WO2008004234A2 - Minimally invasive electro-stimulation system - Google Patents

Minimally invasive electro-stimulation system Download PDF

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Publication number
WO2008004234A2
WO2008004234A2 PCT/IL2007/000840 IL2007000840W WO2008004234A2 WO 2008004234 A2 WO2008004234 A2 WO 2008004234A2 IL 2007000840 W IL2007000840 W IL 2007000840W WO 2008004234 A2 WO2008004234 A2 WO 2008004234A2
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WO
WIPO (PCT)
Prior art keywords
electrode
subject
expandable device
stimulation
organ
Prior art date
Application number
PCT/IL2007/000840
Other languages
French (fr)
Other versions
WO2008004234A3 (en
Inventor
Michael Arad
Mark Shilkrut
Adrian Paz
Original Assignee
Stimpulse Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to US81839706P priority Critical
Priority to US60/818,397 priority
Application filed by Stimpulse Ltd. filed Critical Stimpulse Ltd.
Publication of WO2008004234A2 publication Critical patent/WO2008004234A2/en
Publication of WO2008004234A3 publication Critical patent/WO2008004234A3/en

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Classifications

    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61NELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N1/00Electrotherapy; Circuits therefor
    • A61N1/02Details
    • A61N1/04Electrodes
    • A61N1/05Electrodes for implantation or insertion into the body, e.g. heart electrode
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61NELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N2/00Magnetotherapy
    • A61N2/004Magnetotherapy specially adapted for a specific therapy
    • A61N2/006Magnetotherapy specially adapted for a specific therapy for magnetic stimulation of nerve tissue

Abstract

A system for electro-stimulation of an internal organ or a mezothelial cavity wall covering. The system is installed within a cavity wall adjacent the organ or tissue to be stimulated, and in electrical communication therewith, but without necessarily being in physical contact with it. The system can be deployed using a minimally invasive surgical procedure. The system comprises one or more stimulation electrodes, one or more sensors outputting a signal in accordance with a physiological characteristic of the subject, and a controller for applying the stimulation in accordance with the sensor output. The electrodes or sensors are deployed using a thin delivery tube inserted into the desired region. The electrodes are carried to the deployment site attached to an inflatable balloon, passed uninflated down the delivery tube, and inflated after passage therethrough, thus deploying the electrode in the intended region. The inflated balloon holds the electrode(s) in place.

Description

MINIMALLY INVASIVE ELECTRO-STIMULATION SYSTEM

FIELD OF THE INVENTION

The present invention relates to the field of devices and methods for electrostimulation, especially as applied to the control of gastric functions.

BACKGROUND OF THE INVENTION

Electro-stimulation of the gastrointestinal (Gl) tract has raised a lot of interest recently in the treatment of obesity and gastroparesis arising from diabetes. The setting of the electrical current used for the electro-stimulation may be used to determine whether the effect will be stimulatory or inhibitory on gastrointestinal motility. The contraction of various segments of the gastrointestinal tract is coordinated by the oscillating electrical activity that spontaneously emerges in different regions of the Gl tract. These sites are named pacemakers. Such pacemakers were identified in the gastric wall, small bowel and large bowel. A slow wave of depolarization starts at these sites and propagates distally through the Gl tract, and after propagating for some distance it gradually vanishes. This depolarization wave has a slow frequency of a few cycles per minute and causes a coordinated contraction wave that propagates in a distal caudal direction known as the peristaltic wave. Peristalsis is important for the propulsion of food and intestinal secretions from a proximal to a distal direction, and for digestion. The pacemaker activity of the Gl tract and its peristalsis is influenced by various humoral, hormonal and nervous factors.

Various diseases of the gastrointestinal tract are influenced by the Gl tract peristaltic activity and contraction. For instance, gastroesophageal reflux disease (GERD) is caused by regurgitation of gastric content into the lower esophagus and causes retrosternal pain or heartburn due to local irritation and inflammatory changes in the mucosa and esophageal wall. This disease is caused by a relative weakness of the lower esophageal sphincter (LES). Stimulation of LES contraction during gastric contraction may prevent GERD. Gastric contraction may be connected to other two common diseases. One of them is gastro paresis which is associated with an uncoordinated and/or weak gastric contraction caused mainly by diabetes, which affects the autonomic inervation of the stomach. The result is slow gastric emptying resulting in bloating epigastric pain nausea, vomiting and weight loss. Proper stimulation of gastric peristalsis may alleviate these symptoms and improve gastric emptying.

Obesity may be also treated by gastric stimulation. In this case an effective mechanism to be used could be by influencing the sensation of satiety. Satiety may be induced by contracting the stomach and reducing its compliance, which causes a sensation of premature distension, or by stimulating the afferent signals from the stomach wall to the central nervous system.

Irritable bowel syndrome and chronic constipation are two frequent functional diseases of the large bowel that are intimately connected to dysfunctional peristalsis. Stimulation of coordinated peristalsis of the large bowel may improve chronic constipation, while on the other hand, inhibition of peristalsis may reduce bowel movements in case of irritable bowel syndrome.

