Abstract:
A gastrointestinal stimulation system includes a remote controlled capsule adapted for positioning in the gastrointestinal tract (GT) of a patient, in which the capsule is secured to the inner wall of the gastrointestinal tract (GT) of a patient by a magnetic coupling system. The capsule is configured to activate at least one chosen area of the patient&#39;s GI tract, including when desired, the vagus nerve, thereby facilitating gastro motility or having other interaction with the GI tract, such as monitoring thereof. The remote controlled capsule also may be configured to activate patient&#39;s lower esophageal sphincter (LES), stimulating the LES muscle and restoring the barrier between the stomach and the esophagus for treatment of Gastroesophageal reflux disease (GERD). The capsule also may be inserted to the anal canal for treatment of constipation.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims priority to U.S. Provisional Patent Application No. 61/714,756, filed on Oct. 17, 2012. 
     FIELD OF THE INVENTION 
     The present invention relates to systems for treating gastrointestinal disorders. 
     BACKGROUND OF THE INVENTION 
     There are known in the art various devices for the electrical stimulation of the vagus nerve or other portions of gastrointestinal tract (GT), in order to provide relief or treatment of gastrointestinal disorders. Such devices are also known for the treatment of obesity. 
     The known art includes US patent application publication no. 2003/0114895 A1 and U.S. Pat. Nos. 5,423,872, 5,690,691, 6,098,629, 6,285,897, 6,453,199, 6,571,127, 6,689,056, 6,889,076, 7,076,305, 7,107,100, 7,221,978, 7,738,961, 7,840,269 and 8,160,709. 
     SUMMARY OF THE INVENTION 
     The present invention provides a gastrointestinal stimulation system including a remote controlled capsule adapted for positioning in the gastrointestinal tract (GT) of a patient, in which the capsule is secured to the inner wall of the gastrointestinal tract (GT) of a patient by a magnetic coupling system. The capsule is configured to activate at least one chosen area of the patient&#39;s GI tract, including when desired, the vagus nerve, thereby facilitating gastro motility or having other interaction with the GI tract, such as monitoring thereof. The remote controlled capsule also may be configured to activate patient&#39;s lower esophageal sphincter (LES), stimulating the LES muscle and restoring the barrier between the stomach and the esophagus for treatment of Gastroesophageal reflux disease (GERD). The capsule also may be inserted to the anal canal for treatment of constipation. 
     There is thus provided in accordance with an embodiment of the invention, a gastrointestinal electro stimulation system including: 
     (I) a remote controlled capsule adapted for ingression into the gastrointestinal tract of a patient, 
     (II) a remote control device for controlling and sharing information with the capsule, and 
     (III) a magnetic coupling system for securing the capsule within the gastrointestinal tract of the patient, 
     wherein the capsule has a main body main body portion and a plurality of electrodes arranged in electrical isolation from each other, the capsule containing:
         (a) a first RF transceiver operative to receive capsule operating instructions from and to transmit information to the remote control device;   (b) a capsule control unit electrically coupled to the first RF transceiver and operative to process the received operating instructions;   (c) a pulse generator electrically coupled to the capsule control unit and to the electrodes and configured to activate the electrodes so as to emit electrical stimuli pulses in accordance with the operating instructions; and   (d) a power supply for supplying electrical power to the first RF transceiver, to the control unit and to the pulse generator,       

     wherein the remote control device includes:
         (e) a system control unit operative to generate the operating instructions;   (f) a second RF transceiver coupled to the system control unit and configured to transmit the operating instructions and to receive information from the first RF transceiver, and       

     wherein the magnetic coupling system includes:
         (g) a first magnetic element associated with the capsule and a second magnetic element configured for placement externally of the body of patient,       

     wherein selectable operation of the pulse generator is operative to expose to electrical stimuli a portion of the gastrointestinal tract where the capsule is secured. 
     Additionally in accordance with an embodiment of the invention, the first magnetic element includes a permanent magnet arranged within the capsule. 
     Further in accordance with an embodiment of the invention, the system also includes position sensor apparatus for sensing the position of the capsule. 
     Additionally in accordance with an embodiment of the invention, the position sensor unit includes a magnetic field sensor. 
     Further in accordance with an embodiment of the invention, the position sensor apparatus includes: 
     a capsule position verification system having two or more electrodes located externally of the patient; 
     a recording module connected to the two or more externally located electrodes, and having an output adapted to provide capsule position output data to the system control unit of remote control device. 
     Additionally in accordance with an embodiment of the invention, the capsule and the contents thereof have a specific weight approximately equal to the specific weight of stomach juices. 
     Further in accordance with an embodiment of the invention, wherein the capsule also contains one or more sensors of a predetermined type coupled to the capsule control unit, wherein the one or more sensors is selected from the group which consists of: 
     a pH-sensor, 
     a pressure sensor, 
     an electric impedance sensor, 
     a temperature sensor, and 
     an electrical muscular activity sensor. 
     Additionally in accordance with an embodiment of the invention, the capsule is further adapted for egression from the pyloric region of the gastrointestinal tract after at least a predetermined dwell time therein, and wherein main body portion of the capsule includes:
         one or more gastric juice-responsive expandable elements adapted for storage within a storage compartment formed within the main body portion of the capsule; and       

     a gastric-juice responsive cover for the storage compartment which when closed, prevents the one or more expandable elements from exposure to gastric juices and, when open, facilitates exposure of the one or more expandable elements to gastric juices such that the element expands so as to be forced out of the storage compartment and so as to increase the overall size of the capsule system thereby preventing the system from egression from the pyloric region of the stomach; 
     wherein the one or more expandable elements are connected to the main body portion of the capsule by means of a gastric-juice responsive releasable connector element. 
