Abstract:
A fixation device for holding stimulating electrodes in electrical contact with the wall of a portion of the gastrointestinal tract is provided. In one embodiment, the fixation device includes an expandable member that fixes the electrodes in electrical contact with the gastrointestinal tract wall. Also provided is an implantable device and method for controlling the opening and/or closing of the pylorus. In particular a device and method is provided for stimulating the duodenum to control the closing/and or opening of the pylorus. 
     Finally, a method is provided for treating obesity by controlling the pylorus to retain food in the stomach for a desired period of time, among other things to provide a feeling of-satiety and/or to reduce hunger. One aspect includes controlling the pylorus&#39;s contraction by electrical stimulation of the duodenum.

Description:
CROSS REFERENCE TO RELATED APPLICATION DATA 
       [0001]    The present application is a Continuation of U.S. application Ser. No. 11/281,228 filed Nov. 16, 2005 (Allowed), which application is a Divisional of U.S. application Ser. No. 10/691,735 filed Oct. 22, 2003 (now U.S. Pat. No. 7,054,690); the full disclosures of which are incorporated herein by reference in their entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The invention relates to a stimulation device and method for stimulating a portion of the gastrointestinal tract and in one particular embodiment to a device and method for stimulating the duodenum to control the pylorus and/or to treat obesity. 
         [0004]    2. Background of the Invention 
         [0005]    In general when food is ingested into the stomach, initially, the elastic upper portion or fundus accommodates the food and the fundus expands. As food enters and the fundus expands there is a pressure gradient created in the stomach between the fundus and the antrum (fundus pylori). A number of things occur at this time. Fluids tend to be pushed through the pylorus, which acts as a leaky valve. Peristaltic contractions move down the stomach from the fundus into the antrum to mix and break down food and propel small particles through the pylorus into the duodenum. In healthy human stomachs, peristalsis is believed to be controlled at least in part by a region of the stomach identified near the interface of the fundus and the corpus along the greater curvature. In this region, there are cells believed to govern the organs&#39; periodic contractile behavior that generate and propagate rhythmic electrical signals that correspond to the contractile behavior of the stomach. These characteristic contractions are believed to create, a pressure gradient between the fundus pylori (or antrum) and duodenum that relates to the rate of gastric emptying. When the contractions begin, the pylorus is generally closed, although fluid and small particles leak through the valve. As contractions or electrical activity corresponding to the contractions reach pylorus, the pylorus begins to open or relax. Thus, as the stomach churns and breaks down food in a healthy stomach, the pylorus begins to open. As this is occurring, there may be electrical activity in the duodenum as well. Retrograde electrical activity from the duodenum, i.e. contractions or electrical activity in the direction of the pylorus tends to cause the pylorus to close, thus preventing bile and pancreatic juices from backing up into the stomach. Accordingly, the opening and closing of the pylorus is influenced by electrical stimulation input from both of its ends. 
         [0006]    In a number of disease states or conditions, the contractions of the stomach and/or the opening and closing of the pylorus is irregular. Gastroparesis may result from insufficient contractions to churn food, move food through the pylorus, and/or open the pylorus, among other things, resulting in gastro-retention of food. In another motility disorder known as dumping syndrome, the stomach empties at an abnormally high rate into the small intestine causing various gastrointestinal disorders. It has also been observed that in obese patients, gastric emptying tends to be at a higher than normal rate. It is believed that obesity may be treated by altering gastric motility to cause the stomach to slow gastric emptying. 
         [0007]    Accordingly, it would be desirable to provide a device and method for controlling gastric emptying. Further, it would be desirable to provide a device and method that controls the contracting and relaxation of the pylorus according to a desired increase or decrease in gastric emptying. 