Other applications of electro-stimulation to the Gl tract are stimulation and coordination of small bowel peristalsis for treatment of small bowel chronic obstruction; stimulation of a coordinated small bowel contraction after peritonitis and bowel resection, which often result in a temporary paresis and/or uncoordinated peristalsis and signs of paralytic bowel obstruction.

Gl tract stimulation may serve not only for inducing a coordinated contraction of the tubular muscular walled organs but also for inducing secretion of glands associated with the Gl tract. Thus, for instance, electro-stimulation may serve for stimulating the endocrine secretion of the pancreas in patients suffering from diabetes type I or type II, or for stimulating exocrine secretion in case of chronic pancreatitis.

Furthermore, electro-stimulation can also serve for stimulating the urinary bladder and external urinary sphincter. Using a suitable setting, such as a low frequency wave, a coordinated contraction may be induced which is suitable for treating the urinary retention that accompanies acontractile or hypocontractile bladders, such as are common in diabetic patients, and for treating other neuropathic atonic bladder conditions. On the other hand, using a different stimulation setting, such as a high frequency, stimulation of the bladder depolarization and a reduced contractility state may be induced, which is suitable for overactive urinary bladder syndrome.

Stimulation of the external urinary sphincter can serve to treat conditions such as urinary stress or urge incontinence.

Despite the fact that the scientific basis and effectiveness of electrostimulation of the Gl tract and urinary system organs is well established, this therapeutic method has not yet gained significant usage, because implantation of the electrodes generally requires an operation under general anesthesia.

There therefore exists a need for a minimally invasive electro-stimulation system which overcomes at least some of the disadvantages present in prior art systems and in particular, that can be implanted using only local anesthesia.

SUMMARY OF THE INVENTION

The present invention seeks to provide a new system for electro-stimulation of an internal organ or a tissue of a subject, which is capable of being deployed in a minimally invasive way, preferably using only local anesthesia and sedation. The system is installed within the wall of a cavity adjacent to the organ or tissue to be stimulated, and in electrical communication with that organ or tissue, but without necessarily being in physical contact with it. This allows a less invasive surgical procedure to be followed in deploying the system. The system can be inserted using an imaging system such as ultrasound, CT, MRI, fluoroscopy, or direct inspection, for guiding the insertion.

The electro-stimulation system of the present invention preferably comprises one or more stimulation electrodes, generally located within the tissues of the wall of a body cavity which encloses the internal organ to be stimulated, and in proximity to the organ, such that their activation causes stimulation of the organ. The electrodes may alternatively and preferably serve for stimulation of the mesothelial internal coating of the cavity wall, such as the parietal peritoneum in the case of the abdominal wall, the mezothelium of parietal pleura and the parietal pericardium in the case of the thoracic cavity. This layer is very rich in autonomic (sympathetic and parasympathetic) nerve endings and its stimulation can result in significant afferent stimulation of the parasympathetic and/or sympathetic nerves. The electrodes and sensors may preferably be implanted retroperitoneally, in a percutaneous, minimally invasive manner, under the guidance of an imaging system, close to the sympathetic nerves and/or ganglions. In this case, stimulation may result in powerful afferent stimuli that may result in a sensation of satiety or nausea.

One or more sensors output a signal in accordance with a physiological characteristic of the subject, and this output is used to define when the electrostimulation is to be applied, according to a predetermined criterion. The physiological characteristic may preferably be a characteristic of the internal organ to be electro- stimulated. A controller uses the signal from the sensor or sensors in order to adjust the level of the electro-stimulation to a predetermined level according to the effect sought. The sensor(s), controller and electrode(s) are preferably connected by means of leads implanted in the wall of the cavity in proximity to the organ to be stimulated, such as in the abdominal wall.

The electrodes, whether they are electro-stimulation electrodes or sensor electrodes, are preferably deployed within the subject at the predetermined location, using a thin delivery tube inserted into the subject into the region where the electrode is to be positioned. Although electrical sensors using electrodes are a common implementation for sensing, and in this application, the invention is generally described using such electrodes, it is to be understood that any other form of suitable sensor can also be used in the present invention, such as, but not limited to, ultrasonic sensors, proximity sensors, temperature sensors, motion sensors, position sensors, or audio sensors.

The electrodes, whether stimulating electrodes or sensing electrodes, or any other sensors, are preferably carried to the site attached to an inflatable balloon, or by any other expandable means, such as a folded mechanical structure, akin to an umbrella or a functionally similar mechanical structure, which is deployed when the electrode(s) are at the intended site. If the electrode deploying means is a balloon, it is passed in an uninflated state down the delivery tube, and an inflation tube attached to the proximal end of the balloon is preferably used to inflate the balloon after passage through the delivery tube, thus deploying the electrode in the region where it is to be positioned. The electrodes are introduced in the correct orientation with their stimulating or sensing surface directed towards the tissue or organs they are respectively intended to stimulate or sense. The electrode is held in position by the inflated balloon. Likewise, if a mechanical device is used for deploying the electrodes and/or sensors, it too is passed down the tube undeployed, and is opened up only when the electrode or electrodes are in the desired position

In the case of organs within the abdominal cavity, the electrodes are preferably situated above the peritoneum. The balloon or any other expandable device used to deploy the electrodes and/or sensors, are operative to isolate the electrodes and/or sensors from other tissues or organs that it is not intended to stimulate. The expandable device is also configured to ensure after deployment, that the predetermined spatial orientation of the electrodes/sensors is maintained, and also that the predetermined mutual position between the electrodes, the sensors and the region to be stimulated, is too maintained.

