US20050143784A1 - Gastrointestinal anchor with optimal surface area - Google Patents

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.

Description

RELATED APPLICATION DATA
• 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
• This invention relates to an anchor for attaching a device to the stomach.
BACKGROUND OF THE INVENTION
• 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.
• 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 Endoscopy40/6:730-734 (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
• 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.
• 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 mm²and preferably less than about one (1) gram per mm². 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.
• 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.
• 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.
• 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.
• 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.
• 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
• Alternatively, the device may be delivered laparoscopically through the abdomen to the stomach wall.
• 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.
• 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.
• 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.
• 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.
• 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.
• 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.
• 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/mm²or less, preferably about 1 g/mm²or less and more preferably about 0.1 g/mm²or 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.
• Preferred embodiments of various aspects of the invention are described in the following detailed description.
DETAILED DESCRIPTION OF THE DRAWINGS
• 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.
• FIG. 2 is a partial cross section view, illustrating placement of an overtube in the first embodiment of the system of the present invention.
• 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.
• FIGS. 4-6 are detailed partial cross sectional views illustrating the placement of the anchor in the first embodiment.
• FIG. 7 is a side partial cross sectional view of the proximal end of an endoscope of the inventive system.
• FIG. 8 is a side view of a distal end of the endoscope of the inventive system.
• FIG. 9 is distal end view of the endoscope ofFIGS. 7 and 8.
• FIG. 10 illustrates a partial cut away side elevational view of an anchor of the first embodiment initially placed in the stomach wall
• FIG. 11 illustrates a partial cut away side elevational view of a fully deployed anchor ofFIG. 10.
• FIG. 12 illustrates a side elevational view of the main body of the stimulator of the first embodiment of the present invention.
• 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.
• 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.
• 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.
• FIG. 18 illustrates a side cross sectional view of the deployed anchor ofFIG. 11.
• FIG. 19 illustrates a side cross sectional view of the main body illustrated inFIG. 12.
• FIG. 19A illustrates an enlarged view of the latch mechanism of the main body portion shown inFIG. 19 with the latch in a closed position.
• FIG. 20 illustrates an end cross sectional view of the main body illustrated inFIG. 12 with a quick connect in an open, unlocked position.
• FIG. 20A illustrates an enlarged view of the latch mechanism of the main body portion shown inFIG. 20 with the latch in an open position.
• FIG. 21 illustrates an end cross sectional view of the main body illustrated inFIG. 12 with a quick connect in a closed, locked position.
• FIG. 22 illustrates a side cross sectional view of the main body and anchor of the first embodiment locked together.
• FIG. 23 illustrates a side elevational view of the anchor and main body of a second embodiment of the stimulator of the present invention.
• FIG. 24 illustrates a side elevational view of the embodiment ofFIG. 23 with the anchor and main body attached.
• FIG. 25 illustrates a schematic diagram of the circuit of an electronic stimulator of the present invention.
• FIG. 26 illustrates a schematic diagram of the circuit of a programmer/recorder of the present invention.
• FIG. 27A illustrates a third embodiment of the present invention showing an alternative anchor as it is inserted through the stomach wall.
• FIG. 27B illustrates the anchor ofFIG. 27A anchored to the stomach wall.
• FIG. 28A illustrates a fourth embodiment of the present invention showing an alternative stimulation device.
• FIG. 28B illustrates an enlarged view of an anchor of the stimulation device ofFIG. 28A.
• FIGS. 29A and 29B illustrate an alternative endoscopic instrument for placing an attachment device through a stomach wall
• FIGS. 30A and 30B illustrate a fifth embodiment of present invention in which an anchor is placed using the instruments ofFIGS. 29A and 29B.
• FIGS.31A illustrates a sixth embodiment of the present invention including an anchor and stimulator
• FIG. 31 B illustrates the anchor and stimulator ofFIG. 31 B attached within the stomach.
• FIG. 32 illustrates a stimulator with an anchor according to the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
• Referring toFIGS. 10-14 and18-22, astimulator10 of a first embodiment is illustrated. Thestimulator10 comprises ananchor123 and amain body portion20. Theanchor123 comprises anelongate member124 having and expandabledistal end125 and a stimulatingelectrode126 in the form of a ring of a corrosion resistant metal conductor such as Platinum, Gold, Tantalum, Titanium or suitable alloys thereof, extending around theelongate member124 just proximal of theexpandable end125. Theanchor123 may be constructed of a radiopaque material. Alternatively, theanchor123 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 theanchor123 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. Anotch127 extending around theelongate member124 is located proximally of the stimulatingelectrode126, for connecting theanchor123 to themain body portion20, containing the stimulatorelectronic circuitry25. Anelectrical contact member128 comprising a corrosion resistant metal ring extends circumferentially around theelongate member124 proximal of thenotch127. Theelectrode126 and thecontact128 are electrically coupled through awire129 or other conductor extending through theelongate member124. The proximal end of theanchor123 has anopening130. Atether131 is secured to theopening130. Thetether131 is used to guide themain body portion20 into place. Thetether131 is also used to pull on theanchor123 while the main body portion is pushed into place both to provide a guide and to hold theanchor123 in place.
