U.S. patent application number 13/959301 was filed with the patent office on 2014-03-13 for anchoring apparatus and methods for use.
This patent application is currently assigned to Boston Scientific Neuromodulation Corporation. The applicant listed for this patent is Boston Scientific Neuromodulation Corporation. Invention is credited to Purvis Bedenbaugh.
Application Number | 20140074202 13/959301 |
Document ID | / |
Family ID | 39789052 |
Filed Date | 2014-03-13 |
United States Patent
Application |
20140074202 |
Kind Code |
A1 |
Bedenbaugh; Purvis |
March 13, 2014 |
ANCHORING APPARATUS AND METHODS FOR USE
Abstract
An apparatus for securing an implantable lead within tissue of a
patient includes a base adapted to be secured to a patient's skull
adjacent a craniotomy. The base has an upper surface and a lower
surface with a central passage therebetween. The central passage is
adapted to receive the implantable lead therethrough. The apparatus
also has a cover that is releasably coupled to the base so as to
substantially cover the central passage and capture the implantable
lead therebetween. A first rotating member is also coupled with the
base and the first member is rotationally movable so as to meet and
engage the implantable lead at a plurality of positions within the
central passage.
Inventors: |
Bedenbaugh; Purvis; (Tampa,
FL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Boston Scientific Neuromodulation Corporation |
Valencia |
CA |
US |
|
|
Assignee: |
Boston Scientific Neuromodulation
Corporation
Valencia
CA
|
Family ID: |
39789052 |
Appl. No.: |
13/959301 |
Filed: |
August 5, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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13234005 |
Sep 15, 2011 |
8500752 |
|
|
13959301 |
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12056752 |
Mar 27, 2008 |
8038685 |
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13234005 |
|
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60908367 |
Mar 27, 2007 |
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Current U.S.
Class: |
607/116 |
Current CPC
Class: |
A61N 1/0539 20130101;
A61M 25/02 20130101; A61M 2039/0279 20130101; A61M 2039/0261
20130101; A61M 2039/0294 20130101; A61B 90/11 20160201; A61M
2025/0246 20130101; A61B 2090/103 20160201; A61M 2039/025 20130101;
A61M 2025/028 20130101 |
Class at
Publication: |
607/116 |
International
Class: |
A61N 1/05 20060101
A61N001/05 |
Claims
1. A method of securing an implantable lead into tissue of a
patient, the method comprising: positioning a base having an upper
surface, a lower surface and a central passage therebetween
adjacent a craniotomy in a skull of the patient; securing the base
to the skull; inserting an implantable lead through the central
passage and into the tissue; and rotating a first rotating member
coupled with the base so as to meet and engage the implantable lead
at a plurality of positions within the central passage.
Description
CROSS-REFERENCE
[0001] This application is a continuation of U.S. patent
application Ser. No. 13/234,005 (Attorney Docket No. 33872-705.401)
filed on Sep. 15, 2011, now U.S. Pat. No. 8,500,752, which is a
divisional of U.S. patent application Ser. No. 12/056,752 (Attorney
Docket No. 33872-705.201), filed on Mar. 27, 2008, now U.S. Pat.
No. 8,038,685, which is a non-provisional of, and claims benefit of
priority of U.S. Provisional Patent Application No. 60/908,367
(Attorney Docket No. 33872-705.101), now expired, filed Mar. 27,
2007; the entire contents of each of which are incorporated herein
by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates generally to medical apparatus and
methods, more specifically to instrument immobilizers and even more
specifically, but not by way of limitation to an apparatus and
methods for anchoring an intracranial probe or lead to the
cranium.
[0004] Implanting medical devices within the cranium is an
increasingly important approach for treatment of disorders such as
Parkinson's Disease, essential tremor and dystonia. This approach
may also be used to treat a wide array of neuropsychiatric
problems, such as depression, epilepsy, obsessive compulsive
disorder, obesity and chronic pain. Most of these devices interact
with the brain by delivering current through an implanted probe to
modulate brain activity. In addition, infusion of drugs through a
permanently implanted probe has been proposed as a primary
treatment, or as an adjunctive treatment to electrical stimulation,
for Alzheimer's and Parkinson's Diseases, among others.
[0005] As part of the implant procedure, the probe must be
stabilized in the brain. Ideally, any prosthetic device is attached
directly to the tissue on which it operates, in this case, the
brain. Direct attachment of electrical and chemical probes to brain
tissue is impractical. A more easily implementable solution is a
system of flexible probes that bend and float with the brain as the
brain moves within the cranial cavity. Such probes are secured to
the cranium. In this manner, mechanical forces from outside the
cranium are prevented from acting on the brain-to-probe
interface.
[0006] There are a number of current techniques for securing a
probe to the cranium. For example, in one approach, a permanently
implanted probe is fixed by a sliding door which closes to form a
slot just wide enough to slightly compress and grip the body of the
probe. A common feature of such devices is that they grip the probe
somewhere within the craniotomy opening, and that the slot has a
fixed orientation relative to the cranium.
[0007] In another approach, the probe passes through a narrow
aperture at the center of a craniotomy opening The probe is held in
place by a surgeon as it is bent over into a slot leading to the
exit from the device. Hinged arms swing into place to narrow the
slot and anchor the probe within the slot.
[0008] Current anchoring devices are typically positioned over the
craniotomy opening, and they are attached to the cranium with
several peripheral screws. An implantable lead is placed through
the cranial opening and the lead is gripped by two opposing thin
bars. In some cases, it is possible to damage the lead by crushing
it between the thin bars. It would therefore be desirable to grip
the lead with wider bars to more evenly distribute the gripping
force over a greater axial length of the implantable lead. It would
also be desirable to provide a more stable mounting for the
skull-mounted portion of the anchoring device. Additionally,
current devices often have a small opening for receiving the lead
and thus it would be desirable to provide an anchoring device
having a wider opening for the lead, to permit adjustment of lead
position for optimal placement, especially when using a large
multi-channel probe array, a feature shared by only a few currently
available anchoring systems.