Although the various preferred embodiments of apparatus and methods of the present invention are generally described in terms of their use in stimulation of a gastric organ from within the abdominal wall, it is to be understood that the invention is not meant to be limited to this application, but is equally applicable to stimulation of any organ or tissue region from within an adjacent bodily cavity wall. A major advantage of the invention is that of performing the placement and activation of the stimulating electrodes and/or sensors without the need to penetrate the wall concerned. Stimulation from within the abdominal wall, as described and claimed herewithin, is thus only one preferred example of this invention.

Other applications of the system and methods of the present invention include: electro-stimulation of the Gl tract for stimulation and coordination of small bowel peristalsis, for the treatment of small bowel chronic obstruction; stimulation of a coordinated small bowel contraction after peritonitis and bowel resection, which often results in a temporary paresis and/or uncoordinated peristalsis and signs of paralytic bowel obstruction.

Gl tract stimulation may serve not only for inducing a coordinated contraction of the tubular muscular walled organs but also for inducing secretion of glands associated with the Gl tract. Thus, for instance, electro-stimulation may serve to stimulate the endocrine secretion of the pancreas in patients suffering from diabetes type I or type II, or for stimulating exocrine secretion in cases of chronic pancreatitis.

Furthermore, electro-stimulation can also serve for stimulating the urinary bladder and external urinary sphincter. Using a suitable setting, such as a low frequency wave, a coordinated contraction may be induced which is suitable for treating the urinary retention that accompanies acontractile or hypocontractile bladders, such as are common in diabetic patients, and for treating other neuropathic atonic bladder conditions. On the other hand, using a different stimulation setting, such as a high frequency, stimulation of the bladder depolarization and a reduced contractility state may be induced, which is suitable for overactive urinary bladder syndrome.

Stimulation of the external urinary sphincter can serve to treat conditions such as urinary stress or urge incontinence.

In order to clarify the nomenclature used, it is again to be emphasized that the term "within a wall" as used in this application and as thuswise claimed, is understood to have the meaning "within the tissue of the wall itself, and is not meant to be understood as referring to within the confines of the space bounded by the wall.

There is thus provided in accordance with a preferred embodiment of the present invention, a system for electro-stimulation of an internal body part of a subject, comprising:

(i) at least one electro-stimulation electrode adapted to be disposed within a wall of a body cavity enclosing the internal body part;

(ii) at least one sensor outputting a signal in accordance with a physiological characteristic of the subject, and (iii) a controller utilizing the signal to adjust the level of the electro-stimulation.

In accordance with further preferred embodiments of the present invention, the body part may be either an organ, such as a gastro-intestinal organ, or a tissue. If the body part is a gastro-intestinal organ, the at least one electro-stimulation electrode is preferably disposed outside of the parietal peritoneum of the subject. The cavity wall may preferably be an abdominal wall or a thoracic wall. In such cases, the at least one sensor may be an elastic element disposed laterally within the abdominal cavity of the subject, and attached subcutaneously to either fascial or bone parts on both sides of the abdominal cavity, such that changes in length of the element enable detection of changes in abdominal extension.

In any of the above described systems, the physiological characteristic of the subject may preferably be a characteristic of the internal body part. In those cases where the body part is a tissue, the at least one electro-stimulation electrode is preferably disposed such that it stimulates the parietal peritoneum, or the sympathetic nerves in the upper abdomen, so reducing the appetite of the subject. According to a further preferred embodiment, the at least one electro-stimulation electrode is disposed at at least one of the retroperitoneum and the lesser sac.

There is further provided in accordance with still another preferred embodiment of the present invention, a system for deploying at least one electrostimulation electrode within a subject, the system comprising: (i) a delivery tube for insertion into a cavity wall of the subject, wherein the at least one electrode is to be deployed,

(ii) an expandable device for passing along the delivery tube, the expandable device carrying the at least one electrode at its distal end, and

(iii) an activating mechanism for expanding the expandable device after passage through the delivery tube, such that the at least one electrode is deployed within the cavity wall and is held in position by the expandable device.

In the above mentioned deploying system, the expandable device may preferably comprise an insulating shielding layer for providing a level of electrical isolation of the at least one electro-stimulation electrode from surrounding conducting paths in the subject.