• Astrain gauge121 is located on theelongate member124 of theanchor123. Thestrain gauge121 is coupled throughconductors121a and121b toelectrical contacts128a,128b respectively.Electrical contacts128a and128b are constructed and sealed when coupled to themain body20, in a manner similar to contact128.
• Themain body portion20 comprises a sealedhousing21 includingelectronic circuitry25. Theelectronic circuitry25 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. Thehousing21 includes an outer shell having adistal face26 for interfacing with the stomach wall. Themain body20 also includes aradiopaque marker31, preferably a radiopaque stimulator serial number (e.g., sprayed onto a location in the housing21) 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™ (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. Thedistal face26 is preferably coated with an antibiotic material, such as gentamicin or silver/ silver salts coating. Themain body20 further comprises anelectrode32 located on the distal face. Theelectrode32 is constructed of an acid corrosion resistant material such as Platinum, Gold, Tantalum, Titanium, or any suitable alloys thereof.
• Themain body portion20 further comprises achannel23 through which thetether131 is threaded for alignment with the anchor123 (FIG. 13) and for receiving theelongate member124 of the anchor123 (FIGS. 14 and 22). Asecond channel23aextends parallel to thechannel23 from an opening in the proximal side of themain body20 and ending within themain body20. Thesecond channel23ais for receiving a connect/release tool38 described in more detail below.
• Thechannel23 includes anopening24 in thedistal face26 of thebody portion20 as well as anopening22ain the proximal side22 of themain body20. The walls of thechannel23 include a plurality of acid resistantelastomeric seals27 formed of a material such as, for example, polyurethanes, rubbers or C-Flex type block copolymers. In between theseals27 is a flexibleelectrical contact28 for contacting theelectrical contact128 of theanchor123 and alatch29 for engaging thenotch127 of theanchor123. Thus, theelectrical contact28 will be located in a sealed area of thechannel23, betweenseals27, protecting it from the highly acidic environment of the stomach. Theseals27 also act as electrical insulators that prevent unintended current pathways between theelectrical contact28 and theelectrode32. Theelectrical contact28 is coupled to theelectronic circuitry25 of themain body portion20 through aconductor30 extending from thecircuitry25 through thehousing21 to thecontact28. The secondstimulating electrode32 located on thedistal face26 of themain body20 is coupled to theelectronic circuitry25 by way of aconductor33. As an alternative to being coupled to the electronic circuitry through a sealed contact, theelectrode126 may be constructed in a manner similar toelectrode32 using a corrosion resistant material that is directly coupled to the electronic circuitry (for example, where the anchor is integrally formed with thestimulator10 or where theelectrode26 is located on the housing).
• As illustrated inFIG. 22, when themain body portion20 and theanchor123 are connected, theelongate member124 of theanchor123 extends into thechannel23 so that thenotch127 and theelectrical contact128 are located between seals27. Theelectrical contacts128,128a,and128bare in contact with flexibleelectrical contacts28,28a,and28brespectively, and thelatch29 is located within thenotch127 so that theelongate member124 of theanchor123 is fixed within themain body portion20.
• FIGS. 19-21 show thelatch mechanism29 in themain body20 that is used to connect themain body20 to theanchor123. Thelatch29 is located within aclosed channel34 in themain body20 that is oriented perpendicular to thechannels23 and23a.Aspring member36 is located at theend35 of theclosed channel34 between theend35 and thelatch29. Thespring36 biases thelatch29 in a closed position as illustrated inFIG. 20 and described below. Thelatch29 comprises a connectingend29athat extends into thechannel23 when thelatch29 is in its closed position. Thelatch29 further comprises anopening29bformed in part by acam surface29cending intip29d.When thelatch29 is in an open position (FIG. 19), thespring36 is compressed and thecam surface29aand thetip29dare recessed into theclosed channel34. When thespring36 is released, thelatch29 moves into the closed position where thecam surface29aextends into thechannel23 and thecam surface29candtip29dextend into thechannel23a.
• In use, thelatch29 tends toward the closed position. In order to connect theanchor123 with themain body20, a connectingtool38 is inserted into thechannel23aand thetool38 engages thecam surface29cto move thelatch29 into the open position.Channel23aincludes an elastomeric, self-sealingplug23bwith a slit for receiving the connectingtool38. Theplug23bseals the opening in thechannel23afrom external fluids, etc. Thetool38 includes anotch39 in its distal end. Thetool38 may be locked into position in thechannel23aby rotating the tool so that thetip29dof thecam surface29cengages thenotch39. This prevents removal of thetool38 from thechannel23a.Thus thetool38 may be temporarily locked in thechannel23awith thelatch29 in an open position for insertion of theanchor123 into thechannel23. Thetool38 may be released when theanchor123 is in place, by rotating the tool so that thetip29dof thelatch29 no longer engages thenotch39 in thetool38. When connected, theelongate member124 of theanchor123 is located in thechannel23 and thelatch connector29aextends into the notch137 in theelongate member124, thereby connecting theanchor123 and themain body portion20. Alternatively, themain body portion20 may be connected to theanchor123 without the use of such a tool. In this case, theanchor123 causes the latch to retract as theanchor123 is inserted until the connectingend29aof the spring-loadedlatch29 locks into place in the notch137.
• Thetool38 may be used in a similar manner as described above, to remove themain body20 from theanchor123, for example to replace themain body20 or remove thestimulator10. Thetool38 is preferably a device that may be inserted through a lumen in an endoscope. In such case, thetool38 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 thestimulator10 ormain body20. 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 themain body20 in an aligned position with respect to theanchor123. The main body, anchor insertion tool or endoscope may have magnets that provide for aligned connection between themain body20 andanchor123.