[0009] 2. Description of the Background Art
[0010] Prior patents and publications describing anchors for
cranial probes include: U.S. Pat. Nos. 4,328,813; 5,464,446;
6,044,304; 2004/0267284; 2005/0192594; and WO 2004/026161.
SUMMARY OF THE INVENTION
[0011] The invention generally provides an anchor for securing an
implantable lead within tissues in a patient. The terms "lead" and
"probe" will be used interchangeably with one another in this
disclosure, as will the terms "anchor base" and "cylinder." Often
the lead may comprise an electrode or a catheter, and the lead is
often implanted into brain tissue through a craniotomy in the
patient's skull. A current and/or therapeutic agent may be
delivered through the lead to the tissue and the anchor is usually
composed of materials that are compatible with magnetic resonance
imaging. The anchor may be fabricated from metals that do not
interfere with MRI and/or polymers such as polyphenylene sulfide,
polyetheretherketone (PEEK), polyetherimide, polyimide, polysulfone
and the like.
[0012] In a first aspect of the present invention an apparatus for
securing an implantable lead within tissue of a patient comprises a
base that is adapted to be secured to a patient's skull adjacent a
craniotomy. The base has an upper surface, a lower surface and a
central passage therebetween which is adapted to receive the
implantable lead. The apparatus also includes a cover that can be
releasably coupled to the base so as to substantially cover the
central passage and also to capture the lead therebetween. A first
rotating member or door, is coupled with the base and is
rotationally movable so as to meet and engage the lead at a
plurality of positions within the central passage. Rotating the
door also adjusts the position of an opening within the central
passage in which the lead may pass through and also closes or
reduces the size of the central passage while still allowing the
lead to pass therethrough.
[0013] Often, the first rotating member comprises a removable
insert that is adapted to releasably grip the lead and that may be
received in a recessed region of the rotating member. The removable
insert is usually adapted to be removably coupled to the first
rotating member with a rotationally actuated tool that may be
coupled to the first rotating member. The first rotating member may
have a surface defining a wedge shaped or indented region that is
adapted to receive and align the tool.
[0014] The apparatus may have a pin or rivet engaged with the first
rotating member that secures the first rotating member to the base
while allowing rotation of the first rotating member relative to
the base. The first rotating member may also have a surface that
defines a receptacle that is adapted to receive a tool for turning
the first rotating member into a desired position so as to engage
the lead and fix the lead into a position. The first rotating
member may further comprise a resilient end that is adapted to
releasably grip the lead. The resilient end may lie in the same
plane as the first rotating member and may be composed of an
elastomer. The resilient end often is constructed with a
substantially solid core while sometimes it may be porous. Often
the resilient end comprises surface features that are adapted to
capture the lead. The surface features may include a plurality of
convex or concave regions adjacent to one another or the surface
features may be scallops. Sometimes the surface features may
comprise a plurality of resilient fingers that extend outward from
the resilient end. The surface features may also comprise
combinations thereof.
[0015] The apparatus may further comprise a ratchet mechanism that
is adapted to restrict the first rotating member to motion in one
direction. Often the apparatus also comprises a fixing element such
as a set screw that is adapted to immobilize the first rotating
member. The apparatus also often comprises a second rotating member
that is coupled with the base and a spacer may be used to separate
the first and second rotating members from one another. The second
rotating member is rotationally movable so as to meet and engage
the lead at a plurality of positions within the central passage.
Rotating the second door also adjusts the position of an opening
within the central passage in which the lead may pass through and
also closes or reduces the size of the central passage while still
allowing the lead to pass therethrough. Usually, the first and
second rotating members are movable independently of one another
and they may be retained in the base with a retaining member such
as a ring. Also, the first and second rotating members may lie in
the base adjacent to one another. Sometimes the second rotating
member comprises a removable insert that is adapted to releasably
grip the lead. The insert on the second rotating member may take
the same form as the insert on the first rotating member. Often the
resilient end on the first rotating member lies in a plane between
the first and second rotating members.
[0016] The apparatus may further comprise a locking mechanism
coupled with the first and second rotating members. The locking
mechanism locks the first and second members together thereby
preventing relative motion therebetween. The locking mechanism may
be a detent and comprise a protuberance on either the first or
second rotating member and a receptacle for receiving the
protuberance on the other rotating member. These features allow the
rotating members to snap into position with one another thereby
ensuring the lead is gripped therebetween.
[0017] Often, the apparatus further comprises one or more tabs that
extend radially outward from the base. The tabs are adapted to be
secured to the skull adjacent the craniotomy. The tabs often define
apertures that can receive a fastener such as a screw, thereby
securing the base adjacent the craniotomy.
[0018] Sometimes the base is cylindrical and may be sized to fit at
least partially within the craniotomy, and at least a portion of
the base may be securely press fit into the craniotomy. The base
may comprise a discrete upper and a discrete lower portion that are
fastened together, or the base may be of unitary construction. The
base may be recessed at least partially into the craniotomy, or the
lower surface of the base may sit substantially flush with the top
of the skull. The base may also have one or more receptacles that
are adapted to releasably receive at least a portion of the cover.
Often, the upper surface of the base defines one or more channels
that are sized and shaped to accept the lead after the lead has
been disposed therein. The base may also be adapted to receive and
retain other surgical instruments such as instrument positioning
guides or other reference devices often used during neurosurgery.
These other surgical instruments may releasably lock with a flange
in the base, a retaining member in the base or any other portion of
the base or components therein.