There is further provided in accordance with yet another preferred embodiment of the present invention, the deploying system as mentioned above, wherein the cavity wall is the abdominal wall of the subject, and the at least one electrode is adapted to be deployed outside the parietal peritoneum, such that when activated, it stimulates at least one of the peritoneum and an organ internal to the peritoneum without being in contact therewith. The organ is then a gastric organ, and the system is such that it enables deployment of the electro-stimulation device without surgical penetration of the peritoneum.

Furthermore, the at least one electrode may preferably be a plurality of electrodes, carried by the expandable device.

In accordance with still another preferred embodiment of the present invention, in the above-described deploying system, the expandable device is preferably an inflatable balloon and the activating mechanism is an inflation tube attached to the proximal end of the balloon for inflating the balloon after passage through the delivery tube. The expandable device may, according to a further preferred embodiment, be an inflatable balloon configured to be expanded by means of filling material inserted therein after passage through the delivery tube. Alternatively and preferably, the expandable device may be a mechanical assembly and the activating mechanism a mechanical system for expanding the mechanical assembly.

There is further provided in accordance with still another preferred embodiment of the present invention, a method of electro-stimulating an internal body part of a subject, comprising the steps of:

(i) providing an electro-stimulation electrode for disposing within a wall of a body cavity in which the internal body part is disposed,

(ii) inserting a delivery tube into the cavity wall into the region where the electrode is to be disposed,

(iii) passing an expandable device along the delivery tube, the expandable device carrying the electrode at its distal end,

(iv) withdrawing the delivery tube to leave the expandable device in the region where the electrode is to be disposed,

(v) expanding the expandable device such that the electrode is deployed within the region, and is held in position by the expandable device, and (vi) activating the electrode such that the internal body part is stimulated.

Such a method may also preferably comprise the additional steps of providing a sensor which outputs a signal in accordance with a physiological characteristic of the subject, implanting the sensor into the subject, and utilizing the signal to adjust the level of activation of the electro-stimulation electrode.

In any of the above mentioned methods, the body part may be an organ or a portion of tissue. The organ may preferably be a gastric organ. Furthermore, in this method of stimulating a gastric organ, the step of inserting the delivery tube into the subject may preferably be performed such that delivery tube does not penetrate the parietal peritoneum of the subject. According to a further preferred embodiment, the electrode may preferably be deployed outside of the peritoneum of the subject. Furthermore, it may be deployed in either of the retroperitoneum and the lesser sac of the subject.

In accordance with a further preferred embodiment of the present invention, the electro-stimulation electrode may be disposed to stimulate either the parietal peritoneum, or the sympathetic nerves in the upper abdomen, or both, such that the appetite of the subject is reduced. Furthermore, in accordance with yet another preferred embodiment of the present invention, the physiological characteristic of the subject may preferably be a characteristic of the internal body part.

In accordance with yet another preferred embodiment of the present invention, in any of the above mentioned methods, the sensor may be an elastic element disposed laterally within the abdominal cavity of the subject, and attached subcutaneously to either one of fascial and bone parts on either side of the abdominal cavity, such that changes in length of the element enable detection of changes in abdominal extension.

Furthermore, in any of the above mentioned methods, the expandable device may preferably be an inflatable balloon and the step of expanding the expandable device comprises inflating the balloon after passage through the delivery tube. Alternatively and preferably, the expandable device may be an inflatable balloon and the step of expanding the expandable device comprises the step of introducing filling material into the balloon after passage through the delivery tube. It may alternatively be a mechanical assembly, in which case the step of expanding the expandable device is preferably performed using a mechanical system for expanding the mechanical assembly.

There is even further provided in accordance with a preferred embodiment of the present invention, a method for detecting the filling of an organ situated behind the anterior abdominal wall, the method comprising the steps of: (i) attaching subcutaneously an extendible mechanical element to either one of fascial and bone parts on either side of the abdominal wall, (ii) detecting the change in length of the extendible mechanical element, and (iii) utilizing the detected change in length to determine the filling of the organ. In such a method, the organ may preferably be the stomach of the subject.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be understood and appreciated more fully from the following detailed description, taken in conjunction with the drawings in which:

Fig.1 shows an arrangement for the deployment of a gastric electro-stimulation system, according to a first preferred embodiment of the present invention; Fig. 2 illustrates schematically the introduction of the electro-stimulation system of the present invention to its intended location close to or in contact with the peritoneum;

Fig. 3 illustrates schematically the deployment of the electrode and/or sensor of the electro-stimulation device of the present invention, by means of inflation of a balloon;

Fig. 4 illustrates schematically, according to a further preferred embodiment of the present invention, a complete bio-feedback system using the electro-stimulation device of the present invention;

Fig. 5 illustrates schematically a mechanical strap or filament fixed at its two ends to the fascia or ribs at either side of the abdomen, in order to sense the level of gastric expansion;

Fig. 6 is a schematic illustration of an inflated balloon for use in the present invention, carrying a number of electrodes over its surface; and

Fig. 7 is a schematic illustration of a mechanically operated expandable device, according to another preferred embodiment of the present invention, for deploying an implanted electrode(s) or sensor(s).