     Further in accordance with an embodiment of the invention, the gastric-juice responsive cover is formed of a first gastric-juice soluble substance which is soluble at a first predetermined rate so as to permit exposure of the expandable element to gastric juices after a first dwell time in the gastrointestinal tract of a patient, and 
     the gastric-juice responsive releasable connector element is formed of a second gastric-juice soluble substance which is soluble at a second predetermined rate so as to dissolve the connector element after a second dwell time in the gastrointestinal tract of a patient, the second dwell time being longer than the first dwell time, 
     wherein dissolution of the connector element causes detachment of the one or more expandable elements from the main body portion of the capsule, thereby permitting egression of the capsule from the gastrointestinal tract. 
     Additionally in accordance with an embodiment of the invention, each the expandable element is adapted to expand to a size which is sufficiently small to permit egression thereof from the gastrointestinal tract. 
     In accordance with a further embodiment of the invention, there is provided an extendible capsule adapted for ingression into the gastrointestinal tract of a patient, which includes: 
     first and second capsule portions;
         a resilient element disposed between the first and second capsule portions for normally urging them apart into an extended arrangement; and       

     a gastric juice-responsive release unit operative to retain the first and second capsule portions in a non-extended arrangement in a first operative state of the capsule, and further operative, in response to contact with gastric juices for at least a predetermined period of time to permit the capsule to move into a second operative state by mutual extension of the first and second capsule portions thereby to extend the effective length of the capsule. 
     Additionally in accordance with an embodiment of the invention, the gastric juice-responsive release unit includes: 
     a first gastric juice-responsive locking element for resisting an urging force of the resilient element, thereby locking together the first and second capsule portions in the non-extended arrangement when the capsule is in the first operative state; and 
     a second gastric juice-responsive, selectably releasable locking element operative to maintain a mechanical connection between the first and second capsule portions when the capsule is in the extended arrangement in the second operative state, wherein the first and second locking elements are adapted to selectably disconnect the first and second capsule portions from each other so as to move the capsule into a third operative state, 
     wherein, when the capsule is in the first operative state, the first locking element is deactivated, such that the resilient element is operative to force the first and second capsule portions and thus the capsule into the extended arrangement of the second operative state, 
     and wherein, the second locking element is subsequently deactivated so as to disconnect the first and second capsule portions from each other such that the capsule splits into two portions and moves into the third operative state. 
     Further in accordance with an embodiment of the invention, the gastric juice-responsive release unit is formed of a solid substance which is soluble in gastric juices. 
     Additionally in accordance with an embodiment of the invention, 
     the first gastric juice-responsive locking element is formed of a first gastric-juice soluble substance which is soluble at a first predetermined rate so as to permit extension of the capsule after a first dwell time in the gastrointestinal tract of a patient, and 
     the second gastric juice-responsive locking element is formed of a second gastric-juice soluble substance which is soluble at a second predetermined rate so as to disconnect the first and second capsule portions from each other permit after a second dwell time in the gastrointestinal tract of a patient, the second dwell time being longer than the first dwell time. 
     Further in accordance with an embodiment of the invention, the first capsule portion includes a main body portion formed of a dielectric material, and a first electrode, and the second capsule portion includes a second electrode, 
     wherein the first capsule portion contains:
         (i) an RF transceiver operative to receive capsule operating instructions from a remote control unit and to transmit information thereto;   (ii) a capsule control unit electrically coupled to the RF transceiver and configured to process received operating instructions;   (iii) a pulse generator electrically coupled to the capsule control unit and to the first and second electrodes and configured to activate the first and second electrodes so as to emit electrical stimuli pulses in accordance with the processed operating instructions, and   (iv) a power supply for supplying electrical power to the RF transceiver, to the control unit and to the pulse generator,       

     and wherein upon extension of the capsule, the first and second electrodes are moved laterally apart so to increase the distance between them, and thus to expose a greater portion of the GI tract to the electrical stimuli pulses. 
     There is also provided, in accordance with yet a further embodiment of the invention, for use with a gastrointestinal capsule system which includes a capsule adapted for ingression into the gastrointestinal tract of a patient, and a magnetic coupling system for securing the capsule within the gastrointestinal tract of the patient, wherein the coupling system has a first magnetic element associated with the capsule and a second magnetic element configured for placement externally of the body of the patient, 
     one or more capsule-securing devices implantable in the wall of the gastrointestinal tract at selected locations, the capsule-securing device including: 
     a location pin; and 
     a third magnetic element associated with the location pin, 
     wherein, when the capsule is located within the gastrointestinal tract of the patient, movement of the second magnetic element, externally of the patient&#39;s body, to a position corresponding to that of the capsule-securing device, causes a corresponding movement of the first magnetic element and a consequent magnetic coupling of the first and the third magnetic elements, thereby to position the capsule at the selected location in the gastrointestinal tract. 