[0019] Often the cover is adapted to be removably coupled to the
base. Sometimes the cover comprises one or more legs that are
adapted to releasably snap fit into engagement with the base.
Alternatively, the legs may be disposed on the base or on a
retaining member that fits in the base. The cover may have a
surface that defines one or more channels that are sized and shaped
to accept the lead after it has been disposed therein. One or more
plugs may be placed into the channels or a gasket may be disposed
between the cover and the base in order to seal any gaps
therebetween.
[0020] In another aspect of the present invention, a system for
securing an implantable lead within tissue of a patient comprises
an apparatus for securing the implantable lead within tissue. The
apparatus comprises a base adapted to be secured to a patient's
skull adjacent a craniotomy, the base having an upper and lower
surface and a central passage therebetween. The implantable lead is
often disposed in the central passage. The apparatus also comprises
a first rotating member coupled with the base and having a
removable insert adapted to engage the lead. A retaining pin may
couple the insert with the first rotating member. The first
rotating member is rotationally movable so as to meet and engage
the lead at a plurality of positions within the central passage.
Rotating the door also adjusts the position of an opening within
the central passage in which the lead may pass through and also
closes or reduces the size of the central passage while still
allowing the lead to pass therethrough. The system also includes a
tool having a proximal end, a distal end and a handle, the tool
being adapted to introduce and remove the removable insert to or
from the first rotating member.
[0021] Often the tool also comprises a pin disposed near the distal
end that is adapted to retain the insert when the insert is
decoupled from the first rotating member. The tool is usually
adapted to be rotated so as to simultaneously engage the insert and
withdraw the retaining pin from the insert. The tool may have an
angled surface that facilitates seating of the tool against the
first rotating member.
[0022] The system may also include a cover that can be coupled to
the base so as to substantially cover the central passage and also
to capture the lead therebetween. The system may also comprise a
potting material that is used to fill gaps between the base and the
craniotomy in order to reduce or eliminate leakage of body fluids,
such as cerebral spinal fluid (CSF), from around the base.
[0023] In another aspect of the present invention, a method of
securing an implantable lead into tissue of a patient comprises
positioning a base having an upper surface, a lower surface and a
central passage therethrough, adjacent a craniotomy in a skull of a
patient. The base may be secured adjacent the craniotomy and to the
skull and an implantable lead is inserted through the central
passage into the tissue. Rotating a first rotating member that is
coupled to the base moves the rotating member so that it meets and
engages the implantable lead at a plurality of positions within the
central passage.
[0024] The method may also comprise the step of rotating a second
rotating member that is also coupled to the base so as to meet and
engage the lead at a plurality of positions within the central
passage thereby securing the lead in the tissue. Rotating the
second door also adjusts the position of an opening within the
central passage in which the lead may pass through and also closes
or reduces the size of the central passage while still allowing the
lead to pass therethrough. The method may also include rotationally
adjusting the first and second rotating members in order to capture
the lead therebetween or to release the lead therefrom. Often the
method includes attaching and/or removing an insert that is adapted
to engage the lead and that is coupled to the first or second
rotating members.
[0025] The method may also comprise inserting one or both of the
two rotating members into a secure base ring intraoperatively. In
early stages of the lead implantation procedure, a wide lumen is
available. After the lead is placed, an opening in such rotating
members allows them to pass around the lead and rest in the base,
and grip the lead. The method may further comprise retaining the
two rotating members within the base by interlocking a retaining
member placed over the rotating members and within the base,
thereby restricting axial movement of the rotating members relative
to the base.
[0026] Sometimes securing the base comprises press fitting at least
a portion of the base into the craniotomy and often securing the
base comprises coupling the base to the skull adjacent the
craniotomy with a fastener such as a screw. Sometimes securing the
base comprises recessing at least a portion of the base in the
craniotomy, or the base may be coupled adjacent the craniotomy such
that a bottom surface of the base is substantially flush with the
craniotomy.
[0027] Usually, a cover is engaged with the base so as to
substantially cover the central passage and capture the implantable
lead therebetween. The cover and/or base may have channels which
can accept the lead after being positioned therein. Often the first
and second rotating members are locked and this may be accomplished
by threadably engaging the rotating members with a set screw or by
using detents in order to prevent relative motion therebetween.
Sometimes, the lead may be bent into a channel that is defined by a
top surface of the base and a potting material may be applied in
order to fill gaps between the base and the craniotomy, thereby
reducing or eliminating leakage of body fluids such as CSF from
around the base.
[0028] These and other embodiments are described in further details
in the following description related to the appended drawing
figures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] FIGS. 1A-1D illustrate cross-sections of several anchor
assembly embodiments having fixation tabs that allow the anchor to
be placed within a craniotomy at varying depths.
[0030] FIG. 1E shows an anchor attached to a patient's cranium.
[0031] FIGS. 2A-2G show top and cross section views of rotating
doors.
[0032] FIGS. 3A-3F show alternative embodiments of the grip
bars.
[0033] FIGS. 4A-4F show alternative embodiments of the rotating
doors.
[0034] FIG. 5A shows a top view of the cylinder without the
rotating doors.
[0035] FIG. 5B shows a side view of an exemplary embodiment of a
cover.
[0036] FIG. 5C shows a bottom view of an exemplary embodiment of a
cover.
[0037] FIG. 6A shows a cross section view of an assembled anchor
with rotating doors.
[0038] FIGS. 6B-6K show the components of the anchor depicted in
FIG. 6A.
[0039] FIG. 7A shows an alternative embodiment of a mechanism for
retaining the moving members within the cylinder.
[0040] FIG. 7B shows a bottom view of the anchor assembly in FIG.
7A.
[0041] FIGS. 8A-8C show an anchor base of unitary construction.