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Reference is now made to Fig. 1 which illustrates schematically, according to a first preferred embodiment of the present invention, apparatus for the deployment of the components of the system for electro-stimulation of the stomach. A cross- section of the abdominal wall and stomach wall is shown, with the site arrangement for the insertion of the electro-stimulation device through an introducer tube 10. The introducer tube 10 is inserted in a minimally invasive manner, through the skin 14, layers of fatty tissue 15 and muscle layers 16, preferably down to the outer surface of the peritoneum 11 , and preferably at a position close to the desired stimulation location on the stomach wall 12. The naturally occurring conductive liquid layer 13 between the peritoneum and the stomach wall ensures that, even though it is outside of the peritoneum, this location provides efficient electro-stimulation of the organ. The location of the stimulation device outside of the peritoneum provides the present invention with significant advantages over prior art gastric electro-stimulation applications, where penetration of the peritoneum is used in order to bring the stimulation electrodes into contact with the stomach wall, with the possible complications that that such a surgical procedure may involve.

Reference is now made to Fig. 2 which illustrates schematically the introduction of the electro-stimulation system of the present invention through the introducer tube 10, to its intended location close to or in contact with the peritoneum 13. The electro-stimulation device itself preferably comprises a balloon 20 carrying on its front or distal surface a curled-up conductive electrode (not visible in Fig. 2, but shown in Fig. 3) attached to an electrically conductive lead 21 trailed out behind it back through the delivery tube. An inflation tube 22 is preferably attached to the rear or proximal side of the balloon, and back through the introducer tube, such that the balloon can be inflated from outside. The terms "front" and "rear" used in connection with the balloon are understood to relate to the direction of introduction of the electrostimulation device through the introducer tube, and are not intended to limit the invention to any particular geometry or orientation.

The electro-stimulation device is preferably introduced using an introducer kit, constructed and operative according to another preferred embodiment of the present invention. Firstly, a needle, preferably blunt tipped, with a pointed trocar is introduced through the abdominal wall to the desired location above the peritoneum. The location of the tip of the needle is determined using an imaging modality such as US or CT. However any other imaging modality such as MRI, fluoroscopy or direct inspection may be used. The imaging system may be a three-dimensional system in order to improve determination of the desired location. According to further preferred embodiments of the present invention, it is possible to use a flexible steerable catheter, guided into position by the guiding system, in order to reach a desired location, and, for instance, to avoid an obstacle or a vital organ in the direct path. The localization of the tip may be determined by introducing a small volume of physiologic liquid and observing the gradual separation of the peritoneum from the fatty tissue situated above it as this space develops by hydro-dissection. Such a space can be easily observed by using US or CT and its creation enables the determination of the proper positioning of the needle tip and the prevention of peritoneal perforation, the elimination of the need for peritoneal penetration being one of the advantages of the present invention. A guide wire is then preferably introduced into this space through the needle and a dilation set to enlarge the opening is passed over the guide-wire to the proper location, using the imaging means for monitoring its progress. The sheath of the dilation set is used for introducing the electrodes and their conveying medium to their proper position - in the case of the abdominal wall, immediately above the peritoneum.

This introducing system and method can also preferably be used to introduce sensors to provide signals for control of the electro-stimulation process. The electrodes and/or the sensors are carried on a carrier or conveyor constructed for that purpose, such as the balloon structure described above, which permits the introduction and deployment of the electrodes and/or sensor elements to their correct position and orientation. The electrode(s) or sensor(s) with their associated uninflated balloon are preferably contained within a separate container tube to keep the balloon folded during insertion down the dilation set sheath. After insertion, the dilation set sheath, the container tube and the guide wire, if still in place, are all withdrawn, leaving the balloon with its electrode(s) or sensor(s) positioned ready for deployment. The above described introducer method and kit is only one preferred method of inserting the balloon with its associated electrode(s) and/or sensor(s), and it is to be understood that any alternative method or system which achieves the same result may equally well be used. The electro-stimulation device should preferably have an electrically conducting electrode surface facing toward the peritoneum and the organ below it, and an electrically isolated surface facing other directions away from the peritoneum.

The deployment apparatus of the present invention brings the electrodes into position above the peritoneum and prevents their displacement therefrom. Similarly, sensors such as pressure sensors, movement sensors or electrical sensing electrodes can be positioned in a similar manner with their sensing areas facing towards the peritoneum and the subjacent organs, and situated in the correct location by similarly designed deployment means.

As shown in the embodiments of Figs. 1 and 2, this deployment can be performed by a slender catheter with an inflatable balloon at its distal end. A flat electrode is preferably attached to the distal surface of the balloon, as previously described.

Reference is now made to Fig. 3 which illustrates schematically how the deployment of the electrode and/or sensor is achieved by inflation of the balloon 30. The electrode 31 preferably comprises a flexible sheet, or a net or other such form that can be spread out above the peritoneum by inflating the balloon. The electrode may be made of a biocompatible material such as stainless steel, palladium, iridium- palladium, titanium or any other such suitable material. An additional insulating layer 32 may preferably be attached to the proximal end of the balloon such that when the balloon is inflated, this insulating layer provides electrical isolation of the electrode from the surrounding body signal conduction paths.