         [0008]    Some devices have been proposed to constrict the stomach to reduce stomach volume. These devices are typically implanted in a relatively invasive procedure and operate to constrict the stomach but do not enable periodic control of the stomach emptying. Some devices have been proposed to interfere with the peristaltic motion of the gastrointestinal tract and especially, the stomach, to slow the movement of food from the stomach. These devices control the contractions of the stomach but are not directed to opening and closing the pylorus outside of the context of controlling peristalsis of the stomach. Furthermore, most of these devices require open or laparoscopic surgery in which a stimulator unit is implanted subcutaneously adjacent the abdomen wall with leads extending to the stomach where electrodes are attached. Artificial sphincters, for opening and closing sphincters including the pylorus have been proposed. These devices typically involve placing a constricting member around the sphincters in a relatively invasive procedure. 
         [0009]    Accordingly it would be desirable to provide a relatively easily implanted device and method for controlling the opening and/or closing of the pylorus. It would further be desirable to provide a method and device for treating obesity. 
       BRIEF SUMMARY OF THE INVENTION 
       [0010]    The invention provides a fixation device for holding stimulating electrodes in electrical contact with the wall of a portion of the gastrointestinal tract. In one embodiment, the fixation device includes an expandable member that fixes the electrodes in electrical contact with the gastrointestinal tract wall. According to one embodiment, the fixation device comprises a relatively tubular shaped structure that holds stimulating electrodes adjacent the wall of the duodenum while permitting the passage of materials through the device. According to another embodiment of the invention, the fixation device comprises a self-expanding tubular member. 
         [0011]    The present invention further provides an implantable device and method for controlling the opening and/or closing of the pylorus. In particular, one embodiment comprises a device and method for stimulating the duodenum to control the closing/and or opening of the pylorus. According to this embodiment, electrodes are coupled to the wall of the duodenum. In one embodiment, the electrodes are coupled to the duodenum above the duct through which bile and pancreatic secretions empty into the small intestine. Electrical stimulation pulses are delivered by an electronic circuit through the electrodes. The stimulation pulses that travel in a deep retrograde direction end to cause the pylorus to contract and close. The stimulation may be delivered after sensing a meal or that food has been ingested. For example, detecting a change in temperature due to food particles not at body temperature. Or, the stimulation may be user activated whereby the user turns on the device after ingesting a meal. The stimulation in one embodiment is set to continue for a Predetermined period of time. Thus, where a patient&#39;s typical rate of gastric emptying is greater that desired, such emptying may be slowed using the stimulator. 
         [0012]    The present invention also provides a method for treating obesity by controlling the pylorus to retain food in the stomach for a desired period of time, among other things to provide a feeling of satiety and/or to reduce hunger. According to one embodiment, the pylorus&#39;s contraction is controlled by electrical stimulation of the duodenum. The retrograde propagation of the stimulation acts to close or cause contraction of the pylorus. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1  is a side cutaway view of a stomach and duodenum with an implanted stimulator according to an embodiment of the invention. 
           [0014]      FIG. 1A  is a side view of the fixation device of the stimulator of  FIG. 1  in a compressed configuration. 
           [0015]      FIG. 1B  is a cross sectional view of  FIG. 1A  along the lines  13 - 1 B. 
           [0016]      FIG. 1C  is a side view of the fixation device of the stimulator of  FIG. 1  in an expanded configuration 
           [0017]      FIG. 1D  is a cross-sectional view of  FIG. 1C  along the lines  1 D- 1 D. 
           [0018]      FIG. 1E  is a top view of a portion of the stimulator illustrated in  FIG. 1A . 
           [0019]      FIG. 1F  is a schematic side view of the electrode housing of the stimulator of  FIGS. 1 , and  1 A- 1 E. 
           [0020]      FIG. 2  is an alternative electrode housing for the stimulator of  FIG. 1  in which electronics are encased in the electrode housing. 
           [0021]      FIG. 3  illustrates another embodiment of an implanted stimulator according to the invention. 
           [0022]      FIG. 4  illustrates another embodiment of an implanted stimulator according to the invention. 
           [0023]      FIG. 4A  is a side view of the fixation device of the stimulator of  FIG. 4  in an expanded configuration with a removable replaceable battery unit coupled to the electrode housing. 
           [0024]      FIG. 4B  is a side view of the electrode housing and removable battery unit of the stimulator of  FIG. 4A . 
           [0025]      FIG. 4C  is an enlarged portion of  FIG. 4B  as indicated in  FIG. 4B . 