     Additionally in accordance with an embodiment of the invention, the location pin includes: 
     a pin head having an upper surface to which the third magnetic element is secured and a lower surface for engaging the wall of the gastrointestinal tract when implanted therein; and 
     a pin shaft extending from the lower surface and having a serrated outer edge for mechanically securing the device to the inner wall of the gastrointestinal tract. 
     Further in accordance with an embodiment of the invention, the system is a gastrointestinal system and the capsule is used for gastrointestinal electro stimulation, and wherein the capsule-securing device is formed of an electro-conductive material. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention is herein described, by way of example only, with reference to the accompanying drawings, in which like components are designated by like reference numerals, wherein: 
         FIG. 1A  is a schematic representation of a gastrointestinal (GT) stimulation system, constructed and operative in accordance with a preferred embodiment of the present invention; 
         FIG. 1B  is a schematic representation of the capsule depicted in  FIG. 1A , in accordance with a preferred embodiment of the present invention; 
         FIG. 2  shows a Nerve Conduction Study system electrically coupled to at least one branch of the vagus nerve or other chosen region of the GT of a patient for sensing the location of the capsule relative thereto, in accordance with an embodiment of the present invention; 
         FIG. 3  shows the capsule secured at different locations in the GT for treating different gastro disorders, in accordance with an embodiment of the present invention; 
         FIG. 4A  shows a general view of a capsule, in accordance with another embodiment of the present invention; 
         FIG. 4B  shows the capsule of  FIG. 4A  in an extended state following ingression thereof into the GT, in accordance with another preferred embodiment of the present invention; 
         FIG. 5A  shows a general view of a capsule, in accordance with yet another embodiment of the present invention, in a first operative state; 
         FIG. 5B  shows the capsule of  FIG. 5A  in an extended, second operative state following ingression of the capsule into the GT; 
         FIG. 5C  shows the capsule of  FIGS. 5A and 5B  in a severed, third operative state; 
         FIGS. 6A-6C  show a capsule adapted to float on gastric juices, in accordance with a further embodiment of the present invention, in a first operative state; 
         FIG. 6D  shows the capsule of  FIGS. 6A-6C  in a deployed, second operative state, floating within the pyloric region of the patient&#39;s stomach; 
         FIG. 6E  shows the capsule of  FIGS. 6A-6D  in a disconnected, third operative state; 
         FIGS. 7A and 7B  show an implantable gastrointestinal tract capsule-securing device for securing a capsule adapted for ingression into the GT and having an integral electrode, in accordance with an embodiment of the present invention; 
         FIG. 8  shows use of the capsule of the invention in conjunction with a single device of  FIGS. 7A and 7B ; and 
         FIG. 9  shows use of the capsule of the invention in conjunction with a pair of the devices of  FIGS. 7A and 7B . 
     
    
    
     DETAILED DESCRIPTION 
     Reference is now made to  FIG. 1A , which is a schematic representation of a gastrointestinal stimulation system  10 , constructed and operative in accordance with an embodiment of the present invention. System  10  includes, inter alia, a remotely controlled capsule  12  and a control device  14  for controlling and monitoring the operation of capsule  12 . In use, capsule  12  is swallowed by a patient. After it has entered the gastrointestinal tract (GT)  16  of the patient it is secured to the inner wall  18  of the GT  16  by means of a magnetic coupling system, as described below. Capsule  12  may have an external enteric coating, which remains stable in the relatively less acidic juices (pH≈3) of the stomach, but dissolves in the alkaline juices (pH≈7-9) in the small intestine. Materials used for enteric coated may be, inter alia, fatty acids, waxes, Shellac, plastics, and plant fibers. 
     Control device  14  includes, inter alia, a system control unit  22  and a position sensor  24 . System control unit  22  is configured to receive input instructions and parameters from an operator and/or medical personnel in accordance with medical requirements of the patient, to provide capsule operating instructions and parameters to capsule  12  and to otherwise share information therewith. 
     Position sensor  24  senses, inter alia, the position of capsule  12 , as described below and is configured to locate capsule  12  at the required location in the GT  16 , in accordance with instructions received from the system control unit  22 . The system control unit  22  and the position sensor  24  intercommunicate via a communications link  31 . 
     There is also provided an RF transceiver  32  which communicates with system control unit  22  via a communications bus  34 . Capsule operation instructions and other data are transmitted to capsule  12  via a wireless communications link (not shown in  FIG. 1A ). 
     The parameters and information forwarded by the system control unit  22  to capsule  12  and received therefrom may also be forwarded to a user-notification device with a user interface (not shown). Thus, the operation of the stimulation system  10  may be monitored and controlled by the operator and/or user. 
     The RF transceiver  32  also receives feedback information from capsule  12 , such as the location of capsule  12 , as described below. The RF transceiver  32  forwards the information to the system control unit  22 , which then forwards this information to the user-notification device for notifying the operator of the location of capsule  12 , as described below. 
     The required instructions and parameters for the operation of the stimulation system  10  are inputted via a suitable data input device associated with the control unit  22 . The data input device (not shown) may be a radio frequency (RF) operated remote control unit, an RF transmitter, an RF transceiver, a cellular telephone, a 3G cellular telephone, a smartphone, an ultrasonic transmitter, an ultrasonic transceiver, an infrared (IR) transmitter, an infrared transceiver, a Bluetooth® communication device, an iPod®, an iPAD®, an android tablet, a laptop computer, any suitable device with wireless communication capability and any combinations thereof. Various portions of the system control system may be implemented as one or more Smartphone software application. 
