U.S. patent application number 10/992382 was filed with the patent office on 2005-06-30 for gastrointestinal anchor with optimal surface area.
Invention is credited to Imran, Mir A..
Application Number | 20050143784 10/992382 |
Document ID | / |
Family ID | 46205399 |
Filed Date | 2005-06-30 |
United States Patent
Application |
20050143784 |
Kind Code |
A1 |
Imran, Mir A. |
June 30, 2005 |
Gastrointestinal anchor with optimal surface area
Abstract
A device, system and method for anchoring a device to a stomach
is provided. The device may be, among other things, a sensor for
sensing various parameters of the stomach or stomach environment,
or may be a therapeutic delivery device. The anchor of the device
is constructed to resist pull out forces. An anchor has an optimal
weight to surface area ratio.
Inventors: |
Imran, Mir A.; (Los Altos
Hills, CA) |
Correspondence
Address: |
Susan M. Schmitt
Peters, Verny, Jones & Schmitt LLP
Suite 230
425 Sherman Avenue
Palo Alto
CA
94306
US
|
Family ID: |
46205399 |
Appl. No.: |
10/992382 |
Filed: |
November 18, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10992382 |
Nov 18, 2004 |
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10295115 |
Nov 14, 2002 |
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10295115 |
Nov 14, 2002 |
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09847884 |
May 1, 2001 |
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6535764 |
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Current U.S.
Class: |
607/40 ;
604/175 |
Current CPC
Class: |
A61B 17/3478 20130101;
A61B 2017/306 20130101; A61M 25/02 20130101; A61M 2025/0233
20130101; A61N 1/0517 20130101; A61B 2017/00026 20130101; G01N
27/126 20130101; A61B 2017/3488 20130101; A61M 2025/028 20130101;
A61N 1/36007 20130101; A61N 1/372 20130101; A61F 5/0003 20130101;
A61B 17/3421 20130101; A61B 2017/00477 20130101; A61N 1/0509
20130101; A61B 2017/00084 20130101; A61B 2017/00017 20130101; A61B
5/4238 20130101; A61B 2017/00004 20130101; A61B 5/6882
20130101 |
Class at
Publication: |
607/040 ;
604/175 |
International
Class: |
A61N 001/08 |
Claims
What is claimed is:
1. An anchor for attaching to a gastrointestinal tract wall
comprising: a first portion configured to interface with the
gastrointestinal tract wall; and a second portion coupled to the
first portion wherein the first portion has a surface area
interfacing with the gastrointestinal tract wall and wherein the
second portion has a weight creating a load borne by the first
portion interfacing the gastrointestinal tract wall wherein the
ratio of the weight to surface area is less than about
5g/mm.sup.2.
2. The anchor of claim 1 wherein the ratio is less than about 1
g/mm.sup.2
3. The anchor of claim 1 wherein the ratio is less than about 0.1
g/mm.sup.2.
4. The anchor of claim 1 wherein the first portion comprises a
plurality of interfacing portions having interfacing surface areas
and wherein the surface area of the first portion comprises the sum
of each of the surface areas of the interfacing portions.
5. The anchor of claim 4 wherein the ratio is less than about 1
g/mm.sup.2.
6. The anchor of claim 4 wherein the ratio is less than about 0.1
g/mm.sup.2.
7. The anchor of claim 1 wherein the anchor is configured to be
attached to the stomach wall.
8. The anchor of claim 7 wherein the anchor is configured to be
attached to the antrum of the stomach.
9. The anchor of claim 7 wherein the second portion comprises an
electrical stimulator.
10. The anchor of claim 7 wherein the second portion comprises an
electrode configured to be attached to the stomach wall.
11. The anchor of claim 10 wherein the electrode is configured to
be attached to the stomach wall with the first portion.
12. The anchor of claim 1 wherein the first portion comprises an
expandable distal portion having an interfacing surface area for
interfacing the gastrointestinal wall, and wherein the surface area
of the first portion comprises the interfacing surface of the
expandable distal portion.
13. The anchor of claim 12 wherein further comprising a proximal
elongate member coupled to the distal portion configured to extend
through the gastrointestinal tract wall.
14. The anchor of claim 13 wherein the proximal elongate member is
configured to extend through the gastrointestinal wall in a
substantially perpendicular direction with respect to the wall.
15. A anchor for attaching to a stomach wall comprising a first
means for interfacing with the stomach wall to bear a load from a
second means and a second means for treating or diagnosing a
portion of a gastrointestinal tract wherein the first means has a
surface area and the second means has a weight, and wherein the
weight has a ratio to the surface area of less than about 5
g/mm.sup.2.
16. The anchor of claim 15 wherein the ratio is less than about 1
g/mm.sup.2.
17. The anchor of claim 15 wherein the ratio is less than about 0.1
g/mm.sup.2.
18. A method for attaching a device to a gastrointestinal tract
wall comprising: providing an anchor comprising a first expandable
portion, an elongate portion and a device portion; positioning the
elongate portion through a gastrointestinal tract wall wherein the
first portion is expanded to interface and engage a
gastrointestinal tract wall on a first side of the gastrointestinal
tract wall and so that the device portion is positioned on an
opposite side of the gastrointestinal tract wall from the first
portion; and wherein the expandable portion has an interfacing
portion with a surface area interfacing the gastrointestinal tract
wall and the device portion and elongate member have a weight
creating a load between the stomach wall and the interfacing
portion wherein the weight has a ratio to the surface area of less
than about 5 g/mm.sup.2.
19. The method of claim 18 wherein the ratio is less than about 1
g/mm.sup.2.
20. The method of claim 18 wherein the ratio is less than about 0.1
g/mm.sup.2.
21. The method of claim 18 wherein the step of positioning the
elongate portion through the gastrointestinal tract comprises
positioning the elongate portion through a stomach wall.
22. The method of claim 21 wherein the step of positioning the
elongate portion through a stomach wall comprises positioning the
elongate portion through the stomach wall at a contractile region
of the stomach.
23. The method of claim 18 wherein the device further comprises a
stimulator coupled to the anchor; and further comprising the step
of stimulating the gastrointestinal tract.
Description
RELATED APPLICATION DATA
[0001] This application is a continuation in part of U.S.
application Ser. No. 10/295,115, filed Nov. 14, 2002, which is a
divisional of U.S. application Ser. No. 09/847,884 filed May 1,
2001 all of which are incorporated herein by reference.
FIELD OF THE INVENTION
[0002] This invention relates to an anchor for attaching a device
to the stomach.
BACKGROUND OF THE INVENTION
[0003] Attaching devices to the stomach has a number of challenges
including avoiding detachment, for example, due to the contractions
of the stomach dislodging the device. In particular, attaching
device to the inside of the stomach wall has been challenging for a
variety of reasons. The inside of the stomach is highly acidic and
the stomach wall tends to remodel making it difficult to retain a
device attached to the stomach wall. Attaching a device to the
stomach becomes more difficult where the stomach is more active or
contractile, for example, in the antrum region. Also the purpose of
the stomach muscle contractions and acidic stomach environment is
to breakdown and grind its contents.
[0004] A machine that places a nylon tag has been proposed for
attaching a "payload" to the inner wall of a stomach in C. Paul
Swain, et al, An Endocopically Deliverable Tissue-Transfixing
Device For Securing Biosensors in The Gastrointestinal Tract,
Gastrointestinal Endoscopy 40/6:730-734 (1994). The machine places
the tag through the stomach wall and back into the stomach in a
manner that causes folding and may cause tissue damage when the
smooth muscle of the stomach wall contracts. The tag may pull out
of the stomach at least in part because of the small surface area
of the end of the nylon tag where the load, tension or forces are
concentrated. U.S. Pat. No. 6,689,056 discloses a probe for
monitoring physiological parameters in the gastrointestinal tract
that is attached to the inside of the gastrointestinal tract with a
pin passing perpendicular through the mucosa. This construction is
believed to be inadequate to retain a device attached to the
stomach for a substantial amount of time, particularly in a more
contractile region of the stomach, for example, the antrum. It
would be therefore be desirable to provide an attachment device for
attaching a device within the stomach wall that will not erode
through a stomach wall over a desired treatment time.
SUMMARY OF THE INVENTION
[0005] The present invention provides a device, system and method
for attaching an anchor to the stomach wall. The device includes an
anchor that distributes forces on the anchor over a large surface
area. One aspect may include such device, system or method wherein
the anchor is attached to the stomach wall and resides within the
stomach. The anchor may be positioned on one side of a stomach wall
and extend through the stomach wall to an opposite side of the
stomach wall wherein it is coupled to a functional portion, e.g., a
diagnostic or therapeutic portion or device. One aspect of the
anchor provides an attachment mechanism configured to attach a
device to a highly contractile portion of the stomach for a
relatively long term use.