The introduced catheter and balloon should also be manufactured of a biocompatible material. After inflation of the balloon and deployment of the electrode or sensor, the deployment apparatus may be removed or may be left implanted. The catheter is either sealed in order to keep the inflation fluid in its place, as shown in Fig. 3, or it may preferably be connected to an inflation port to enable the balloon inflation to be topped up, adjusted or removed. If the deployment apparatus is left in situ, it should be made of an implantable plastic material such as silicone. The conducting leads should preferably be electrically isolated by biocompatible plastic such as silicone.

Reference is now made to Fig. 4, which illustrates schematically, according to a further preferred embodiment of the present invention, how the electro-stimulation device of the present invention can be incorporated into a complete bio-feedback system. The bio-feedback system is shown in Fig. 4 in its deployed state, such that the insertion catheters and inflation balloons are not shown. The system comprises a sensor 40 for detecting the bio-parameter used to determine the stimulation required, a control unit (CPU) 41 for interpreting the output of the sensor 40 and for converting it into the correct stimulation signal, and the stimulation electrode or electrodes for applying the electro-stimulation to the desired organ in accordance with the sensor output. The electrode is shown in Fig. 4 having two parts, the lower part 43, facing the organ to be stimulated, which is the conductive stimulation electrode, and the upper part 42, which is the insulating part for shielding the stimulating electrode from the surrounding body signal conduction paths. Separate introducer catheters are preferably used for the sensor or sensors and for the electrode or electrodes, since their location is generally separate. Connecting leads 44 are attached to the electrode(s) and sensor(s) for transmitting signals from and to the control unit 41. The leads 44 are preferably installed through the bores of the introducer catheters of the electrodes, and run to the subcutaneous tissue, where they are connected to the control unit 41. In such a case, the electrically conductive lead 21 shown in the insertion drawing of Fig. 2, will not emerge from the subject's skin, but will remain subcutaneous, for connection to the control unit 41. The control unit 41 is preferably implanted subcutaneously. The control unit 41 is preferably self-powered by an internal battery. The application electrodes can preferably either be of bi-poplar construction, such that the stimulation signal is applied between the bipolar electrodes, or of mono-polar construction, with the stimulation signal applied between the embedded electrode and another electrode located elsewhere either on or in the subject's body. In Fig. 4, the electrode and sensor are shown with conductive and isolating elements.

The sensor is used to detect a bodily characteristic whose value is used to control the level of electro-stimulation required. The sensor can preferably be any one of an electrical, motion, sound, temperature or pressure sensor.

According to a further preferred embodiment of the present invention, and as shown in Fig. 5, in order to detect gastric filling, the sensor could comprise a mechanical strap or filament 50. Such a strap or filament 50 is preferably implanted subcutaneously, fixed at its two ends 51 , 52, to the fascia or ribs at either side of the abdomen, such that either measurement of the strain on the sensor, or measurement of the expanded length of the sensor, enables the expansion of the abdomen to be determined, and hence the gastric filling. This data is then input to the control unit of the system, where the appropriate stimulation output is directed to the gastric stimulation electrode.

Reference is now made to Fig. 6 which is a schematic illustration of an inflated balloon 60 carrying a number of electrodes 62, 64, 66, over its surface. According to this preferred embodiment of the present invention, use of such a balloon, or of an equivalent mechanical deployment device, enables a number of sensors and/or stimulation electrodes to be deployed with only a single insertion procedure. Additionally, the electrodes are deployed at predefined positions, such that an electric field is generated between electrodes having well defined positions. This generally provides a better defined stimulation field than one generated between an electrode and the subject's body as the opposing ground plane.

Reference is now made to Fig. 7, which is a schematic illustration of a mechanically operated expandable device 70, according to a preferred embodiment of the present invention, for deploying an implanted electrode(s) or sensor(s) 71 against the peritoneum 72 of a subject. The device is constructed of a foldable mechanical structure 74, which is extended after passage down the insertion tube 75 so as to deploy the electrode(s) or sensor(s) at their intended site. The extending operation can preferably be executed mechanically or electro-mechanically, such as by applying downward pressure on the actuating ring 76, so that the mechanical arms open radially outwards 77. Alternative mechanisms may preferably use an assembly of preshaped flexible wires, which is passed down the insertion tube and whose wires open up in radial directions after exiting the insertion tube, in accordance with the prestressed shapes of the wires. It is to be understood that many such mechanically expandable devices are known in the art, and that the specific device shown schematically in Fig 7 is only one non-limiting example thereof.

Although not shown in the drawing of Fig. 7, it may be advantageous to incorporate the expandable mechanical structure within a skin-like cover similar to a balloon, or within a netting cover, which opens as the mechanical structure is deployed. Use of such a cover or netting may facilitate the positioning of the electrodes, and may assist in providing a level of electrical isolation of the electrode from regions of the surrounding bodily tissue environment from which isolation is desirable.