     In alternative embodiments of the invention, RF transceiver  32  can be replaced by an ultrasonic transceiver for transmitting the capsule operating instructions to capsule  12  and for receiving feedback information from capsule  12 . In such an embodiment, capsule  12  may include a microphone or any type of acoustic sensor which is suitably linked to the control unit  22  and is operational to activate, deactivate and/or control the operation of capsule  12 . 
     The above-mentioned magnetic coupling system for coupling capsule  12  to control device  14  includes first and second magnetic elements, respectively referenced  40  and  42 . First magnetic element  40  is associated with capsule  12  and second magnetic element  42  is associated with control device  14  and is located externally to the patient&#39;s body. The position sensor  24  includes, inter alia, a magnetic field position sensor such as Hall Effect Sensor, which senses the position of capsule  12  within the GT  16 , by measuring the output voltage in response to a magnetic field. Preferably, first magnetic element  40  is located in main body portion  50  of capsule  12 , as described below in conjunction with  FIG. 1B . 
     Magnetic elements  40  and  42  may be formed of any of a variety of materials, such as a suitable ferromagnetic material, a ceramic composite, a ferrite composite, an injection molded magnet, a magnet constructed from a flexible material, such as FlexIRON™ and a rare-earth magnet, such as a Neodymium magnet. Additionally or alternatively, the magnetic element  42  is an electromagnet. 
     Reference is now made to  FIG. 1B , which is a schematic layout of capsule  12 , in accordance with an embodiment of the present invention. Capsule  12  has a main body portion  50  and at least first and second electrodes, respectively referenced  56  and  58 . It will be appreciated that there may be advantageously provided additional electrodes and that they are electrically isolated from each other. Typically, this is provided by forming the main body portion  50  of a dielectric material. Further, main body portion  50  and first and second electrodes  56  and  58  are sealed together in a suitable manner, which may be mechanical, bonding, welding and the like. Capsule  12  includes, inter alia, an RF transceiver  59  for transmitting capsule status information as well as for receiving capsule operating instructions and parameters from the remote control device  14  via the above-described communications link. Capsule  12  also includes a capsule control unit  60 , which is electrically coupled to the RF transceiver  59 . 
     It will be appreciated that electrodes  56  and  58  may be located on one side of capsule  12  only, and in this case, while dielectric main body portion  50  as it shown on  FIG. 1B  is not located in the center of the capsule. 
     Capsule control unit  60  receives data, such as the capsule operating instructions and parameters via RF transceiver  59 , and also provides data, such as capsule location information, to RF transceiver  59 , as shown. 
     The capsule control unit  60  includes a processor for processing instructions and parameters received via RF transceiver  59 . Unit  60  forwards to a pulse generator  64  instructions for the pulse generator  64  to generate pulses with specific parameters which conform to medical instructions inputted into the system  10  as described above. 
     Pulse generator  64  is operative to generate electrical stimuli pulses in accordance with the received instructions and parameters, and taking into consideration additional factors such as tissue impedance, forwarding pulses to the first and second electrodes  56  and  58 . The operating instructions conveyed from control device  14  to capsule  12  include the technical specifications of the stimuli pulses to be generated by the pulse generator  64 . These include the amplitude, frequency, and waveform and duty cycle of the pulses. 
     It is appreciated that the technical specifications of the stimulation signals are dependent on the gastro disorder to be treated, as described below. 
     Capsule  12  further includes a sensor unit  80  for sensing GT parameters and forwarding them to control unit  60 . Sensor unit may include one or more of a fluid pressure sensor, a fluid pressure gradient sensor, a temperature sensor, a pH-sensor, a bio-potential sensor, an acoustical sensor, a mechanical sensor (strain gauge for instance), an electrical conductivity sensor, an electric impedance sensor, a sensor for measuring muscle activity or any combination thereof. Control unit  60  forwards the received data to the RF transceiver  59 , which transmits the data to the control device  14  for analysis and interpretation by the operator. Sensor unit  80  thus enables the operator both to determine the location of capsule  12  and to monitor its operation. 
     A power supply  76 , which may be a direct current power source, an alternating current power source, a battery, a primary electrochemical cell, a rechargeable electrochemical cell, a mechanical power source, or any combination thereof, supplies electrical operational power to RF transceiver  59 , control unit  60 , pulse generator  64  and sensor unit  80 . 
     In addition, capsule  12  and all elements included therewithin as described above, preferably have a specific weight approximately equal to the specific weight of gastric juices. This enables capsule  12  to float thereon, thereby in turn enabling a user to relatively easily control the movement of capsule  12  by means of second magnetic element  42 . 
     Reference is now made to  FIG. 2 , which shows a muscular or gastric electrical activity positioning system  900  in operation while searching for the location of capsule  12  relative to a branch  934  of the vagus nerve, in accordance with a preferred embodiment of the present invention. 