• FIGS. 1-9 and15-17 illustrate an endoscope of the system of the present invention and the placement of theelectrical stimulator10 using the endoscope and associated instruments.FIG. 1 illustrates aflexible endoscope110 such as, for example, of a type that used by gastroenterologists in treating the upper gastrointestinal tract. Theendoscope110 is used to locate an attachment site in thestomach100 and attach thestimulator device10 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.
• As illustrated inFIGS. 7-9, the endoscope comprises an elongate tube having aproximal handle portion106 and adistal portion115. The endoscope includes anaspiration channel112 and irrigation/air channel113. A fiberoptic light source93 for illuminating the stomach site extends through a fiber optic channel. Avideo lens94 is located at the distal end of the endoscope, for receiving and focusing the image that is transmitted back through a channel in theendoscope110. Correspondinglight source input95,video output96,irrigation port97,aspiration port98 andauxiliary port99, are located on theproximal handle portion106.Knobs107 and108 are coupled at theproximal handle106 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. Theendoscope110 further includes anauxiliary channel114 extending through theendoscope110 and providing an opening through which surgical instruments may extend to reach thesite105. An additional auxiliary port may be provided for additional instruments or alternatively, theaspiration channel112 may be used for additional tools if not otherwise required in a procedure. Thedistal portion115 of theendoscope110 includes an opendistal tube116, the end of which is placed against the stomach wall at thesite105. Thedistal tube116 provides a space for stomach tissue to enter and be held in place when a vacuum pressure is applied.
• During the procedure the patient is given a numbing agent that helps to prevent gagging. As shown inFIG. 2 aprotective overtube111 with theendoscope110 is passed through themouth101,pharynx102, into theesophagus103 and opening into thestomach100. Theovertube111 is used to protect the esophagus, which may become irritated with repeated insertion and removal of instruments. Theovertube111 also helps prevent instruments and devices from inadvertently dropping into the trachea. In addition, theovertube111 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 inFIG. 9, the overtube11amay also include additional channels11aand11bfor inserting additional instruments.
• 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 inFIG. 3, theendoscope110 is extended distally out of theovertube111 and is used to locate asite105 on thestomach100 for attaching thestimulator10. 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.
• As shown inFIGS. 4-6 anintroducer117 is inserted through theauxiliary channel114. Theintroducer117 comprises anouter cannula118, adilator119 extending through thecannula118, and aneedle120 extending through thedilator119. Each of the cannula,118,dilator119 andneedle120 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 opendistal tube116 is located at asite105 in thestomach100, a vacuum pressure is applied through theaspiration channel112 to engage, stabilize and hold the tissue at thesite105. As illustrated inFIG. 4, theneedle120 is advanced distally through the tissue of the stomach wall. As illustrated inFIG. 5, thedilator119 is then advanced over theneedle120 through the stomach wall. Theneedle120 is then retracted proximally out of thedilator119 and is removed from theendoscope110. Thecannula118 is advanced over thedilator119 and thedilator119 is removed proximally from theendoscope110.
• As illustrated inFIG. 6, with thecannula118 through the stomach wall, theanchor123 may be placed into thecannula118 from the proximal end of the endoscope. Using apush tube122 having a diameter that is small enough to fit within thecannula118, placed proximally of theanchor123, theanchor123 is distally advanced through thecannula118 located within the stomach wall (FIG. 10).
• Thepush tube122 pushes theanchor123 through thecannula118 until the expandabledistal end125 extends out of the stomach wall in the peritoneal cavity. (FIG. 11) Before insertion, atether131 is secured to theopening130 and extends through thepush tube122 out of the proximal end of theendoscope110. The expandabledistal end125 is formed of an elastic or spring material that tends to spring open into its expanded shape when thedistal end125 is no longer constrained by thecannula118. (FIG. 11). Once theanchor123 is in place, thecannula118 is withdrawn from theendoscope110 and theendoscope110 may also be removed from the over tube111 leaving thetether131 in place extending from theanchor123 out of through the overtube111 and out of the patient'smouth101. Thetether131 is to be used to guide themain body20 of the stomach to theanchor123. Thetether131 may comprise a thread or suture-like device or may be a thin flexible guide wire like device. Thetether131 may be tied or otherwise anchored to hole130 inanchor123 or it may be looped throughhole130 inanchor123 such that two strands lie parallel to each other in theovertube111 and pass out of the patient's mouth.
• FIGS. 15-17 illustrate a preferred procedure for connecting themain body portion20 of thestimulator10 to theanchor123 in place in the stomach wall. Themain body20 is threaded on to thetether131 that is attached to theanchor123 through thechannel23 in themain body20. Thetether131 which extends through the overtube111, guides thechannel23 to theelongate member124 of theanchor123 for attachment. The threadedmain body portion20 is preferably placed within the overtube111 with theendoscope110 located proximal of themain body portion20 within theovertube111. Thetether131 is also preferably threaded through theovertube111, placed in parallel with theendoscope110 through theovertube111 or one of its channels11a,11b.The tether may be placed in a lumen extending through theendoscope110.Tool38 extends through theauxiliary channel114 and is coupled distally of thedistal end115 of the endoscope, to themain body20 through thechannel23a.Theendoscope110distal portion115 also engages themain body portion20 and provides a force to move themain body portion20 through the overtube111. (FIG. 15). Theendoscope110 further provides visualization of the coupling process. Thetool38 andtether131 together further locate themain body portion20 with theanchor123 as it extends through thestomach100 to thesite110. (FIG. 16). Finally, thetool38 provides additional force to attach the main body portion to the anchor123 (FIG. 17). Thetool38 is then removed from thechannel23ain themain body20 and out of the endoscope's proximal end. Alternatively themain body20 may be placed in position, coupled to theanchor123 by using thetether131 and thedistal portion115 of the endoscope to guide themain body20 into place. (See e.g.,FIGS. 15-17). In an alternative embodiment, a magnetic docking system is used wherein thedistal end115 of theendoscope110,main body20, and/oranchor123 includes a magnet and/or corresponding metal used to align and position theanchor123 andmain body20 with respect to each other.