[0006] In accordance with one aspect of the invention, the anchor
distributes the load of the device on the stomach wall. According
to the invention, the load to surface area distribution of the
anchor is less than about five (5) grams per mm.sup.2 and
preferably less than about one (1) gram per mm.sup.2. Accordingly,
to an embodiment of the invention, the load is distributed
relatively evenly on a surface area. However, it is contemplated
that such load distribution may include an unevenly distributed
load that has the same general effect of bearing the load of the
anchor such that the anchor is less likely to erode through or
dislodge.
[0007] In one variation the device comprises an electrical
stimulator anchored in accordance with the invention. Electrical
stimulation is generally defined herein to mean any application of
an electrical signal or of an electromagnetic field to tissue of
the stomach for a therapeutic purpose. In one variation, the device
is designed to facilitate or expedite mixing or breaking down of
food matter or liquids in the stomach. In another variation, the
device is designed to control, facilitate or expedite movement of
food matter or liquids through the stomach and into the small
intestine. In another variation, the device is designed to
stimulate the stomach to delay passage of food from the stomach and
into the small intestine. Other stimulation effects are also
contemplated, including but not limited to using stimulation to
treat nausea, obesity or pain symptoms. The stimulation may affect
the smooth muscle contractions and/or nerves associated with the
stomach.
[0008] The stimulating (or diagnostic) device of the present
invention may reside within the patient's stomach. However, it is
also contemplated that the device reside outside the stomach wall
or may be attached to any other portion of the gastrointestinal
tract, e.g., the esophagus, the small bowel, or the large bowel. A
preferred device includes: at least one stimulating electrode in
electrical contact with the stomach wall; an electronics unit
containing the electronic circuitry of the device; and an
attachment mechanism for attaching the device to the stomach wall.
One or more stimulating electrodes may be secured to the wall of
the stomach by the attachment device. One or more stimulating
electrodes may also be located on the electronics unit that is
attached to the stomach wall with an anchor. In a preferred
embodiment, at least one stimulating electrode is embedded in the
wall of the stomach. The stimulation may be provided through at
least one pair of bipolar electrodes or with a monopolar and return
electrode.
[0009] An attachment device may be either integrally formed with
the electronics unit or removably attachable to the electronics
unit. The attachment device and electronics unit may be deployed in
two steps: first by identifying a site for attachment and attaching
the anchor and second by attaching the electronics unit. The
electronics unit may be removable from the attachment device and or
deployed electrodes so that the electronics unit may be replaced
after time. The stimulating electrodes may be coupled to the
attachment device and/or the electronics unit. The attachment
device may include a release mechanism for easy endoscopic removal
of the stimulating device from the stomach.
[0010] The stimulation device may be constructed of size and shape
such that it can be deployed through the mouth and esophagus with
the aid of an endoscope. As such, the electronics unit is
preferably of a generally cylindrical shape. The device components
are constructed of materials that allow it to withstand and
function in the highly acidic environment of the stomach for two or
more years. (The pH in the stomach may be, at times, as low as
1.0). Such materials are relatively inert to the environment. An
example of such materials are: suitable inert polymers, for
example, materials from the Polyolefin family like HDPE (high
density polyethylene), LLDPE (linear low density polyethylene), and
UHMWPE (ultra high molecular weight polyethylene); fluoropolymer
materials like PTFETM (poly tetrafluoroethylene), FEPTM
(fluorinated ethylene propylene) and others; polymethylpentene, and
polysulphons; some elastomers such as thermoplastic polyurethanes
and C-Flex type block copolymers that are stable in acidic
environments. The electrodes are preferably made of corrosion
resistant metals such as, e.g. Platinum, Gold, Tantalum, Titanium
and corrosion resistant alloys or one or more of these metals. The
electronics unit or shell may alternatively be constructed of one
or more of these metals or alloys. Electrodes are preferably
coupled to the electronic circuitry through sealed electrical
contacts or through leads extending into the housing through molded
corrosion resistant materials such as those described above.
[0011] A preferred system of the present invention includes an
endoscopic delivery system for delivering the stimulator through
the esophagus and into the stomach where it is attached the stomach
wall
[0012] Alternatively, the device may be delivered laparoscopically
through the abdomen to the stomach wall.
[0013] In addition to the device being capable of stimulating the
stomach wall, electrodes of a stimulation device may also be used
for diagnostic purposes. For example, the electrodes may be used to
sense and observe electrical activity in the stomach wall. Such
sensing may be used over time to identify patterns, diagnose
diseases and evaluate effectiveness of various treatment protocols.
For example irregular or lack of EMG activity may be sensed.
Stimulation may be provided in response to sensed EMG activity or
lack of activity.
[0014] In one variation, sensors can be included in the device or
separately for sensing various parameters of the stomach. The
sensors may be mounted on the electronics unit, an attachment
mechanism, or by other means, for example, in an independently
attached device for example attached with an anchor. The
stimulation device may include a mechanical sensor that senses, for
example, stomach wall contractions. As the stomach contracts, the
stomach wall typically becomes thicker.
[0015] In an embodiment, a device implanted in the stomach wall
includes a strain gauge that is able to sense change in stomach
wall thickness. Alternatively, electrical sensors may detect
changes in impedance due to changes in wall thickness from smooth
muscle contractions. Other examples of such sensors may include,
for example, pH sensors, impedance sensors, pressure sensors and
temperature measuring devices such as a thermocouple or
accelerometers to determine sleep state.
[0016] The stimulation device may be programmed to deliver
stimulation in response to sensing electrical parameters or other
sensed parameters. For example, a pH or temperature sensor may be
used to determine when food has been ingested.
[0017] When the pH or temperature changes in a manner, indicating
food ingestion, the stimulation device may be instructed to deliver
stimulation pulses to stimulate or reduces or prevents gastric
motility. The device may also be user controlled, where the
recipient of the device is able to externally activate the device,
for example by using an external unit which delivers a control
signal via telemetry. A temperature sensor may be used, for
example, to determine when food has been ingested, by a change in
temperature. The device may begin stimulating the stomach upon
detecting sudden change in temperature. Pressure sensors may be
used to sense motility patterns, e.g. presence, strength or
frequency of contractions. Mean pressure shifts may be observed to
identify fundal contractility. The stimulation device may also use
sensed parameters to program or reprogram the device stimulation
program. For example, measuring impedance changes through a circuit
coupled to the electrodes (e.g., delivering a constant current or
voltage across the electrodes to determine impedance) or
determining the contractile behavior of the stomach using a strain
gauge, in response to stimulation pulses, the effectiveness of the
stimulation pulses may be monitored and adjusted to provide optimal
response. The stimulation program may also include an automatic
adjustment in response to changes in pressure measurement.
[0018] Other diagnostic or treatment devices may be attached to the
inside of the stomach wall, for example using a separate or
integrally formed anchoring device. Preferably such devices are
introduced and attached to the stomach wall endoscopically.
However, a laparoscopically delivered device may be attached with
an anchor according to the invention. Such devices may include, for
example, drug delivery devices, a gastric balloon, sensing or
diagnostic devices. In one embodiment when excessive acid
concentration is sensed using a pH sensor, a device is triggered to
release an antacid drug, e.g., using a drug delivery pump.
[0019] The present invention also provides an attachment device for
attaching a functional device to the stomach wall. The functional
device may be a sensor for sensing various parameters of the
stomach or stomach environment, or may be a therapeutic delivery
device. The devices may be attached to the attachment device in a
separate housing or may be integral with the attachment device. The
functional devices may be powered by a battery included with the
device or the functional devices may be inductively powered. In one
embodiment, the attachment device is attached such that the device
does not substantially constrain the stomach in the plane of smooth
muscle contractions and to minimize stresses in the tissue, to
reduce the potential for tissue damage or device dislodgement.
Preferably the attachment device attaches in a manner that avoids
folding of the stomach wall. In one preferred embodiment, the
attachment device is attached by piercing at least a portion of the
stomach wall at a single point of penetration into the stomach
wall. Also, in one embodiment the attachment device pierces the
stomach wall in a direction perpendicular to the natural
orientation of the stomach wall. Further, in a preferred
embodiment, the attachment device extends through the stomach wall
with a backing mechanism located external to the stomach wall.