     A Nerve Conduction Study (NCS) is a known non-invasive tool for measuring the speed of propagation or the rate at which an electrical impulse moves along a nerve. It is used for the diagnosis of disorders of the peripheral nerves and muscle. It is presently useful as a way of locating capsule  12  within stomach  16 , and works by measuring and monitoring action potential that propagates along the nerve as a result of electrical stimulation. In a conventional NCS the nerve is stimulated, usually by surface electrodes which are placed on the skin over the nerve at various locations. The resulting electrical activity, recorded by recording electrodes, is known to have a high correlation with the stimulating sequence delivered by the surface electrode. Accordingly, by measuring the time difference between the activities at the surface electrodes and the recording electrodes, and knowing the distance therebetween, it is possible to calculate the speed of propagation. A significant deviation from a ‘normal’ speed is an indication of the existence of neural pathological conditions. It will be appreciated that if the stimulating electrode does not deliver the stimulation to the nerve, no neural activity will be recorded. 
     In operation of system  10 , stimulating capsule  12  resides in stomach  16 . When properly located, it will stimulate one of the branches of the vagus nerve  934 . Excitation of the vagus nerve caused by operation of the capsule will propagate along the nerve, and can be identified by a surface detection and recording of the electrical activity of a proximal portion  938  of the vagus nerve. By way of example, recording surface electrodes  940  can be placed on the lower part of the patient&#39;s neck. The electrical signals detected by at least one pair of surface electrodes  940  are then transmitted to and analyzed by a recording and analyzing module  930 . Module  930  may be a separate device which is connected to the remote control device  14 , as shown, or it may be included within remote control device  14 . 
     The stimulation pattern delivered by capsule  12  is determined by the analyzing recording module  930 . The stimulation pattern may be either pre-defined or adaptive. With an adaptive scheme, capsule  12  can communicate the real time stimulation parameters to the analyzing device  930 . Since the frequency of stimulation is known, analyzing/recording module  930  can employ a filtering algorithm, which may be implemented in software, hardware, or both, in order to identify the frequency of evoked potentials propagating along proximal portion  938  of the vagus nerve. If the stimulating frequency of the evoked potentials is identified as being the same as that of the stimulation frequency, it means that the vagus nerve is being successfully stimulated. 
     If the stimulating frequency is not identified as being the same as that of the stimulation frequency, however, this is taken to mean that the nerve is not stimulated, and that the location of capsule  12  and/or the stimulating parameters, such as amplitude, should be changed. It is appreciated that due to the physical size of capsule  12 , it may advantageously positioned so as to be in proximity to other vagus nerve branches  936 , so as to cause stimulation of the nerve. 
     In operation, prior to the patient or “user” ingesting capsule  12 , the required region for the treatment by capsule  12  is typically externally marked on the patient&#39;s body. Positioning unit  900  is located outside the patient&#39;s body and in proximity to the required capsule location. 
     The above-described positioning system  900  operates as a feedback system. Following the securing of capsule  12  at the required location in proximity to vagus nerve branches  934  and  936 , the operator and/or medical personnel select the operational parameters for the required medical treatment, and thereafter input the relevant capsule operational parameters and activate capsule  12 . 
     Referring now also to  FIGS. 1A and 1B , the patient then swallows capsule  12  and after a short period of time, usually in the region of approximately 10 minutes, capsule  12  enters the fundus region of the patient&#39;s stomach. The operator activates the position sensor  24  which commences a search for first magnetic element  40  located within capsule  12 . Upon detecting the magnetic field generated by first magnetic element  40 , the position sensor  24  forwards a “magnet-found” signal to control unit  22 . 
     It will be appreciated that the present system may be used for treating different gastric disorders by adjustment of the operating parameters of the capsule electrodes. 
     For example, in order to generate a feeling of satiety so to control obesity, the values of the input parameters are typically in the following ranges: 
     Amplitude: 1-10 mA; 
     Frequency: 20-200 kHz, and 
     Waveform: symmetric or asymmetric 
     Reference is now made to  FIG. 3 , which shows capsule  12  secured at different locations in the stomach  16  for treating different gastro disorders, in accordance with a preferred embodiment of the present invention. 
     At the various stomach locations, different branches of the vagus nerve may be stimulated in accordance with required medical treatments. 
     Thus, for treating stomach disorders of the stomach&#39;s fundus region  124 , capsule  12  is positioned at location  126 , while in order to treat gastro disorders of the stomach&#39;s pyloric region  122 , capsule  12  is positioned at location  128 . 
     By activating capsule  12  so as to stimulate one or more branches of the vagus nerve in proximity to various stomach locations, it is possible to control and monitor the function of the stomach, such as digestion and removal of food therefrom. 
     Referring now also to  FIGS. 1A and 1B , on conclusion of the treatment protocol, stimulation system  10  is deactivated by inputting an appropriate “termination” instruction which is forwarded to capsule  12  via RF transceiver  32  to cease operation. Control unit  14  then forwards a “capsule-release” signal to position sensor  24  and an instruction for the operator or user to release the control device  14  from the patient&#39;s body, is displayed. 
     Reference is now made to  FIGS. 4A and 4B , which show an extendible capsule  1210  which is generally similar to capsule  12 , shown and described above in conjunction with  FIGS. 1A-3 , except as specifically described herein. Accordingly, components and portions of capsule  1210  are denoted in the drawings by reference numerals which are the same as their counterpart portions in  FIGS. 1A-3 , but with the addition of the prefix “10.” Furthermore, these components and portions are not specifically described again herein except as may be necessary to understand the present embodiment of the invention. 
     An important feature of capsule  1210  is that it is adapted for egression from the pyloric region of the gastrointestinal tract after at least a predetermined dwell time. This is described at greater length below. 