• After themain body portion20 has successfully been coupled to theanchor123, an endoscopic scissor or other cutting device may be provided through theauxiliary channel114 in theendoscope110 to cut thetether131. As illustrated inFIG. 14, when the stimulator is attached to the stomach wall, the stimulatingelectrode32 is located within the tissue of the stomach wall, providing electrical contact. While the secondstimulating electrode32 on thedistal face26 interfacing with thestomach100, is in electrical contact with theinner surface100bof the stomach wall.
• FIGS. 23 and 24 illustrate a second embodiment of the stimulator of the present invention.Stimulator210 comprises amain body portion220 and ananchor223. Theanchor223 comprises an elongateproximal member225. The elongateproximal member225 includes atether opening235 in the proximal end,electrical contacts228,238, and anotch227 for connecting themain body portion220 to theanchor223. Thedistal portion240 of theanchor223 comprises twoprongs241,242.Prongs241,242 have expandable distal ends243,244 respectively that are constructed in a similar manner as the expandabledistal end125 described above with respect to the first preferred embodiment. A stimulatingelectrode245 is located onprong241 and an electrically opposite secondstimulating electrode246 is located onprong242. Stimulatingelectrode245 and secondstimulating electrode246 are coupled toelectrical contacts228 and238 respectively byconductors229 and239 extending throughprongs241,242 respectively into the elongateproximal member225.Prongs241 and242 are connected by aspacer237.
• Main body portion220 includes a channel215 with an opening216 on thedistal face226. The channel215 and the opening216 on the distal face have shapes that allow them to respectively receive the elongateproximal member225 and thespacer237, thereby sealing the opening216. Theelectrical contacts228,238 to theanchor223 are coupled to electrical contacts within the channel215 of themain body portion220 in a manner similar to the coupling ofcontacts128,128aand128bofanchor123 andcontacts28,28a,and28bofmain body portion20 described with reference to the first embodiment herein. Also thenotch227 engages a latch similar to thelatch29 described above. Thenotch227 and latch and theelectrical contacts228,238 are isolated from the acidic environment of the stomach using seals such as theseals27 described above with respect to the first embodiment. Alternatively, theelectrodes245,246 may be constructed in a manner similar toelectrode32 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 theelectrodes245,246 are located on the main body portion).
• The anchor prongs241,242 may be deployed in a similar manner asanchor123 is deployed, using a dual needle introducer or, alternatively by deploying eachprong241,242 independently and later connecting theprongs241,242 with thespacer237.
• In use, once the stimulator (e.g.,10,210,310 or380) is deployed, electrical stimulation is provided throughelectronic circuitry25. Theelectronic circuitry25 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 waveform1 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 waveform2 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 thecircuitry25, the principal focus being providing electrically stimulating parameters for the stomach.
• A preferred embodiment of theelectronic circuitry25 is illustrated inFIG. 25. Theelectronic circuitry25 of the stimulator is located in the main housing. Thecircuitry25 comprises, a microprocessor orcontroller40 for controlling the operations of theelectronic circuitry25, aninternal clock41, andbattery device44 such as a pair of lithium iodine batteries for powering the various components of thecircuit25. As such, thecontroller40 andbattery device44 are coupled to each of the major components of the circuit as would be apparent to one of ordinary skill in the art. Thecontroller40 is coupled tostimulation driver42, which is coupled to stimulating electrodes (e.g.,126,32 or245,246,266,267,326,327,356,357,524,525 that are used to provide electrical stimulation in accordance with programmed parameters
• Thecontroller40 is coupled toROM43, which contains the program instructions for thecontroller40 and any other permanently stored information that allows the microprocessor/controller40 to operate. Thecontroller40 addresses memory inROM43 throughaddress bus43aand theROM43 provides the stored program instruction to thecontroller40 viadata bus43b.Thecontroller40 controls thetelemetry coil45, which communicates with an external control or programming device60 (FIG. 26), preferably via a modulated RF signal.Processor40 is coupled to anoscillator51 that provides an RF signal to be emitted from thetelemetry coil45. The RF signal is preferably at about 500 kHz or higher so that the signal is efficiently transmitted through tissue. Thecontroller40 controls theoscillator51 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 thetelemetry coil45.
• Thecircuit25 may also be coupled through A/D converters46a,46b,46c,46dto one ormore sensors47a(e.g., strain gauge),47b(e.g., pressure), orelectrodes32,126. Suitable types of these sensors are generally known in the art and may be located within, on, or external to thehousing21 of themain body portion20.Controller40 is coupled to RAM50 via anaddress bus50afor addressing a location inRAM50 and abi-directional data bus50bfor delivering information to and fromRAM memory50. TheRAM memory50 includesevent memory48 that temporarily stores data recorded bysensors47a,47b,32 and126 and aprogrammable memory49 which may be programmed, for example, by anexternal programmer60, to provide treatment protocols, e.g. to specify operating modes such as waveform, frequency, etc. Thestrain gauge47ais coupled through A/D converter46a,which converts the representative electrical signal output by the strain gauge into a digital signal, which is delivered to the microprocessor/controller40 and stored in theevent memory48 in theRAM50. Thesensor47bis coupled through A/D converter46b,which converts the representative electrical signal output by thesensor47binto a digital signal, which is delivered to the microprocessor/controller40 and stored in theevent memory48 in theRAM50. Theelectrodes32,126 are coupled through A/D converters46cand46dto themicroprocessor40. A/D converter46cconverts the electrical EMG signal sensed by theelectrodes32,126 into a digital signal representative of the EMG electrical activity, which is delivered to the microprocessor/controller40 and stored in theevent memory48 in theRAM50. Also, the A/D converter46dconverts the electrical signal sensed by theelectrodes32,126 and provided through theimpedance circuit53 described below, into a digital signal representative of tissue impedance, which is delivered to the microprocessor and stored in theevent memory48 in theRAM50. The data stored in theevent memory48 may be sent intermittently as data bursts via thetelemetry RF coil45, as opposed to continuously in order to save battery power.