[0042] FIGS. 8D-8M show various components in various stages of
assembly with the anchor base of FIGS. 8A-8C.
[0043] FIGS. 9A-9C illustrate the use of set screws to lock the
rotating doors in position.
[0044] FIGS. 10A-10J show the use of a tool for placement and
removal of inserts into the rotating doors.
[0045] FIGS. 11A-11D show side views of a tool as it us used to
insert, place, attach and detach inserts into the anchor.
[0046] FIGS. 12A-12C show an alternative embodiment of rotating
doors that are adapted to pass around a placed lead
intraoperatively and snap together.
[0047] FIGS. 13A-13C show an alternative embodiment of the anchor
base which may be used with the doors of FIGS. 12A-12C.
[0048] FIGS. 14A-14E illustrate exemplary embodiments of retaining
members which hold the rotating doors in the anchor base.
[0049] FIGS. 15A-15D illustrate an exemplary embodiment of a
retaining member which retains the rotating doors and the cap.
[0050] FIG. 16 illustrates an exemplary embodiment of an anchor
base with rotating doors that are held in place with a retaining
member.
DETAILED DESCRIPTION OF THE INVENTION
[0051] In the drawings like numerals describe substantially similar
components. Now turning to FIG. 1A is a cross section exploded view
of the anchor assembly, showing the probe 5, cap 200, and cylinder
body 10, also referred to as an anchor base in this application,
assembled with parts that grip the probe. In this embodiment, the
radial tabs 20 are elevated relative to the bottom surface of base
10 so that the cylinder body 10 may be recessed into a craniotomy.
The cylinder 10 is fixed to the cranium by screws which pass
through openings 25 in tabs 20 and secure the tabs to the cranium.
In an alternative embodiment, the cylinder may have ridges,
protrusions or other surface features (not shown) which generate a
friction fit with the wall of the craniotomy, in conjunction with
or in lieu of the radial tabs. Rotating doors 110 and 120 are shown
rotated to a position such that the grip bars 70 are positioned to
grip the probe 5. In the section shown in FIG. 1A, the grip bars 70
are positioned by removable inserts 140 and 150, which in turn are
captured in the doors 110 and 120 by rotating rivets 130. An upper
rivet plate 134 and a lower rivet plate 136 coupled to rivet 130
help lock the inserts into position. A ring-like spacer 16
separates doors 110 and 120. The cap 200 has legs or pins 220 with
catches 225 which snap into receiving sockets 40 within the
cylinder 10. The receiving sockets 40 not only provide fixation for
a cap, but also provide a site and mechanism for attaching other
instruments to the device. Examples of other devices that could be
attached thereto include positioning guides or other reference
instruments commonly used during neurosurgery.
[0052] The grip bars 70 may be made of a soft material, for example
an elastomer, such as silicone rubber, polyurethane, or
Santoprene.TM., or they may be made of the same material as the
doors. Grip bars 70 may be porous or have holes running through
them to make them compressible. Pores could be produced by many
methods, including gas bubbles forming during the curing process,
dissolving filler materials, or by withdrawing filaments introduced
at the time the bars are formed or molded. During implantation, the
probe 5 is placed intracranially, and the rotating doors 110 and
120 are rotated to place the grip bars 70 against the probe 5. The
probe 5 is bent to course along a groove 30 on the superior surface
of the cylinder 10, and onto the surface of the cranium. The cap
200 is then lowered so that pins of the cap 220 are inserted into
sockets of the cylinder 40, and the cap presses against the probe
5. In some embodiments, a groove in the cap 210 wraps around the
probe 5. As the cap is lowered, pins 220 and protrusions from the
pins 225 are displaced towards the center of the cylinder by
catches 45, until the protrusions snap outward under the catches,
retaining the cap. In other embodiments, the cap may have an
elastomeric gasket shaped so as to seal the space between the cap
and the base, except for allowing passage for the probe through one
set of grooves 30 and 210. In other embodiments, the elastomeric
gasket shall leave all sets of grooves open, and the unused probe
passages are filled with separate plugs with radial dimension
similar to the probe.
[0053] FIG. 1B shows the embodiment of FIG. 1A with the probe 5
positioned intracranially, and the cap 200 snapped into the closed
position. In this embodiment, the tabs 20 are elevated so that
cylinder 10 may be recessed in the craniotomy allowing the top of
the cylinder to be substantially level with the cranium. Such an
embodiment has the advantage that the top of the cap extends
minimally above the cranium.
[0054] FIG. 1C shows an alternative embodiment of the assembly
shown in FIGS. 1A-1B, in which the cylinder 10 is partially
recessed into the cranium. FIG. 1D shows an alternative embodiment
of the assembly shown in FIGS. 1A-1C, in which the tabs 20 are
positioned so that the lower surface of the cylinder 10 is at the
level of the outer surface of the cranium. Such an embodiment has
the advantage that the craniotomy opening need only be as large as
the inner lumen of the cylinder 10. The rotating door grip
mechanism provides the particular advantage that if the probe 5 is
inserted through the center of the device as shown in FIG. 1B, the
doors may be rotated together, thereby rotating the probe while
still retaining vertical fixation.
[0055] FIG. 1E illustrates the anchor base or cylinder 10 attached
to a patient's cranium C. In FIG. 1E, anchor 10 is positioned over
a craniotomy so that a portion of the anchor fits within the
craniotomy opening in order to reduce the portion of anchor 10
protruding out of the patient's cranium C. Fixtures F such as
screws removably couple the anchor 10 to the cranium and a lead 5
is place through the central opening of the anchor 10 into the
patient's brain B. A cover 200 may then be snap fit into engagement
with the anchor 10, thereby capturing the lead 5 in a desired
position.