Preferably such backing mechanism is relatively atraumatic to the
stomach outer wall and surrounding tissue and has a relatively high
surface area in relation to the width of the attachment device or
puncture hole. In particular the ratio of weight to surface area is
about 5 g/mm.sup.2 or less, preferably about 1 g/mm.sup.2 or less
and more preferably about 0.1 g/mm.sup.2 or less. Another preferred
embodiment provides an adjustable bumper holding the anchor to the
inside of the stomach wall. Such bumper is also preferably designed
to have a relatively high surface area and to be relatively
atraumatic to the stomach wall. Another preferred embodiment
provides an attachment device with a quick release mechanism that
enables relatively easy endoscopic removal of the attachment device
from the stomach.
[0020] Preferred embodiments of various aspects of the invention
are described in the following detailed description.
DETAILED DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 is a partial cross sectional view of a system of a
first embodiment of the present invention in use in placing an
electric stimulator in a patient's stomach.
[0022] FIG. 2 is a partial cross section view, illustrating
placement of an overtube in the first embodiment of the system of
the present invention.
[0023] FIG. 3 is a partial cross sectional view of the placement of
an anchor in the stomach in the first embodiment of the system of
the present invention.
[0024] FIGS. 4-6 are detailed partial cross sectional views
illustrating the placement of the anchor in the first
embodiment.
[0025] FIG. 7 is a side partial cross sectional view of the
proximal end of an endoscope of the inventive system.
[0026] FIG. 8 is a side view of a distal end of the endoscope of
the inventive system.
[0027] FIG. 9 is distal end view of the endoscope of FIGS. 7 and
8.
[0028] FIG. 10 illustrates a partial cut away side elevational view
of an anchor of the first embodiment initially placed in the
stomach wall
[0029] FIG. 11 illustrates a partial cut away side elevational view
of a fully deployed anchor of FIG. 10.
[0030] FIG. 12 illustrates a side elevational view of the main body
of the stimulator of the first embodiment of the present
invention.
[0031] FIG. 13 illustrates a side elevational view of the main body
and anchor of the stimulator where a tether coupled to the anchor
is threaded through an opening in the main body to guide the main
body to the anchor.
[0032] FIG. 14 illustrates a partial cut away side elevational view
of the stimulator of the first embodiment of the present invention
attached to the stomach wall.
[0033] FIGS. 15-17 illustrate respectively the main body of the
first embodiment of the stimulator as it is placed through the
esophagus, into the stomach and connected with the anchor.
[0034] FIG. 18 illustrates a side cross sectional view of the
deployed anchor of FIG. 11.
[0035] FIG. 19 illustrates a side cross sectional view of the main
body illustrated in FIG. 12.
[0036] FIG. 19A illustrates an enlarged view of the latch mechanism
of the main body portion shown in FIG. 19 with the latch in a
closed position.
[0037] FIG. 20 illustrates an end cross sectional view of the main
body illustrated in FIG. 12 with a quick connect in an open,
unlocked position.
[0038] FIG. 20A illustrates an enlarged view of the latch mechanism
of the main body portion shown in FIG. 20 with the latch in an open
position.
[0039] FIG. 21 illustrates an end cross sectional view of the main
body illustrated in FIG. 12 with a quick connect in a closed,
locked position.
[0040] FIG. 22 illustrates a side cross sectional view of the main
body and anchor of the first embodiment locked together.
[0041] FIG. 23 illustrates a side elevational view of the anchor
and main body of a second embodiment of the stimulator of the
present invention.
[0042] FIG. 24 illustrates a side elevational view of the
embodiment of FIG. 23 with the anchor and main body attached.
[0043] FIG. 25 illustrates a schematic diagram of the circuit of an
electronic stimulator of the present invention.
[0044] FIG. 26 illustrates a schematic diagram of the circuit of a
programmer/recorder of the present invention.
[0045] FIG. 27A illustrates a third embodiment of the present
invention showing an alternative anchor as it is inserted through
the stomach wall.
[0046] FIG. 27B illustrates the anchor of FIG. 27A anchored to the
stomach wall.
[0047] FIG. 28A illustrates a fourth embodiment of the present
invention showing an alternative stimulation device.
[0048] FIG. 28B illustrates an enlarged view of an anchor of the
stimulation device of FIG. 28A.
[0049] FIGS. 29A and 29B illustrate an alternative endoscopic
instrument for placing an attachment device through a stomach
wall
[0050] FIGS. 30A and 30B illustrate a fifth embodiment of present
invention in which an anchor is placed using the instruments of
FIGS. 29A and 29B.
[0051] FIGS. 3 1A illustrates a sixth embodiment of the present
invention including an anchor and stimulator
[0052] FIG. 31 B illustrates the anchor and stimulator of FIG. 31 B
attached within the stomach.
[0053] FIG. 32 illustrates a stimulator with an anchor according to
the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0054] Referring to FIGS. 10-14 and 18-22, a stimulator 10 of a
first embodiment is illustrated. The stimulator 10 comprises an
anchor 123 and a main body portion 20. The anchor 123 comprises an
elongate member 124 having and expandable distal end 125 and a
stimulating electrode 126 in the form of a ring of a corrosion
resistant metal conductor such as Platinum, Gold, Tantalum,
Titanium or suitable alloys thereof, extending around the elongate
member 124 just proximal of the expandable end 125. The anchor 123
may be constructed of a radiopaque material. Alternatively, the
anchor 123 may include radiopaque markers located on the device so
that the location and orientation of the device may be identified,
particularly after it has been placed. At least a portion of the
anchor 123 is preferably coated with an antibiotic material, such
as gentamicin sulphate or a silver/silver salts coating,
particularly in locations that it will extend through or come in
contact with the stomach wall. A notch 127 extending around the
elongate member 124 is located proximally of the stimulating
electrode 126, for connecting the anchor 123 to the main body
portion 20, containing the stimulator electronic circuitry 25. An
electrical contact member 128 comprising a corrosion resistant
metal ring extends circumferentially around the elongate member 124
proximal of the notch 127. The electrode 126 and the contact 128
are electrically coupled through a wire 129 or other conductor
extending through the elongate member 124. The proximal end of the
anchor 123 has an opening 130. A tether 131 is secured to the
opening 130. The tether 131 is used to guide the main body portion
20 into place. The tether 131 is also used to pull on the anchor
123 while the main body portion is pushed into place both to
provide a guide and to hold the anchor 123 in place.
[0055] A strain gauge 121 is located on the elongate member 124 of
the anchor 123. The strain gauge 121 is coupled through conductors
121a and 121b to electrical contacts 128a, 128b respectively.
Electrical contacts 128a and 128b are constructed and sealed when
coupled to the main body 20, in a manner similar to contact
128.
[0056] The main body portion 20 comprises a sealed housing 21
including electronic circuitry 25. The electronic circuitry 25
provides sensing, stimulating electronic pulses through the
electrodes to the stomach wall, and telemetry communication with an
external unit such as a reader, recorder or controller. The housing
21 includes an outer shell having a distal face 26 for interfacing
with the stomach wall. The main body 20 also includes a radiopaque
marker 31, preferably a radiopaque stimulator serial number (e.g.,
sprayed onto a location in the housing 21) so that the device and
its location may be identified. The outer shell is constructed of
an acid corrosion resistant material such as a suitable inert
polymer, for example, materials from the Polyolefin family like
HDPE (high density polyethylene), LLDPE (linear low density
polyethylene), and UHMWPE (ultra high molecular weight
polyethylene); fluoropolymer materials like PTFETM (poly
tetrafluoroethylene), FEP.TM. (fluorinated ethylene propylene) and
others; polymethylpentene, and polysulphons; some elastomers such
as thermoplastic polyurethanes and C-Flex type block copolymers
that are stable in acidic environments. Additionally the outer
shell may be constructed of an acid corrosion resistant metal such
as Platinum, Gold, Tantalum, Titanium, or suitable alloys thereof.
The distal face 26 is preferably coated with an antibiotic
material, such as gentamicin or silver/ silver salts coating. The
main body 20 further comprises an electrode 32 located on the
distal face. The electrode 32 is constructed of an acid corrosion
resistant material such as Platinum, Gold, Tantalum, Titanium, or
any suitable alloys thereof.
[0057] The main body portion 20 further comprises a channel 23
through which the tether 131 is threaded for alignment with the
anchor 123 (FIG. 13) and for receiving the elongate member 124 of
the anchor 123 (FIGS. 14 and 22). A second channel 23a extends
parallel to the channel 23 from an opening in the proximal side of
the main body 20 and ending within the main body 20. The second
channel 23a is for receiving a connect/release tool 38 described in
more detail below.
