
[0112] The implantation tool embodiment shown in FIGS. 6A-6C
comprises a shaft (604) that may allow a user to extend a
microstimulator into a nasal cavity when the microstimulator is
attached to the implantation tool. As shown, the shaft may have
rounded edges, which may reduce the risk of trauma to tissue (e.g.
nasal tissue) that the shaft may contact.
[0113] As shown in FIGS. 6A-6C, the implantation tool may comprise
a handle (606) positioned at a proximal end of the implantation
tool (600) that may allow a user to manipulate and control the
implantation tool. Generally, the handle is sized and configured to
be held by a user. While shown in FIGS. 6A-6C as having a
rectangular cross-sectional shape, the handle may have a
cross-section having any suitable shape (e.g., circle, oval,
irregular shape). In some variations, the handle may comprise one
or more grooves and/or finger indentations that may allow a user to
more easily grasp or hold the implantation tool. The handle may be
integrally formed with the shaft or may be formed separately and
attached to the shaft in any suitable way.
[0114] The implantation tool shown in FIGS. 6A-6C comprises a
friction system that facilitates the releasable attachment of a
microstimulator (602) to the implantation tool. The friction system
comprises a holder (608) that may hold the microstimulator at a
distal end of the implantation tool utilizing friction between one
or more portions of the holder and the microstimulator.
Accordingly, the microstimulator may be released from the
implantation tool when the static friction between the
microstimulator and holder is overcome. In some variations, as is
shown in FIGS. 6A-6C, the static friction may be overcome by a
pusher (610) that is pushed against a proximal surface of the
microstimulator. A user may advance a control slider (612) to
advance the pusher and push the microstimulator from the
holder.
[0115] Generally, a friction holder may comprise one or more
elements at the distal end of the implantation tool that contact at
least a portion of the microstimulator and resist its movement. The
structure and/or materials of the holder and/or microstimulator may
create frictional forces between the surfaces of the holder and
microstimulator that are great enough to reduce the risk of the
microstimulator being dislodged or inadvertently moved from its
desired orientation (e.g., the correct orientation at
implantation). Structures used in a friction holder may include,
but are not limited to pockets or lumens, grooves, and/or
clamps.
[0116] FIGS. 7A and 7B depict perspective views of distal portions
of an implantation tool (700) comprising a holder (701) attached to
a shaft (702). FIG. 7A depicts the holder detached from a
microstimulator (706), and FIG. 7B depicts the microstimulator
releasably attached to the implantation by the holder. The holder
comprises a shaft attachment (708) and two grippers (710). The
shaft attachment connects the grippers to the shaft and may be
attached to the shaft in any suitable manner (e.g., adhesive,
overmolding). When the microstimulator is releasably attached to
the implantation tool, the grippers extend along the sides (711,
712) of the housing (713) of the microstimulator in order to grip
the housing. The grippers may exert an inward force on the housing
in order to hold the microstimulator in place. For example, the
grippers may be inwardly biased, and may be deflected or displaced
outwardly when a microstimulator is pushed into the holder. When
deflected or displaced outwardly, the inward bias of the grippers
may exert compressive forces on the microstimulator that may create
a static friction between the microstimulator and the gripper
surfaces. In some variations, the grippers may comprise compliant
materials that may alternatively or additionally deform when a
microstimulator is pushed into the holder. Deformation of the
grippers may similarly exert compressive forces on the
microstimulator.
[0117] The example shown in FIGS. 7A and 7B comprise two grippers
configured to be located on opposing sides of a portion of a
microstimulator, but a friction holder may comprise any number of
grippers that may contact any number of sides of the
microstimulator, including a single unitary gripper that extends
around housing of a microstimulator. The inner surface of the
grippers may comprise one or more suitable structures (e.g.
grooves, protrusions) and/or materials (rubber, adhesive) that may
increase the coefficient of friction between the surfaces of the
microstimulator and the grippers.
[0118] In order to release the microstimulator from the
implantation tool in variations that comprise a friction system,
static friction between the microstimulator and implantation tool
holder may be overcome. In the embodiment of implantation tool
shown in FIGS. 6A-6C, a pusher (610) and control slider (612) may
facilitate the release of the microstimulator (602) in this manner.
Generally, the pusher (608) may contact and push against a proximal
surface (614) of the microstimulator to overcome the static
friction between the microstimulator and holder surfaces. A user
may advance a control slider (612) to advance the pusher and push
the microstimulator from the holder to release the microstimulator
at an implantation site.
[0119] FIGS. 8A-8C show cross-sections of an implantation tool that
comprises a pusher (802) and control slider (804). The pusher may
be at least partially disposed in a lumen (806) of the implantation
tool shaft (808). A distal end of the pusher may exit a distal
opening (810) of the shaft to contact a portion of the
microstimulator (812), which is shown in cross section in FIGS. 8A
and 8C. As shown, the pusher is in a retracted, proximal position,
and the microstimulator is held by the holder grippers (814). While
the pusher is shown extending from the distal opening of the shaft
in a retracted position, it should be appreciated that the distal
end of the pusher may be aligned with the distal opening of the
shaft or may be proximal to the distal opening of the shaft in the
retracted position. In some variations, at least a portion of the
microstimulator may be positioned within the shaft lumen when the
pusher is in a retracted position.
[0120] The pusher (802) may be advanced or retracted relative to
the shaft (808) by moving the control slider (804). The control
slider may be connected to the pusher within the shaft lumen (806)
and exit the shaft lumen through a side opening (816). A user may
manipulate the portion of the control slider that is outside of the
shaft lumen. In some variations, the side opening may limit the
distance the control slider and pusher may be moved and/or may
indicate when the pusher is in a retracted or advanced position.
For example, as shown in FIG. 8B, the control slider is at a
proximal end of the side opening (816), which prevents the control
slider from moving further proximally relative to the shaft, and
which may indicate that the pusher is in a fully retracted
position. Advancing the control slider distally relative to the
shaft to the distal end of the side opening (818) may advance the
pusher and indicate that the pusher is in the fully advanced
position. FIG. 6C shows a variation of the implantation tool where
the control slider (612) is positioned at the distal end of the
side opening (816) and the pusher (610) is in the fully advanced
position. The implantation tool may comprise one or more features
(e.g., a lock) that may reduce the risk of moving the control
slider into an advanced position and releasing the microstimulator
inadvertently.
[0121] FIG. 9 shows the distal portion of the implantation tool
(700) of FIG. 7 comprising a holder (701) and a pusher (714). The
pusher is shown in an advanced position, pushing the
microstimulator (706) distally beyond the grippers (710) of the
holder to release the microstimulator from the implantation tool. A
pusher may comprise any suitable shape (e.g., cylindrical) and/or
be moved in in any suitable way (e.g., by pushing a portion of the
pusher that may extend out of a proximal end of an implantation
tool shaft). In some variations, a portion of the holder may be
moved (e.g. the grippers retracted or opened) in order to release
the friction holding the microstimulator to the implantation
tool.
[0122] It should be appreciated that the features described herein
with respect to the different implantation tools may be combined or
rearranged as appropriate. For example, FIGS. 27A-E show another
variation of an implantation tool (3000). Implantation tool (3000)
comprises a shaft (3004), a retractable cover (3006), and a
friction system to releasably attach a microstimulator (3002). The
friction system comprises a gripper (3008) to hold the
microstimulator while it is delivered to an implantation site, and
a pusher (3010) to release the microstimulator at the implantation
site. A portion of the pusher may be slidably disposed within a
lumen of the shaft, and may be movable between a proximal,
retracted position and a distal, advanced position. A portion of
the pusher that extends proximal to the proximal end (3012) of the
shaft may be pushed to advance the pusher relative to the shaft. In
this variation of implantation tool, the retractable cover (3006)
and/or gripper (3008) may be fixed to the shaft (3004), such that
movement of the pusher (3010) relative to the shaft may also move
the pusher relative to the retractable cover and gripper.
[0123] FIG. 27A shows the implantation tool (3000) with the pusher
(3010) in a proximal, retracted position. FIG. 27C shows a
magnified view of a distal portion of the implantation tool (3000)
and microstimulator (3002) with the pusher in this position. In the
retracted position, the inner surface of the gripper (3008) may
contact a portion of the microstimulator surface to create a static
friction between the surfaces. This friction may resist movement of
the microstimulator away from the implantation tool and decrease
the risk of the microstimulator being inadvertently dislodged from
the implantation tool during implantation. The friction may be
increased by one or more materials (e.g., rubber, adhesive) of the
gripper and/or microstimulator surfaces that may increase the
coefficient of friction between the surfaces. The gripper may be
configured to exert a compressive force on the microstimulator, as
was discussed in more detail with respect to FIGS. 7A and 7B, which
may also increase friction between the gripper and the
microstimulator.
[0124] When the pusher (3010) is in the retracted position, a
portion of the retractable cover (3006) may cover a portion of the
microstimulator (3002). In other words, when the pusher is in the
retracted position, the retractable cover may be in an advanced
position relative to the microstimulator. In this position, as was
discussed in more detail with respect to FIGS. 5A and 5B, the
retractable cover may cover and protect one or more electrodes (not
shown) on the microstimulator. In variations where the retractable
cover comprises one or more electrodes, this position may
facilitate testing of the electrical stimulation delivered by the
microstimulator. The retractable cover may comprise a distal tip
(3014), which may extend beyond the distal end of the
microstimulator and may facilitate opening and/or forming a tissue
pocket. In some variations, as was discussed in more detail with
respect to FIGS. 5A and 5B, the distal tip may comprise a curved
portion that wraps around a portion of the distal end of the
microstimulator. This configuration may further protect the
microstimulator and/or facilitate tissue pocket opening and/or
formation.
[0125] A proximal end (3013) of the pusher (3010) may be pushed
relative to the shaft (3004) to distally slide the pusher relative
to shaft, retractable cover (3006), and/or gripper (3008). FIG. 27B
shows the implantation tool and microstimulator with the pusher in
an advanced position (i.e., with the retractable cover in a
retracted position relative to the microstimulator). FIGS. 27D and
27E show close-up views of the microstimulator and a distal portion
of the implantation tool in the advanced position. When the
microstimulator is held by the gripper, it may be adjacent to a
distal end (3016) of the pusher, and distal advancement of the
pusher may push the microstimulator distally. When the pusher is
advanced, friction may be overcome between the gripper and the
microstimulator, and the microstimulator may be advanced distal to
the gripper to be released.
[0126] As seen in FIGS. 27A and 27B, the pusher may comprise a
proximal cap (3018). The cap may comprise a dimension that is
larger than the diameter of the shaft (3004) lumen, which may
prevent the proximal end (3013) of the pusher (3010) from entering
the lumen of the shaft. Abutment of the cap against the proximal
end (3012) of the shaft may indicate that the pusher is in an
advanced position. A cap may have one or more cross-sectional
dimensions that are larger than corresponding cross-sectional
dimensions of other portions of the pusher, which may make pushing
and/or pulling of the shaft easier and/or more comfortable for a
user.
[0127] The implantation tool may comprise a handle (3020), which
may be at least partially disposed around a portion of the shaft.
The handle may facilitate manipulation of the device by a user, for
example by increasing the diameter of implantation tool. In some
variations the handle may comprise one or more different materials
than the shaft (e.g., silicone), which may provide a more
comfortable gripping surface for a user. The handle may comprise
one or more finger grooves, ridges, and/or other features to
further improve gripping of the implantation tool by a user.