     Extendible capsule  1210  has first and second portions, respectively referenced  1052  and  1054  ( FIG. 4B ) and a resilient element  1018  disposed therebetween. First portion  1052  includes main body portion  1050  of extendible capsule  1210  and first electrode  1056 , and second portion  1054  consists of second electrode  1058 . A gastric juice-responsive release unit  1020  coats resilient element  1018  in a non-extended state ( FIG. 4A ) and is operative to retain first and second capsule portions  1052  and  1054  portions in the non-extended arrangement in a first operative state of said capsule. Release unit  1020  is further operative, in response to contact with gastric juices for at least a predetermined period of time to permit the extendible capsule  1210  to move into a second operative state by release of resilient element  1018  so as to cause mutual extension thereby of first and second portions  1052  and  1054 , thereby to extend the effective length of capsule  1210 , as seen in  FIG. 4B . 
     Resilient element  1018  includes an electrically-conductive expandable element  1017  ( FIG. 4B ) and a dielectric flexible membrane  1016 . Expandable element  1017  may be a metallic spring, a leaf spring, a helical spring, a leaf spring having two arms, a pair of rigid arms movably joined to a spring at their meeting point, shape memory alloy member or other suitable compression member, extending from pulse generator  64  ( FIG. 1B ) to second electrode  1058  so as to conduct electrical signals thereto. A dielectric flexible membrane  1016  ( FIG. 4B ) is provided so as to connect between main body portion  1050  and second electrode  1058 , and so as to surround and insulate expandable element  1017 . 
     An advantage of capsule  1210  having a non-extended, compact state initially is that it is easier to swallow. Due to the dissolution of the gastric juice-responsive release unit  1020 , the extendible unit  1018  expands so as to become fully deployed, and first and second electrodes  1056  and  1058  are moved apart. For example, if capsule  1210  when in a non-extended, first operative state has a length of 15 mm, after the gastric juice-responsive release unit  1020  is dissolved, the length of capsule  1210  may extend to approximately 30 mm. Extension of capsule  1210  renders it more likely that the electrodes will engage at least one branch of the vagus nerve or other selected region of the GT ( FIG. 3 ). 
     Gastric juice-responsive release unit  1020  is formed of a material that is dissolvable under different endo-luminal conditions, such as low pH, temperature and enzymatic degradation. Thus, release unit  1020  may be formed of a material known to dissolve in a predetermined portion of the stomach. Suitable materials include a biodegradable polymer, such as Poly(lactic-co-glycolic acid) (PLGA); any of a variety of sugars, for example, a caramel substance; or an enteric material. 
     Reference is now made to  FIGS. 5A-5C , which show an extendible capsule  1220 , constructed and operative in accordance with another embodiment. Capsule  1220  is generally similar to capsule  1210 , shown and described above in conjunction with  FIGS. 4A-4B , except as specifically described herein. Accordingly, components and portions of capsule  1220  are denoted in the drawings by reference numerals which are the same as their counterpart portions in  FIGS. 4A-4B , but with the addition of the prefix “10” by the prefix “20”. Furthermore, these components and portions are not specifically described again herein except as may be necessary to understand the present embodiment of the invention. 
     Extendible capsule  1220  has first and second portions, respectively referenced  2052  and  2054  ( FIG. 5C ) and resilient element  2018  disposed therebetween. First portion  2052  includes main body portion  2050  of extendible capsule  1220  and first electrode  2056  and second portion  2054  consists of electrode  2058 . Gastric juice-responsive release unit  2020  coats resilient element  2018  when in a non-extended state ( FIG. 5A ) and is operative to retain first and second capsule portions  2052  and  2054  portions in the non-extended arrangement in a first operative state of said capsule. Release unit  1020  is further operative, in response to contact with gastric juices for at least a predetermined period of time to permit the extendible capsule  1220  to move into a second operative state by release of resilient element  2018  so as to cause mutual extension thereby of first and second portions  2052  and  2054 , thereby to extend the effective length of capsule  1220 , as seen in  FIG. 5B . 
     Gastric juice-responsive release unit  2020  differs from unit  1020  of capsule  1210  described in conjunction with  FIGS. 4A and 4B , since it consists of first and second selectably releasable, gastric juice-responsive, locking elements, respectively referenced  2020  ( FIG. 5A) and 2022  ( FIG. 5B ). First locking element  2020  is used for resisting an urging force of resilient element  2018 , thereby locking together first and second capsule portions  2052  and  2054  in a non-extended arrangement when capsule  1220  is in first operative state ( FIG. 5A ). Second locking element  2022  is operative to maintain a mechanical connection between first and second capsule portions  2052  and  2054  when capsule  1220  is in extended arrangement in second operative state, after which, in a third operative state, second locking element  2022  is operative to disconnect first and second capsule portions  2052  and  2054  from each other ( FIG. 5C ), as described below in more detail. 
     Resilient element  2018  includes an electrically-conductive expandable element  2017  ( FIG. 5B ) and a dielectric flexible membrane  2016 . Expandable element  2017  may be a metallic spring, a leaf spring, a helical spring, a leaf spring having two arms, a pair of rigid arms movably joined to a spring at their meeting point, shape memory alloy member or other suitable compression member, extending from pulse generator  64  ( FIG. 1B ) to second electrode  2058  so as to conduct electrical signals thereto. A dielectric flexible membrane  2016  ( FIG. 5B ) is provided so as to connect between main body portion  2050  and second electrode  2058 , and so as to surround and insulate expandable element  2017 . 