[0058] The channel 23 includes an opening 24 in the distal face 26
of the body portion 20 as well as an opening 22a in the proximal
side 22 of the main body 20. The walls of the channel 23 include a
plurality of acid resistant elastomeric seals 27 formed of a
material such as, for example, polyurethanes, rubbers or C-Flex
type block copolymers. In between the seals 27 is a flexible
electrical contact 28 for contacting the electrical contact 128 of
the anchor 123 and a latch 29 for engaging the notch 127 of the
anchor 123. Thus, the electrical contact 28 will be located in a
sealed area of the channel 23, between seals 27, protecting it from
the highly acidic environment of the stomach. The seals 27 also act
as electrical insulators that prevent unintended current pathways
between the electrical contact 28 and the electrode 32. The
electrical contact 28 is coupled to the electronic circuitry 25 of
the main body portion 20 through a conductor 30 extending from the
circuitry 25 through the housing 21 to the contact 28. The second
stimulating electrode 32 located on the distal face 26 of the main
body 20 is coupled to the electronic circuitry 25 by way of a
conductor 33. As an alternative to being coupled to the electronic
circuitry through a sealed contact, the electrode 126 may be
constructed in a manner similar to electrode 32 using a corrosion
resistant material that is directly coupled to the electronic
circuitry (for example, where the anchor is integrally formed with
the stimulator 10 or where the electrode 26 is located on the
housing).
[0059] As illustrated in FIG. 22, when the main body portion 20 and
the anchor 123 are connected, the elongate member 124 of the anchor
123 extends into the channel 23 so that the notch 127 and the
electrical contact 128 are located between seals 27. The electrical
contacts 128, 128a, and 128b are in contact with flexible
electrical contacts 28, 28a, and 28b respectively, and the latch 29
is located within the notch 127 so that the elongate member 124 of
the anchor 123 is fixed within the main body portion 20.
[0060] FIGS. 19-21 show the latch mechanism 29 in the main body 20
that is used to connect the main body 20 to the anchor 123. The
latch 29 is located within a closed channel 34 in the main body 20
that is oriented perpendicular to the channels 23 and 23a. A spring
member 36 is located at the end 35 of the closed channel 34 between
the end 35 and the latch 29. The spring 36 biases the latch 29 in a
closed position as illustrated in FIG. 20 and described below. The
latch 29 comprises a connecting end 29a that extends into the
channel 23 when the latch 29 is in its closed position. The latch
29 further comprises an opening 29b formed in part by a cam surface
29c ending in tip 29d. When the latch 29 is in an open position
(FIG. 19), the spring 36 is compressed and the cam surface 29a and
the tip 29d are recessed into the closed channel 34. When the
spring 36 is released, the latch 29 moves into the closed position
where the cam surface 29a extends into the channel 23 and the cam
surface 29c and tip 29d extend into the channel 23a.
[0061] In use, the latch 29 tends toward the closed position. In
order to connect the anchor 123 with the main body 20, a connecting
tool 38 is inserted into the channel 23a and the tool 38 engages
the cam surface 29c to move the latch 29 into the open position.
Channel 23a includes an elastomeric, self-sealing plug 23b with a
slit for receiving the connecting tool 38. The plug 23b seals the
opening in the channel 23a from external fluids, etc. The tool 38
includes a notch 39 in its distal end. The tool 38 may be locked
into position in the channel 23a by rotating the tool so that the
tip 29d of the cam surface 29c engages the notch 39. This prevents
removal of the tool 38 from the channel 23a. Thus the tool 38 may
be temporarily locked in the channel 23a with the latch 29 in an
open position for insertion of the anchor 123 into the channel 23.
The tool 38 may be released when the anchor 123 is in place, by
rotating the tool so that the tip 29d of the latch 29 no longer
engages the notch 39 in the tool 38. When connected, the elongate
member 124 of the anchor 123 is located in the channel 23 and the
latch connector 29a extends into the notch 137 in the elongate
member 124, thereby connecting the anchor 123 and the main body
portion 20. Alternatively, the main body portion 20 may be
connected to the anchor 123 without the use of such a tool. In this
case, the anchor 123 causes the latch to retract as the anchor 123
is inserted until the connecting end 29a of the spring-loaded latch
29 locks into place in the notch 137.
[0062] The tool 38 may be used in a similar manner as described
above, to remove the main body 20 from the anchor 123, for example
to replace the main body 20 or remove the stimulator 10. The tool
38 is preferably a device that may be inserted through a lumen in
an endoscope. In such case, the tool 38 may first be placed through
the endoscope and attached to the stimulator distal of the
endoscope's distal end. This would particularly be the case where
the stimulator is larger than the channels in the endoscope. Other
endoscopic tools may be used to deploy or remove the stimulator 10
or main body 20. For example, a grasping tool may be used
manipulate the device where the grasping tool has an actuator
handle extending out of the proximal end of the endoscope. Also a
magnetic tool may be used to engage and manipulate the stimulator
during insertion or removal. A magnetic docking system may be used
as well, to locate or orient the main body 20 in an aligned
position with respect to the anchor 123. The main body, anchor
insertion tool or endoscope may have magnets that provide for
aligned connection between the main body 20 and anchor 123.
[0063] FIGS. 1-9 and 15-17 illustrate an endoscope of the system of
the present invention and the placement of the electrical
stimulator 10 using the endoscope and associated instruments. FIG.
1 illustrates a flexible endoscope 110 such as, for example, of a
type that used by gastroenterologists in treating the upper
gastrointestinal tract. The endoscope 110 is used to locate an
attachment site in the stomach 100 and attach the stimulator device
10 to the stomach wall of a patient. The flexible endoscope is of
the type that is typically used by gastroenterologists in accessing
the esophagus or stomach. The endoscope allows the physician to
visualize while performing procedures on the upper gastrointestinal
tract. The flexible endoscope may be, for example, a flexible fiber
optic endoscope utilizing optic fibers for imaging or a video
endoscope that uses a CCD (charge coupled device) to provide video
images. Such endoscopes typically include a fiber optic light guide
and a complex objective lens at the distal end to focus the
image.
[0064] As illustrated in FIGS. 7-9, the endoscope comprises an
elongate tube having a proximal handle portion 106 and a distal
portion 115. The endoscope includes an aspiration channel 112 and
irrigation/air channel 113. A fiber optic light source 93 for
illuminating the stomach site extends through a fiber optic
channel. A video lens 94 is located at the distal end of the
endoscope, for receiving and focusing the image that is transmitted
back through a channel in the endoscope 110. Corresponding light
source input 95, video output 96, irrigation port 97, aspiration
port 98 and auxiliary port 99, are located on the proximal handle
portion 106. Knobs 107 and 108 are coupled at the proximal handle
106 for left/right and up/down steering mechanisms, respectively,
that are used to steer the distal portion of the endoscope in a
manner that is generally known to one of ordinary skill in the art.
The endoscope 110 further includes an auxiliary channel 114
extending through the endoscope 110 and providing an opening
through which surgical instruments may extend to reach the site
105. An additional auxiliary port may be provided for additional
instruments or alternatively, the aspiration channel 112 may be
used for additional tools if not otherwise required in a procedure.
The distal portion 115 of the endoscope 110 includes an open distal
tube 116, the end of which is placed against the stomach wall at
the site 105. The distal tube 116 provides a space for stomach
tissue to enter and be held in place when a vacuum pressure is
applied.
[0065] During the procedure the patient is given a numbing agent
that helps to prevent gagging. As shown in FIG. 2 a protective
overtube 111 with the endoscope 110 is passed through the mouth
101, pharynx 102, into the esophagus 103 and opening into the
stomach 100. The overtube 111 is used to protect the esophagus,
which may become irritated with repeated insertion and removal of
instruments. The overtube 111 also helps prevent instruments and
devices from inadvertently dropping into the trachea. In addition,
the overtube 111 serves to protect the tools from the bacteria in
the mouth and esophagus so that such bacteria are not passed on to
the stomach wall. As illustrated in FIG. 9, the overtube 11a may
also include additional channels 11a and 11b for inserting
additional instruments.
[0066] Preferably the instruments inserted into the patient's
stomach are coated with an antibacterial material, in particular,
the instruments that are used to pierce or otherwise come in
contact with the stomach wall. As illustrated in FIG. 3, the
endoscope 110 is extended distally out of the overtube 111 and is
used to locate a site 105 on the stomach 100 for attaching the
stimulator 10. Additionally or alternatively, an endoscope or a
tool inserted through the esophagus may be used to detect intrinsic
gastric electrical activity to help pinpoint the optimal site for a
stimulator and/or electrode attachment to the stomach wall (See for
example, FIG. 35A and 35B and the corresponding description
herein). In such a case sensing electrodes are coupled to the
distal end of the endoscope or tool, with conductors extend out of
the endoscope or patient's esophagus to a unit having a controller
for receiving sensed electrical activity and identifying a surgical
site for stimulator attachment.