[0128] In some variations, a microstimulator (3002) that may be
used with the implantation tool described in FIGS. 27A-27E may
comprise a connector, such as an eyelet (3022). This may facilitate
accessing the microstimulator after implantation for removal or
repositioning. A tensioning element may connect to the connector,
which may facilitate attachment of the microstimulator to one or
more devices via tension, as was discussed in more detail with
respect to FIGS. 5A-5C. In other variations, a tensioning element
may be attached to the connector and implanted with the
microstimulator such that a portion of the tensioning element
remains outside of a tissue pocket. In some variations, the
microstimulator may not comprise a connector and/or an attached
tensioning element.
[0129] While tension and friction systems are described in detail
herein, it should be appreciated that any suitable system may be
used to releasably attach the microstimulator to the implantation
tool. For example, the implantation tool may comprise a holding
compartment that may have a closed configuration to hold the
microstimulator, and may be movable to an open configuration to
release the microstimulator. In some variations, the implantation
tool and microstimulator may be attached with one or more frangible
connections that may be broken in order to release the
microstimulator for implantation. It should also be appreciated
that the implantation tool may comprise any suitable combination of
elements described here to releasably attach a microstimulator. For
example, while the variation shown in FIG. 4 was described as a
tension system, it may also utilize friction to hold the
microstimulator to the implantation tool. Inner surfaces of the
extensions (420) in FIG. 4A may comprise a material or materials
(e.g. adhesive material) or elements (e.g., grooves, protrusions)
that may resist movement of the microstimulator relative to the
contact surface.
[0130] Some variations of the implantation tool may comprise one or
more elements that may facilitate the attachment of another device
to the implantation tool. For example, an implantation tool may
comprise one or more clips to attach an endoscope for viewing
within the nasal cavity during the implantation procedure. In some
variations, an implantation tool may attach to a suction
catheter.
[0131] The implantation tool and microstimulator may be configured
to reattach after being detached for implantation. This may allow
an implantation tool to be used for repositioning or removing the
microstimulator. In some variations, a separate retrieval device
may be used for repositioning or removing the microstimulator. FIG.
10 shows an example of a retrieval tool (1000) that comprises a
distal hook (1002) that may attach to a microstimulator connector,
such as an eyelet.
[0132] The various components of the implantation tool (e.g.,
shaft, retractable cover, holder, handle) may be formed from any of
the same, or different, suitable material or materials. These may
include one or more metals (e.g., stainless steel, titanium,
titanium alloys, or the like), one or more biocompatible plastics
(e.g., polycarbonate, ABS, or the like), or combinations thereof
and the like. One or more materials may be flexible or rigid. As
discussed in more detail herein, a distal tip of a retractable
cover may be flexible, but other components of the implantation
tool may be flexible as well. For example, a flexible portion of
the shaft may facilitate positioning of the microstimulator within
a confined space (e.g., within the nasal cavity). One or more
materials of the implantation tool may be electrically conductive
or insulative. For example, at least a portion of the retractable
cover may be electrically conductive in order to sense if the
microstimulator is delivering an appropriate electrical stimulus,
as described in detail herein. The implantation tool described here
may be sterilizable (and in some instances, resterilizable), and
may or may not be disposable.
Electrical Probe
[0133] The microstimulator may be implanted in a location that may
allow an electrical stimulus from one or more microstimulator
electrodes to stimulate a particular nerve, such as the anterior
ethmoidal nerve. This stimulation may result in tear production.
There may be variability between patients in the preferred
stimulation location, for example due to variability in the
anatomic location of the anterior ethmoidal nerve, and/or the
position on the nerve that may produce a desired effect (e.g.,
maximum tear production). The desired implantation site (e.g., the
site that locates the microstimulator electrode at a position to
produce maximum tear production) may therefore be different for
different patients. Additionally, electrical stimulation of some
areas of the nasal cavity may elicit undesirable effects. For
example, electrical stimulation of some nerves in the nasal cavity
may produce paresthesia or discomfort. Areas that produce
undesirable effects may also be different for different patients
and may be avoided as implantation sites.
[0134] The nasal microstimulator implantation system may comprise a
tool to help select an implantation site within nasal tissue. For
example, an electrical probe may identify the desired implantation
site for each patient by stimulating one or more locations in a
nasal cavity while a patient response (e.g., tearing, sneezing,
discomfort) is monitored. The electrical probe may comprise one or
more electrodes to deliver an electrical stimulus. In some
variations, the electrical probe may be configured to be used
alongside a separate endoscope or other visualization tool so that
the location that is stimulated by the electrical probe can be
visualized. In other variations, rather than the visualization tool
being separate, the electrical probe may comprise an integrated
endoscope or other visualization tool. This may allow the endoscope
and the electrodes to be maneuvered together. Visualizing the areas
that are stimulated by the electrical probe may allow a user to
determine the locations that produce undesired effects (e.g.,
discomfort, paresthesia) and/or desired effects (e.g., tearing,
sneezing) when stimulated. The microstimulator may then be
implanted in the location that elicited desired effects when
stimulated, such that an electrode of the microstimulator is
positioned at this specific location.
[0135] A variation of an electrical probe is shown in FIG. 11,
which comprises an endoscope (1106) and an electrode (1102)
attached to a distal end of a conductive shaft (1104). At least a
portion of the conductive shaft may be covered by an insulation
sheath (1108), which may electrically isolate the electrode and
conducting elements from the other components of the electrical
probe. In this variation, the endoscope comprises an endoscope
shaft (1110) and an optic lens (1112) at a distal end of the
endoscope. The endoscope is coupled to the insulation sheath with a
clip (1114), such that the electrode (1102) is positioned distally
to the optic lens of the endoscope. This configuration may
facilitate visualization of the electrode and a surface (e.g.,
nasal tissue) that the electrode may contact. However, the
endoscope and one or more electrodes may be connected in any
suitable manner. In some variations, one electrode may be
positioned on the electrical probe and a return electrode may be
placed at a suitable location on the surface of a patient's skin
(e.g., on the arm).
[0136] The electrical probe may have dimensions suitable for
intranasal use. In some variations, one or more electrodes may have
a spherical shape, similar to the electrode (1102) of FIG. 11. The
size of an electrode may be such that it may stimulate a nasal
septum without inadvertently making contact with another surface
(e.g., an outside wall of the nose). In some variations, the
diameter of a spherical-shaped electrode may be between about 1.5
mm and about 8 mm. In some of these variations, the diameter may be
between about 3 mm and about 4 mm. The conductive shaft may have a
length between about 5 cm and about 10 cm. In some of these
variations, the length may be about 8 cm. The clip, or any suitable
component for coupling a conductive shaft and electrode to an
endoscope, may accommodate a range of endoscope sizes (e.g.,
between about 2.7 mm and about 10 mm in diameter, between about 2.7
mm and about 5 mm in diameter). In some variations, one clip may be
flexible or otherwise configured for use with more than one
endoscope size. In other variations, different clips may have
different sizes for use with endoscopes of different sizes.
[0137] While one electrode (1102) is shown in FIG. 11, in some
variations it may be advantageous for the electrical probe to
comprise more than one electrode. This may allow more than one area
of nasal tissue to be stimulated without repositioning the probe,
which may reduce the time of the procedure. When the electrical
probe comprises more than one electrode, the electrodes may be
stimulated simultaneously or separately. The characteristics of the
electrical stimulus (e.g., waveform, amplitude, frequency) may be
the same or different than the characteristics of the electrical
stimulus delivered by the microstimulator. In some variations, the
electrical probe may not comprise a visualization element (e.g., an
endoscope). In other variations, the electrical probe may comprise
any suitable visualization element (e.g., endoscope, fiberscope,
videoscope) to visualize the specific location in the nasal cavity
that is stimulated by one or more electrodes. The distal end of the
visualization element may comprise one or more features to change
the field of view (e.g., flexible and controllable tip, zoom
feature). This may be advantageous in variations of the electrical
probe that comprise more than one electrode to allow a user to
visualize the location of each electrode. Optical fibers may be
contained within the endoscope shaft and may be connected
proximally to one or more components (e.g., light source, eyepiece,
monitor). In some variations, a light source may be positioned on
the electrical probe. For example, a light source may be positioned
in proximity to one or more electrodes, which may enhance
visualization of the stimulated area. A light source close to an
electrode may also be seen from outside the nasal cavity through
tissue to give a visual indication of the position of one or more
electrodes relative to external landmarks.
[0138] The electrical probe may comprise one or more channels
and/or ports, which may facilitate one or more functions, such as
irrigation. Irrigating an area of the nasal cavity (e.g., with
saline), may improve visualization and/or improve electrical
conductivity between one or more electrodes and nasal tissue.
[0139] In some variations, the electrical probe may comprise a
marking element to allow a user to locate the desired implantation
site after the endoscope has been withdrawn from the nasal cavity.
For example, the electrical probe may comprise a surgical marking
pen that may be slidably attached to the endoscope with a clip.
When an implantation site is identified, the marking pen may be
advanced and/or angled in order to mark the area of tissue at that
site. In some variations, a marking pen may be positioned on a back
side of an electrode, opposite to a contact side. After
stimulation, with the electrical probe stationary, the electrode
may be rotated to position the marking pen at the same location
that was stimulated. In some variations, the implantation site may
be marked with dye (e.g., India ink).
Dissection Tools
[0140] The nasal microstimulator implantation system may comprise
one or more devices to facilitate dissection of nasal tissue in
order to form a tissue pocket, within which a microstimulator may
be implanted. Generally, a device may be used to incise a portion
of nasal tissue to make an opening of a tissue pocket. A pocket may
then be extended by inserting a portion of the incising device or a
different device into the tissue opening and advancing the device
between tissue layers. In some variations, the mucosal and
submucosal layers may be incised and the pocket may be formed
between the submucosa and the nasal septum (e.g., the cartilaginous
and/or bony part of the nasal septum). It may be advantageous for
the incision to be made with a sharp blade and the pocket extended
with a blunt blade to decrease the risk of puncturing or otherwise
damaging the nasal septum or other structures inadvertently. In
some variations, one device may comprise both sharp and blunt
blades, for example, a sharp blade on one end and a blunt blade on
the other end. In other variations, one device may comprise a sharp
blade and another device may comprise a blunt blade. A dissection
tool may comprise other features to facilitate the formation of a
pocket, such as a suction catheter and/or a handle, as is described
in more detail herein.
[0141] FIGS. 12A and 12B show two variations of dissection tools
(1200 and 1201, respectively) that may be used to open and/or
extend a tissue pocket. The dissection tool (1200) in FIG. 12A
comprises a sharp blade (1202) and a blunt blade (1204) on first
and second ends of a shaft (1206), respectively. This dissection
tool (1200) may be used to open and extend a tissue pocket. The
dissection tool (1201) in FIG. 12B comprises a single blade (1208)
on a distal end of a shaft (1210). As shown, the blade (1208) is a
sharp blade that may be used to open a tissue pocket. However, in
other variations of dissection tools having a single blade on a
distal end of a shaft, the blade may have a blunt edge, which may
be used to extend a tissue pocket.
[0142] The blades in FIGS. 12A and 12B have a scoop shape and may
comprise a rounded edge. The thickness of the blade around its
edges may be less than about 2 mm. In some variations the thickness
may be less than about 1 mm, or in other variations may be less
than about 0.5 mm. In some variations, the thickness may be about
0.5 mm. The variations in FIGS. 12A and 12B each comprise a handle
(1214 and 1216, respectively) that may facilitate gripping and/or
manipulation of the dissection tool by a user. A handle may be
disposed around or otherwise attached to a portion of the shaft in
any suitable way.