     Resilient element  2018  is similar to resilient element  1018  ( FIGS. 4A and 4B ), except that it is formed not only to extend after dissolution of the gastric-juice responsive release unit  2020 , but also so as to subsequently become completely detached from the main body portion  2050 , thereby to ease the excretion of the extended capsule  1220  from the stomach, after capsule portions  2052  and  2054  detach from each other, as seen in  FIG. 5C . 
     As seen in  FIG. 5C . distal end of first portion  2052  of main body portion  2050  terminates in a connector having a pin  2021  which is conductively connected to the pulse generator  64  ( FIG. 1B ) of capsule  1220 . 
     Expandable element  2017  ( FIGS. 5B and 5C ) may be a metallic spring or other suitable compression member described above in relation to expandable element  1017  ( FIG. 4B ). It extends typically from a socket  2023  formed in a proximal end member  2029  of extendible unit  2018  in second portion  2054  of capsule  1220 , to the second electrode  2058 . The connection between pin  2021  and socket  2023  is operative to conduct electrical signals from pulse generator  64  to second electrode  2058 . Dielectric flexible membrane  2016  ( FIGS. 5B and 5C ) is provided so as to mechanically connect proximal end member  2029  of extendible unit  2018  to second electrode  2058 , and so as to surround and insulate expandable element  2017 . 
     In the present embodiment, the two gastric juice-responsive locking elements  2020  and  2022  have predetermined different rates of dissolution. First locking element  2020  is formed of a first gastric-juice soluble substance which is soluble at a first predetermined rate so as to permit extension of said capsule  1220  after a first dwell time in the gastrointestinal tract of a patient. Second locking element  2022  is formed of a second gastric-juice soluble substance which is soluble at a second predetermined rate so as to disconnect said first  2052  and second  2054  capsule  1220  portions from each other permit after a second dwell time in the gastrointestinal tract of a patient, the second dwell time being longer than the first dwell time. 
     An advantage of capsule  1220  having a non-extended, compact state initially, is that it is easier to swallow. Due to the dissolution of gastric juice-responsive release unit  2020  once in the stomach, the extendible unit  2018  expands so as to become fully deployed, and the longitudinal dimension of capsule  1220  between the first electrode  2056  and the second electrode  2058  is increased, as shown in  FIGS. 4A and 4B , and as described in conjunction therewith with regard to capsule  1210 . 
     Gastric juice-responsive locking elements  2020  and  2022  are formed of materials substantially as described above in relation to gastric juice-responsive release unit  1020  of capsule  1210 . 
     Reference is now made to  FIGS. 6A-6E , which show a capsule  1230 , constructed and operative in accordance with another embodiment of the present invention. Capsule  1230  is generally similar to capsule  12 , shown and described above in conjunction with  FIGS. 1A-3 , except as specifically described herein. 
     Accordingly, components and portions of capsule  1230  are denoted in the drawings by reference numerals which are the same as their counterpart portions in  FIGS. 1A-3 , but with the addition of the prefix “30.” Furthermore, these components and portions are not specifically described again herein except as may be necessary to understand the present embodiment of the invention. 
     Capsule  1230  includes at least one gastric juice-responsive expandable element, which is shown in  FIGS. 6A-6E  in different states and denoted by reference numeral  3016 . In the present example three are shown although one or more may be used as required. These elements are adapted for storage within a storage compartment  3012  formed within main body portion  3050  of capsule  1230  ( FIG. 6A ). A gastric juice-responsive cover  3020  closes storage compartment  3012  and prevents expandable elements  3016  from exposure to gastric juices. Cover  3020  is formed of a first gastric-juice soluble substance which is soluble at a first predetermined rate so as to permit exposure of expandable elements  3016  to gastric juices after a first dwell time in the gastrointestinal tract of a patient. 
     Cover  3020  may be made of a material similar to that of gastric juice-responsive locking element  2020  ( FIG. 5A ) as described above. When gastric-juice responsive cover  3020  dissolves it opens storage compartment  3012  so as to expose expandable elements  3016  to gastric juices. Due to this exposure, elements  3016  expand so as to be forced out of storage compartment  3012  and so as to increase the overall size of capsule  1230 , thereby preventing capsule  1230  from egression from the pyloric region of the stomach. 
     Each expandable element  3016  is connected to main body portion  3050  of capsule  1230  by means of a gastric-juice responsive releasable connector element  3018  ( FIG. 6C ). Expandable elements  3016  are typically formed of a super-absorbent polymer (SAP), and connector elements  3018  are made from soluble from absorbable surgical sutures. 
     Cover  3020  is formed of a first gastric-juice soluble substance which is soluble at a first predetermined rate so as to permit exposure of expandable elements  3016  to gastric juices after a first dwell time in the gastrointestinal tract of a patient. Connector elements  3018  is formed of a second gastric-juice soluble substance which is soluble at a second predetermined rate so as to dissolve connector elements  3018  after a second dwell time in the gastrointestinal tract of a patient, wherein the second dwell time is longer than the first dwell time. 