[0067] As shown in FIGS. 4-6 an introducer 117 is inserted through
the auxiliary channel 114. The introducer 117 comprises an outer
cannula 118, a dilator 119 extending through the cannula 118, and a
needle 120 extending through the dilator 119. Each of the cannula,
118, dilator 119 and needle 120 are separately actuable at the
proximal end in a manner that would be apparent to one of ordinary
skill in the art, for example, in a manner similar to such devices
utilized in catheter introducer sets. After the open distal tube
116 is located at a site 105 in the stomach 100, a vacuum pressure
is applied through the aspiration channel 112 to engage, stabilize
and hold the tissue at the site 105. As illustrated in FIG. 4, the
needle 120 is advanced distally through the tissue of the stomach
wall. As illustrated in FIG. 5, the dilator 119 is then advanced
over the needle 120 through the stomach wall. The needle 120 is
then retracted proximally out of the dilator 119 and is removed
from the endoscope 110. The cannula 118 is advanced over the
dilator 119 and the dilator 119 is removed proximally from the
endoscope 110.
[0068] As illustrated in FIG. 6, with the cannula 118 through the
stomach wall, the anchor 123 may be placed into the cannula 118
from the proximal end of the endoscope. Using a push tube 122
having a diameter that is small enough to fit within the cannula
118, placed proximally of the anchor 123, the anchor 123 is
distally advanced through the cannula 118 located within the
stomach wall (FIG. 10).
[0069] The push tube 122 pushes the anchor 123 through the cannula
118 until the expandable distal end 125 extends out of the stomach
wall in the peritoneal cavity. (FIG. 11) Before insertion, a tether
131 is secured to the opening 130 and extends through the push tube
122 out of the proximal end of the endoscope 110. The expandable
distal end 125 is formed of an elastic or spring material that
tends to spring open into its expanded shape when the distal end
125 is no longer constrained by the cannula 118. (FIG. 11). Once
the anchor 123 is in place, the cannula 118 is withdrawn from the
endoscope 110 and the endoscope 110 may also be removed from the
over tube 1 11 leaving the tether 131 in place extending from the
anchor 123 out of through the over tube 111 and out of the
patient's mouth 101. The tether 131 is to be used to guide the main
body 20 of the stomach to the anchor 123. The tether 131 may
comprise a thread or suture-like device or may be a thin flexible
guide wire like device. The tether 131 may be tied or otherwise
anchored to hole 130 in anchor 123 or it may be looped through hole
130 in anchor 123 such that two strands lie parallel to each other
in the overtube 111 and pass out of the patient's mouth.
[0070] FIGS. 15-17 illustrate a preferred procedure for connecting
the main body portion 20 of the stimulator 10 to the anchor 123 in
place in the stomach wall. The main body 20 is threaded on to the
tether 131 that is attached to the anchor 123 through the channel
23 in the main body 20. The tether 131 which extends through the
over tube 111, guides the channel 23 to the elongate member 124 of
the anchor 123 for attachment. The threaded main body portion 20 is
preferably placed within the over tube 111 with the endoscope 110
located proximal of the main body portion 20 within the overtube
111. The tether 131 is also preferably threaded through the
overtube 111, placed in parallel with the endoscope 110 through the
overtube 111 or one of its channels 11a, 11b. The tether may be
placed in a lumen extending through the endoscope 110. Tool 38
extends through the auxiliary channel 114 and is coupled distally
of the distal end 115 of the endoscope, to the main body 20 through
the channel 23a. The endoscope 110 distal portion 115 also engages
the main body portion 20 and provides a force to move the main body
portion 20 through the over tube 111. (FIG. 15). The endoscope 110
further provides visualization of the coupling process. The tool 38
and tether 131 together further locate the main body portion 20
with the anchor 123 as it extends through the stomach 100 to the
site 110. (FIG. 16). Finally, the tool 38 provides additional force
to attach the main body portion to the anchor 123 (FIG. 17). The
tool 38 is then removed from the channel 23a in the main body 20
and out of the endoscope's proximal end. Alternatively the main
body 20 may be placed in position, coupled to the anchor 123 by
using the tether 131 and the distal portion 115 of the endoscope to
guide the main body 20 into place. (See e.g., FIGS. 15-17). In an
alternative embodiment, a magnetic docking system is used wherein
the distal end 115 of the endoscope 110, main body 20, and/or
anchor 123 includes a magnet and/or corresponding metal used to
align and position the anchor 123 and main body 20 with respect to
each other.
[0071] After the main body portion 20 has successfully been coupled
to the anchor 123, an endoscopic scissor or other cutting device
may be provided through the auxiliary channel 114 in the endoscope
110 to cut the tether 131. As illustrated in FIG. 14, when the
stimulator is attached to the stomach wall, the stimulating
electrode 32 is located within the tissue of the stomach wall,
providing electrical contact. While the second stimulating
electrode 32 on the distal face 26 interfacing with the stomach
100, is in electrical contact with the inner surface 100b of the
stomach wall.
[0072] FIGS. 23 and 24 illustrate a second embodiment of the
stimulator of the present invention. Stimulator 210 comprises a
main body portion 220 and an anchor 223. The anchor 223 comprises
an elongate proximal member 225. The elongate proximal member 225
includes a tether opening 235 in the proximal end, electrical
contacts 228, 238, and a notch 227 for connecting the main body
portion 220 to the anchor 223. The distal portion 240 of the anchor
223 comprises two prongs 241, 242. Prongs 241, 242 have expandable
distal ends 243, 244 respectively that are constructed in a similar
manner as the expandable distal end 125 described above with
respect to the first preferred embodiment. A stimulating electrode
245 is located on prong 241 and an electrically opposite second
stimulating electrode 246 is located on prong 242. Stimulating
electrode 245 and second stimulating electrode 246 are coupled to
electrical contacts 228 and 238 respectively by conductors 229 and
239 extending through prongs 241, 242 respectively into the
elongate proximal member 225. Prongs 241 and 242 are connected by a
spacer 237.
[0073] Main body portion 220 includes a channel 215 with an opening
216 on the distal face 226. The channel 215 and the opening 216 on
the distal face have shapes that allow them to respectively receive
the elongate proximal member 225 and the spacer 237, thereby
sealing the opening 216. The electrical contacts 228, 238 to the
anchor 223 are coupled to electrical contacts within the channel
215 of the main body portion 220 in a manner similar to the
coupling of contacts 128, 128a and 128b of anchor 123 and contacts
28, 28a, and 28b of main body portion 20 described with reference
to the first embodiment herein. Also the notch 227 engages a latch
similar to the latch 29 described above. The notch 227 and latch
and the electrical contacts 228, 238 are isolated from the acidic
environment of the stomach using seals such as the seals 27
described above with respect to the first embodiment.
Alternatively, the electrodes 245, 246 may be constructed in a
manner similar to electrode 32 using a corrosion resistant material
that is directly coupled to the electronic circuitry (for example,
where the anchor is integrally formed with the stimulator or where
one or more of the electrodes 245, 246 are located on the main body
portion).
[0074] The anchor prongs 241, 242 may be deployed in a similar
manner as anchor 123 is deployed, using a dual needle introducer
or, alternatively by deploying each prong 241, 242 independently
and later connecting the prongs 241, 242 with the spacer 237.
[0075] In use, once the stimulator (e.g., 10, 210, 310 or 380) is
deployed, electrical stimulation is provided through electronic
circuitry 25. The electronic circuitry 25 is capable of producing
various types of programmable waveforms. FIGS. 36A and 36B
illustrate examples of stimulation waveforms that may be used in
stimulating the smooth muscle lining of the intestinal tract. FIG.
36A illustrates a waveform design for stimulating the intestinal
tract at a pacing rate. In a preferred embodiment, the waveform 1
has a pulse amplitude of between 0.5 and 20 milliamps, a pulse
width of between 0.5 and 10 milliseconds, and a frequency of about
between 1 and 5 pulses per minute. FIG. 36B illustrates an
alternative waveform design for stimulating the intestinal tract.
The waveform 2 utilizes bursts of pulses rather than a single pulse
with a burst repetition rate to be selected, preferably of about 3
cycles per minute. The duration of a burst in this example is about
100 ms and an amplitude of about 10 mA. In this example, the
frequency of the burst pulses during a burst is between about 50 to
100 Hz, and as is well known to those skilled in the art, there are
many different types of electrical stimulation programs and
strategies which can be utilized for providing electrical
stimulation parameters through the circuitry 25, the principal
focus being providing electrically stimulating parameters for the
stomach.