[0143] The scoop shape of the blade may facilitate elevating an
opening of a tissue pocket and/or extending a tissue pocket safely.
An open portion (1212), or lumen, of the scoop shape may face away
from a nasal septum as the blade is advanced along a nasal septum
to extend a tissue pocket. This orientation may reduce the risk of
inadvertently damaging the nasal septum, since the edges of the
blade may be parallel to or face away from the nasal septum.
However, while the blades shown comprise scoop shapes, the blades
may be flat or comprise any other suitable shape.
[0144] FIGS. 13A and 13B show two views of another variation of
dissection tool (1300) that can provide suction to an area of the
procedure. This variation comprises a blade (1302) at a distal end
of a shaft (1304), a handle (1306), and a suction opening (1310) on
the surface of the blade (1302). The blade may be sharp or blunt
and comprise a scoop or any other suitable shape (e.g. rectangular,
triangular) as described above with respect to FIGS. 12A and 12B. A
tube (1308) may extend between a distal suction opening (1310) in
the blade and a proximal opening at a suction port (1312). While
the tube is shown positioned outside of the shaft in FIGS. 13A and
13B, in other variations the tube may be at least partially
disposed within the shaft. In variations where the tube is
positioned outside of the shaft, it may be secured to the shaft,
blade, and/or handle in any suitable way (e.g., clips, adhesive,
welding). The suction opening may be located anywhere on the blade,
or the catheter may be positioned such that the distal catheter
opening is adjacent to the blade.
[0145] The suction port (1312) may be attached to a suction source.
Suction may decrease the amount of fluid (e.g., blood) in the nasal
cavity during tissue pocket opening and/or extension, which may
improve visualization of the implantation site and/or reduce the
risk of a patient aspirating fluid during the procedure. The tube
may be used for irrigation, such as with saline. In some
variations, the same tube may be used for both suction and
irrigation by connecting the port (1312) to a suction source or
fluid source, respectively. In other variations, the tube may be
detachable and different tubes may be used for different functions
(e.g., suction, irrigation).
[0146] A dissection tool (1300) as shown in FIGS. 13A and 13B may
have dimensions suitable for intranasal use. For example, the blade
may have a width between about 4 mm and about 7 mm. In some
variations, the blade width may be about 5 mm, which may facilitate
forming a tissue pocket opening about 5 mm through which a
microstimulator may be advanced. In some variations, the blade may
be sharp, and may have an edge diameter less than about 0.2 mm. The
inner diameter of a suction opening (1310) may be sized to
accommodate a tube (1308) with an inner diameter of at least about
1.5 mm. In some variations, the inner diameter of a tube may be
between about 2 mm and about 3 mm. In variations where the shaft
(1304) comprises a lumen, the lumen may have a diameter between
about 3 mm and about 5 mm.
[0147] While the dissection tool shown in FIGS. 13A and 13B
comprises one blade, it may comprise two blades positioned at
opposite ends of the shaft. One or both blades may comprise a
catheter opening and the catheter may be fixed or movable for use
with either blade. In some variations, the dissection tool may
comprise more than one catheter for use with more than one blade or
for more than one function (e.g., suction, irrigation). In some
variations, a distal end of a dissection tool may comprise a light
(e.g., an LED), which may facilitate visualization within a nasal
cavity and/or indicate the position of the distal end of the
dissection tool in the nasal cavity by viewing the light from
outside the nasal cavity through nasal tissue.
[0148] In some variations, a dissection tool may be configured for
use with an endoscope or may comprise a camera in order to allow a
user to visualize an area around a blade of the dissection tool.
This may be advantageous when the blade of the dissection tool is
used in locations that are difficult to otherwise visualize, such
as in natural anatomic cavities (e.g., a nasal cavity) or in
artificially formed cavities (e.g., a surgically created tissue
pocket). A dissection tool configured to allow visualization of an
area around a blade may be particularly useful for separating nasal
submucosa from septal cartilage or bone, or for separating layers
of submucosa in order to form a pocket for an implantable
microstimulator. Visualizing the layers of tissue that are
separated as the pocket is extended may decrease the chances that
the blade of the dissection tool inadvertently punctures or
otherwise damages cartilage or bone of the septum. However, it
should be appreciated that such dissection tools may be useful in
any procedure involving incision and/or separation of tissues.
[0149] In some variations, a dissection tool may be configured to
at least partially surround a shaft of an endoscope, thereby
forming a sleeve for the endoscope shaft. In this way, the
endoscope shaft and the dissection tool may be maneuvered together.
A distal end of the endoscope shaft, which may comprise a lens, may
be positioned near a blade of the dissection tool to allow
visualization or an area around the blade. In some variations, the
dissection tool may be configured to maintain an unobstructed field
of view for the endoscope. For example, the blade may comprise an
open face positioned such that the view from the endoscope is
substantially through the opening. In some variations, the face of
the blade may be covered to prevent tissue, blood, or other debris
from entering the dissection tool and obscuring the view from the
endoscope. Additionally or alternatively, the dissection tool may
comprise one or more tubes or catheters, as discussed with respect
to FIGS. 13A and 13B, to provide irrigation and/or suctioning to an
area around the blade. In some variations, the dissection tool may
releasably attach to the endoscope shaft in order to prevent
inadvertent separation of the dissection tool and endoscope shaft
during use.
[0150] FIGS. 30A-30C depict a variation of a dissection tool (3500)
configured for use with an endoscope (3502). FIG. 30A shows the
dissection tool (3500) in isolation, FIG. 30B shows the dissection
tool partially surrounding an endoscope shaft (3504), and FIG. 30C
is a magnified view of distal portions of the dissection tool
(3500) and the endoscope shaft (3504). The dissection tool (3500)
may comprise a shaft (3506), a blade (3508) at the distal end of
the shaft (3506), and a lumen. The lumen may extend distally from
an opening at the proximal end (3510) of the dissection tool
(3500). In some variations, the lumen may extend along a portion of
the length of the dissection tool (3500) and terminate proximal to
the blade (3508). In other variations, the lumen may extend into or
through the blade (3508). The lumen may be sized and shaped to
allow the endoscope shaft (3504) to be inserted into the lumen from
the proximal end (3510) of the dissection tool (3500). The lumen
may also be sized and shaped to allow the endoscope shaft (3504) to
be advanced or slid distally inside of the lumen to position a
distal tip (3512) of the endoscope shaft (3504) in proximity to the
dissection tool blade (3508).
[0151] The dissection tool (3500) may comprise a proximal section
(3514) and a distal section (3516), which may include the blade
(3508). In some variations, the proximal section (3514) may be
configured to remain substantially outside of a cavity (e.g., an
anatomic cavity, a surgically created cavity) during use, whereas
at least a portion of the distal section (3516) may be configured
to be inserted into the cavity. The proximal section (3514) may
comprise one or more features to facilitate holding and maneuvering
of the dissection tool (3500). For example, the proximal section
(3514) may comprise ridges (3518) or other protrusions, which may
improve a user's grip on the dissection tool (3500). As will be
described in detail herein, the proximal section (3514) may be
configured to releasably attach the dissection tool (3500) to the
endoscope shaft (3504).
[0152] In some variations, the distal section (3516) of the
dissection tool (3500) may be narrower (i.e., have a smaller
maximum cross-sectional area) than the proximal section (3514) in
order to facilitate insertion into a cavity. The distal section
(3516) of the shaft (3506) comprises a tube, but may have other
shapes. For example, FIG. 31 shows a variation of a dissection tool
(3600) comprising a shaft (3602) with an incomplete circular
cross-sectional shape, which may require less material for
manufacture. Compared to a complete circle, the incomplete circle
may have a smaller cross-sectional area, which may allow the
dissection tool (3600) to be inserted into smaller cavities. As
shown, a gap (3604) in the shaft (3602) may also allow a user to
see a position of a distal tip (3608) of an endoscope shaft (3606)
relative to a blade (3610) of the dissection tool (3600). This may
allow a user to position the endoscope shaft (3606) within a lumen
of the dissection tool (3600) at a location that will produce the
desired field of view.
[0153] Returning to FIG. 30C, the distal section (3516) of the
dissection tool (3500) may comprise the blade (3508). The blade
(3508) may comprise an edge (3520) and a face (3522) enclosed by
the edge (3520). The blade (3508) may comprise any of the blade
features (e.g., size, shape) discussed with respect to any of the
blades (1202, 1204, 1208, or 1302) of FIGS. 12A-13B. For example,
the edge (3520) may be sharp or dull and/or the blade (3508) may
have a scoop shape. In some variations, the face (3522) may
comprise an opening, whereas in other variations, at least a
portion of the face (3522) may be covered or closed. In variations
where the face (3522) comprises an opening, the opening may be
fluidly connected to the lumen of the dissection tool (3500).
[0154] In some variations, the blade (3508) may be configured so
that a view from the endoscope shaft (3504) is substantially
through the face (3522). For example, the face (3522) may have a
size and a position that allows an optical axis of the endoscope to
intersect the face (3522) when the endoscope shaft (3504) is
positioned in the lumen of the dissection tool (3500). In some
variations, the dissection tool (3500) may be configured for use
with an endoscope that has an optical axis aligned with a
longitudinal axis of the endoscope shaft (3504) (i.e., a zero
degree endoscope). In these variations, at least a portion of the
face (3522) may be centrally located relative to a longitudinal
axis of the dissection tool shaft (3506). Additionally or
alternatively, the dissection tool (3500) may be configured for use
with an endoscope that has an optical axis obliquely oriented
relative to the longitudinal axis of the endoscope shaft (3504)
(e.g., a 30 degree endoscope, a 45 degree endoscope). In these
variations, at least a portion of the face (3522) may be obliquely
oriented relative to the longitudinal axis of the dissection tool
shaft (3506).
[0155] In some variations, as shown in FIG. 31, a blade (3608) may
be integral with a shaft (3610) of a dissection tool (3600). In
other variations, as shown in FIGS. 32A and 32B, a blade (3702) and
a shaft (3704) of a dissection tool (3700) may be separate elements
that are attached. FIG. 32A shows the blade (3702) detached from
the shaft (3704), as they may appear before assembly, and FIG. 32B
shows the blade (3702) attached to the shaft (3704).
[0156] FIG. 33 shows a distal portion of a variation of a
dissection tool (3800) comprising a blade (3802) that is configured
to maintain a clear field of view for an endoscope (3804). As
shown, at least a portion of the blade (3802) may be transparent.
For example, at least a portion of the blade (3802) may be formed
from a transparent plastic, glass, crystal (e.g. sapphire), or any
other suitable transparent material. This may allow visualization
through a solid portion the blade (3802) using the endoscope
(3804). The blade (3802) may also be configured to prevent tissue,
blood, and/or other debris from entering the dissection tool (3800)
and obstructing the field of view of the endoscope (3804). For
example, a face (3806) of the blade (3802) may be a solid surface
that is integral with an edge (3808) of the blade (3802). Thus, the
blade (3802) may not comprise any external openings or otherwise
provide a connection between an environment outside of the
dissection tool (3800) and a lumen inside of the dissection tool
(3800) where the endoscope (3804) may be positioned. In some
variations, the blade (3802) may be a single piece of solid,
transparent material that is formed in a scoop shape.