           [0026]      FIG. 5  is a schematic of an electronic circuit of a stimulator according to an embodiment of the invention. 
           [0027]      FIG. 6  is a schematic of an external controller circuit according to an embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0028]    Referring to FIGS.  1  and  1 A- 1 F a stimulator  30  in accordance with the invention is illustrated implanted in the gastrointestinal tract of a patient. The stimulator  30  comprises a fixation device  34  to be implanted in the duodenum  24  and an electronics housing  50  to be located in the stomach  20  and coupled by wire tube  53  enclosing leads  51 ,  52 , to the fixation device  34 . The fixation device  34  includes electrodes  41 ,  42  in electrical contact with the duodenum  24  and the electronics housing  50  includes electronic circuitry  125  and a battery  144  that supply electrical stimulation pulses to the duodenum  24  through the electrodes  41 ,  42 . 
         [0029]    In  FIG. 1 , the fixation device  34  is illustrated in place in the duodenum  24  located adjacent the pylorus  23  of a patient and above the duct  25  (where the ducts for bile and pancreatic secretions merge). The electrodes  41 ,  42  of the fixation device  34  are contained in an electrode housing  43  ( FIG. 1A ) and exposed at the outer circumference of the fixation device  34  so that the electrodes  41 ,  42  may be positioned in electrical contact with the wall  27  of the duodenum  24 . The fixation device  34  operates to engage the inner circumference of the wall  27  of the duodenum  24  to hold and maintain the electrodes  41 ,  42  in electrical contact with the duodenum  24 . The fixation device  34  comprises a plurality of rings  36  including undulating members  37  having peaks and valleys that permit compression and expansion of the rings  36 . 
         [0030]    The rings  36  are preferably formed of Nitinol to provide spring-like properties with sufficient radial strength so that they may be compressed and constrained by a catheter containing the fixation device  34 , and released from the catheter to expand into an expanded engaging position within a lumen of the gastrointestinal tract. The rings  36  define a common axis  39  extending through the rings  36 . The rings  36  are attached to each other by way of the electrode housing  43 , which is molded onto the rings  36  along the axis  39  of the rings  36 . Each ring  36  is formed by a closed wire loop of undulating members  37  and includes a straight portion  38  over which the electrode housing  43  is molded. The electrode housing  43  may be formed of a biocompatible plastic such as polyurethane or polycarbonate. The fixation device  34  further defines a lumen  45  extending along the axis  39  through which materials from the stomach  20  may pass. 
         [0031]    The fixation device  34  may be delivered in a compressed configuration to the duodenum  24  through a catheter or the like, containing the fixation device  34  in its compressed state. The fixation device is then expanded into a configuration in which it engages the wall  27  of the duodenum  24 . As illustrated in  FIGS. 1A and 1B , in a compressed position, the diameter of the fixation device  34  is relatively small so that it can reside with in a catheter of sufficiently small diameter to be placed through upper gastrointestinal tract (i.e., into the mouth of a patient, through the esophagus and stomach, and through the pylorus into the duodenum). The catheter may include a retractable sheath containing the fixation device  34 . The sheath is retractable upon locating the catheter in a desirable position for deployment of the fixation device  34  in the duodenum  24 . This may be guided by an endoscope or fluoroscopy. The fixation device  34  should be position in an orad location from the duct  25  where the bile and pancreatic secretions empty into the duodenum  24  so that the fixation device  34  does not block the duct  25 . When retracted, the sheath permits the self-expanding rings  36  of the fixation device  34  to expand to the expanded position illustrated in  FIGS. 1C and 1D . Thus, when released from the catheter, the fixation device  34  expands to engage the inner circumference of the wall  27  of the duodenum  24 . In its expanded position, the circumference of the fixation device  34  increases while the electrode housing  43  and the straight portion  38  of each ring  36  encased by the electrode housing  43  maintain their original size and shape. The radial strength of the rings  36  serves to hold the fixation device  34  in place. The electrodes  41 ,  42  are located on the outer surface  44  of the electrode housing  43  and the rings  36  hold them in place against the wall  27  of the duodenum  24  to provide electrical contact therewith. Alternatively, the rings  36  may be expandable by a balloon catheter or the like. 