• Theelectrode32,126 outputs are used to provide electrical stimulation delivered through thestimulation driver42 to electrodes. The stimulation modes and parameters can either be set using theexternal programmer60, or they may be set in response to sensory feedback. The same electrode outputs are used to sense impedance throughimpedance circuit53 and to sense electrical activity which is delivered throughdriver56c.Theelectrodes32,126 are coupled throughcoupling capacitors55aand55brespectively, to output ofelectrical stimulation driver42 and input ofdrivers56c,56d.
• Theimpedance circuit53 comprises a constantcurrent source oscillator54 that oscillates at a frequency of 50-100 kHz, and adriver56dcoupled through A/D converter46d to thecontroller40. Theoscillator54 provides a constant current source throughelectrodes32,126 resulting in a voltage across theelectrodes32,126 that is representative of impedance, in view of the constant current. The voltage is provided throughdriver56dand is converted by A/D converter46dto a digital signal representative of impedance.Driver56dhas a bandwidth that includes the50kHz frequency signal while filtering out the electrical stimulation signal that is delivered to theelectrodes32,126 throughelectrical stimulation driver42, and the EMG signal that is sensed by theelectrodes32,126. Both of the outputs are filtered out bydriver56d.Driver56cwhich delivers the EMG signal to A/D converter46c,also has a bandwidth that filters out the 50-100 kHz signal. Further, when a stimulation signal is being delivered, thecontroller40 does not receive signals from A/D converters46cand46d.Thus the EMG and impedance sensing functions and the stimulation deliver functions are separated through theelectronic circuitry25, though using the same electrodes.
• FIG. 26 illustrates theelectronic circuitry63 forexternal programmer60. Theelectronic circuitry63 comprises: a microprocessor orcontroller70 for controlling the operations of the electronic circuitry, aninternal clock71, and apower source74 such as battery device for powering the various components of thecircuit63. As such, thecontroller70 andbattery device74 are coupled to each of the major components of the circuit as would be apparent to one of ordinary skill in the art. Thecontroller70 is coupled to aspeaker67 for that provides audible alerts and adisplay66 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). Thecontroller70 is coupled through abuffer64 toexternal input device65 that is used to provide program parameter input, e.g. from a user, for a user to request data displayed in a desired format throughdisplay66 orspeaker67, or to turn device on and off. Theexternal programmer60 is also provided with anexternal data port68 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/microprocessor70. 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.
• Thecontroller70 is coupled toROM73, which contains the program instructions for thecontroller70 and any other permanently stored information that allows the microprocessor/controller to operate. Thecontroller70 addresses memory inROM73 throughaddress bus73aand theROM73 provides the stored program instruction to thecontroller70 viadata bus73b.Thecontroller70 controls thetelemetry coil75, which communicates with stimulator electronics25 (FIG. 25) through itstelemetry coil45.Processor70 is coupled to anoscillator72 that provides an RF signal, preferably having a characteristic frequency of 500 kHz or higher, to be emitted from thetelemetry coil75. Thecontroller70 controls theoscillator72 and provides data to be modulated with the RF signal, for example, programming information, stimulation parameters, etc. Thetelemetry coil75 also receives information transmitted via RF signal fromtelemetry coil45 on thestimulator10 such as various sensed data, e.g., pressure, pH, impedance, electrical activity (EMG) etc. The received RF signal is passed through A/D converter76 and is transmitted to thecontroller70. The data is delivered to theevent memory78 inRAM77 by way ofdata bus77bfor temporary storage. The data may be retrieved fromRAM77 by addressing the storage location via theaddress bus77a.
• Event memory78 temporarily stores data recorded by sensors47a-47cand delivered via telemetry to theexternal programmer60, until the data is downloaded onto a computer using theexternal data port68. TheRAM77 also includes aprogrammable memory79 which may be programmed, for example, to specify operating modes such as waveform, frequency, etc which programming is then telemetrically communicated to thestimulation device10,210. The modes and parameters can either be set using anexternal programmer60 or set in response to sensory feedback.
• 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. Theanchor263 comprises anelongate body264, an expandabledistal portion265 having asharp tip270, abipolar electrode pair266,267, and abumper275 located on a proximal portion of theelongate body264. The expandabledistal portion265 comprises aflexible disk271 for engaging the outer stomach wall. Thedisk271 has an inner surface271 a that interfaces with theouter surface100aofstomach wall100 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 compriseselectrode266 located on theelongate body264 and a plurality ofelectrodes267 electrically opposite fromelectrode266, located at the end of the expandabledistal portion265. 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.Electrode266 is ring extending circumferentially around theelongate body264.Electrodes267 are circumferentially spaced from each other around the radial extremity271b of thedisk271. As an alternative to a plurality ofelectrodes267 the electrode located on the disk may be a single ring electrode.Electrodes266,267 are electrically coupled to a main body portion containing electronic circuitry (not shown) that is attached in a manner similar tomain body portion20 described above. Conductors268,269electrically couple electrodes266,267 respectively to the electronic circuitry of the main body portion.