[0157] FIG. 34 shows a distal portion of a variation of a
dissection tool (3900) that comprises a blade (3902) with a window
(3904). The window (3904) may be sealed against at least a portion
of an edge (3906) of the blade (3902) in order to prevent material
from entering the blade (3902) through an open face (3908). The
window (3904) may be formed from a transparent material (e.g.,
plastic, glass, crystal, or the like) in order to allow
visualization with an endoscope through the window (3904). In other
variations, a dissection tool may comprise a cap or a sleeve, which
may cover more of a blade than just the face. For example, the
sleeve may be tubular with an open end and a closed end, and in
some variations it may be elastic to fit tightly around a portion
of the dissection tool. In some variations, at least a portion of
the sleeve may have a similar shape and size as at least a portion
of the blade so that the sleeve may fit tightly around the blade.
The closed end of the sleeve may be positioned around at least the
face of the blade in order to prevent material from entering the
blade. In some variations, at least a portion of the sleeve may be
transparent in order to allow visualization from the endoscope
through the sleeve.
[0158] In some variations, instead of a sleeve or a window covering
the outside of an open face of a blade, a dissection tool may
comprise a barrier positioned at least partially within a lumen of
the dissection tool (e.g., within a distal portion of the lumen,
within a portion of the lumen inside of the blade, within a portion
of the lumen inside of a shaft of the dissection tool, combinations
thereof). The barrier may be configured to prevent tissue, blood,
and/or other debris from obstructing a view of an endoscope by
eliminating any connections that may allow debris to move between
the open face of the blade and a portion of the dissection tool
lumen where an endoscope shaft may be positioned. The barrier may
be formed from a solid, gel, foam, or the like. In some variations,
the barrier may be a liquid polymer that solidifies after it is
delivered into the dissection tool. It may be advantageous for the
barrier to conform to a shape of the dissection tool lumen because
this may allow the barrier to form a fluid-tight seal between the
face of the blade and the portion of the lumen where the endoscope
shaft may be positioned. In some variations, the barrier may be
transparent in order to allow visualization from the endoscope
through the barrier. For example, the barrier may comprise an
optically clear epoxy, resin, or the like (e.g., a Master Bond.RTM.
epoxy such as EP30P epoxy, a Hapco, Inc. resin such as
Ultraclear.TM. 480 Series resin, or the like).
[0159] In some variations, the barrier may be positioned at least
partially within the dissection tool after an endoscope shaft has
been positioned in the lumen of the dissection tool. This may
result in a proximal portion of the barrier abutting against a
distal tip of the endoscope shaft, which may allow the barrier to
occupy an entire space between the endoscope shaft and the face of
the blade. For example, a liquid polymer may be poured into the
blade face, and the polymer may flow through the lumen of the
dissection tool until it is stopped at the distal tip of the
endoscope shaft. The liquid polymer may at least partially fill the
lumen distal to the endoscope shaft, and in some variations the
liquid polymer may fill the lumen until it forms a surface at the
face of the blade. The polymer may then solidify, thereby forming a
barrier between the face and the portion of the lumen where the
distal tip of the endoscope is positioned. In other variations, the
barrier may be positioned at least partially within the dissection
tool before the endoscope shaft is inserted into the dissection
tool.
[0160] In some variations, a dissection tool may releasably attach
to an endoscope shaft, thereby preventing the dissection tool and
endoscope from inadvertently separating during use. A secure
connection between the dissection tool and the endoscope shaft may
also improve a user's control of the endoscope and the dissection
tool while maneuvering the devices. FIGS. 35A-35C show an example
of an attachment mechanism for securing a variation of a dissection
tool (4000) to an endoscope (4002). FIGS. 35A and 35B show the
dissection tool (4000) partially surrounding an endoscope shaft
(4004), and FIG. 35C is magnified view of a proximal portion of the
dissection tool (4000). The dissection tool (4000) may comprise a
distal section (4006) with a blade (4008), and a proximal section
(4010) with a screw portion (4012) and a nut portion (4014). The
screw portion (4012) may comprise external threads (4016), and the
nut portion (4014) may comprise mating internal threads, thereby
allowing the nut portion (4014) to be screwed onto the screw
portion (4012). FIG. 35A shows the screw portion (4012) and the nut
portion (4014) screwed together, whereas FIGS. 35B and 35C show
them unscrewed.
[0161] The screw portion (4012) may comprise a compressible splayed
section (4018) at its proximal end, adjacent to the external
threads (4016). The nut portion (4014) may have an internal
diameter that tapers from a first end (4020) to a second end
(4022). When the nut portion (4014) is screwed onto the screw
portion (4012), the splayed section (4018) may be inserted into the
first end (4020). As the nut portion (4014) is screwed farther onto
the screw portion (4012), the splayed section (4018) may move
towards the second end (4022) of the nut portion (4014), which has
a smaller internal diameter. The nut portion (4014) may be
configured such that its internal surface increasingly impinges on
the splayed section (4018) as the nut portion (4014) and screw
portion (4012) are screwed together.
[0162] The splayed section (4018) may comprise one or more wings
(4024), and pressure from the internal surface of the nut portion
(4014) on the wings (4024) may cause them to deflect into a lumen
of the screw portion (4012). In this way, screwing the screw
portion (4012) and the nut portion (4014) together may decrease a
diameter of a lumen of the dissection tool (4000). When the
endoscope shaft (4004) is positioned in the lumen of the dissection
tool (4000), the wings (4024) of the splayed section (4018) may
press against the endoscope shaft (4004) as the nut portion (4014)
is screwed onto the screw portion (4012). Friction between the
wings (4024) and the endoscope shaft (4004) may releasably attach
the dissection tool (4000) to the endoscope (4002). To release the
dissection tool (4000) from the endoscope shaft (4004), the nut
portion (4014) may be at least partially unscrewed from the screw
portion (4012) (i.e., screwing the nut portion (4014) and the screw
portion (4012) apart may increase the diameter of the lumen).
[0163] While the screw portion (4012) and nut portion (4014) are
shown completely separated in FIGS. 35B and 35C, it should be
appreciated in some variations, when the screw portion (4012) and
nut portion (4014) are maximally unscrewed, they may remain
connected. As shown, the proximal section (4010) of the dissection
tool (4000) may comprise the attachment mechanism, but it should be
appreciated that any portion of a dissection tool may comprise a
mechanism for releasably attaching to an endoscope. In addition,
while the attachment mechanism shown in FIGS. 35A-35C comprises a
compressible portion to tighten around an endoscope shaft, a
dissection tool may be configured to releasably attach to an
endoscope in any suitable way (e.g., with friction from a
non-compressible internal surface, with one or more clips, clamps,
hooks, tethers, or the like).
[0164] In some variations, rather than being configured for use
with an endoscope, a dissection tool may comprise a digital camera.
Such a dissection tool may comprise a shaft with a blade positioned
at its distal end. The blade may comprise any of the features
discussed with respect to any of the blades (3508, 3608, 3702,
3802, or 3902) of FIGS. 30A-34. The dissection tool may comprise
one or more lumens or compartments to house one or more elements of
the camera. In some variations, the camera may comprise a maximum
diameter of about 2 mm to about 2.5 mm. The camera may be
configured to be connected to a display, such as an LCD display. A
lens may be positioned near a distal portion of the dissection tool
in order to provide visualization of an area surrounding a blade of
the dissection tool. In some variations, the dissection tool may
also comprise a light source. Some variations of dissection tools
comprising a camera may be configured to be disposable, whereas
others may be configured to be reused.
[0165] In some variations, a dissection tool may also comprise one
or more of the features described above with respect to an
electrical probe, which may allow the dissection tool to
electrically stimulate nasal tissue. In this way, the combination
dissection tool and electrical probe may be used to both identify
an implantation site for a microstimulator and to form a tissue
pocket for the microstimulator. For example, the dissection tool
may comprise a conductive portion, which may be at least a portion
of a blade and/or a portion of a shaft of the dissection tool. The
conductive portion may be at least partially insulated, such as
with an insulation sheath, as was discussed with respect to the
electrical probe (1100) of FIG. 11. In some variations, at least a
portion of the blade (e.g., a distalmost portion of the blade, a
scoop of the blade, a convex portion of the blade) may be
configured to deliver an electrical stimulus to nasal tissue. For
example, a conductive portion of the blade may not be insulated,
which may allow this conductive portion to deliver an electrical
stimulus. In some variations, one or more electrodes may be
positioned on the blade and/or on other portions of the dissection
tool to deliver the electrical stimulus. In some variations, it may
be advantageous for a dissection tool that is configured to be used
with an endoscope, such as the dissection tools described with
respect to FIGS. 30A-35C, to function as an electrical probe
because this may allow the locations that are electrically
stimulated to be visualized.
[0166] It may be desirable to have a depth stop on one or more of
the devices configured to enter a nasal cavity, including the
implantation tool, dissection tool, and electrical probe described
herein. A depth stop may reduce the risk of advancing a device too
far into a nasal cavity, which may cause the device to
inadvertently damage nasal structures (e.g., the cribriform plate).
A depth stop may indicate a distance relative to an inserted end of
a device. In some variations, this distance may indicate a maximum
distance that the device may be inserted into a nasal cavity. In
some variations, a depth stop may be positioned on a device used
for extending a tissue pocket, and the depth stop may indicate the
desired length of a tissue pocket. The position of a depth stop may
be compared to the position of a portion of a patient (e.g. the
nostril, the inferior edge of the nasal septum). In some
variations, a depth stop may be a marker, which may be visually
compared to a portion of a patient. In some variations, a depth
stop may physically resist over-insertion of a device by protruding
from the device such that it may contact a portion of a patient if
the device is advanced a sufficient distance. Depth stops may be
positioned between about 25 mm and about 100 mm from a distal,
inserted end of a device. In some variations, depth markers may be
positioned every millimeter or centimeter from a distal end of a
device to indicate a distance of insertion.
[0167] For example, a retractable cover of an implantation tool may
comprise one or more markings that indicate a distance from the
distal tip of the retractable cover. When the retractable cover and
a microstimulator are inserted into a tissue pocket opening and the
implantation tool is advanced, the position of the one or more
markings on the retractable cover may be compared to the tissue
pocket opening. This may allow a user to advance the implantation
tool a desired distance, such that the microstimulator and
retractable cover are inserted a desired distance into a tissue
pocket. In some variations, this may be advantageous to reduce the
risk of forming a tissue pocket that is too long and/or contacting
structures (e.g., the cribriform plate) that may be inadvertently
damaged.
[0168] Other variations of depth stops are shown in FIGS. 14A and
14B. In this example, the depth stops comprise one or more movable
pins that may be inserted into one or more corresponding holes in a
device. FIG. 14A shows a dissection tool (1402) that comprises a
depth stop pin (1404) and two holes (1406) in the dissection tool
shaft (1408) that the pin may be partially disposed in. As shown,
the depth stop pin has been removed from the device. FIG. 14B shows
a distal portion of an implantation tool (1410) that similarly
comprises a depth stop pin (1412) and three holes (1414) in the
implantation tool. As shown, the pin is partially disposed in the
most distal hole and extends through the width of the implantation
tool shaft (not shown) and retractable cover (1416), such that
portions of the pin are exposed on opposite sides of the
implantation tool. In this variation, the depth stop pin may be
removed prior to retracting the retractable cover and releasing the
microstimulator (1418). These holes may indicate maximum insertion
distances from a distal tip of a device. The holes may be
positioned at different distances from the distal tip, such that a
user may select the best placement of the depth stop pin for the
particular procedure and subject. For example, the holes may be
positioned with one hole at about 25 mm, one at about 35 mm, and
one at about 45 mm. Generally, it may be desirable for holes to be
positioned between about 20 mm and about 50 mm. In some variations,
different holes may be used to indicate maximum insertion distances
for different nasal cavities sizes. A pin may be placed in a
desired hole (e.g., the hole that corresponds to a maximum
insertion distance for a specific patient) such that the pin
protrudes from one or both sides of the dissection tool shaft. As
the distal tip of the dissection tool is advanced into a nasal
cavity, the pin may contact a portion of the patient (e.g., ala,
inferior edge of the nasal septum) to resist further advancement.