         [0032]    A pair of leads  51 ,  52  encased in a tube  53  extend out of the fixation device  34  and are coupled to the electronics housing  50 —When the fixation device  34  is deployed, the tube  53 . and electronics housing  50  extend in an orad direction, through the pylorus  23  and into the stomach  20 . The electronics housing  50  is attached to the stomach  20  wall leaving sufficient slack in the tube  53  to allow for stomach contractions and movement. In this embodiment, the electronics housing  50  contains a battery  144  and electronic circuitry  125  ( FIG. 5 ) for providing electrical stimulation to the duodenum  24  through the leads  51 ,  52  extending thorough tubing  53  and coupled to the electrodes  41 ,  42 .  FIG. 5  illustrates exemplary electronics  125  and battery  144  that may be used with the stimulator  30  or stimulators of other embodiments of the invention, such as, for example, those described herein. The electronics housing  50  also includes a sensor  51  (or plurality of sensors) that may be provided with the capability of sensing one or more of various parameters of the gastrointestinal tract such as, e.g., pressure, temperature, pH, and relative movement (e.g., using an accelerometer). 
         [0033]    The electronics housing  50  may be delivered into the stomach and coupled to the fixation device  34  in a number of manners. With the fixation device  34  in position in the duodenum  24 , the electronics housing  50  may be delivered to the stomach and attached to the fixation device through the wire tubing  53  extending between the stomach  20  and the duodenum  24  by connecting the wire tubing of a first portion  53   a  attached to the fixation device  34 , to a second portion  53   b  of the wire tubing  53  coupled to the electronics housing  50 . The first portion  53   a  has a free end  54  with a connector  55  and an attached end  56  attached to the electrodes  41 ,  42  through the electrode housing  43  on the fixation device  34 . 
         [0034]    The second portion  53   b  includes an attached end  59  coupled to the electronics housing  50  and a free end  57  having a connector  58  that will mate with the connector  55  on the free end  54  of the first portion  53   a  to provide a connected electrical leads between the electrode housing  43  and the electronics housing  50 . The electronics housing  50  is secured to the stomach wall with an attachment mechanism  52  and so that the tube  53  has sufficient slack to permit stomach churning, while not damaging or pulling the housing  50 , fixation device  34  or tube  53 . The attachment mechanism  52  prevents the housing  50  from moving through the pylorus  23 . The attachment mechanism  52  comprises an elongate flexible member  45  attached to the housing  50  and extending through the stomach wall and having a T-shaped end  46  that attaches the elongate member  45  to the stomach wall. 
         [0035]    The electronics housing  50  may be delivered into the stomach and attached to the stomach wall using a needle into which the T-shaped end  46  is loaded. The needle pierces the stomach wall and releases the T-shaped end  46 . The housing  50  is then attached to the fixation device  34  by using grasping tools extending through tool channels of an endoscope, to attach connectors  55  and  58 . The electronics housing  50  may also be detached from the fixation device  34  through connectors  55 ,  58  so that the battery  144  and/or electronics 125  may be replaced. While the electronics housing  50  and fixation device  34  are illustrated as being connected after the fixation device  34  and electrode housing  43  have been deployed, the electronics housing  50  may also be deployed through the catheter in a connected position with the fixation device before or after the fixation device  34  has been positioned and deployed. A catheter accommodating a needle to attach the attachment device  52  and a deployment mechanism for the fixation device  34  would need to be accommodated in a catheter designed for the multiple tasks involved. 
         [0036]    The electronics housing  50  has a round smooth shape that will minimize any trauma to the stomach. The electronics housing  50  is also of a sufficient size that it will not be passed through pylorus  23  into the duodenum  24 . It is further constructed of a material that resists corrosion in the highly acidic stomach environment. Such corrosion resistant materials may include, for example, 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 PTFE′ (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. Additionally the electronics housing  50  may be constructed of an acid corrosion resistant metal such as Platinum, Gold, Tantalum, Titanium, or suitable alloys thereof. 
