Surgery – Miscellaneous – Methods
Reexamination Certificate
1998-05-06
2002-04-02
Peffley, Michael (Department: 3739)
Surgery
Miscellaneous
Methods
C606S041000, C607S133000
Reexamination Certificate
active
06363937
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to the field of electrosurgery, and more particularly to surgical devices and methods which employ high frequency electrical energy to treat tissue in regions of the digestive tract and associated organs, such as the pharynx, esophagus, stomach, intestines, anorectum, liver, pancreas and the like. The present invention is particularly suited for treating the lower esophageal sphincter in patient's suffering from gastroesophageal reflux.
Gastroesophageal reflux, better known as heartburn or acid indigestion, occurs when the esophageal mucosa suffers prolonged exposure to noxious gastric acid and pepsin because of deficiencies of the esophageal reflux barrier and acid-clearing mechanisms. Normally, the hydrocholoric acid and protease pepsin that are present in the stomach are excluded from the esophagus by the valve action of the lower esophageal sphincter (LES). Weakness of LES tone or abnormally frequent relaxations of the LES allow gastric acid and pepsin to reflux into the esophagus and potentially damage the mucosa. Symptoms of gastroesophageal reflux disease include heartburn, regurgitation, chest pain (due to a spasm of the acid-bathed esophagus), coughing, hoarseness, sore throat, gingivitis and asthma.
Treatment of gastroesophageal reflux typically involves pharmaceuticals that either neutralize acids in the stomach, or prevent the secretion of gastric acid into the stomach. Often, the complete control of heartburn requires extremely aggressive acid suppression. These pharmaceuticals, however, do not treat the problem (i.e., a loose lower sphincter). In addition, it has been shown that reflux can produce a broncho-contriction (asthma-like symptoms) either through reflex (vagally induced from reflux in the esophagus) or reflux into the trachea. Changing the ph of the stomach acid does not prevent these conditions.
A second pharmaceutical approach is to administer promotility agents that act to increase LES tone and, in some instances, improve esophageal acid clearance and accelerate gastric emptying. Bethanechol, a cholinergic agonist that enhances LES tone, was frequently used in the past. It is no longer widely employed, however, because of its poor efficacy, a high incidence of side effects, and a tendency to stimulate gastric acid secretion.
Esophageal strictures can be treated by forcible dilatation using flexible tapered bougies that are swallowed by the patient. Dilatation also can be performed by endoscopically using balloons. Although such dilatation is usually effective, strictures frequently recur if gastroesophageal reflux is not controlled.
The lower esophageal acid exclusion barrier can be restored by a surgical procedure in which the distal portion of esophagus is anchored in the abdomen by wrapping part of the fundus of the stomach around it. This procedure, called fundoplication, is intended to reestablish the normal anatomic relationships and reinforce the LES. Although fundoplication typically eliminates gastroesophageal reflux and affords complete resolution of symptoms, this procedure is extremely invasive, and often causes unwelcome side effects. After fundoplication surgery, for example, some patients are unable to belch and complain of frequent abdominal distention, a phenomenon known as gas-bloat syndrome. In addition, some patients who have good relief initially will develop recurrent reflux after a period of years.
SUMMARY OF THE INVENTION
The present invention provides systems, methods and apparatus for applying high frequency electrical energy to treat tissue in regions of the digestive system. The present invention is particularly suited for applying electrical energy to the lower esophageal sphincter to treat gastroesophageal reflux.
In one aspect of the invention, a method of the present invention comprises positioning an electrosurgical instrument adjacent a tissue structure of the lower sphincter so that one or more electrode terminal(s) are brought into at least partial contact or close proximity with the body structure. High frequency voltage is applied between the electrode terminal(s) and one or more return electrode(s) to elevate the temperature of collagen fibers within the tissue of the lower sphincter from body temperature (about 37° C.) to a tissue temperature in the range of about 45° C. to 90° C., usually about 60° C. to 70° C. This temperature elevation substantially irreversibly contracts the collagen fibers within the tissue to tighten the lower sphincter and prevent or greatly reduce gastroesophageal reflux. The electrosurgical instrument may comprise a catheter that is advanced transluminally or through the patient's mouth and esophagus down to the lower sphincter, or a more rigid probe that is introduced through a percutaneous or open penetration in the patient.
In a preferred embodiment, an electrically conducting fluid is provided between the electrode terminal(s) and one or more return electrode(s) positioned proximal to the electrode terminal(s) to provide a current flow path from the electrode terminal(s) away from the tissue to the return electrode(s). The current flow path may be generated by directing an electrically conducting fluid along a fluid path past the return electrode and to the target site, or by locating a viscous electrically conducting fluid, such as a gel, at the target site, and submersing the electrode terminal(s) and the return electrode(s) within the conductive gel. The collagen fibers may be heated either by passing the electric current through the tissue to a selected depth before the current returns to the return electrode(s) and/or by heating the electrically conducting fluid and generating a jet or plume of heated fluid, which is directed towards the target tissue. In the latter embodiment, the electric current may not pass into the tissue at all. In both embodiments, the heated fluid and/or the electric current elevates the temperature of the collagen sufficiently to cause hydrothermal shrinkage of the collagen fibers.
In another aspect of the invention, a sufficient high frequency voltage is applied between the electrode terminal(s) and one or more return electrode(s) to volumetrically remove at least a portion of the lower sphincter. Specifically, high frequency voltage is applied between the electrode terminal(s) and one or more return electrode(s) to remove a small tissue segment, channel or hole from the region near or in the lower sphincter to shrink the sphincter and prevent swelling, due to the formation of scar tissue as the wound heals. The high frequency voltage may be selected to effect a small amount of thermal damage to the walls of the channel or hole to facilitate the formation of scar tissue without extending this thermal damage beyond the immediate region of the target site The electrode terminal(s) may be translated relative to the lower sphincter during or after the application of electrical energy to sculpt a void within the lower sphincter, such as a hole, channel, stripe, crater, or the like. In some embodiments, the electrode terminal(s) are axially translated toward the lower sphincter to bore one or more channel(s) or hole(s) through a portion of the structure. In other embodiments, the electrode terminal(s) are translated across the lower sphincter to form one or more stripe(s) or channel(s). In most embodiments, electrically conducting fluid, such as isotonic saline, is located between the electrode terminal(s) and the tissue. In the bipolar modality, the conducting fluid generates a current flow path between the electrode terminal(s) and one or more return electrode(s). High frequency voltage is then applied between the electrode terminal(s) and the return electrode(s) through the current flow path created by the electrically conducting fluid.
In a specific configuration, the tissue is removed by molecular dissociation or disintegration processes. In these embodiments, the high frequency voltage applied to the electrode terminal(s) is sufficient to vaporize an electrically conductiv
Eggers Philip E.
Hovda David C.
Thapliyal Hira V.
ArthroCare Corporation
Peffley Michael
Raffle John T.
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