This may indicate that a maximum insertion distance has been
reached. In some variations, a pin and/or hole may comprise a
spring and/or other feature to prevent the pin from becoming
unintentionally dislodged from the hole during the dissection
procedure.
[0169] Another variation of depth stop comprises a ring and one or
more protrusions. The ring may be disposed around a distal portion
of a device that enters a nasal cavity (e.g., dissection tool,
implantation tool, electrical probe) and may be positioned at a
maximum insertion distance from a distal tip of the device, as was
described in more detail herein. The ring may have a smooth inner
surface to contact a device shaft. An outer surface of the ring may
comprise one or more protrusions that may extend radially away from
the center of the ring. Advancement of a device comprising a ring
into a nasal cavity may result in one or more protrusions
contacting a portion of the patient (e.g., ala, inferior edge of
the nasal septum) to resist further advancement. In some
variations, the ring may be flexible and may be sized such that it
may be stretched to be positioned around a shaft of a device at
different maximum insertion distances for different patients, and
then relaxed to form a tight fit around the shaft. In some
variations, the ring may be removable and may be used with
different devices. In some variations, the one or more protrusions
may be integrally formed with the ring, and in other variations the
protrusions may be formed separately. Any of the devices that enter
a nasal cavity may comprise depth stops configured in any suitable
manner to provide a visual and/or tactile indication of the
distance a device has been inserted into a nasal cavity.
Controller
[0170] The nasal microstimulator implantation system described here
may comprise a controller, which may communicate with the
stimulation devices described here to transmit and/or receive
power, information, or the like. The controller may remain external
to the body and communicate wirelessly with the microstimulator.
FIG. 24 depicts an exemplary external controller for use with the
nasal microstimulator implantation systems described here. As shown
there, a stimulation system (2700) includes a controller (2702)
comprising a hand-held device. The controller may be brought to the
vicinity of an implanted microstimulator (2704), and may produce an
output signal (2706) received by the implanted microstimulator
(2704). The implanted microstimulator may in turn generate a
stimulation signal (2708) used to stimulate an anatomical target,
as described in more detail herein. While the controller shown in
FIG. 24 comprises a hand-held device, it should be appreciated that
the controller may comprise any suitable form. For example, the
controller may comprise a wearable device (e.g., glasses,
wristwatch), a key fob, or be a component of a pillow configured to
stimulate nasal tissue during sleep.
[0171] The controller may be configured to transmit one or more
signals to an implanted microstimulator. In some variations, the
output signal produced by the controller may provide power to the
microstimulator. For example, in variations in which a nasal
microstimulator implantation system comprises a microstimulator
having a passive stimulation circuit (or a stimulation circuit that
does not otherwise include a battery or internal power supply), the
controller signal may power the stimulation device. In variations
in which a microstimulator of a stimulation system comprises a
power source, the signal of the controller may temporarily provide
power to the microstimulator to assist in microstimulator operation
and/or to recharge the power supply of the microstimulator.
[0172] In some variations, one or more of the signals produced by
the controller may transmit information to one or more portions of
the nasal microstimulator implantation system. For example, in
variations where a nasal microstimulator implantation system
comprises a microstimulator having an implantable pulse generator,
the controller may provide programming instructions (e.g.,
stimulation parameters, stimulation times, etc.) to the implantable
pulse generator. In variations where a microstimulator comprises an
adjustable component, one or more output signals of the controller
may be used to adjust the adjustable component.
[0173] FIG. 25 depicts a schematic diagram of one variation of a
controller (2800) circuit suitable for use with the nasal
microstimulator implantation systems described here. As shown
there, the controller (2800) may include a power source (2802), an
input module (2804), a controller (2806), and a transmission
component (2808). The power source (2802) may provide a voltage or
current to the controller (2806). The supplied power may be a
constant voltage or current or an alternating voltage or
current.
[0174] An input module (2804) may provide one or more input signals
to a controller (2806) based on input received from a user such as
a patient, a health professional, or other external source. For
example, the user input may be a depressed button, an input along a
slide bar, or some other input that indicates whether to apply
stimulation to one or more anatomical targets (such as an anterior
ethmoidal nerve within the nasal cavity), what type of stimulation
to apply, and/or what stimulation parameters to apply. The input
signals may also be generated from logic inside the input module
(2804). For example, an input module (2804) may include logic to
apply stimulation to nasal tissue periodically, in a ramped
fashion, continuously, in a patterned fashion, in response to
detecting a condition of low or decreased tear production, or some
other condition. In some variations the stimulation may be ramped
to prevent activation of pain sensation.
[0175] A controller (2806) may receive power from a power source
(2802) and input signals from an input module (2804) to generate an
output signal. The output signal may be a voltage signal or a
current signal applied to a transmission element (2808). The output
signal may vary in frequency, amplitude, period and/or phase based
on the input received from an input module (2804) and power
received from a controller (2802). The transmission element (2808)
may be any element suitable for conveying energy and/or information
to a microstimulator (not shown), such as one or more coils,
ultrasound generators, optical energy generators, or the like. When
the output signal is applied to a transmission element (2808)
including a coil, the coil may generate a magnetic wave having a
radio frequency and amplitude based on the output signal and coil.
In some variations, the controller (2806) may detect one or more
operating parameters of the microstimulator.
[0176] While the controller (2806) is shown in FIG. 25 as having an
input portion, it should be appreciated that the controller need
not have an input portion. FIG. 26 depicts a block diagram of
another variation of controller circuit (2900) comprising a power
source (2902), a controller (2904), and a transmission portion
(2906). The power source (2902) may provide power to the controller
(2904). The controller (2904) may be programmed or otherwise
configured to produce one or more output signals, which may be
transmitted to a microstimulator via a transmission portion
(2906).
[0177] In some variations, it may be desirable to allow for a
patient to alter the intensity of stimulation by increasing or
decreasing the output strength of the controller. In some
variations, a controller may comprise one or more buttons, sliders,
levers, knobs, or other mechanisms a patient may manipulate to
alter the output strength of the controller. In other variations, a
nasal microstimulator implantation system may comprise one or more
external programmers which may be used to alter the output of the
controller. For example, the hand-held controller (2702) described
with respect to FIG. 24 may be configured to communicate with and
provide programming instructions to one or more other
controllers.
[0178] In some variations, a controller may comprise one or more
safety elements. For example, in some variations a controller may
comprise a temperature sensor which measures the temperature inside
the controller. In these variations, the controller may be
configured to shut down when the temperature inside the controller
exceeds a certain threshold. This may prevent the controller from
reaching a temperature which may injure a patient (e.g., when the
patient is holding the controller).
[0179] In some variations, a stimulation set may comprise a
plurality of controllers, wherein each controller is configured to
produce a different output signal. Other variations of controllers
that may be suitable for use with a nasal microstimulator
implantation system are described in more detail in U.S. patent
application Ser. No. 13/441,806, filed Apr. 6, 2012, and titled
"Stimulation Devices and Methods," which was previously
incorporated by reference in its entirety.
Methods
[0180] Generally, the methods described herein comprise locating a
desired microstimulator implant site within a nasal cavity,
implanting the microstimulator, and activating the microstimulator
to generate lacrimation. Locating the desired microstimulator
implant site within a nasal cavity may comprise using an electrical
probe to stimulate areas adjacent to the nasal septum and visualize
the area that produces a desired patient response (e.g., sneezing,
tearing). The microstimulator may then be implanted in this area.
Implanting the microstimulator may comprise forming a tissue pocket
between the nasal septum and submucosa with devices that may
include one or more dissection tools and/or an implantation tool.
An implantation tool may then be used to insert a microstimulator
into the tissue pocket. In some variations of the implantation
methods, the ability of the microstimulator to produce an
electrical stimulus may be assessed, and the microstimulator
repositioned or otherwise adjusted if desired. After release of the
microstimulator into a nasal tissue pocket of a patient, the area
of implantation may be allowed to heal. The implanted
microstimulator may then be activated to stimulate nasal tissue and
increase tear production. Increasing tear production in this manner
may be an effective treatment for patients with dry eye disease
(DED).
Identification of Implantation Site
[0181] Electrical stimulation of certain areas within the nasal
cavity may increase tear production. As seen in the cutaway view of
the nasal cavity in FIG. 15, one such area may be in proximity to
the anterior ethmoidal nerve (1502). An anterior ethmoidal nerve,
sometimes referred to as the nasociliary nerve, is generally
located in an anterior and superior area within the nasal cavity on
both sides of the nasal septum (1504). The exact location of this
nerve in an individual may vary, as may the area of this nerve that
may produce a desired patient response (e.g., sneezing, tearing)
when stimulated. Identifying the desired microstimulator
implantation site may comprise identifying the area adjacent to the
nasal septum that produces the desired patient response. An
electrical probe comprising one or more electrodes may be used to
stimulate one or more areas adjacent to the nasal septum or at
other locations in the nasal cavity while monitoring for a desired
patient response to the stimulation. An endoscope, which may or may
not be integrated into or attached to the electrical probe, may
allow a user to visualize the area that produces the desired
patient response and identify that area as the desired implantation
site.
[0182] In some variations of identifying an implantation site, a
patient may be partially or fully sedated. An electrical probe,
such as the one described herein with respect to FIG. 11, may be
inserted into a nostril of a patient and areas adjacent to the
nasal septum may be electrically stimulated by the electrical
probe's one or more electrodes. A patient response (e.g., sneezing,
tearing, movement of nasal muscles) may be monitored while one or
more areas are stimulated. In some variations of the electrical
probe comprising two electrodes, the electrodes may deliver a
stimulus simultaneously or separately before the electrical probe
may be moved to a new position. In variations of the electrical
probe comprising one electrode, the electrical probe may be moved
to a new position after the electrode delivers a stimulus. The
implantation site may be determined by the locating the area that
produces a desired patient response or the greatest patient
response when stimulated. In some variations, a test to measure
tear output, such as a Schirmer test or measurement of tear
meniscus height, may be performed during stimulation at one or more
locations to help identify a desired implantation site.
[0183] One or both sides of the nasal septum may be stimulated. In
variations of the methods comprising an implantation of one
microstimulator, stimulation of both sides of the nasal septum may
be advantageous, since in some patients, stimulation on one side
may be more effective than on the other side. In variations of the
methods comprising implantation of two microstimulators,
stimulating both sides of the nasal septum with the electrical
probe may identify a desired implantation site on each side of the
nasal septum.
[0184] In some variations of the methods, a microstimulator may be
implanted adjacent to a cartilaginous portion of the nasal septum.
In other variations, a microstimulator may be implanted adjacent to
a bony portion of the nasal septum. The bony portion of the nasal
septum has its own blood supply, and therefore disruption of the
submucosal layer to form a tissue pocket may not disrupt the blood
supply of this portion of the septum. Nasal fractures may also
occur more frequently at the transition points between the bony and
cartilaginous parts of the septum, and implantation adjacent to the
bony part may prevent a fracture from damaging and/or dislodging
the microstimulator. In order to identify the bony and
cartilaginous portions of the septum, a distal portion of the
electrical probe or another device may be pushed laterally against
the septum. The bony portion of the nasal septum may be less
flexible than the cartilaginous portion of the nasal septum.