Furthermore, although the balloon embodiments have been described hereinabove as being inflated in the usual manner by inputting fluid through an inflation tube, it is to be understood that this is not the only way by which the balloon can be inflated. It is also feasible to "inflate" the balloons using a filling material such as beads, which, when pushed into the balloon through the inflation tube, cause it to inflate. Likewise, the filling material used to "inflate" the balloon could preferably be a long length of wire or cord having a predetermined level of stiffness, such that when folded or bent, it will tend to straighten itself again. As the increasing length of cord is pushed into the balloon, it will fill the balloon in a manner which will expand the skin of the balloon where the bends in the wire or cord push against the balloon skin from the inside. The length of cord or wire used should be long enough such that within the balloon several loops of the wire or cord maintain the balloon skin extended. In this respect, such embodiments have some functional similarity to the mechanically operated expandable devices described hereinabove, having a covering over the expanding mechanism.

The above described embodiment of the present invention has been described in terms of the use of the electro-stimulation system deployed on the parietal peritoneum for stimulation of the wall of the organ situated adjacent the abdominal wall. The effect may be a sensation of satiety or nausea by stimulation of the afferent receptors, which then send an input to brain, or by causing contraction or relaxation of a hollow organ, which then stretches the receptors in its wall resulting in an afferent stimulus to the brain, this being an indirect effect. Stimulation systems according to the present invention may also serve for stimulation of the parasympathetic (vagus) afferent receptors situated in the parietal peritoneum. Such stimulation, according to its nature, may cause a sensation of satiety or of nausea. Additionally, according to further preferred embodiments, a system for stimulation these receptors is provided based on mechanical, magnetic, electromagnetic or chemical stimulation using an implantable system in the abdominal wall, but not limited thereto. Furthermore, for the gastric application described above, instead of in front of the stomach, the electro-stimulation device could be deployed percutaneously behind the stomach in the posterior abdominal wall, in the retroperitoneum or in the lesser sac, such that the sympathetic (celiac plexus) nerves are stimulated. These can cause either nausea or a feeling of satiation if stimulated. Alternatively and preferably, these nerves may be stimulated by magnetic or electromagnetic fields, mechanical distension, or chemical means.

It is to be understood that the invention is not intended to be limited to such gastric applications alone, but is equally applicable for use in other regions of the body where electro-stimulation may be operative, such as on the urinary bladder, other areas of the Gl tract, or other bodily organs, as outlined in some of the examples brought in the Background section of this application.

It is appreciated by persons skilled in the art that the present invention is not limited by what has been particularly shown and described hereinabove. Rather the scope of the present invention includes both combinations and subcombinations of various features described hereinabove as well as variations and modifications thereto which would occur to a person of skill in the art upon reading the above description and which are not in the prior art.