[0076] A preferred embodiment of the electronic circuitry 25 is
illustrated in FIG. 25. The electronic circuitry 25 of the
stimulator is located in the main housing. The circuitry 25
comprises, a microprocessor or controller 40 for controlling the
operations of the electronic circuitry 25, an internal clock 41,
and battery device 44 such as a pair of lithium iodine batteries
for powering the various components of the circuit 25. As such, the
controller 40 and battery device 44 are coupled to each of the
major components of the circuit as would be apparent to one of
ordinary skill in the art. The controller 40 is coupled to
stimulation driver 42, which is coupled to stimulating electrodes
(e.g., 126, 32 or 245, 246, 266, 267, 326, 327, 356, 357, 524, 525
that are used to provide electrical stimulation in accordance with
programmed parameters
[0077] The controller 40 is coupled to ROM 43, which contains the
program instructions for the controller 40 and any other
permanently stored information that allows the
microprocessor/controller 40 to operate. The controller 40
addresses memory in ROM 43 through address bus 43a and the ROM 43
provides the stored program instruction to the controller 40 via
data bus 43b. The controller 40 controls the telemetry coil 45,
which communicates with an external control or programming device
60 (FIG. 26), preferably via a modulated RF signal. Processor 40 is
coupled to an oscillator 51 that provides an RF signal to be
emitted from the telemetry coil 45. The RF signal is preferably at
about 500 kHz or higher so that the signal is efficiently
transmitted through tissue. The controller 40 controls the
oscillator 51 and provides data to be modulated with the RF signal.
For example, various sensed data such as pressure, pH, temperature,
strain, impedance, electrical activity (EMG) etc., may be delivered
through the telemetry coil 45.
[0078] The circuit 25 may also be coupled through A/D converters
46a, 46b, 46c, 46d to one or more sensors 47a (e.g., strain gauge),
47b (e.g., pressure), or electrodes 32, 126. Suitable types of
these sensors are generally known in the art and may be located
within, on, or external to the housing 21 of the main body portion
20. Controller 40 is coupled to RAM 50 via an address bus 50a for
addressing a location in RAM 50 and a bi-directional data bus 50b
for delivering information to and from RAM memory 50. The RAM
memory 50 includes event memory 48 that temporarily stores data
recorded by sensors 47a, 47b, 32 and 126 and a programmable memory
49 which may be programmed, for example, by an external programmer
60, to provide treatment protocols, e.g. to specify operating modes
such as waveform, frequency, etc. The strain gauge 47a is coupled
through A/D converter 46a, which converts the representative
electrical signal output by the strain gauge into a digital signal,
which is delivered to the microprocessor/controller 40 and stored
in the event memory 48 in the RAM 50. The sensor 47b is coupled
through A/D converter 46b, which converts the representative
electrical signal output by the sensor 47b into a digital signal,
which is delivered to the microprocessor/controller 40 and stored
in the event memory 48 in the RAM 50. The electrodes 32, 126 are
coupled through A/D converters 46c and 46d to the microprocessor
40. A/D converter 46c converts the electrical EMG signal sensed by
the electrodes 32, 126 into a digital signal representative of the
EMG electrical activity, which is delivered to the
microprocessor/controller 40 and stored in the event memory 48 in
the RAM 50. Also, the A/D converter 46d converts the electrical
signal sensed by the electrodes 32, 126 and provided through the
impedance circuit 53 described below, into a digital signal
representative of tissue impedance, which is delivered to the
microprocessor and stored in the event memory 48 in the RAM 50. The
data stored in the event memory 48 may be sent intermittently as
data bursts via the telemetry RF coil 45, as opposed to
continuously in order to save battery power.
[0079] The electrode 32, 126 outputs are used to provide electrical
stimulation delivered through the stimulation driver 42 to
electrodes. The stimulation modes and parameters can either be set
using the external programmer 60, or they may be set in response to
sensory feedback. The same electrode outputs are used to sense
impedance through impedance circuit 53 and to sense electrical
activity which is delivered through driver 56c. The electrodes 32,
126 are coupled through coupling capacitors 55a and 55b
respectively, to output of electrical stimulation driver 42 and
input of drivers 56c, 56d.
[0080] The impedance circuit 53 comprises a constant current source
oscillator 54 that oscillates at a frequency of 50-100 kHz, and a
driver 56d coupled through A/D converter 46d to the controller 40.
The oscillator 54 provides a constant current source through
electrodes 32, 126 resulting in a voltage across the electrodes 32,
126 that is representative of impedance, in view of the constant
current. The voltage is provided through driver 56d and is
converted by A/D converter 46d to a digital signal representative
of impedance. Driver 56d has a bandwidth that includes the 50kHz
frequency signal while filtering out the electrical stimulation
signal that is delivered to the electrodes 32, 126 through
electrical stimulation driver 42, and the EMG signal that is sensed
by the electrodes 32, 126. Both of the outputs are filtered out by
driver 56d. Driver 56c which delivers the EMG signal to A/D
converter 46c, also has a bandwidth that filters out the 50-100 kHz
signal. Further, when a stimulation signal is being delivered, the
controller 40 does not receive signals from A/D converters 46c and
46d. Thus the EMG and impedance sensing functions and the
stimulation deliver functions are separated through the electronic
circuitry 25, though using the same electrodes.
[0081] FIG. 26 illustrates the electronic circuitry 63 for external
programmer 60. The electronic circuitry 63 comprises: a
microprocessor or controller 70 for controlling the operations of
the electronic circuitry, an internal clock 71, and a power source
74 such as battery device for powering the various components of
the circuit 63. As such, the controller 70 and battery device 74
are coupled to each of the major components of the circuit as would
be apparent to one of ordinary skill in the art. The controller 70
is coupled to a speaker 67 for that provides audible alerts and a
display 66 such as a CRT to display data such as recorded data,
sensed parameters treatment parameters and status of device (e.g.
position or battery charge status). The controller 70 is coupled
through a buffer 64 to external input device 65 that is used to
provide program parameter input, e.g. from a user, for a user to
request data displayed in a desired format through display 66 or
speaker 67, or to turn device on and off. The external programmer
60 is also provided with an external data port 68 to interface with
a computer and provide a means for bi-directional communication of
data or commands. The computer may provide programming or data to
the controller/microprocessor 70. A user may also interface with
the computer to provide treatment protocols or changes in
protocols, etc. Also, a user may control the turning on and off of
the stimulation program.
[0082] The controller 70 is coupled to ROM 73, which contains the
program instructions for the controller 70 and any other
permanently stored information that allows the
microprocessor/controller to operate. The controller 70 addresses
memory in ROM 73 through address bus 73a and the ROM 73 provides
the stored program instruction to the controller 70 via data bus
73b. The controller 70 controls the telemetry coil 75, which
communicates with stimulator electronics 25 (FIG. 25) through its
telemetry coil 45. Processor 70 is coupled to an oscillator 72 that
provides an RF signal, preferably having a characteristic frequency
of 500 kHz or higher, to be emitted from the telemetry coil 75. The
controller 70 controls the oscillator 72 and provides data to be
modulated with the RF signal, for example, programming information,
stimulation parameters, etc. The telemetry coil 75 also receives
information transmitted via RF signal from telemetry coil 45 on the
stimulator 10 such as various sensed data, e.g., pressure, pH,
impedance, electrical activity (EMG) etc. The received RF signal is
passed through A/D converter 76 and is transmitted to the
controller 70. The data is delivered to the event memory 78 in RAM
77 by way of data bus 77b for temporary storage. The data may be
retrieved from RAM 77 by addressing the storage location via the
address bus 77a.
[0083] Event memory 78 temporarily stores data recorded by sensors
47a-47c and delivered via telemetry to the external programmer 60,
until the data is downloaded onto a computer using the external
data port 68. The RAM 77 also includes a programmable memory 79
which may be programmed, for example, to specify operating modes
such as waveform, frequency, etc which programming is then
telemetrically communicated to the stimulation device 10, 210. The
modes and parameters can either be set using an external programmer
60 or set in response to sensory feedback.