• Theanchor263 may be deployed without requiring an introducer such as described above with reference toFIGS. 4-6. As illustrate inFIG. 27A, thesharp tip270 is used to pierce thestomach wall100. Theflexible disk271 folds within recessed portion265aextending around the distal portion of theanchor263 so that thedisk271 is flush with the outer surface of theelongate body264 and forms a taper to thesharp tip270. Thetip270 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 theelongate body264.
• Referring toFIG. 27B as thedistal portion265 of theanchor263 extends through the stomach wall, theexpandable disk271 opens. Theanchor263 is retracted slightly so that the radial extremity of thedisk271 engages theouter surface100aof thestomach wall100, preventing proximal movement of theanchor263. Theelectrodes267 are in electrical contact with theouter surface100aof the stomach wall. Theelectrode266 on theelongate body264 is embedded within thestomach wall100 and is in electrical contact with the tissue therein. Thebumper275 may be advanced distally so that is engages theinner surface100band secures theanchor263 in position, preventing distal movement. Preferably thebumper275 and thedisk271 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 thestomach wall100. Thebumper275 may be secured in position by a ratchet mechanism or other means such as a frictional fit. Thetip270 is constructed of a bioabsorbable material such a glucose based absorbable material or polyglycolic acid or polylactic acid, so that thesharp tip270 readily dissolves and is absorbed by the body, preventing the tip from injuring tissue external to the stomach.
• FIGS. 28A and 28B illustrate a fourth embodiment of the present invention showing a stimulator.Stimulator310 comprises ananchor323, anelectronics unit320 andelectrodes326,327 coupled byleads328,329 respectively to theelectronics unit320. Thestimulator310 is attached to theinner surface100bof thestomach wall100 byanchor323 which may be constructed or attached in a manner similar toanchors123,223,or263 described above, either with or without electrodes. Theelectrodes326,327 are anchored into thestomach wall100 withanchors324,325 respectively. Referring toFIG. 28B, ananchor325 is shown deployed in thestomach wall100.Lead329 extends from themain body portion320 through the stomach to thesite105 where stimulation is desired. Theanchor325 is preferably constructed in a manner similar toanchor263 with a bioabsorbable or resorbable tip and so that theelectrode327 is embedded in thestomach wall100. 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 orbumper321 operates to preventanchor325 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.Anchor324 is deployed in a similar manner withelectrode326 embedded in thestomach wall100 at thesite105 for stimulation. Preferably the stimulatingelectrodes326,327 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 themain body20 delivers electrical stimulation in a manner similar to thestimulation device10 described above.
• Referring now toFIGS. 29A and 29B, an alternative instrument is illustrated for placing an anchor from theinner surface100bof thestomach wall100 through to theouter surface100aof the stomach wall. Theinstrument330 comprises a hollow piercingneedle331 having alumen332 therethrough and a stomach piercing tapereddistal end333. Aguide wire334 extends through thelumen332 in theneedle331. Theneedle331 is relatively stiff to allow it to pierce the stomach wall while theguide wire334 is more flexible. As illustrated inFIG. 29A, thedistal end115 of the endoscope is located at a desired site on the inside100bof thestomach wall100. A vacuum pressure is applied to the wall to stabilize it and theneedle331 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 inFIG. 29B, theneedle331 is removed, leaving theguide wire334 in place. Preferably, theinstrument330 is inserted through theauxiliary channel114 in the endoscope or through achannel111aor111bin the overtube111 and then is located to the desired site using theendoscope110 for visualization.
• Referring toFIGS. 30A and 30B, ananchor340 is illustrated placed into thestomach wall100 over theguide wire334. Theanchor340 includes anelongate member341 that is to be placed through thestomach wall100 in a direction substantially perpendicular to the stomach wall. Theanchor340 has adistal portion343 that is to at least partially extend through the stomach wall, and aproximal portion342 having a threadedproximal end342afor engaging with a threaded end of an instrument used to advance theanchor340 into place. Theanchor340 includes aguide wire lumen345 extending through theanchor340 from theproximal portion342 to thedistal portion343 with an opening in theproximal portion342 anddistal portion343 for receiving theguide wire334 of theinsertion instrument330. As shown inFIG. 30A, theanchor340 is inserted over theguide wire334 which guides theanchor340 into position through thestomach wall100. Theguide wire lumen345 at thedistal portion343 of theanchor340 is sealed with a self-sealingplug344 formed of an elastomer and having a slit along theplug344 so that theguide wire334 can open theplug344 while theguide wire334 extends through thelumen345.
• Anexpandable member348 is located on thedistal portion343 of theanchor340. Theexpandable member348 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 thedistal portion343 of theanchor340 and providing aninflation chamber350. 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). Aninflation lumen351 extends from an opening in theproximal portion342 to anopening349 in thedistal portion343. Theopening349 in theinflation lumen351 is in fluid communication with the inner chamber of theexpandable member348 so that an inflation medium may be supplied through the inflation lumen to inflate theexpandable member348. As illustrated inFIG. 30B, theanchor340 is placed in the stomach wall and theexpandable member348 is inflated by supplying theinflation chamber350 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 lumen151. The polymer thus allows the balloon to conform to the outer stomach wall and surrounding tissue to secure theanchor340 toouter surface100aof 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 theanchor340 in place while having sufficient surface area and being malleable enough that the anchor is sealed into place in a relatively atraumatic manner.
• Theanchor340 further comprisesratchets365 on the outer circumference of theelongate member341 and a sealingbumper ring366 having anopening367 forming an inner circumferential wall withratchet teeth368 for engaging theratchets365 on theelongate member341. Thebumper ring366 is moveable in a distal direction to sealingly secure theanchor340 to the stomach wall and prevent distal movement of theanchor340. Thebumper ring366 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.