[0056] FIG. 2A shows the lower rotating door 120, apart from the
rest of the anchor. The door is a disk with a large cutout 122
within its interior. Along one edge of the cutout is a bar 70 which
can grip the probe placed in an intracranial position. Near the bar
is a ledge depressed into the door 80 into which a gripping insert
can be placed. The insert is retained from movement towards the
open portion of the disk by terminating the depression at two stops
85. FIG. 2B shows both rotating doors overlayed, with the both
rivets 130 in the open position and both inserts removed. In this
configuration a relatively large opening in the center of the
anchor is available for the probe or any related test or accessory
instrumentation.
[0057] FIG. 2C shows the upper rotating door 110 with the rivet 130
in the closed position, and gripping insert 140 in place. The upper
door also has a cutout 112, a gripping bar 70 and a place for
seating the insert. The insert 140 rests on the depressed ledge 80.
Motion of the insert towards the open part of the door 140 is
prevented by the stops 85, as in the lower door. Motion of the
insert up out of the ledge, or rotation of the insert out of the
ledge is prevented by the rivet 130. The upper plate of the rivet
134 is a partial disk. When it is in the closed position, as shown
in FIG. 2C, the upper plate covers the edge of the insert, so that
it is locked into place on the depressed seating ledge 80. When it
is open, the insert may be removed. The upper plate has three
sockets 132 which may accept prongs from an insertion and removal
tool, in order to rotate the rivet. A lower plate of the rivet 136
is similar to the upper plate 134 and also helps hold the insert.
Lower plate 136 may be seen in FIG. 1A.
[0058] FIG. 2D shows a side view of the two rotating doors 110,
120, with the inserts 140, 150 in place, and the rivets in the
closed position. When the rotating doors 110, 120 are rotated, the
inserts are pushed toward each other by their corresponding doors.
FIG. 2E shows the two rotating doors 110, 120 overlayed, with the
inserts locked in place by the rivets 130. FIG. 2F also shows the
two rotating doors overlayed, with the inserts removed and the
doors opened to their maximum aperture. FIG. 2G shows both top and
side views of the two inserts 140 and 150. The head or top portion
164 of insert 150 along with the head or top portion 162 of insert
140 is seen in the side view of FIG. 2G. The divots in the inserts
165, 166 accommodate the rivets. When the rivets are rotated into
the closed position, the tails of the inserts 160 fit between the
head of the rivet 134 and the seating depression in the rotating
door 80. When the inserts are in place, their grip bars 70 are
continuous with the grip bars of the rotating doors. The tails of
the inserts 160 sit in recessed ledges 80 in the rotating
doors.
[0059] FIGS. 3A-3F show alternative embodiments of the grip bars
70, with greater contact between the grip bars and the probe
compared to the embodiment shown in previous Figures. Only views
from above are shown. In FIG. 3A, the grip bars are scalloped to
conform to the shape of the probe, and the spacing between scallops
is less than the diameter of the probe, allowing many prospective
positions where the probe could be placed. In FIG. 3B, the grip
bars are also scalloped, but with a shape complementary to the
shape in FIG. 3A. This shape generates as many prospective
positions as the shape in FIG. 3A, but instead of apposing the
probe with conforming surfaces, this shape contacts the probe at 4
points, compared to two points in the embodiment shown in the other
Figures. In FIG. 3C, the grip bars completely surround the probe,
generating fewer prospective fixation positions compared to the
embodiments of FIGS. 3A-3B. In FIG. 3D, thin flanges or resilient
fingers protrude from the grip bars, such that the flanges from one
grip bar are out of phase or alternate with the flanges from the
other grip bar. FIGS. 3E-3F are similar to the embodiment of FIG.
3D, except that the flanges on opposite grip bars are in phase with
one another so that they oppose each other, rather than the out of
phase or alternating pattern seen in FIG. 3D. FIG. 3E has longer
flanges, while FIG. 3F has shorter flanges. These different
embodiments illustrate examples of how the contact area of the grip
bar with the probe may be increased compared to the embodiments
shown in the other Figures.
[0060] FIGS. 4A-4F show alternative embodiments of the grip bars
70, with one or both grip bars attached directly to the rotating
door 110, 120, without an insert or the possibility of removing a
portion of the grip bar 70. In FIGS. 4A-4D, the grip bars are
centered on a plane between the rotating doors, as in FIG. 2D,
while in FIGS. 4E and 4F, the grip bars 70 are centered in the
planes of their respective rotating doors. When the grip bars are
centered on a plane between the rotating doors, they do not
transmit a bending moment to a probe inserted parallel to the axis
of the cylindrical anchor body, while the embodiment in FIGS. 4E-4F
the grip bars could potentially transmit a bending moment to such a
probe.
[0061] FIGS. 4A-4B show an embodiment with an upper rotating door
110 similar to the embodiments shown in FIGS. 2A-2G, while the
lower rotating door has no insert, and its grip bar is one
continuous member. FIG. 4A shows the rotating doors in position to
grip the probe, while FIG. 4B shows the rotating doors opened to
their maximum aperture. The maximum aperture of this embodiment is
nearly the same as the maximum aperture illustrated in FIG. 2F,
except near the center of the cylinder.
[0062] FIGS. 4C-4D, show an embodiment in which neither rotating
door has an insert, and both grip bars are single, continuous
members. FIG. 4C shows the rotating doors in position to grip the
probe, while FIG. 4D shows the rotating doors opened to their
maximum aperture. In this embodiment, the maximum aperture is
smaller than in the embodiments of FIGS. 2A-2G and FIGS. 4A-4B.