Claims

CLAIMS We claim:
1. A system for electro-stimulation of an internal body part of a subject, comprising: at least one electro-stimulation electrode adapted to be disposed within a wall of a body cavity in which said internal body part is disposed; at least one sensor outputting a signal in accordance with a physiological characteristic of said subject; and a controller utilizing said signal to adjust the level of said electrostimulation.
2. A system according to claim 1 and wherein said body part is an organ.
3. A system according to claim 1 and wherein said body part is a portion of tissue.
4. A system according to any of the previous claims and wherein said wall is either one of an abdominal wall and a thoracic wall.
5. A system according to claim 2 and wherein said organ is a gasto-intestinal organ.
6. A system according to claim 5 and wherein said at least one electrostimulation electrode is disposed outside of the parietal peritoneum of the subject.
7. A system according to any of the previous claims and wherein said physiological characteristic of said subject is a characteristic of said internal body part.
8. A system according to claim 5 and wherein said at least one sensor is an elastic element disposed laterally within the abdominal cavity of the subject, and attached subcutaneously to either one of fascial and bone parts on both sides of said abdominal cavity, such that changes in length of said element enable detection of changes in abdominal extension.
9. A system according to claim 3 and wherein said at least one electrostimulation electrode is disposed such that it stimulates the parietal peritoneum, such that the appetite of the subject is reduced.
10. A system according to claim 3 and wherein said at least one electrostimulation electrode is disposed such that it stimulates the sympathetic nerves in the upper abdomen, such that the appetite of the subject is reduced.
11. A system according to claim 10 and wherein said at least one electrostimulation electrode is disposed at at least one of the retroperitoneum and the lesser sac.
12. A system for deploying at least one electro-stimulation electrode within a subject, the system comprising: a delivery tube for insertion into a cavity wall of the subject, wherein said at least one electrode is to be deployed; an expandable device for passing along said delivery tube, said expandable device carrying said at least one electrode at its distal end; and an activating mechanism for expanding said expandable device after passage through said delivery tube, such that said at least one electrode is deployed within said cavity wall and is held in position by said expandable device.
13. A system according to claim 12 and wherein said expandable device comprises an insulating shielding layer for providing a level of electrical isolation of said at least one electro-stimulation electrode from surrounding conducting paths in said subject.
14. A system according to claim 12 and wherein said cavity wall is the abdominal wall of the subject, and the at least one electrode is adapted to be deployed outside the parietal peritoneum, such that when activated, it stimulates at least one of said peritoneum and an organ internal to said peritoneum without being in contact therewith.
15. A system according to claim 14 and wherein said organ is a gastric organ.
16. A system according to either of claims 14 and 15 and wherein said system enables a deployment of a gastric organ electro-stimulation device without surgical penetration of the peritoneum.
17. A system according to any of claims 12 to 16 and wherein said at least one electrode is a plurality of electrodes, carried by said expandable device.
18. A system according to any of claims 12 to 16 and wherein said expandable device is an inflatable balloon and said activating mechanism is an inflation tube attached to the proximal end of said balloon for inflating said balloon after passage through said delivery tube.
19. A system according to any of claims 12 to 16 and wherein said expandable device is an inflatable balloon configured to be expanded by means of filling material inserted therein after passage through said delivery tube.
20. A system according to any of claims 12 to 16 and wherein said expandable device is a mechanical assembly and said activating mechanism is a mechanical system for expanding said mechanical assembly.
21. A method of electro-stimulating an internal body part of a subject, comprising the steps of: providing an electro-stimulation electrode for disposing within a wall of a body cavity in which said internal body part is disposed; inserting a delivery tube into said cavity wall into the region where said electrode is to be disposed; passing an expandable device along said delivery tube, said expandable device carrying said electrode at its distal end; withdrawing said delivery tube to leave said expandable device in said region where said electrode is to be disposed; expanding said expandable device such that said electrode is deployed within said region, and is held in position by said expandable device; and activating said electrode such that said internal body part is stimulated.
22. A method according to claim 21 , and further comprising the steps of: providing a sensor which outputs a signal in accordance with a physiological characteristic of said subject; implanting said sensor into said subject; and utilizing said signal to adjust the level of activation of said electrostimulation electrode.
23. A method according to either of claims 21 and 22 and wherein said body part is an organ.
24. A method according to either of claims 21 and 22 and wherein said body part is a portion of tissue.
25. A method according to claim 23 and wherein said organ is a gastric organ.
26. A method according to claim 25 and wherein said step of inserting said delivery tube into said subject is performed such that delivery tube does not penetrate the parietal peritoneum of the subject.
27. A method according to claim 26 and wherein said electrode is deployed outside of the peritoneum of the subject.
28. A method according to claim 26 and wherein said electrode is deployed in either of the retroperitoneum and the lesser sac of the subject
29. A method according to claim 22 and wherein said physiological characteristic of said subject is a characteristic of said internal body part.
30. A method according to claim 25 and wherein said sensor is an elastic element disposed laterally within the abdominal cavity of the subject, and attached subcutaneously to either one of fascial and bone parts on either side of said abdominal cavity, such that changes in length of said element enable detection of changes in abdominal extension.
31. A method according to claim 24 and wherein said electro-stimulation electrode is disposed such that it stimulates the parietal peritoneum, such that the appetite of the subject is reduced.
32. A method according to claim 24 and wherein said electro-stimulation electrode is disposed such that it stimulates the sympathetic nerves in the upper abdomen, such that the appetite of the subject is reduced.
33. A method according to any of claims 21 to 32 and wherein said expandable device is an inflatable balloon and said step of expanding said expandable device comprises inflating said balloon after passage through said delivery tube.
34. A method according to any of claims 21 to 32 and wherein said expandable device is an inflatable balloon and said step of expanding said expandable device comprises the step of introducing filling material into the balloon after passage through the delivery tube.
35. A method according to any of claims 21 to 32 and wherein said expandable device is a mechanical assembly and said step of expanding said expandable device is performed using a mechanical system for expanding said mechanical assembly.
36. A method for detecting the filling of an organ situated behind the anterior abdominal wall, said method comprising the steps of: attaching subcutaneously an extendible mechanical element to either one of fascial and bone parts on either side of said abdominal wall; detecting the change in length of said extendible mechanical element; and utilizing said detected change in length to determine the filling of said organ.
37. A method according to claim 36 and wherein said organ is the stomach of the subject.
PCT/IL2007/000840 2006-07-05 2007-07-05 Minimally invasive electro-stimulation system WO2008004234A2 (en)

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US6535764B2 (en) * 2001-05-01 2003-03-18 Intrapace, Inc. Gastric treatment and diagnosis device and method

Patent Citations (1)

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Publication number Priority date Publication date Assignee Title
US6535764B2 (en) * 2001-05-01 2003-03-18 Intrapace, Inc. Gastric treatment and diagnosis device and method

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9724036B2 (en) 2009-11-13 2017-08-08 Academisch Ziekenhuis Groningen Probe system and a probe for measuring functionality of an orifice in the human pelvic region

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