• Theanchor340 further compriseselectrode lumens346,347 havingopenings346a,347ain theelongate member341.Conductor members352,353 extend through theelectrode lumens346,347, respectively, and include flexible conductors insulated along their length. Theflexible conductor members352,353 are preferably constructed of an elastic or superelastic alloy with an insulative coating. Electricallyopposite electrodes356,357 are located ondistal portions360,361 of moveableflexible conductor members352,353 respectively. Exposedelectrical contacts354,355 are located on the proximal portions of theconductor members352,353. Theelectrical contacts354,355 are in electrical contact withcontacts362,363 respectively that are electrically coupled to contacts in a main body of a stimulator unit in a manner similar to the sealing electrical connection ofmain body20 andanchor123 described herein. Theadjustable electrodes356,357 are contained within theelectrode lumens346,347 when theanchor340 is initially placed as illustrated inFIG. 30A. Theadjustable electrodes356,357 are deployed within thestomach wall100 by advancing theconductors members352,353 distally through theelectrode lumens346,347 where theopenings346a,347a are configured to direct theelectrodes356,357 laterally from each other and within the stomach wall as illustrated inFIG. 30B. Theelectrodes356,357 are moved with respect to one another into a selectable optimal deployment position with an optimal distance between theelectrodes356,357.
• Anendoscopic instrument370 is used to place theanchor340, inflate theexpandable member348 and deploy theelectrodes356,357. Theinstrument370 is preferably used through theovertube111, an opening111 a or111 b in theovertube111 and/or through aninstrument channel114 in the endoscope110 (while the procedure is visualized through theendoscope110.) Theinstrument370 includes aninflation tube373 removably attached to theinflation lumen351 of theanchor340. Theinflation tube373 forms a continuous conduit with the inflation lumen351 a conduit through which an inflation medium is supplied to inflate theexpandable member348. Apush tube371 comprises a threadedend371a that engages theproximal end342aof theanchor340. Thepush tube371 is used to advance theanchor340 over theguide wire334. Aninner tube372 includesprongs374,375 that engage theconductor members352,353 and are used to advance theelectrodes356,357 into the stomach wall by pushing theinner tube372 while holding theanchor340 in place with thepush tube371. Theprongs374,375 comprise electrically conductive wires that extend within the insulative material of theinner tube372 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 theelectrodes356,357 or to measure the impedance of the stomach wall tissue between theelectrodes356,357. (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.
• After theanchor340 is in place, an inflation medium is supplied through theinflation tube373 to inflate theexpandable member348 adjacent the outside100aof the stomach wall. Theinflation tube373 has a thin walled region at its distal end where it joins theinflation lumen351. After theexpandable member348 is inflated, the inflation tube is removed by twisting or pulling the tube to break it away from theanchor340. Thepush tube374 serves to hold theanchor340 into place in the stomach wall as theinflation tube373 is disengaged. Thebumper ring366 is then advanced distally to engage the inner wall of the stomach withratchets365engaging ratchets368 to prevent further distal movement of the anchor through the stomach wall. After theanchor340 is in place, thepush tube371 may be removed by unthreading theend371a on thepush tube371 from the threaded end372aof theanchor340. A stimulator unit such as themain body portion20 described herein is coupled to theanchor340 in a manner similar to that described herein with reference to anchor123 withelectrical contacts354,355 coupled to the electronics unit within the stimulator through electrical contacts362,363.Electrical contacts362,363 are to be coupled to a stimulator unit in as similar manner as arecontacts28,28a,or28bdescribed herein.
• Alternatively the laterally extendingconductive members352,353 may be used to secure the anchor to the stomach wall without requiring an additional expandable distal portion.
• Referring toFIGS. 31A and 31B analternative stimulator380 is illustrated comprising amain body portion382 and ananchor383. Theanchor383 includes an expandabledistal end385 for securing the anchor to the stomach wall, seals398 for sealing the anchorelectrical contacts394,395 andelectrical contacts396,397 of the housing from the acidic environment of the stomach. Anotch384 in the anchor is arranged to engage alatch399 in themain body382 to couple theanchor383 and themain body382 together so thatcontacts396,397 of thehousing382 are in electrical contact withanchor contacts394,395, respectively. Theanchor383 further comprises insulatedflexible conductors386,387 extending from theanchor383. Theconductors386,387 are coupled to electrode anchors388,389 that are constructed and attached to the stomach wall in a manner similar to theanchors324,325 described herein with reference toFIGS. 28A and 28B.
• Referring toFIG. 32, astimulator510 is illustrated with electronics housing511 containingelectronics circuit25 that is electrically coupled toelectrodes524,525 throughleads521,522 extending out of thehousing511. Theelectrodes524,525 are attached to the stomach wall. Thehousing511 is anchored to the stomach wall by anchor portion514 which includes an expandabledistal portion515 and an elongateflexible portion516 coupling thedistal portion515 to thehousing511. The expandabledistal portion515 may be unfolded inflated or otherwise expanded, e.g., as a spring, from a first configuration to a second configuration. The expandabledistal portion515 has a surface area sa that interfaces with the stomach wall. The expandabledistal portion515 may be placed through the stomach wall and expanded in a manner similar, for example, to expandable ends125,271,348.
• The expandabledistal portion515,expandable end125,disc271, orinflatable member348 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/mm², preferably less than about 1 g/mm , and most preferably less than about 0.1 g/mm²An 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.
• 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 themain body20.
• 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.
• 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.
• 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.