         [0037]    Referring to  FIG. 5 , the electronics  125  and battery  144  are illustrated that may be used with the various embodiments of the stimulator described herein. The electronic circuitry may be on a chip or otherwise have a standard configuration that may be used in a number of different embodiments of the stimulator device. In general, the electronic circuitry includes a controller that delivers electrical stimulation pulses through the electrodes to the wall of the duodenum, the stimulation tends to cause the pylorus  23  to close. The stimulation may be actuated by a user upon ingesting food and the stimulation may continue for a predetermined period of time thereafter. In one embodiment the stimulation parameters are preprogrammed into the controller. The stimulation device may also be provided with the capability of sensing various parameters of the gastrointestinal tract such as, e.g., pressure, temperature and relative movement (e.g., using an accelerometer). The parameters may be used to determine various conditions, for example, patient is awake, sleeping and the type, period, or other parameters of stimulation may be modified according to a program or by a user or health care provider. The electronic circuitry  125  of the stimulator is located in the stimulator housings of the various implants described herein such as, for example, a subcutaneously implanted stimulator unit; a stimulator unit included with the fixation device; a removable attachable housing that may be attached to the fixation device; or in a another housing located within the gastrointestinal tract (e.g., the stomach) and attached by way of leads to the fixation device. Likewise, the battery  144  that powers the electronic circuitry  125  may be located in a number of different housings in various embodiments and configurations of the stimulator. In these different locations, the battery  144  may be removable and replaceable with the electronic circuitry  125  or on its own in a modular device. If the stimulator is included with the fixation device, the battery may also be removably and replaceably attachable to the electronics or electrode housing on the fixation device. The battery  144  may be located with the electronic circuitry  125  attached by way of leads to the stimulator. 
         [0038]    The stimulation of the duodenum occurs for a predetermined period of time after which the stimulation is discontinued to allow emptying of the stomach. The circuitry  125  of one embodiment as illustrated in  FIG. 5  comprises: a microprocessor or controller  140  for controlling the operations of the electronic circuitry  125 , and an internal clock  141 . The circuitry  125  may also include a battery device  144  such as a pair of lithium iodine batteries for powering the various components of the circuitry  125 . Alternatively, the battery device  144  may be housed in a separate unit that may be coupled to the circuitry  125 . As such, the controller  140  and battery device  144  are coupled to each of the major components of the circuit as would be apparent to one of ordinary skill in the art. The controller  140  is coupled to stimulation driver  142 , which is coupled to stimulating electrodes  41 ,  42  (or any of the other electrodes described herein) that are used to provide electrical stimulation in accordance with programmed parameters. 
         [0039]    The controller  140  is coupled to ROM  143 , which contains the program instructions for the controller  140  and any other permanently stored information that allows the microprocessor/controller  140  to operate. The controller  140  addresses memory in ROM  143  through address bus  143   a  and the ROM  143  provides the stored program instruction to the controller  140  via data bus  143   b . The controller  140  controls the RF coil  145 , which communicates with an external control or programming device  160  ( FIG. 6 ), preferably via a modulated RF signal. Processor  140  is coupled to a buffered oscillator  151  that provides an RF signal to be emitted from the RF coil  145 . The RF signal is preferably at about 100 kHz to 5 MHz so that the signal is efficiently transmitted through tissue. The controller  140  controls the oscillator  151  and may provide data to be modulated with the RF signal to be delivered through the RF coil  145 . Such data may include, for example, data sensed by a sensor  51  located on the electronics housing  50  (or alternatively the fixation device  34 ), such as pressure, pH, temperature, movement (accelerometer), or sensed electrical information such as impedance, electrical activity (EMG) etc. One or more sensors  147   a  (e.g., accelerometer),  147   b  (e.g., pressure),  147   c  (e.g., pH),  147   d  temperature, or electrodes— 41 ,  42  (for sensing EMG, EGG, or impedance as well as providing stimulation), may be coupled to the controller  140  through A/D converters (with amplifiers)  146   a ,  146   b ,  146   c ,  146   d ,  146   e  which convert a representative analog electrical signal into a digital signal. Suitable types of these sensors are generally known in the art and may be located within, on, or external to the electronics housing  50 , fixation device  34  or electrode housing  43  on the fixation device  44 . When the RF coil  145  is receiving an external telemetry signal, the buffered oscillator  151  is disabled. Telemetry signals received on the RF coil  145  are detected in a detector circuit  151   a  and to communicated controller  140 . The detector circuit  151   a  is preferably selected based on the modulation used for telemetry signals. The sensed parameters may indicate e.g. the ingestion of food or activity level of a patient. Pacing may be turned on or off based on these parameters. 