[0063] FIGS. 4E-4F show an embodiment in which neither rotating
door has an insert, and both grip bars 70 are single, continuous
members, as in FIGS. 4C-4D. FIG. 4E is a cross section view, which
shows that in this embodiment the grip bars 70 are centered in the
plane of their respective rotating doors. FIG. 4F shows that the
maximum aperture of this embodiment is wider than any of the other
illustrated embodiments, except near the center.
[0064] In other embodiments, the grip bars could be attached
directly to the rotating doors for their full length, without any
inserts or rivets. It will be obvious to those skilled in the art
that many other specific forms are possible.
[0065] FIG. 5A shows a top view of the cylinder or anchor base 10,
without the rotating doors. The anchor is fixed to the cranium by
screws through screw-holes 25 in radial tabs 20. A relatively short
set screw 50 inserts into a threaded hole 56 to impinge upon the
upper rotating door 110, (not shown) and lock it into place. A
relatively long set screw 52 having a flat point 51 inserts into a
threaded hole 56 to impinge upon the lower rotating door 120, (not
shown) and lock it into place. Another relatively long set screw 54
having a cone point 55 inserts into a threaded hole 56 to impinge
upon both rotating doors 110 and 120 (not shown) and lock them into
place. In the illustrated embodiment, screws 50 and 52 have a flat
tip, and impinge upon the outer upper corner of the rotating doors,
while the screw 54 has an angled tip, and impinges upon the flat
edge of both rotating doors. Receiving sockets 40 having catches 45
are adapted to receive the cap thereby snap fitting the two
components together. Additionally, grooves or channels 30 radially
extend outward from anchor 10 and provide a channel for holding the
lead when the lead is captured between the anchor 10 and the
cap.
[0066] Alternatively, one of the rotating doors could be held in
place by a one-way ratcheting mechanism. In such an embodiment, a
no-back pawl is a beam integrated with the anchor cylinder, in the
plane of one of the rotating doors. The outer edge of the
corresponding rotating door has the gear teeth. The pawl permits
the gear teeth to pass freely in the direction which moves the grip
bar 70 towards the probe, closing the door, but prevents the
rotating door from opening Such an embodiment makes fixing the
doors faster, as only one set screw must be tightened, yet still
permits the opening between the doors to be adjusted to any angular
position, multiple times if necessary.
[0067] FIG. 5B shows a cross section view of the cap 200. It is
dome shaped. Three pins 220 protrude downward, one of which is
visible in this view. FIG. 5C shows a bottom view of the cap. The
shape is a dome, truncated adjacent to pins 220 which protrude
downward to snap into sockets 40 in the cylinder 10. The
dome-shaped disk is truncated adjacent to the pins so that a tool
may be inserted into the socket 40, alongside a pin 220 to
facilitate removing the cap 200 when necessary. In the preferred
embodiment, grooves 210 in the cap 200 increase the area of the cap
200 contacting the probe, compared to grooveless embodiments. FIG.
5C shows a bottom view of cap 200 highlighting grooves 210 and pins
220.
[0068] Initially the probe is gripped by the rotating doors and
fixed into position. The probe is then bent to lay in grooves 30 on
the upper surface of the cylinder. The cap is lowered, with pins
220 sliding into sockets 40 and protrusions 225 from the pins
snapping into place under catches 45. When the cap is snapped in
place, it presses upon the probe. In the preferred embodiment,
grooves in the cap 210 increase the surface area of the cap in
contact with the probe, increasing stability and decreasing point
pressure on the probe.
[0069] FIGS. 6A shows an exemplary embodiment of an anchor base
assembled with all of its components. FIGS. 6B-6K show the various
components of the assembly in FIG. 6A. In FIG. 6A, the anchor base
is composed of upper 12 and lower 14 portions. In the illustrated
embodiment, radial tabs 20 are attached to the upper portion 12 of
the cylinder 10, so that the cylinder may be recessed into the
craniotomy opening In other embodiments the tabs may be attached to
the lower portion 14 of the cylinder 10. A shelf 26, which retains
the moving members within the cylinder, is integrated into the
lower portion of the cylinder 14. The upper portion 12 of the
cylinder is the more massive, because it must contain the threaded
holes 56 for the set screws (seen in FIG. 6B). Within the cylinder
the upper 110 and lower 120 rotating doors are separated by a
spacer ring 16. The upper 12 and lower 14 portions of the cylinder
are attached by an adhesive. In alternative embodiments, the base
could be attached by welding or other mechanism of plastic
deformation, by screws or other mechanisms which will be obvious to
those skilled in the art. FIG. 6B shows the upper 12 portion of the
anchor assembly while FIG. 6C shows a cross-section take along line
6C-6C and FIG. 6D shows a cross section taken along line 6D-6D.
FIG. 6E shows the upper door 110 with insert 140 and rivet 130 that
is positioned in the upper 12 portion of the anchor assembly. A
spacer ring 6F is then positioned next in the anchor assembly and a
cross section of ring 16 taken along line 6G-6G is shown in FIG.
6G. Next lower door 120 with rivet 130 and insert 150 is loaded
into the anchor assembly. The lower 14 portion of the anchor base
is seen in FIG. 61. When the lower portion 14 is fastened to the
upper 12 portion, the upper and lower doors 110, 120 and spacer 16
are captured therebetween. FIG. 6J shows a cross section of lower
portion 14 taken along line 6J-6J and FIG. 6K shows a cross section
of lower portion 14 taken along line 6K-6K.
[0070] FIGS. 7A-7B show an alternative embodiment of assembling the
anchor employing a plurality of pins 17 penetrating the anchor
cylinder wall, and extending beneath the lower rotating door 120.
The pins course through narrow channels 18 in the cylinder wall.
