Surgery – Diagnostic testing – Structure of body-contacting electrode or electrode inserted...
Reexamination Certificate
2000-08-16
2003-01-21
Cohen, Lee (Department: 3739)
Surgery
Diagnostic testing
Structure of body-contacting electrode or electrode inserted...
C607S116000, C607S133000
Reexamination Certificate
active
06510332
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a medical implant device for electrostimulation and/or electrical monitoring of endo-abdominal tissue or viscera. More specifically, this invention provides a medical implant device having electrode leads which can be attached or affixed to the enteric or endo-abdominal tissue or viscera such that the electrode leads resist detachment in spite of the vigorous and/or periodic action or movement of the enteric or endo-abdominal tissue or viscera. The medical implant device of this invention is especially adapted for location or implantation in the endo-abdominal cavity over extended periods of time.
BACKGROUND OF THE INVENTION
It is well known that more than 70% of illnesses affecting the digestive tract are of a functional nature. Today such illnesses are treated predominantly using pharmacological means. Since drugs generally have side effects, particularly when the drugs cure the symptom and not the underlying problem or dysfunction, they must often be administered temporally. Indeed, if the side effects are sufficiently serious, the drug may have to be discontinued before full benefit to the patient is realized; in many cases the underlying illness remains.
The important role played by electrophysiology in controlling gastrointestinal activity has become increasingly apparent in recent years. Thus, the possibility exits of correcting dysfunction by means of electrostimulation applied at specific frequencies, sites, and modalities and with regard to the self-regulating electromotor physiology of the gastrointestinal organs or tract. It has recently been shown, for example, that changes occur in the motility and electromotor conduct of the gastric tract in eating disorders (e.g., obesity, thinness, bulimia, anorexia). Disturbances in electromotor activity in diabetic gastroparesis, reflux in the upper digestive tract, and numerous other gastroenterological functional pathologies have also been observed.
Stimulation of the intrinsic nervous system of the stomach is likely to have two major consequences or effects: (1) the correction and direct control of the electromotor activity of the intestines and (2) the stimulation of increased incretion of specific substances (i.e., gastroenteric neuromediators) produced by the intrinsic nervous system itself through the myenteric plexus. Curing of functional illnesses involving the digestive system and, more broadly, involving disorders in any way connected to, or associated with, the digestive system is, therefore, closely linked to the progress of research in the field of electrophysiology.
An indispensable condition for modifying the electrical activity of the digestive system's intestinal tract and related neurohormonal incretions is the use of an implant system to generate electrical impulses (electrical stimuli) and means (e.g., electrocatheters) to connect them to the viscera and/or intestines to be stimulated. These treatment methods involve an “invasive” surgical technique to implant the electrocatheter in the abdomen. This may involve open or, preferably, micro-invasive surgery (i.e., video-laparoscopic surgery). Current electrocatheters to stimulate electrically and/or monitor endo-abdominal viscera normally have metal microbarbs which are angled in such a way as to permit application of the end of the catheter and to prevent it subsequently from being dislodged. However, this type of catheter is often very complicated to make and, consequently, is very costly. Moreover, metal microbarbs can damage surrounding tissue especially when exposed to the vigorous action of the digestive tissue and/or organs. Among the undesirable consequences of such damage is evasion of the electrode into the lumen of the gastrointestinal tract. This would result in contamination of the abdominal cavity and the electrode. The subsequent infection would, at a minimum, require removal of the catheter and involve an additional operation.
During laparoscopic procedures, after administering a general anesthetic, the patient's abdomen is inflated with CO
2
or another inert inflammable gas, thereby transforming the abdominal cavity from a virtual to a real cavity. Rigid tubes with air-tight valve mechanisms (“trocars”) are then inserted into the gas-filled abdominal cavity so that a video camera and other surgical instruments can be introduced into the abdomen. The operation then proceeds by viewing the video images transmitted by the camera. Multiple trocars are required. Generally, the first trocar provides access to the abdomen by the video camera in order to monitor the surgical procedure. A clamp is normally inserted in the second trocar to move or retain the hepatic edge that normally covers the lesser curve of the stomach or other viscera depending on the type of operation to be performed. A third trocar provides access for a maneuvering clamp or laparoscopic forceps. The fourth trocar is used for the introduction of instruments as well as the electrocatheter to be implanted in the stomach wall of the patient. The structure of the electrocatheter plays an important part in facilitating the specific operation for whichever of the patient's organs and/or viscera the surgeon aims to stimulate.
Each of the trocars used, of course, requires a separate tract through the skin and abdominal wall. To keep the abdomen inflated, valves are used with the trocars to provide a gas-tight seal. Introduction of a medical device, such as an electrocatheter or implantable electrode, into the abdomen generally requires the use of laparoscopic forceps to grasp the device. Such devices, which are generally inherently fragile in nature, could be damaged if grasped too firmly by the forceps. Thus, for example in the case of an electrocatheter having electrode leads, the interior conductor wires could be broken, rendering the device dysfunctionally or completely useless.
It is, of course, desirable in laparoscopic surgery to limit the number of trocars used since each trocar requires a separate incision which results in additional visible scars for the patent. More importantly, each additional incision increases the chance of infection and other complications resulting therefrom. Therefore, to reduce the number of trocars required, implantable devices are often inserted completely through the trocar and into the abdomen so that a single trocar can serve for multiple uses (e.g., for insertion of other instruments and/or manipulation devices). Thus, the surgeon will often need to pull the distal end of the inserted device back through a trocar and/or remove the device entirely. In this case, the device needs to “line up” to the trocar passageway to be pulled back through the trocar. Of course, if the device is grasped by the forceps in a manner so the longitudinal dimension of the device is not alined with the trocar passageway, the device cannot be pulled back through the trocar.
It is also desirable to place the electrocatheter adjacent to the tissue or organ of interest and “lock” it in place so that the target tissue or organ can then be electrostimulated and/or electrically monitored. As noted above, metal microbarbs have been used to lock the device in place. Such metal microbarbs can damage or tear surrounding tissue—especially when the implant device is subjected to the vigorous action or peristaltic movement of the digestive organs. More recently, flexible microbarbs have been used for such implant device. Although such flexible microbarbs are less likely to damage the surrounding tissue, so-equipped electrocatheters are prone to displacement when acted on by the vigorous action or movement of the digestive organs, especially when the implant device is to remain within the patient for prolonged periods of time. Additionally, the peristaltic movement may fracture the barbs, or cause erosion through the organ wall and into the lumen of the organ to which it was affixed. Once displaced, of course, the implant device can no longer provide the desired electrostimulation and/or electrical monitoring of the
Cohen Lee
Fitch Even Tabin & Flannery
Transneuronix Inc.
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