Alternatively or additionally, a light source (e.g., a light source
on the electrical probe, a light source on another device) may be
used to identify the bony and cartilaginous parts of the septum.
For example, a light source may be turned on within a nasal cavity,
and the transition point between the cartilaginous and the bony
part of the nasal bridge may be visualized from outside the nasal
cavity, as the cartilaginous part allows more light to be
transmitted. The transition point between the cartilaginous and
bony parts of the nasal bridge may correspond in part with the
transition point between the cartilaginous and bony parts of the
nasal septum. In some variations, a light source may be turned on
while located on one side of the nasal septum, and a detector
(e.g., photodiode) may be placed on the other side of the septum to
assess changes in light absorption, which may indicate the
transition point from cartilage to bone.
[0185] An electrical probe may use similar electrical settings
(e.g., amplitude, frequency, waveform) as the microstimulator in
order to increase the likelihood that an implanted microstimulator
will produce a similar response as the electrical probe. Different
electrical waveforms may be tested using the electrical probe in
order to identify an implantation site and/or to determine a
stimulus waveform. For example, waveforms tested may include a
constant on waveform having a frequency between 20 Hz and 150 Hz
(e.g., about 30 Hz, about 70 Hz), an on/off waveform of similar
frequency, and/or waveforms having modulated amplitude, frequency,
and/or pulse widths may be tested.
[0186] Once the desired implantation site is determined, it may be
marked for subsequent tissue pocket formation. For example, the
relationship between the implantation site and one or more anatomic
landmarks (e.g., nostril, nasal turbinate) may be visualized by a
user. In other variations, the distance the electrical probe is
inserted into the nasal cavity may be observed (e.g., by
visualizing one or more depth stops on the electrical probe in
relation to a nostril). In other variations, the desired
implantation site may be physically marked, such as with a surgical
marking pen or temporary surgical clip.
[0187] It should be appreciated that some variations of the methods
may not comprise the use of an electrical probe. In these
variations, anatomic landmarks may determine a desired implantation
site. For example, a desired implantation site may be in the
superior and anterior portion of the nasal cavity and/or a specific
distance from an anatomic structure (e.g., a nostril, a nasal
turbinate).
Tissue Pocket Formation
[0188] A tissue pocket for microstimulator implantation may be
formed at a desired implantation site. Forming the tissue pocket
may comprise incising nasal tissue to create a tissue pocket
opening and extending the tissue pocket from the opening. Prior to
the surgical procedure, the nasal cavity may be flushed with one or
more antibacterial and/or cleansing agents (e.g., chlorhexidine). A
medication that may produce local anesthesia and/or
vasoconstriction (e.g., cocaine, lidocaine, epinephrine) may be
administered to the area of implantation. A device, such as a
dissection tool described herein, may then be used to form the
tissue pocket opening by making an incision through nasal tissue.
In some variations, the incision may be made in the nasal cavity
through a portion of nasal mucosa and submucosa adjacent to the
nasal septum. In other variations, the incision may be made at the
columella, lateral to the nasal septum. The same device that was
used to make the incision, or a different device, such as a
different dissection tool or an implantation tool described herein,
may then be advanced through the tissue pocket opening to extend
the tissue pocket a desired length. The tissue pocket may be
extended parallel to the nasal septum, between the mucosal layer
and the nasal septum, either through the submucosal layer or
between the submucosal layer and the nasal septum. One or more of
these steps may be visualized with a visualization tool (e.g., an
endoscope used alongside a dissection tool, an endoscope releasably
attached to a dissection tool, an endoscope positioned within a
lumen of a dissection tool, a camera incorporated into a dissection
tool, as described herein).
[0189] FIG. 16 shows a cutaway view of a nasal cavity with an
incision (1602) that may be the opening of a tissue pocket (1604).
Any sharp edge may incise a portion of nasal mucosa and submucosa
to form a tissue pocket opening. For example, any of the dissection
tools described with respect to FIGS. 12A-13B and 30A-35C may
comprise a curved, sharp blade to incise nasal tissue. In other
variations, a flat blade may be used. The length of the incision
may be at least as long as a dimension of the microstimulator that
is parallel to the incision, but need not be. For example, the
opening may be dilated as the microstimulator is inserted through
the opening, or the opening may be dilated by a portion of a
device. For example, in variations of the implantation tool that
comprise a retractable cover with a distal tip, as shown in FIGS.
5A-5C, the distal tip (510) may have a tapered width such that a
narrow portion may enter a tissue pocket opening first. As the
implantation tool is advanced, the portion of the retractable cover
at the tissue pocket opening may become wider, and the opening may
be dilated.
[0190] After an incision has been made in nasal tissue, the amount
of bleeding may be monitored and/or controlled. Significant
bleeding may make visualization of the implant site difficult,
which may increase the risk of a user inadvertently damaging nasal
structures (e.g., the nasal septum, the cribriform plate) and/or
extending the tissue pocket in an undesirable orientation. If
significant bleeding occurs, a vasoconstrictive agent (e.g.,
cocaine, epinephrine) may be administered, the area irrigated,
and/or the patient repositioned. A dissection tool (e.g., the
dissection tool shown in FIGS. 13A, 13B, 30A-30C, 31) may
additionally or alternatively be used to clear blood and/or other
fluid from the implantation site. In some variations, bleeding may
be controlled with electrocautery, which may be a capability of a
dissection tool or another device.
[0191] After an incision has been made in nasal tissue to form an
opening of a tissue pocket, the pocket may be extended. Generally,
this may be accomplished by advancing at least a portion of a
device into the tissue pocket opening and separating and/or
elevating the submucosa from the nasal septum (e.g., the
cartilaginous and/or bony portions of the nasal septum).
Alternatively, the tissue pocket may be extended between layers of
submucosa, and a thin layer of submucosa may remain covering the
nasal septum. In some variations, extending a tissue pocket between
layers of submucosa may be advantageous to preserve blood flow to
the nasal septum and/or to decrease the risk of inadvertently
damaging the nasal septum. Extending the tissue pocket may be done
with the sharp edge used to incise the tissue, but using a blunt
edge may reduce the risk of inadvertently damaging the nasal septum
and/or other tissue. In some variations of the methods, the same
device (e.g., dissection tool) may be used to make the tissue
pocket opening and to extend the tissue pocket. For example, a
dissection tool may comprise both a sharp blade and a blunt blade,
as described in more detail with respect to FIG. 12A. The sharp
blade (1212) may be used to form the tissue pocket opening, and the
blunt blade (1204) may be used to extend the pocket. In other
variations, different devices may be used to extend the tissue
pocket and incise the tissue. For example, any of the variations of
dissection tools shown in FIGS. 12A-13B and 30A-35C may comprise a
blunt blade that may be used to separate and/or elevate the
submucosa from nasal septum.
[0192] In some variations, the implantation tool may be used to
extend the tissue pocket. For example, the implantation tool shown
in FIGS. 5A-5C comprises a retractable cover (501) with a distal
tip (510). In variations in which the distal tip (510) of the
retractable cover (501) extends beyond the distal end (512) of the
releasably attached microstimulator (502), the distal tip may be
the most distal portion of the implantation system as it is
advanced into a tissue pocket opening. When the retractable cover
is in a distal, advanced position, as seen in FIGS. 5A and 5B, the
curve of the distal tip may cover and/or shield the microstimulator
from the forces involved in extending the tissue pocket. As
described in more detail here, this configuration may reduce the
risk of the microstimulator becoming dislodged from the
implantation tool during tissue pocket extension. In other
variations, when releasably attached to an implantation tool, a
microstimulator may be used to extend the tissue pocket. For
example, FIG. 6B shows a variation of implantation tool with a
microstimulator (602) releasably attached to a distal end. The
microstimulator may be advanced into a tissue pocket opening by the
implantation tool and the distal end of the microstimulator may
separate the submucosa from the nasal septum.
[0193] In some variations, the length of the formed tissue pocket
may be at least the length of the microstimulator. For example, a
microstimulator may comprise a length between about 15 mm and about
20 mm, and the tissue pocket may be about 2 mm to about 10 mm
longer than this (that is, in this example, the tissue pocket may
be about 17 mm to about 30 mm in length). In some of these
variations, the length of the microstimulator may be approximately
17 mm, and the length of the tissue pocket may be approximately 2
mm. In some variations the length of the tissue pocket may be
indicated and/or regulated by one or more depth stops or markings
on the device being used to extend the tissue pocket (e.g.,
dissection tool, implantation tool). The relative position of one
or more length markings may be compared to a portion of the patient
(e.g., the ala) to indicate the length of the portion of the device
that has been inserted into the nasal cavity. Similarly, the one or
more length markings may be compared to the opening of the tissue
pocket to indicate the length of a portion of the device that is
within the tissue pocket, which may indicate the length of the
tissue pocket. In some variations, a device may comprise
protrusions that contact a portion of the patient (e.g., the
nostril, inferior edge of the nasal septum) to limit further
advancement of the device. These protrusions or depth stops may be
positioned at a maximum insertion distance from a distal end of a
device and reduce the risk of the device being advanced beyond this
maximum insertion distance. This may reduce the risk a tissue
pocket being extended farther than desired and inadvertently
damaging tissue or a structure (e.g., cribriform plate). In some
variations, as shown in FIG. 14, one or more depth stops on a
dissection tool (1402) may comprise a movable pin (1404) that may
be positioned in different holes (1406) on the device. Prior to
extension of the tissue pocket, the pin may be positioned in a
desired hole that may correspond to a desired maximum insertion
distance from the pin to the distal end of the dissection tool. The
maximum insertion distance may be estimated for a specific patient
by one or more characteristics of the patient, such as nose size or
height.
[0194] The tissue pocket may be extended from the pocket opening to
orient the pocket such that an electrode of an implanted
microstimulator may stimulate a desired area of tissue. For
example, when the target nerve is the anterior ethmoidal nerve, the
desired area of tissue stimulation may be located in a superior and
anterior portion of a nasal cavity, and a tissue pocket may be
extended towards that position. In some variations it may be
desirable to stimulate other areas in the nasal cavity, and a
tissue pocket may be formed at those areas. For example, FIG. 17
shows a cutaway view of a nasal cavity illustrating two alternative
tissue pocket locations. The first location (1702) is over the
middle turbinate, and the second location (1704) is over the
inferior turbinate. A microstimulator (1706) is shown being
advanced towards an opening (1708) of the tissue pocket over the
inferior turbinate. FIG. 18 shows a cutaway view of a nasal cavity
with portions of the pockets (1702 and 1704) of FIG. 17 cut-away. A
microstimulator (1706) is shown positioned in a pocket (1704) over
the inferior turbinate, as it may appear after implantation.
Implantation
[0195] After a tissue pocket has been formed, a microstimulator may
be implanted into the tissue pocket. Generally, this comprises
inserting a microstimulator into an opening of a tissue pocket and
advancing it into the tissue pocket. FIG. 19 shows a cutaway view
of a nasal cavity with a microstimulator (1900) partially advanced
through a tissue pocket opening (1902). An implantation tool such
as those described herein may be used to insert a releasably
attached microstimulator into a tissue pocket. In some variations,
the microstimulator and/or a portion of the implantation tool
(e.g., a distal tip of a retractable cover) may be used to elevate
the submucosa and mucosa of the tissue pocket to allow the
microstimulator to be advanced into the tissue pocket. In other
variations, a different tool may be used to separate the layers of
the tissue pocket opening to allow the microstimulator to enter the
tissue pocket.