         [0040]    Controller  140  is coupled to RAM  150  via an address bus  150   a  for addressing a location in RAM  150  and a bi-directional data bus  150   b  for delivering information to and from RAM  150 . The RAM  150  includes event memory  148  that temporarily stores data recorded by sensors  147   a - d  or electrodes  41 ,  42  (or other—electrode pairs described herein). RAM  150  also includes a programmable memory  149  which may be programmed, for example, by an external programmer  160 . The data stored in the programmable memory may include specifications for the electrical stimulation operating modes or parameters. Such programming may be done in response to sensed information or it may be done automatically by an external controller or as desired by a treating physician, etc. Sensed data acquired from sensors  147   a - d  and electrodes  41 ,  42  or other electrode pairs described herein, provided to the controller  140  may be stored in event memory  148  in the RAM  150 . The data stored in the event memory  148 , may be sent intermittently as data bursts via the RF coil  145 , as opposed to continuously in order to save battery power. 
         [0041]    The electrode  41 ,  42  outputs are used to provide electrical stimulation delivered through the stimulation driver  142  to the electrode  41 ,  42 . The stimulation modes and parameters may be pre-programmed or may be set using the external programmer  160  or in response to sensory feedback. The same electrode outputs may be used to sense impedance through impedance circuit  153  and to sense electrical activity, which is delivered through A/D converter  146   e . The electrodes  41 ,  42  are coupled through coupling capacitors  155   a  and  155   b  respectively, to the output of electrical stimulation driver  142  and the inputs of A/D converters  146   e ,  146   f.    
         [0042]    The impedance circuit  153  comprises a constant current source oscillator  154  that oscillates at a frequency of 50-100 kHz, and an A/D converter  146   f  coupled to the controller  140 . The oscillator  154  provides a constant current source through electrodes  41 ,  42  resulting in a voltage across the electrodes  41 ,  42  that is representative of impedance, in view of the constant current. The voltage is provided through and is converted by A/D converter  146   f  to a digital signal representative of impedance. A/D converter  146   f  has a bandwidth that includes the 50 kHz frequency signal while filtering out the electrical stimulation signal that is delivered to the electrodes  41 ,  42  through electrical stimulation driver  142 , and the EMG signal that is sensed by the electrodes  41 ,  42 . Both of the outputs are filtered out by A/D converter  146   f  A/D converter  146   e  has a bandwidth that filters out the 50-100 kHz signal. Further, when a stimulation signal is being delivered, the controller  140  does not receive signals from A/D converters  146   e  and  146   f . Thus the EMG and impedance sensing functions and the stimulation delivery functions are separated through the electronic circuitry  1 - 25 , though using the same electrodes. 
         [0043]    The battery  144  has its output supplied to a DC-to-DC converter  144   a  to provide a higher voltage, which is utilized for electrical stimulation pulses. The DC-to-DC converter  144   a  is conventional and provides an output voltage of 15 to 20 volts. 
         [0044]      FIG. 6  illustrates the electronic circuitry  163  for external programmer  160 . The electronic circuitry  163  comprises: a microprocessor or controller  170  for controlling the operations of the electronic circuitry, an internal clock  171 , and a power source  174  such as a battery device for powering the various components of the circuit  163 . As such, the controller  170  and battery device  174  are coupled to each of the major components of the circuit as would be apparent to one of ordinary skill in the art. The controller  170  may be coupled to a speaker  167  for that provides audible alerts and a display  166  such as a CRT to display data such as recorded data, sensed parameters, treatment parameters and status of the device (e.g. position or battery charge status). The controller  170  is coupled through a buffer  164  to external input device  165  that is used to provide program parameter ‘input, e.g. from a user, for a user to request data displayed in a desired format through display  166  or speaker  167 , or to turn the device on and off. The external programmer  160  is also provided with an external data port  168  to interface with a computer and provide a means for bi-directional communication of data or commands. The computer may provide programming or data to the controller/microprocessor  170 . 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. 