Together, the pins provide a support that retain the moving members
within the cylinder. FIG. 7A shows a cross section of the anchor
assembled with all of its components and FIG. 7B shows a bottom
view of the anchor base with channels 18. It is clear to those
skilled in the art that this embodiment may be combined with the
embodiments shown in FIGS. 6A-6I and FIGS. 8A-8M. In embodiment of
FIGS. 6A-6I, the pins would provide the additional advantage of
helping to retain the base of the cylinder. In the embodiment of
FIG. 5, the pins provide further support for the moving members
around the cutout that facilitates insertion of the rotating doors
28.
[0071] FIGS. 8A-8M show an alternative embodiment of an anchor
assembly employing a different assembly method. In this embodiment,
the body of the cylinder is monolithic. The bottom of the cylinder
has a shelf 26 which retains the moving members. One side of the
shelf is cut away 27 so that the rotating doors may be inserted
from below during assembly. Such an embodiment is most compatible
with a cylinder body which recesses into the craniotomy, because in
such embodiments the slot is not impeded by the radial attachment
tabs 20. To assemble this embodiment, the upper rotating door 110
is slid into the central chamber of the cylinder. Next, the spacer
16 is inserted below the upper rotating door. Finally, the lower
rotating door 130 is inserted. One side of the bottom of the
cylinder is cutout 28 to facilitate sliding the rotating doors and
the spacer parts into the center of the cylinder. The rivets 130
may be attached to the rotating doors in sequence after each is
inserted into the central chamber, or after both rotating doors
have been inserted. The rotating doors may be prevented from
exiting the central chamber by tilting the slot slightly, so that
the final door is strained as it is inserted and then snaps into
place, or by placing one or more pins in the slot opening so as to
constrain the motion of the lower door to rotational motion only.
Alternatively, in both of these embodiments, an extended shelf may
be fixed in the entry slot. FIG. 8A shows the anchor base that
holds the upper 110 and lower 120 rotating doors. FIG. 8B shows a
cross section of the anchor base of FIG. 8A taken along line 8B-8B
and FIG. 8C shows a cross section of the anchor base taken along
line 8C-8C. FIG. 8D shows the bottom of the anchor base and FIG. 8E
shows the anchor base after upper door 110 has been inserted into
the base. FIG. 8F shows the anchor base after both upper 110 and
lower 120 doors and spacer 16 have been loaded into the anchor
base. FIGS. 8G-8L illustrate the sequence of loading components
into the anchor base during assembly and FIG. 8M shows the
assembled anchor.
[0072] FIGS. 9A-9C show cross section views, illustrating how set
screws can be positioned in three different positions, so as to
impinge on the upper rotating door 110 alone, lower rotating door
120 alone, or on both rotating doors 110, 120 simultaneously.
Exemplary embodiments are shown, illustrating how the rotating
doors may be fixed with standard set screws. Small diameter screws,
such as 0-80, are appropriate for this application, because the
cylinder body 10 is thin. A thin body 10 is desired so that it does
not protrude much above the surface of the cranium.
[0073] FIG. 9A shows a set screw 50 positioned to fix the upper
rotating door 110. In this embodiment, a flat set screw is used.
The tip of such a screw typically has a wide flat surface
orthogonal to the screw's axis of symmetry, bounded by a narrow
conical ring 51. When the screw is deployed with its long axis
tilted at approximately 30 degrees from horizontal, one edge of the
conical ring is nearly parallel to the outer edge of the upper
rotating door 110. As the screw is tightened, the conical ring 51
impinges upon the outer edge of the upper rotating door, but away
from the lower rotating door 120.
[0074] FIG. 9B shows a similar set screw 52 positioned to fix the
lower rotating door 120. This screw is similar to the upper door
fixation screw 50, except that it is longer. FIG. 9C shows a set
screw 54 positioned so as to impinge upon both rotating doors 110
and 120 simultaneously. In this embodiment a cone-point set screw
is illustrated. Such a set screw has a wide conical ring 55
terminating at the tip of the screw, with a tip angle of
approximately 118 degrees. When the screw 54 is deployed with its
long axis tilted approximately 60 degrees from horizontal, it fixes
both rotating doors.
[0075] FIGS. 10A-10J show an insertion tool 300 with handle 350 for
placement and removal of inserts 140 and 150 into the rotating
doors 110 and 120. FIGS. 10A-10F show portions of the tool 300 from
several views. A side view of the tool is seen in FIGS. 10A-10C and
the tool is seen from a top view in FIGS. 10D-10F. FIGS. 10A and
10D show only the lowest portion, which interfaces directly with
the insert, rotating door, and upper plate of the rivet. An
orienting edge 320 at the bottom of the tool is complementary to
the shape of the upper plate of the rivet 134. Tabs 310 at the
bottom of the tool fit precisely into matching sockets 132 in the
upper portion of the rivets. In an alternative embodiment of the
tool and the top of the rotating rivet, the tabs 310 are slightly
larger at their lower most position, and/or the sockets 132 are
narrower at their upper most position, to facilitate a snap fit of
the tool with the rivet rotor.
[0076] FIGS. 10B and 10E show a platform 340 at the base of the
insertion/removal tool. The platform forms a bridge between the
small features and tight tolerances of the components shown in
FIGS. 10A-10B, and the grip or handle 350 through which the surgeon
applies torque, is shown in FIGS. 10C and 10F. In the embodiment
illustrated, the grip 350 is a hexagonal post with an angled
handle, which may be turned digitally or with a wrench. In other
embodiments, the grip may take another form, for example, a cap
screw. In another embodiment, it could be a cylindrical post, with
one or a plurality of radial holes into which a lever arm can be
inserted.