[0196] Once a microstimulator is positioned a desired distance into
a tissue pocket, the microstimulator may be released from the
implantation tool. This process is shown in FIGS. 28A and 28B,
which are fluoroscopic images taken during implantation of a
microstimulator (3100) in a goat using a variation of implantation
tool (3102) described herein. In FIG. 28A, the microstimulator is
releasably attached to the implantation tool, and in FIG. 28B, the
microstimulator has been released from the implantation tool. The
method of release may be different for different embodiments of
implantation tool and/or microstimulator. For example, in
variations of the implantation tool that comprise a retractable
cover, the retractable cover may be moved into a proximal,
retracted position to expose the microstimulator, as seen in FIG.
5C, in preparation for release.
[0197] In variations of the implantation tool that comprise a
tension system to releasably attach a microstimulator, the tension
may be released in order to detach the microstimulator. For
example, FIGS. 4A-4C illustrate a tension system for releasably
attaching a microstimulator (410) to an implantation tool shaft
(404). As is described in more detail herein, a tensioning element
(406) may be looped through a microstimulator eyelet (412), travel
through a lumen of the implantation tool shaft (404), and be
secured at a proximal end of the shaft using a knob (408). Tension
in the tensioning element may hold the microstimulator against the
implantation tool at a contact surface (402). In some variations,
the tension in the tensioning element may be released by cutting
the tensioning element with a blade or scissors at a location
between the knob of the implantation tool and the eyelet of the
microstimulator. For example, the tensioning element may be cut
close to the microstimulator eyelet, between the knob and proximal
end of the shaft, or at a distal end of the knob. In some
variations, the tensioning element may be secured between the knob
and a portion of the shaft (e.g. between threaded portions of the
knob and shaft that are screwed together). In these variations, the
knob may be detached or loosened from the shaft in order to release
the tensioning element.
[0198] After releasing the tension in the tensioning element (406)
connecting the microstimulator (410) to the implantation tool, the
tensioning element may remain looped through the eyelet (412) of
the microstimulator as the implantation tool is withdrawn over the
tensioning element. In some variations, leaving at least a portion
of the tensioning element looped through the microstimulator eyelet
may facilitate removal or repositioning of the device if needed. In
some variations, the tensioning element may be pulled out of the
microstimulator eyelet after the implantation tool is withdrawn
over the tensioning element. In some variations, after releasing
the tensioning element from the knob, the implantation tool may
remain positioned near the microstimulator and the tensioning
element may be withdrawn from the proximal opening (416) of the
implantation tool lumen. This may pull the tensioning element out
of the microstimulator eyelet. This variation of the release method
may reduce the risk of inadvertently moving the microstimulator
from its implantation site while the tensioning element is removed.
This release method may be facilitated by positioning a tensioning
element such that it has a short end and a long end extending
proximal to the implantation tool when the tensioning element is
secured at the knob. After releasing tension in the tensioning
element, the long end may be easily accessed and pulled through the
microstimulator connector and implantation tool lumen to withdraw
the tensioning element.
[0199] In variations of an implantation tool that comprise a
friction system for releasably attaching a microstimulator, the
friction between the implantation tool and microstimulator may be
overcome to release the microstimulator into a tissue pocket. FIGS.
6A-6C illustrate a nasal implant stimulation system that comprises
a friction system. As shown, friction between the holder (608) of
the implantation tool and the microstimulator may hold the
microstimulator at the distal end of the implantation tool. A
pusher (610) may be at least partially disposed in a lumen of the
implantation tool shaft (604) and may be pushed against the
microstimulator in order to overcome the friction holding the
microstimulator to the implantation tool. A control slider (612)
may be connected to the pusher (610) within the shaft lumen, and
distal advancement of the control slider may distally advance the
pusher. As shown in FIG. 6C, advancement of the pusher (610) may
push the microstimulator (602) distally beyond the holder. When at
least a portion of the microstimulator is in a tissue pocket, this
may release the microstimulator from the implantation tool and
deposit the microstimulator in the tissue pocket. The implantation
tool may then be withdrawn through the nostril.
[0200] While the methods described here use an implantation tool to
insert a microstimulator, it should be appreciated that in some
variations, the microstimulator may be delivered to the tissue
pocket in other suitable ways, such as with tweezers or forceps. In
variations where release of a microstimulator from the implantation
tool does not result in the microstimulator being completely within
the tissue pocket, the microstimulator may be advanced farther so
that it is completely within the pocket. This may be done by
pushing a side of the microstimulator that is out of the tissue
pocket with a distal end of the implantation tool or another
device. In some variations, it may be advantageous for the
microstimulator to be advanced into a tissue pocket such that there
is at least about 5 mm between the microstimulator and the tissue
pocket opening. This may increase the likelihood of proper closure
and/or healing of the tissue pocket opening. In some variations,
the layers of tissue surrounding a microstimulator may hold the
microstimulator stationary within a tissue pocket via friction. In
some variations, the microstimulator may be sutured or glued to
increase the likelihood that the microstimulator remains stationary
after implantation.
[0201] The tissue pocket may be closed in any suitable manner. For
example, the tissue pocket opening may be closed with sutures
and/or with tissue glue. FIG. 20 shows a cutaway view of a nasal
cavity with the submucosa and mucosa partially cut-away to reveal a
microstimulator (2000) in an implanted position adjacent to the
anterior ethmoidal nerve (2002). The microstimulator is within a
tissue pocket (2004) that has been closed with sutures (2006). In
some variations, packing the nasal cavity with an absorbent
material (e.g., gauze) may exert pressure on the tissue pocket
opening to facilitate closure. In some variations, the duration of
the procedure from incision to closure may be about 5 minutes.
Stimulation Testing
[0202] The ability of a microstimulator to produce a desired
electrical stimulus may be confirmed before, during, and/or after
implantation of the microstimulator in a tissue pocket. In some
variations, the electrical stimulus produced by a microstimulator
in response to a signal from a controller may be tested prior to
implantation. In some variations, a portion of the implantation
tool may be used to test the electrical stimulus of the
microstimulator. As was described in more detail with respect to
FIGS. 5A and 5B, an implantation tool may comprise a retractable
cover (504) that may be slidable over a portion of a shaft between
a proximal retracted position and a distal advanced position. In
the advanced position, as shown in FIGS. 5A and 5B, the retractable
cover may cover at least a portion of one or more electrodes (514)
of the microstimulator, which may facilitate sensing an electrical
stimulus produced by the one or more electrodes. The implantation
tool maybe configured to sense an electrical stimulus by comprising
one or more electrodes. Before implantation, the retractable cover
and microstimulator may be submerged in a conductive solution
(e.g., saline), and a controller may be used to activate the
microstimulator. If the microstimulator is functioning properly, it
may generate an electrical signal, which may be detected by the one
or more electrodes of the retractable cover. In some variations, a
similarly configured implantation tool may test the electrical
stimulus generated by the microstimulator during implantation. A
controller may activate the microstimulator while it is attached to
the implantation tool in a tissue pocket, and the implantation tool
may detect whether the microstimulator produces the expected
electrical stimulus.
[0203] After implantation, effectiveness of the microstimulator's
electrical stimulus may be tested by monitoring a patient's
response to stimulation. For example, after a patient has at least
partially recovered from anesthesia, a controller may be used to
activate the implanted microstimulator. A patient's response (e.g.,
tearing, sneezing, sensing paresthesia in the nasal cavity) may
indicate that the microstimulator is providing an appropriate
electrical stimulus to a desired location. In some variations, a
Schirmer test or other suitable method for measuring tear
production may be performed and compared to results of a Schirmer
test done prior to implantation to determine if stimulation
increases tear production. If the desired response is not observed,
one or more settings on the controller may be adjusted and
stimulation repeated. Alternatively or additionally, the
implantation site may be confirmed, such as by using an electrical
probe, as was previously described. The electrical probe may be
used to deliver an electrical stimulus to the implantation site
area, and a patient's response may be monitored. If a less than
desired patient response is observed with stimulus to the
implantation site area, other areas of the nasal cavity may be
tested. If another area is found to generate a more robust patient
response, the microstimulator may be repositioned to that area. If
stimulation of the implantation site by the electrical probe
produces a desired patient response (e.g., tearing, sneezing), the
implantation site may be correct, but the microstimulator may not
be delivering an appropriate electrical stimulus. In this case, the
microstimulator may be removed.
Repositioning/Removal
[0204] A microstimulator may be removed from a nasal cavity or
repositioned within a nasal cavity. To remove a microstimulator, at
least a portion of the microstimulator may be exposed, which may
comprise incising tissue overlying or in proximity to the
microstimulator. In some variations, a tissue pocket opening may be
reopened, such as by cutting sutures on the opening, to expose a
portion of the microstimulator. The exposed portion of the
microstimulator may be accessed to withdraw the microstimulator
from the tissue pocket. In some variations, the exposed portion of
the microstimulator may comprise a connector, which may have been
used to attach the microstimulator to an implantation tool during
insertion. An implantation tool or a separate device may connect to
the connector to withdraw the microstimulator from the tissue
pocket. For example, the microstimulator (200) shown in FIG. 2A
comprises a connector in the form of an eyelet (204). A retrieval
tool, such as is seen in FIG. 10, may hook onto the connecter of
the microstimulator in order to withdraw the microstimulator from
the tissue pocket. In some variations, a portion of the tensioning
element that was used to attach the microstimulator connector to
the implantation tool may still be connected to the connector.
Pulling the tensioning element may remove the device through an
incised opening in tissue.
[0205] In order to reposition a microstimulator, it may be removed
and implanted in a different location using the methods described
previously for implantation. In other variations, the
microstimulator may be repositioned without completely removing the
microstimulator. For example, a portion of the device may be
accessed through the tissue pocket opening or an incision in the
nasal tissue overlying or adjacent to the microstimulator. This
exposed portion of the microstimulator may be manipulated (e.g.,
pushed in a particular direction) to reposition the
microstimulator. For example, the microstimulator may be advanced
farther into a tissue pocket.
Treatment
[0206] A patient may use a controller to activate an implanted
microstimulator, such that the microstimulator delivers an
electrical stimulus according to one or more treatment regimens.
For example, to treat dry eye disease, stimulation may be delivered
as-needed and/or according to a pre-determined regimen. In some
variations, a patient may use a controller to activate an implanted
microstimulator to deliver a round of stimulation when the patient
experiences dry eye symptoms. A round of stimulation may have any
suitable duration (e.g., between 1 second and 10 minutes).
[0207] In other instances, stimulation may be delivered on a
scheduled basis. A patient may use a controller to activate a
microstimulator according to a schedule or a microstimulator and/or
controller may be configured to automatically deliver a stimulus
according to a schedule. In some variations the microstimulators
described here may be used to provide a round of stimulation at
least once daily, at least once weekly, or the like. In some
variations, the microstimulators may be used to deliver multiple
rounds of stimulation each day (e.g., at least two treatments
daily, at least three treatments daily, at least four treatments
daily, at least five treatments daily, at least six treatments
daily, at least seven treatments daily, at least eight treatments
daily, between two and ten times daily, between four and eight
times daily, or the like). In some variations, the stimulation may
be delivered at certain times of day.
