APPARATUS AND METHOD FOR TREATING GASTROESOPHAGEAL REFLUX DISEASE
 This application claims priority from provisional application serial No. 60/342,540 filed December 20, 2001, the entire contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION  1. Field of the Invention
 The subject invention is directed to a minimally invasive surgical procedure, and more particularly, to an endoscopic surgical procedure for treating gastroesophageal reflux disease, and apparatus for performing the procedure.
 2. Background of the Related Art
 Gastroesophageal reflux disease (GERD) is one of the most common upper-gastrointestinal disorders in the western world, with a prevalence of approximately 360 cases per 100,000 population per year. Approximately 25% of individuals with GERD will eventually have recurrent, progressive disease and are candidates to undergo anti-reflux surgical procedures for effective long term therapy.
 GERD is a condition in which acids surge upward from the stomach into the esophagus. Backflow of acid into the esophagus makes it raw, red and inflamed, producing the condition known as esophagitis; it also causes the painful, burning sensation behind the breastbone known as heartburn. Backflow or reflux of acid can occur when the sphincter or band muscle at the lower end of the esophagus fails to stay closed. This sphincter is called the lower esophageal sphincter (LES). The LES acts as a valve to the stomach, remaining closed until the action of swallowing forces the valve open to allow food to pass from the esophagus to the stomach. Normally the valve closes immediately after swallowing to prevent stomach contents from surging upward. When the LES fails to provide that closure, stomach acids reflux back into the esophagus, causing heartburn.
 The general approach for corrective surgery involves creating a new valve or tightening the existing valve. This procedure is known as "fundoplication" and is used to prevent the back flow of stomach acids into the esophagus. Various fundoplication procedures have been developed to correct GERD and are known as Nissen fundoplication, Belsey Mark IV repair, Hill repair and Dor repair. Each surgical procedure has its own unique attributes; however, each requires an invasive surgical procedure, whereby the individual must endure trauma to the thoracic cavity. The individual remains hospitalized after the procedure for about six to ten days.
 The Nissen fundoplication technique involves enveloping the lower esophagus with the gastric fundus by suturing the anterior and posterior fundal folds about the esophagus. Modifications of this procedure include narrowing of the esophageal hiatus posterior to the esophagus, anchoring of the fundoplication to the preaortic fascia and surgical division of the vegus nerve. The degree of the fundal wrap can be modified to incompletely encircle the esophageal tube to avoid gas float syndrome and has also been modified to include a loose wrap. Similarly, the Belsey Mark IV repair, Hill repair and Dor repair are directed to modifications for encirclement of the esophageal tube by fascia.
 Complications of these fundoplication procedures include the inability to belch or vomit, dysphagia, gastric ulcer, impaired gastric emptying and slippage of the repair that may foil the best surgical results. Therefore, the fundoplication procedures have been modified to adjust the length and tension of the wrap, include or exclude esophageal muscle in the sutures and leaving the vagus nerves in or out of the encirclement.
 A relatively new fundoplication technique is known as Nissen fundoplication laparoscopy. In contrast to the traditional Nissen fundoplication procedure, which requires a 6 to 10 inch incision and a 6 to 10 day hospital stay with up to 8 weeks of recovery at home, the laparoscopy technique is performed through small openings about the abdominal cavity and most patients tend to leave the hospital in two days and can return to work and other activities within a week or two. Despite the benefits of less invasive laparoscopic fundoplication procedures, there is still a need for a minimally invasive corrective treatment for GERD that can be performed on an out-patient basis.
SUMMARY OF THE INVENTION
 The subject invention is directed to a new and useful minimally invasive surgical procedure for treating Gastroesophageal reflux disease by reducing the diameter of the esophagus proximate to the lower esophageal sphincter, and to an endoscopic surgical apparatus for performing the procedure. The method includes the steps of forming a fold of esophageal tissue proximate to the lower esophageal sphincter, and extending at least one needle through the fold of esophageal tissue. Each of the needles has an interior lumen containing a tissue fastener. The method further includes the steps of ejecting a distal portion of the tissue fastener from the interior lumen of each needle such that the distal portion of each tissue fastener is disposed against a distal surface of the fold of esophageal tissue, and retracting each needle from the fold of esophageal tissue such that a proximal portion of each tissue fastener is deployed from the interior lumen of each needle and is disposed against a proximal surface of the fold of esophageal tissue.
 The method further comprises the step of providing an endoscopic device having a an interior lumen for supporting the needles in a manner that permits the reciprocal movement thereof, and a tissue reception cavity for receiving the fold of esophageal tissue. The method includes guiding the endoscopic device through the esophagus to a location wherein the tissue reception cavity is disposed proximate to the lower esophageal sphincter. Thus, the step of forming the fold of esophageal tissue includes the step of drawing esophageal tissue into the tissue reception cavity of the endoscopic device. This may be accomplished using suction or with a tissue grasping device.
 Preferably, a tissue fastener of shape memory alloy or a similar bio-compatible material having memory characteristics is provided within the interior lumen of each needle in a generally elongate orientation. The step of ejecting a tissue fastener from the interior lumen of a needle includes permitting the distal portion of the tissue fastener to move to a normally unstressed condition (at body temperature) wherein the distal portion of the tissue fastener is in a curved or coiled orientation. The step of retracing the needle from the fold of esophageal tissue includes permitting the