[0077] FIGS. 10G-10J show how the tool mates to the upper plate of
the rivet 134 and couples with an insert 150 on lower rotating door
120. The lower portion of the tool has an angled shape 320
complementary to the edge of the upper plate of the rivet 134, to
facilitate alignment of the tool with the rivet, and to apply
torque to the rivet as the tool is rotated. For fine positioning
and additional torque, the tool has tabs 310 which insert into
matching divots in the upper plate of the rivet 132. A curved pin
335 holds an insert 140 or 150 in position next to the tool 300
while the insert is placed into or removed from a rotating door 110
or 120. A bulge 330 is provided for mounting the pin 335. This
mounting bulge 330 is positioned so that it does not impinge upon
the upper portion of the insert 140 as the tool is rotated.
[0078] FIGS. 11A-11D show the tool and insert through the cycle of
positioning, attachment and detachment. In FIG. 11A, two insertion
tools are above the anchor, and the inserts are seated in the
rotating doors, retained by the rivets. In FIG. 11B, the tools are
lowered to a position adjacent to the upper portion of the rivets
134 and the inserts 140 and 150. The inserts are seated in the
rotating doors, retained by the rivets. In FIG. 11C, the tools have
been rotated as indicated by the double headed arrows, so that the
holding pins retain the inserts to the bottom of the insertion
tools. The rivets no longer retain inserts. In FIG. 11D, the
inserts 140 and 150 are retained against the insertion tools by the
holding pins 335 and lifted away from the rotating doors. The lower
surface of the insertion tool fits into divots 165 and 166, (not
shown) in the inserts, so that the insert has a definite position
relative to the insertion tool. The rotating doors and rivets lie
below the tool as the tool is lifted away.
[0079] FIG. 12A-12C show an exemplary embodiment of the rotating
doors adapted for intraoperative assembly. In FIG. 12A the rotating
doors 110 and 120 have gaps 71 positioned so that they can be
passed around an indwelling medical lead and placed in a receiving
anchor base. The gaps 71 may be positioned as in FIG. 12B, so that
the doors may be passed around the lead in a single movement.
Intraoperative handling is facilitated by holes 74 in the doors.
Once inserted into the receiving base, the doors can be rotated as
in FIG. 12C in order to grip the medical lead. A snap mechanism can
operate whereby a protrusion or detent from one door 73 lodges into
a cavity 72 on the other, so as to maintain the doors in apposition
against the lead.
[0080] FIGS. 13A-13C show exemplary embodiments of the anchor base
10 and cap 200 adapted for intraoperative assembly with doors such
as shown in FIGS. 12A-12C. In the exemplary embodiment of FIG. 13C,
base 10 has two tabs 20 for attachment to the cranium, but the
number of tabs may be modified as required. The doors pass around
the lead, and they are placed so that the lower door rests upon a
shelf 26, and the upper door rests upon the lower door. A retaining
member, such as those illustrated in FIGS. 14A-14E may optionally
be inserted interfacing with an annular groove 41 in such a way as
to partially occlude the lumen of the base 10 and prevent removal
of the rotating doors. Two embodiments of the cap 200 are shown in
FIG. 13A and 13B, with pins 220 placed so that the cap 200 can be
attached to the base 10 by protrusions 225 from the pins 220 into
the annular groove 41. In the embodiment of FIG. 13B, cavities 226
are placed in the cap 200, so as to extend the effective length of
the pins 220 and control the strain of the pin and mating forces,
as will be familiar to those skilled in the art. The annular groove
41 can also be a point of attachment for additional instruments
used intraoperatively such as a positioning guide or other
reference instruments often used during neurosurgery. The retaining
member may similarly be modified to permit attachment of other
instruments used intraoperatively. The base 10 and cap 200 could
optionally have features to force a particular alignment of the cap
and base. For example, a pin may extend from the cap and seat in a
groove on the base.
[0081] FIGS. 14A-14E show several exemplary embodiments of a
retaining member which may be placed intraoperatively, so as to
hold or retain the doors within the base. All of these embodiments
include a hole feature to facilitate manipulation of the member.
One embodiment 400 is a conventional retaining ring, as will be
well familiar to those skilled in the art and this is seen in FIG.
14A. In FIG. 14B, retaining member 410 includes a member 415 to
increase the security of placement of the retention member.
Additional security may be desirable if mounting features for a cap
or intraoperative instruments are added to the retention feature.
In FIG. 14C, the retaining member 420 occupies half, more or less,
of the annular groove, so as to generate less interference with a
medical lead placed in the lumen of the base. In FIGS. 14D and 14 E
the ends of retaining members 430 and 440 interface with a groove,
such as 41 of FIG. 13C, but the body of these retaining members
cross through the lumen of the base. Such disposition of the body
of the retaining member keeps the groove free to accept other
attachments. Retaining member 430 passes straight across, while
retaining member 440 curves away from the center, so that it is
clear of the center during placement. The depictions of retaining
members 430 and 440 also include material 450 above the plane of
the annular groove. Such material may be arranged so as to
strengthen or stiffen the retaining member, or to interface with
other parts.
[0082] FIGS. 15A-15D show an embodiment where retaining member 460
has pins 220 extending in such a way that they could snap into the
cap 200 and thereby attach it to the base 10. FIG. 15A is a
perspective view of the anchor base 10 with retaining member 460
and cap 200 assembled together. FIG. 15B shows cap 200 and FIG. 15C
shows the retaining member 460. Anchor base 10 is seen in FIG. 15D.
FIG. 16 is a perspective view of anchor base 10 with the doors 110
and 120 and retaining member 440 assembled together. The retaining
member 440 scats into an annular groove 41, but its body is within
the center of the base, leaving much of the groove 41 clear.
[0083] While the exemplary embodiments have been described in some
detail for clarity of understanding and by way of example, a
variety of additional modifications, adaptations and changes may be
clear to those of skill in the art. Hence, the scope of the present
invention is limited solely by the appended claims.
* * * * *