[0208] When the microstimulator is used to provide stimulation on a
scheduled basis, in some variations each round of stimulation may
be the same length (e.g., about 30 seconds, about 1 minute, about 2
minutes, about 3 minutes, about 4 minutes, about 5 minutes, about
10 minutes, or longer than 10 minutes). In other variations, some
rounds of stimulation may have different predetermined lengths. In
yet other variations, the patient may choose the length of the
round of stimulation. In some of these variations, the patient may
be given a minimum stimulation time (e.g., about 5 seconds, about
10 seconds, about 30 seconds, about 1 minute, about 2 minutes,
about 3 minutes, about 5 minutes, or the like) and/or a maximum
stimulation time (e.g., about 1 minute, about 2 minutes, about 3
minutes, about 5 minutes, about 10 minutes, about 20 minutes, or
the like). In some instances, the delivery schedule or stimulation
parameters may be changed based on the time of day (e.g., daytime
use vs. nighttime use). In some instances, stimulation may be
delivered on a continuous basis.
[0209] In some variations, the treatment regimens of providing the
stimuli described herein may cause periodic or regular activation
of the nasolacrimal reflex, which may in turn treat dry eye and/or
improve ocular health. Further details regarding the mechanisms by
which nasal stimulation may improve ocular health and treatment
regimens may be found in U.S. patent application Ser. No.
14/256,915, filed Apr. 18, 2014, and titled "Nasal Stimulation
Devices and Methods," which is hereby incorporated by reference in
its entirety.
EXAMPLE #1
[0210] Two goats were implanted under sterile conditions with a
microstimulator and stimulated at least once weekly for 33 days
while collecting Schirmer score data to quantify tear production. A
Schirmer score recorded in millimeters was determined by using
Schirmer test strips, with a greater distance corresponding to
greater tear production. The microstimulator implanted was similar
to the microstimulator (200) of FIGS. 2A and 2B. The
microstimulator was composed primarily of medical grade silicone,
titanium (CP Grade 2), and titanium nitride-coated titanium. The
microstimulator dimensions were approximately 17 mm.times.5
mm.times.2 mm (L.times.W.times.H) and the approximate total surface
area was 190 mm.sup.2. The microstimulator was placed into the left
nasal cavity in both animals, below the submucosa of the nasal
septum, in one animal on the cartilage and in the other animal on
the bony part of the septum.
[0211] Using an electrical probe similar to the electrical probe
(1100) of FIG. 11, the desired implantation location was identified
as a position where electric stimulation of the anterior ethmoidal
nerve caused the goat to sneeze. To do so, prior to the
implantation surgery, the septal mucosa was electrically
stimulated, confirming the medial side inside the nasal cavity as
the best location, approximately 7 cm to 10 cm cranially measured
from the nostril. Animals showed movement of some nasal musculature
at the nostril and one animal sneezed when stimulated electrically;
both animals produced large amounts of nasal mucous and saliva with
electrical stimulation. This effect had been previously determined
not to occur with mechanical stimulation alone.
[0212] The procedure was done under endoscopic visualization, and
videos and photos were recorded. A pocket was created below the
submucosa, approximately 5 cm to 7 cm from the nostril and extended
to a depth of about 4 cm. A sterile microstimulator (rated up to
2.4 mA) was placed (coil-first) into the pocket below the submucosa
of the nasal septum, approximately 9 cm from the nostril opening of
the goat. The pocket was closed, in one animal by packing the
nostril with sterile gauze for twenty minutes, in a second animal
by pressing the pocket wall to adhere to the septum (no packing).
FIG. 21 is a fluoroscopic image of a goat skull with an implanted
microstimulator (2100).
[0213] The surgery was performed under partial sedation. Each time
electric stimulation was applied, animals were only lightly sedated
to preserve reflexes. The depth of anesthesia was assessed by
testing for various reflexes (blinking of the eye in response to
noise, and tickle of the periorbital skin, withdrawal of the head,
and ear-wiggle responding to tickle).
[0214] Three hours after the successful implant procedure, each
animal responded with repeated sneezing to stimulation using a
controller similar to controller (2702) described with respect to
FIG. 24. One day post implant, each animal was stimulated
repeatedly using the controllers to collect Schirmer score data.
Schirmer tests were first collected as basal Schirmer (no
stimulation), followed by repeated Schirmer tests using electric
stimulation. Average Schirmer score test results are reported
below. Subsequent Schirmer tests were collected on days 3, 5, 6,
12, 21, 27, and 33 of the study.
[0215] Unilateral electric nasal stimulation using the implanted
microstimulators lead to a bilateral increase in Schirmer test
scores. Schirmer scores recorded with electric stimulation ("acute"
Schirmer scores) showed an increase in tear output in comparison to
basal Schirmer scores (without stimulation). FIG. 22 is a bar graph
showing the average tear output from both eyes (left eye tear
output+right eye tear output/2) for each goat with and without
stimulation, reported by Schirmer score. Across both goats, the
acute Schirmer scores (during stimulation) were about 40% higher
than basal Schirmer scores on average. For the first goat, tear
output increased by an average of 44.5%, from 17.1.+-.1.7 mm
(mean.+-.SEM) to 24.7.+-.2.0 mm. For the second goat, tear output
increased by an average of 36.4%, from 20.0.+-.1.5 mm to
27.3.+-.1.2 mm.
[0216] The table below shows the basal and acute (stimulation)
Schirmer scores averaged from both eyes for each goat during
multiple stimulation sessions. As seen, the effectiveness of
stimulation did not diminish over time.
TABLE-US-00001 TABLE 1 Basal and acute (stimulation) Schirmer
scores, average for both eyes. Goat 1 Goat 2 Schirmer Score (mm)
Schirmer Score (mm) (average of both eyes) Stim/ (average of both
eyes) Stim/ Test Date Basal Stim Basal Ratio Test Date Basal Stim
Basal Ratio 18 Jul. 2014 15.3 -- -- 18 Jul. 2014 15.0 -- -- 21 Jul.
2014 9.0 13.3 1.5 21 Jul. 2014 25.5 30.3 1.2 23 Jul. 2014 17.5 25.7
1.5 23 Jul. 2014 16.5 26.3 1.6 24 Jul. 2014 24.5 25.2 1.0 24 Jul.
2014 20.5 22.7 1.1 30 Jul. 2014 16.0 26.3 1.6 30 Jul. 2014 22.0
29.3 1.3 8 Aug. 2014 19.0 29.3 1.5 8 Aug. 2014 19.5 26.2 1.3 14
Aug. 2014 20.0 25.2 1.3 15 Aug. 2014 24.5 31.7 1.3 20 Aug. 2014
15.5 28.0 1.8 20 Aug. 2014 16.5 24.7 1.5 Change in Change in
Schirmer Schirmer Mean 17.1 24.7 7.6 Mean 20.0 27.3 7.3 (percent)
100.0 144.5 (percent) 100.0 136.4 StDev 4.5 5.3 StDev 3.9 3.2 SEM
1.7 2.0 SEM 1.5 1.2 Summary: 7.4 Improvement in Schirmer score (mm)
with stimulation 40.5 % improvement in Schirmer score with
stimulation
[0217] Average ipsilateral increases in tear output were also
analyzed. In the eye on the implanted (left) side, the acute
Schirmer score was about 45% greater than the basal Schirmer score
in each animal. In the eye on the contralateral (right) side, the
acute Schirmer score was about 56% greater than the basal Schirmer
score in the first animal and 33% greater than the basal Schirmer
score in the second animal. It is hypothesized that anesthesia
might have affected more reflex pathways in the second animal. The
table below shows the average basal and acute (stimulation)
Schirmer scores for the left and right eyes of each goat.
TABLE-US-00002 TABLE 2 Basal and acute (stimulation) Schirmer
scores for each eye. Left (implanted) Right Ratio of Ratio of Acute
to Acute to Basal Acute Basal Basal Acute Basal Schirmer Schirmer
Schirmer Schirmer Schirmer Schirmer Animal Score Score Score Score
Score Score 1 17.7 25.4 1.44 16.0 25.2 1.56 2 19.0 27.9 1.47 20.0
26.5 1.33
[0218] The mechanical and electrical probing of the nasal cavity
prior to implantation surgery revealed that there was no preference
for either the left or the right side from an efficacy standpoint:
electric stimulation on either side caused the animal to sneeze and
increased the production of nasal (then rather liquid) mucous, as
well as saliva output.
EXAMPLE #2
[0219] Four goats were each implanted with one functional
microstimulator and four non-functional replica implants, all of
which remained in place for a 49-day study period. An objective of
the study was to determine the efficacy of electrical stimulation
using a microstimulator operating at 1.2 mA. In addition, surgical
tools and techniques for implantation and explantation were
evaluated. The microstimulator implanted was similar to the
microstimulator (200) of FIGS. 2A and 2B. The microstimulator was
composed primarily of medical grade silicone, titanium (CP Grade
2), and titanium nitride-coated titanium. The microstimulator
dimensions were approximately 17 mm.times.5 mm.times.2 mm
(L.times.W.times.H) and the approximate total surface area was 190
mm.sup.2. The replica implants had approximately the same
dimensions and surface area as the microstimulator, but they were
composed entirely of silicone.
[0220] For each goat, the implantation site for the microstimulator
was determined using an electrical probe, similar to the electrical
probe (1100) of FIG. 11, to identify an area that produced a
desired response (e.g., sneezing) when stimulated. Under sterile
conditions, an incision was made in this area through the nasal
mucosa and submucosa, adjacent to the nasal septum. Using a blunt
dissection tool with suction, a tissue pocket was extended from the
incision with visualization provided by an endoscope. A
microstimulator was then delivered to the pocket with its electrode
facing laterally using an implantation tool similar to the
implantation tool (3000) of FIGS. 27A-27E. The implantation
procedure was similar for the replica implants, but the
implantation sites were determined based on anatomic landmarks and
the positions of other implants, not the results of stimulation
with an electrical probe.
[0221] On the final day of the study, additional surgical tools and
techniques were evaluated through the successful implantation and
immediate explantation of three microstimulators in one goat.
During this procedure, the dissection tool used to extend the
tissue pocket (i.e., separate the submucosa from the septal
cartilage) was a blunt dissection tool that formed a sleeve around
an endoscope shaft, similar to the dissection tool (3500) of FIGS.
30A-30C.
[0222] In order to determine the efficacy of the 1.2 mA
microstimulator, each goat underwent electrical stimulation with
the implanted microstimulator on the day of implantation (the first
day of the study) and 14, 21, 27, 35, and 45 days after
implantation. For each goat and on each day of stimulation, the
minimum intensity of stimulation that resulted in the goat sneezing
was determined. Over the course of the study, the average
stimulation intensity required to produce sneezing was different
for each goat. However, none of the goats required stimulation at
the maximum intensity that the 1.2 mA microstimulator was capable
of producing. All of the implanted microstimulators remained
functional (i.e., capable of producing an electrical stimulus that
led to sneezing) between implantation and the final day of
electrical stimulation, 45 days after implantation.
EXAMPLE #3
[0223] A human cadaver study was performed to evaluate surgical
tools and techniques for implanting a microstimulator similar to
the microstimulator (200) of FIGS. 2A and 2B. This study indicated
that an implantation procedure similar to those described with
respect to Examples #1 and #2 could be successfully performed on
human anatomy. For example, a tissue pocket was formed adjacent to
the nasal septum and the microstimulator was implanted using an
implantation tool similar to the implantation tool (3000) of FIGS.
27A-27E. FIGS. 29A-29C are fluoroscopic images obtained during this
procedure. FIG. 29A depicts the formation of a tissue pocket in the
nasal cavity using a dissection tool with a blunt blade (3400).
FIG. 29B shows a microstimulator (3402) attached to the distal end
of an implantation tool (3404) as the microstimulator (3402) is
inserted into the tissue pocket. FIG. 29C depicts the
microstimulator (3402) implanted in the nasal tissue pocket after
the implantation tool has been withdrawn.
* * * * *