     Referring now briefly to  FIG. 6D , capsule  1230  with SAP elements  3016  is seen to be floating within the patient&#39;s stomach  24 . As seen in  FIG. 6E , after a predetermined stay in the stomach, connector elements  3018  dissolve, thereby releasing the expandable elements  3016  from capsule  1230  and so enabling both the capsule and the expandable elements  3016  to be excreted. Typically, connector elements  3018  are formed so as to dissolve after a stay or dwell time in the stomach normally in the range 48-72 hours. 
     It will be appreciated floating capsule  1230  as described above obviates the need for a user to wear a control device such as control device  14  ( FIG. 1A ) except during the positioning of capsule  1230 , thereby rendering its use more comfortable. 
     Reference is now made to  FIGS. 7A and 7B , which show an implantable gastrointestinal tract capsule-securing device  4000  for securing a capsule  1240  adapted for ingression into the GT  16 , in accordance with yet a further embodiment of the present invention. The capsule-securing device  4000  includes, inter alia, a location pin  4013  comprising a pin shaft  4014  and a pin head  4018  having an upper surface  4020  and a lower surface  4022 . Pin shaft  4014  is attached to the lower surface  4022  of the pin head  4018  and includes preferably a serrated outer edge  4016  for mechanically securing the device  4000  within the GT  16 . The device  4000  is implanted into the wall  18  of the GT  16  at a required location, by a known medical method, such as gastrointestinal endoscopy and the device  4000  is secured in the GT  16  by inserting the serrated edge  4016  into the wall  18  of the GT  16  ( FIG. 7A ). The serrated edge  4016  grips the wall of the GT  16  at the required location in the GT  16 , and the lower surface  4022  of the pin head  4018  abuts against the outer surface of the wall  18  of the GT  16 . 
     In the present embodiment the system includes a capsule  1240  adapted for ingression into the gastrointestinal tract of a patient, and a magnetic coupling system for securing capsule  1240  within the gastrointestinal tract  16  of the patient, wherein the coupling system has a first magnetic element  4228  associated with capsule  1240  ( FIG. 7B ) and a second magnetic element configured for placement externally of the body of the patient (not shown in  FIGS. 7A and 7B ). Capsule system also includes at least one capsule-securing device  4000  implantable in the wall  18  of the gastrointestinal tract  16  at a selected location and a third magnetic element  4026  associated with location pin  4013  ( FIG. 7A ). 
     In  FIG. 7B , the pin head  4018  is seen to include a magnetic element  4026 . In combination with the magnetic element  4228  located within capsule  1240 , the pin head magnetic element  4026  forms a magnetic coupling system  4030  for magnetically securing the capsule  4012  to the capsule-securing device  4000 . The capsule  1240  is attached to the pin head  4018  by the magnetic attraction between the magnetic element  4228  and the magnetic element  4026 . 
     The length L ( FIG. 7A ) of the pin shaft  4014  is predetermined in accordance with the required location the pin shaft  4014  in the GT  16  ( FIG. 7A ). Preferably, the pin shaft  4014  should have a longitudinal length which is approximately 50-80% of the thickness of the wall  18  at the required location in the GT  16 . For example, if the pin shaft  4014  is to be inserted into the stomach of the patient, it should have a length, L, of approximately 2.5-4 mm, assuming that the average stomach thickness of the patient is approximately 5 mm. 
     Preferably, the width W of the pin head  4018  is approximately 3-5 times the length L of the pin shaft  4014  and is approximately 7.5-12 mm. 
     In accordance with a further embodiment of the invention, and referring now to  FIGS. 8 and 9 , device  4000  may have an electrode  5000  ( FIGS. 8 and 9 ) formed integrally therewith, such that it can be advantageously positioned so as to be in electrically conductive connection with one of the electrodes  4056  or  4058 . As the pin shaft  4014  extends through the stomach wall and into closer proximity with the vagus nerve or other chosen area, the ability to provide the electrical signals from the electrodes of capsule  1240  to an electrode terminating at the tip  5001  of the pin shaft  4014 , increases the ease of positioning and effectiveness of the treatment. In this embodiment, device  4000  is seen to secure the capsule to the stomach wall magnetically so that the capsule is positioned on the pin head, but next to it, by appropriate positioning of magnetic axis. 
       FIG. 8  illustrates the use of a single device  4000  to secure capsule  1240 , while  FIG. 9  illustrates the use of a pair of devices,  4000  and  4010 , both of which convey electrical signals into proximity with the vagus nerve or other chosen area. 
     Referring now particularly to  FIG. 8 , use of the presently described system is thus as follows: 
     The pin device  4000  is implanted into the stomach wall at a desired location. 
     Capsule  1240  is ingested into the stomach. 
     A powerful, guiding magnet  5004  is used by an operator to guide the capsule  4012  to the location of the implanted pin device  4000 , so as to expose the capsule to the magnetic field of the pin device&#39;s magnet. 
     The guiding magnet is removed, and the capsule remains magnetically secured to pin device  4000 , after which the capsule is operated and treatment can commence. 
     After termination of treatment, the guiding magnet  5004  is used to magnetically drag capsule  1240  away from pin device  4000 , after which the capsule will be able to exit the body. 
     It will be appreciated that this approach obviates the need for a patient to wear a magnet during the treatment. 
     It will be appreciated by persons skilled in the art that the scope of the present invention is not limited by what has been particularly shown and described hereinabove with reference to the drawings. Rather, the scope of the present invention is limited solely by the claims which follow.