[0084] FIGS. 27A and 27B illustrate a third embodiment of the
present invention showing an anchor device for use with a
stimulator or other functional device of the present invention. The
anchor 263 comprises an elongate body 264, an expandable distal
portion 265 having a sharp tip 270, a bipolar electrode pair 266,
267, and a bumper 275 located on a proximal portion of the elongate
body 264. The expandable distal portion 265 comprises a flexible
disk 271 for engaging the outer stomach wall. The disk 271 has an
inner surface 271 a that interfaces with the outer surface 100a of
stomach wall 100 and may, for example be coated with an antibiotic
material, such as gentamicin sulphate or a silver/silver salts
coating such as a powder. The bipolar stimulating electrode pair
comprises electrode 266 located on the elongate body 264 and a
plurality of electrodes 267 electrically opposite from electrode
266, located at the end of the expandable distal portion 265. The
electrodes may be separately coupled to electrical contacts and may
be individually selected to provide optimal stimulation pulses, for
example, based on contractile response when stimulation pulses are
delivered to a particular electrode or electrodes. Electrode 266 is
ring extending circumferentially around the elongate body 264.
Electrodes 267 are circumferentially spaced from each other around
the radial extremity 271b of the disk 271. As an alternative to a
plurality of electrodes 267 the electrode located on the disk may
be a single ring electrode. Electrodes 266, 267 are electrically
coupled to a main body portion containing electronic circuitry (not
shown) that is attached in a manner similar to main body portion 20
described above. Conductors 268, 269 electrically couple electrodes
266, 267 respectively to the electronic circuitry of the main body
portion.
[0085] The anchor 263 may be deployed without requiring an
introducer such as described above with reference to FIGS. 4-6. As
illustrate in FIG. 27A, the sharp tip 270 is used to pierce the
stomach wall 100. The flexible disk 271 folds within recessed
portion 265a extending around the distal portion of the anchor 263
so that the disk 271 is flush with the outer surface of the
elongate body 264 and forms a taper to the sharp tip 270. The tip
270 is preferably conically tapered so as to atraumatically dilate
the stomach wall as it is inserted and help insure a good seal
formed by the elastic rebound of the stomach wall tissue around the
elongate body 264.
[0086] Referring to FIG. 27B as the distal portion 265 of the
anchor 263 extends through the stomach wall, the expandable disk
271 opens. The anchor 263 is retracted slightly so that the radial
extremity of the disk 271 engages the outer surface 100a of the
stomach wall 100, preventing proximal movement of the anchor 263.
The electrodes 267 are in electrical contact with the outer surface
100a of the stomach wall. The electrode 266 on the elongate body
264 is embedded within the stomach wall 100 and is in electrical
contact with the tissue therein. The bumper 275 may be advanced
distally so that is engages the inner surface 100b and secures the
anchor 263 in position, preventing distal movement. Preferably the
bumper 275 and the disk 271 lock the anchor in place and may also
further serve to help seal the opening formed in the stomach from
the acidic internal stomach environment and the environment
external the stomach wall 100. The bumper 275 may be secured in
position by a ratchet mechanism or other means such as a frictional
fit. The tip 270 is constructed of a bioabsorbable material such a
glucose based absorbable material or polyglycolic acid or
polylactic acid, so that the sharp tip 270 readily dissolves and is
absorbed by the body, preventing the tip from injuring tissue
external to the stomach.
[0087] FIGS. 28A and 28B illustrate a fourth embodiment of the
present invention showing a stimulator. Stimulator 310 comprises an
anchor 323, an electronics unit 320 and electrodes 326, 327 coupled
by leads 328, 329 respectively to the electronics unit 320. The
stimulator 310 is attached to the inner surface 100b of the stomach
wall 100 by anchor 323 which may be constructed or attached in a
manner similar to anchors 123, 223,or 263 described above, either
with or without electrodes. The electrodes 326, 327 are anchored
into the stomach wall 100 with anchors 324, 325 respectively.
Referring to FIG. 28B, an anchor 325 is shown deployed in the
stomach wall 100. Lead 329 extends from the main body portion 320
through the stomach to the site 105 where stimulation is desired.
The anchor 325 is preferably constructed in a manner similar to
anchor 263 with a bioabsorbable or resorbable tip and so that the
electrode 327 is embedded in the stomach wall 100. The ends of the
leads are molded into the housing using corrosion resistant
materials suitable for long term use in the stomach. Adjustable
sealing ring or bumper 321 operates to prevent anchor 325 from
moving out of the stomach and may help to seal the opening in the
stomach wall formed by the anchor from the acidic stomach
environment and. Anchor 324 is deployed in a similar manner with
electrode 326 embedded in the stomach wall 100 at the site 105 for
stimulation. Preferably the stimulating electrodes 326, 327 are
located at a distance from each other between 5 and 10 mm so that
the electrical stimulation is delivered efficiently to the area of
interest. The electronic circuitry of the main body 20 delivers
electrical stimulation in a manner similar to the stimulation
device 10 described above.
[0088] Referring now to FIGS. 29A and 29B, an alternative
instrument is illustrated for placing an anchor from the inner
surface 100b of the stomach wall 100 through to the outer surface
100a of the stomach wall. The instrument 330 comprises a hollow
piercing needle 331 having a lumen 332 therethrough and a stomach
piercing tapered distal end 333. A guide wire 334 extends through
the lumen 332 in the needle 331. The needle 331 is relatively stiff
to allow it to pierce the stomach wall while the guide wire 334 is
more flexible. As illustrated in FIG. 29A, the distal end 115 of
the endoscope is located at a desired site on the inside 100b of
the stomach wall 100. A vacuum pressure is applied to the wall to
stabilize it and the needle 331 pierces the stomach wall through a
single point, preferably in a direction that is substantially
perpendicular to the natural orientation of the stomach wall to
prevent folding of the stomach wall and tearing forces during
smooth muscle contraction, at the point of attachment. As
illustrated in FIG. 29B, the needle 331 is removed, leaving the
guide wire 334 in place. Preferably, the instrument 330 is inserted
through the auxiliary channel 114 in the endoscope or through a
channel 111a or 111b in the over tube 111 and then is located to
the desired site using the endoscope 110 for visualization.
[0089] Referring to FIGS. 30A and 30B, an anchor 340 is illustrated
placed into the stomach wall 100 over the guide wire 334. The
anchor 340 includes an elongate member 341 that is to be placed
through the stomach wall 100 in a direction substantially
perpendicular to the stomach wall. The anchor 340 has a distal
portion 343 that is to at least partially extend through the
stomach wall, and a proximal portion 342 having a threaded proximal
end 342a for engaging with a threaded end of an instrument used to
advance the anchor 340 into place. The anchor 340 includes a guide
wire lumen 345 extending through the anchor 340 from the proximal
portion 342 to the distal portion 343 with an opening in the
proximal portion 342 and distal portion 343 for receiving the guide
wire 334 of the insertion instrument 330. As shown in FIG. 30A, the
anchor 340 is inserted over the guide wire 334 which guides the
anchor 340 into position through the stomach wall 100. The guide
wire lumen 345 at the distal portion 343 of the anchor 340 is
sealed with a self-sealing plug 344 formed of an elastomer and
having a slit along the plug 344 so that the guide wire 334 can
open the plug 344 while the guide wire 334 extends through the
lumen 345.
[0090] An expandable member 348 is located on the distal portion
343 of the anchor 340. The expandable member 348 comprises a
balloon formed of either a compliant or non-compliant material such
as, e.g., polyurethane, polyethylene or polyester bonded to the
outer surface of the distal portion 343 of the anchor 340 and
providing an inflation chamber 350. Accordingly, the balloon may be
inflated to a predetermined pressure (typically using a
non-compliant material) or a predetermined volume (typically using
a compliant material). An inflation lumen 351 extends from an
opening in the proximal portion 342 to an opening 349 in the distal
portion 343. The opening 349 in the inflation lumen 351 is in fluid
communication with the inner chamber of the expandable member 348
so that an inflation medium may be supplied through the inflation
lumen to inflate the expandable member 348. As illustrated in FIG.
30B, the anchor 340 is placed in the stomach wall and the
expandable member 348 is inflated by supplying the inflation
chamber 350 with an inflation medium. In a preferred embodiment, a
curable elastomeric polymer is used as an inflation medium, e.g., a
two-part curable elastomeric polymer mixed just prior to delivery
through the inflation lumen 151. The polymer thus allows the
balloon to conform to the outer stomach wall and surrounding tissue
to secure the anchor 340 to outer surface 100a of the stomach wall.
The balloon is preferably designed and the inflation medium is
selected to provide an inflated distal end that is sufficiently
firm to secure the anchor 340 in place while having sufficient
surface area and being malleable enough that the anchor is sealed
into place in a relatively atraumatic manner.