         [0045]    The controller  170  is coupled to ROM  173 , which contains the program-instructions for the controller  170  and any other permanently stored information that allows the microprocessor/controller to operate. The controller  170  addresses memory in ROM  173  through address bus  173   a  and the ROM  173  provides the stored program instructions to the controller  170  via data bus  173   b . The controller  170  controls the RF coil  175 , which communicates with stimulator electronic circuitry  125  ( FIG. 5 ) through its RF coil  145 . Processor  170  is coupled to an oscillator  172  that provides an RF signal, preferably having a characteristic frequency of 500 kHz or higher, to be emitted from the RF coil  175 . The controller  170  controls the oscillator  172  and provides data to be modulated with the RF signal, for example, programming information, stimulation parameters, etc. The RF coil  175  also receives information transmitted via RF signal from RF coil  145  on the stimulator electronic circuitry  125  such as various sensed data, e.g., pressure, pH, impedance, electrical activity (EMG) etc. The received RF signal is passed through demodulator  176  and is transmitted to the controller  170 . The data is delivered to the event memory  178  in RAM  177  by way of data bus  177   b  for temporary storage. The data may be retrieved from RAM  177  by addressing the storage location via the address bus  177   a.    
         [0046]    Event memory  178  temporarily stores data recorded by sensors  147   a - 147   e  and electrodes  41 ,  42  and delivered via telemetry to the external programmer  160 , until the data is downloaded onto a computer using the external data port  168 . The RAM  177  also includes a programmable memory  179  which may be programmed, for example, to specify operating modes such as waveform, frequency, etc. which programming is then telemetrically communicated to the stimulator electronic circuitry  125 . The modes and parameters can either be set using an external programmer  160  or set in response to sensory feedback. 
         [0047]    In an alternative embodiment, the device includes a housing, electrodes and minimal electronics and an electromagnetic coil. This device is powered by an external electromagnetic coil, which is placed on the patient&#39;s abdomen near the implanted device. The electrical stimulation parameters are controlled real-time by an external unit. 
         [0048]    Referring to  FIG. 2 , an alternative stimulator  70  having an alternative electronics/electrode housing  73  is illustrated. The stimulator  70  comprises a fixation device  75  with a housing  73  for the electrodes  81 ,  82 . The fixation device  75  is similar to fixation device  34  described above with reference to  FIGS. 1-1F . The housing  73  in this embodiment also contains the electronics  125 . The electrodes  81 ,  82  are coupled to the electronic circuitry  125  by way of connectors  83 ,  84 . The electronic circuitry  125  is coupled to leads  76 ,  77  encased in corrosion resistant wire tubing  78  that extends out of the housing  73  and fixation device  75 . When the stimulation device  70  is deployed in the duodenum  24 , wire tubing  78  similarly extends out of the duodenum  24  in an orad direction, through the pylorus  23  and into the stomach  20 —where it is coupled to the battery  144  contained in a battery housing. The fixation device  75  is placed in the duodenum  24  in a manner similar to fixation device  34  described above with reference to  FIGS. 1-1F . The battery housing  74  is configured similarly to the electronics housing  50  of  FIGS. 1-1F  of a corrosion resistant material and rounded configuration, with the battery  144  but without the electronic circuitry  125 . The battery  144  is electrically coupled through leads  76 ,  77  to the electronic circuitry  125  located in the housing  73 . The battery housing  74  is removable and replaceable in a manner similar to electronics housing  50  described above with reference to  FIGS. 1-1F  and the stimulation-programming and protocol may be delivered in a similar manner as well. 