Claims (23)

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 about5g/mm².

2. The anchor ofclaim 1 wherein the ratio is less than about 1 g/mm²

3. The anchor ofclaim 1 wherein the ratio is less than about 0.1 g/mm².

4. The anchor ofclaim 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 ofclaim 4 wherein the ratio is less than about 1 g/mm².

6. The anchor ofclaim 4 wherein the ratio is less than about 0.1 g/mm².

7. The anchor ofclaim 1 wherein the anchor is configured to be attached to the stomach wall.

8. The anchor ofclaim 7 wherein the anchor is configured to be attached to the antrum of the stomach.

9. The anchor ofclaim 7 wherein the second portion comprises an electrical stimulator.

10. The anchor ofclaim 7 wherein the second portion comprises an electrode configured to be attached to the stomach wall.

11. The anchor ofclaim 10 wherein the electrode is configured to be attached to the stomach wall with the first portion.

12. The anchor ofclaim 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 ofclaim 12 wherein further comprising a proximal elongate member coupled to the distal portion configured to extend through the gastrointestinal tract wall.

14. The anchor ofclaim 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/mm².

16. The anchor ofclaim 15 wherein the ratio is less than about 1 g/mm².

17. The anchor ofclaim 15 wherein the ratio is less than about 0.1 g/mm².

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/mm².

19. The method ofclaim 18 wherein the ratio is less than about 1 g/mm².

20. The method ofclaim 18 wherein the ratio is less than about 0.1 g/mm².

21. The method ofclaim 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 ofclaim 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 ofclaim 18 wherein the device further comprises a stimulator coupled to the anchor; and

further comprising the step of stimulating the gastrointestinal tract.

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