[0091] The anchor 340 further comprises ratchets 365 on the outer
circumference of the elongate member 341 and a sealing bumper ring
366 having an opening 367 forming an inner circumferential wall
with ratchet teeth 368 for engaging the ratchets 365 on the
elongate member 341. The bumper ring 366 is moveable in a distal
direction to sealingly secure the anchor 340 to the stomach wall
and prevent distal movement of the anchor 340. The bumper ring 366
preferably has sufficient surface area and is formed of an
elastomer that spreads the load and minimizes friction or other
trauma to the stomach wall.
[0092] The anchor 340 further comprises electrode lumens 346, 347
having openings 346a, 347a in the elongate member 341. Conductor
members 352, 353 extend through the electrode lumens 346, 347,
respectively, and include flexible conductors insulated along their
length. The flexible conductor members 352, 353 are preferably
constructed of an elastic or superelastic alloy with an insulative
coating. Electrically opposite electrodes 356, 357 are located on
distal portions 360, 361 of moveable flexible conductor members
352, 353 respectively. Exposed electrical contacts 354, 355 are
located on the proximal portions of the conductor members 352, 353.
The electrical contacts 354, 355 are in electrical contact with
contacts 362, 363 respectively that are electrically coupled to
contacts in a main body of a stimulator unit in a manner similar to
the sealing electrical connection of main body 20 and anchor 123
described herein. The adjustable electrodes 356, 357 are contained
within the electrode lumens 346, 347 when the anchor 340 is
initially placed as illustrated in FIG. 30A. The adjustable
electrodes 356, 357 are deployed within the stomach wall 100 by
advancing the conductors members 352, 353 distally through the
electrode lumens 346, 347 where the openings 346a, 347a are
configured to direct the electrodes 356, 357 laterally from each
other and within the stomach wall as illustrated in FIG. 30B. The
electrodes 356, 357 are moved with respect to one another into a
selectable optimal deployment position with an optimal distance
between the electrodes 356, 357.
[0093] An endoscopic instrument 370 is used to place the anchor
340, inflate the expandable member 348 and deploy the electrodes
356, 357. The instrument 370 is preferably used through the
overtube 111, an opening 111 a or 111 b in the overtube 111 and/or
through an instrument channel 114 in the endoscope 110 (while the
procedure is visualized through the endoscope 110.) The instrument
370 includes an inflation tube 373 removably attached to the
inflation lumen 351 of the anchor 340. The inflation tube 373 forms
a continuous conduit with the inflation lumen 351 a conduit through
which an inflation medium is supplied to inflate the expandable
member 348. A push tube 371 comprises a threaded end 371a that
engages the proximal end 342a of the anchor 340. The push tube 371
is used to advance the anchor 340 over the guide wire 334. An inner
tube 372 includes prongs 374, 375 that engage the conductor members
352, 353 and are used to advance the electrodes 356, 357 into the
stomach wall by pushing the inner tube 372 while holding the anchor
340 in place with the push tube 371. The prongs 374, 375 comprise
electrically conductive wires that extend within the insulative
material of the inner tube 372 to a stimulator/sensor circuit
located externally of the patient's body. The stimulator/sensor may
be used to deliver test stimulation pulses to the stomach wall
through the electrodes 356, 357 or to measure the impedance of the
stomach wall tissue between the electrodes 356, 357. (e.g. to
determine sufficient response to stimulation, sense electrical
activity). The stimulation response may be determined by observing
through the endoscope, contractions of the stomach wall, or by
determining contractions using one or more sensors, e.g. as
described with respect to the various embodiments herein.
[0094] After the anchor 340 is in place, an inflation medium is
supplied through the inflation tube 373 to inflate the expandable
member 348 adjacent the outside 100a of the stomach wall. The
inflation tube 373 has a thin walled region at its distal end where
it joins the inflation lumen 351. After the expandable member 348
is inflated, the inflation tube is removed by twisting or pulling
the tube to break it away from the anchor 340. The push tube 374
serves to hold the anchor 340 into place in the stomach wall as the
inflation tube 373 is disengaged. The bumper ring 366 is then
advanced distally to engage the inner wall of the stomach with
ratchets 365 engaging ratchets 368 to prevent further distal
movement of the anchor through the stomach wall. After the anchor
340 is in place, the push tube 371 may be removed by unthreading
the end 371a on the push tube 371 from the threaded end 372a of the
anchor 340. A stimulator unit such as the main body portion 20
described herein is coupled to the anchor 340 in a manner similar
to that described herein with reference to anchor 123 with
electrical contacts 354, 355 coupled to the electronics unit within
the stimulator through electrical contacts362, 363. Electrical
contacts 362, 363 are to be coupled to a stimulator unit in as
similar manner as are contacts 28, 28a, or 28b described
herein.
[0095] Alternatively the laterally extending conductive members
352, 353 may be used to secure the anchor to the stomach wall
without requiring an additional expandable distal portion.
[0096] Referring to FIGS. 31A and 31B an alternative stimulator 380
is illustrated comprising a main body portion 382 and an anchor
383. The anchor 383 includes an expandable distal end 385 for
securing the anchor to the stomach wall, seals 398 for sealing the
anchor electrical contacts 394, 395 and electrical contacts 396,
397 of the housing from the acidic environment of the stomach. A
notch 384 in the anchor is arranged to engage a latch 399 in the
main body 382 to couple the anchor 383 and the main body 382
together so that contacts 396, 397 of the housing 382 are in
electrical contact with anchor contacts 394, 395, respectively. The
anchor 383 further comprises insulated flexible conductors 386, 387
extending from the anchor 383. The conductors 386, 387 are coupled
to electrode anchors 388, 389 that are constructed and attached to
the stomach wall in a manner similar to the anchors 324, 325
described herein with reference to FIGS. 28A and 28B.
[0097] Referring to FIG. 32, a stimulator 510 is illustrated with
electronics housing 511 containing electronics circuit 25 that is
electrically coupled to electrodes 524, 525 through leads 521, 522
extending out of the housing 511. The electrodes 524, 525 are
attached to the stomach wall. The housing 511 is anchored to the
stomach wall by anchor portion 514 which includes an expandable
distal portion 515 and an elongate flexible portion 516 coupling
the distal portion 515 to the housing 511. The expandable distal
portion 515 may be unfolded inflated or otherwise expanded, e.g.,
as a spring, from a first configuration to a second configuration.
The expandable distal portion 515 has a surface area sa that
interfaces with the stomach wall. The expandable distal portion 515
may be placed through the stomach wall and expanded in a manner
similar, for example, to expandable ends 125, 271, 348.
[0098] The expandable distal portion 515, expandable end 125, disc
271, or inflatable member 348 each have an interfacing portion that
interfaces with the stomach wall. The interfacing portions each
have a surface area where the ratio of the weight of the remainder
of the stimulator, i.e. the anchor and diagnostic/therapeutic
portions, to the surface area interfacing with the stomach wall is
less than about five (5) grams/mm.sup.2, preferably less than about
1 g/mm , and most preferably less than about 0.1 g/mm.sup.2 An
equivalent anchor may include a plurality of anchor members bearing
together the stimulator weight and having a combined surface area
wherein the weight to surface area ratio is as set forth above.
[0099] The materials of the attachment devices, stimulators and
housings of the present invention are preferably selected for
long-term use in the stomach, i.e., two or more years. Suitable
materials include the materials described herein, such as those
described with respect to the construction of the main body 20.
[0100] The invention has been described with reference to preferred
embodiments and in particular to a gastric stimulator, the present
invention contemplates that the attachment devices may be used to
attach a number of functional devices to the wall of the stomach
for sensing parameters of the stomach or its environment, or for
diagnosing or providing treatment to the stomach. The attachment
device may incorporate such sensing, diagnostic or treatment
devices within the attachment device. Such functional devices may
also be separately attached to the stomach and/or to the attachment
device or to another functional device. The attachment device or
functional devices may communicate to an external recorder or
controller by way of telemetry. They may be battery powered or
powered by inductive coupling. A plurality of functional devices
may be attached to the stomach wall. The functional devices may be
programmed to respond to information or signals delivered by other
functional devices whether the signals are delivered from one
device to another through conductors or whether the signals are
delivered, e.g. through the stomach wall or medium within the
stomach.
[0101] It is also contemplated that instruments described herein to
attach or remove the attachment devices and stimulators may be used
to attach and remove a variety of functional devices or to perform
a number of different endoscopic procedures. Alternative mechanisms
for attaching the various elements to the stomach wall are also
contemplated, including for example staples, sutures and other
means.
[0102] While the invention has been described with reference to
preferred embodiment, it will be understood that variations and
modifications may be made within the scope of the following claims.
Such modifications may include substituting elements or components
which perform substantially the same function in substantially the
same way to achieve substantially the same result that the
invention can be practiced with modification within the scope of
the following claims.
* * * * *