         [0049]    Referring to  FIG. 3  an alternative stimulator  30 ′ is illustrated comprising a fixation device  34 ′ implanted in a duodenum  24  in a similar manner as fixation device  34  described above with reference to  FIGS. 1-1F . In this embodiment however, the wire tubing  53 ′ extends out of the wall  27  of the duodenum  24 , into the abdominal cavity  28  where it is coupled to electronics housing  50 ′ containing the electronics unit  125  and battery  144 . In implanting the stimulator  30 ′, the fixation device  34 ′ is placed in the duodenum  24  and the electronics housing  50 ′ is implanted subcutaneously within the abdominal cavity  28 . The wire tubing  53 ′ coupled to and extending from the electronics housing  50 ′ is then laparoscopically placed through the abdomen and through the wall  27  of the duodenum  24  where it is coupled through connector  44 ′ to the electrodes  41 ′,  42 ′ encased in the electrode housing  43 ′. The stimulation is provided from the electronic circuitry  125  to the inner wall of the duodenum  24  wall in a manner similar to that described above with reference to  FIGS. 1-1F ,  5  and  6 . 
         [0050]    Referring to  FIG. 3  an alternative stimulator  30 ′ is illustrated comprising a fixation device  34 ′ implanted in a duodenum  24  in a similar manner as fixation device  34  described above with reference to  FIGS. 1-1F . In this embodiment however, the wire tubing  53 ′ extends out of the wall  27  of the duodenum  24 , into the abdominal cavity  28  where it is coupled to electronics housing  50 ′ containing the electronics unit  125  and battery  144 . In implanting the stimulator  30 ′, the fixation device  34 ′ is placed in the duodenum  24  and the electronics housing  50 ′ is implanted subcutaneously within the abdominal cavity  28 . The wire tubing  53 ′ coupled to and extending from the electronics housing  50 L—is then laparoscopically placed through the abdomen and through the wall  27  of the duodenum  24  where it is coupled through connector  44 ′ to the electrodes  41 ′,  42 ′ similarly encased in the electrode housing  43 ′ as electrodes  41 ,  42  are encased in housing  43  with reference to  FIGS. 1 , and  1 A- 1 F. The stimulation is provided from the electronic circuitry  125  to the inner wall of the duodenum  24  wall in a manner similar to that described above with reference to  FIGS. 1-1F ,  5  and  6 . 
         [0051]    Referring to  FIGS. 4 , and  4 A- 4 C, an alternative embodiment of the invention is illustrated. A stimulator  90  comprises a fixation device  93  including an electronics housing  94  with electrodes  91 ,  92  and electronic circuitry  125  coupled to the electrodes  91 ,  92 . The electronic circuitry  125  is powered by battery  144  contained in a removable battery housing  95  that is configured to be removably coupled to the fixation device  93  in electrical communication with the electronics unit  125  contained in the electronics housing  94 . 
         [0052]    In particular, the battery housing  95  includes magnets  98 ,  99  that may be coupled with magnets  104 ,  105  on the inner wall  106  of the electronics housing  94 . Electrical contacts  96 ,  97  on the battery housing  95  align with electrical contacts  102 ,  103  on the inner wall  106  of the electronics housing  94  when the magnets  98 ,  99  are correspondingly aligned with magnets  104 ,  105  on the electronics housing  94 . When the magnets  98 ,  99  are aligned with magnets  104 ,  105  and the battery housing is coupled to the electronics housing  94 , contacts  96 ,  97  are correspondingly electrically coupled to contacts  102 ,  103  so that the battery  144  provides power to the electronic circuitry  125  among other things, to deliver stimulating pulses to the duodenum  24  as described herein with reference to  FIGS. 5 and 6 . As shown in  FIG. 4C , contact  96  comprises a protruding portion  107  that is positioned in recess  108  in inner wall  106  in electronics housing  94 . Contact  102  engages protruding member  107  so that electrical contact is made with contact  96 . O-ring  109  seals electrical contacts within recess  108 . 
         [0053]    While the invention has been described with reference to particular embodiments, it will be understood to one skilled in the art that variations and modifications may be made in form and detail without departing from the spirit and scope of the invention.