Laparoscopic partial myectomy: an experimental reflux model.

BACKGROUND: A number of different surgical procedures have been described for the treatment of gastroesophageal reflux disease. Moreover, modifications and completely new techniques are being introduced on a regular basis. Nonetheless, in most cases of novel laparoscopic techniques profound experimental data have not been collected prior to their clinical introduction. Due to the lack of an animal model of inadequate esophageal sphincter function, most experimental studies on antireflux procedures were done on normally functioning esophageal sphincters.
METHODS: It is well-known that myotomy alone cannot induce sphincter insufficiency in animal models. In addition, complete myectomy is associated with severe mortality and, therefore, is not useful as an experimental model. This study introduces a new model of laparoscopic partial in vivo myectomy. The procedure described here forms a myectomy of the esophagus using scissors and a sponge on the side of the greater gastric curvature. The size of the myectomy is approximately 6 x 1.5 cm and was successfully performed in a consecutive series of eight experimental animals (male German house pigs).
RESULTS: Following an intensive team training on dead animals, the procedure was performed with success via the laparoscope in all study animals (n = 8). The sphincter pressure as determined by manometry was significantly reduced from 7.7 mmHg (range, 4.5-9.1; preoperative values) to 2.2 mmHg (range, 0-6.8; early postoperative values) and 2.3 mmHg (range, 0-3.7) at 8 weeks after surgery (p < 0.001). In addition, the length of the lower esophageal sphincter as well as the sphincter pressure vector volume were significantly reduced early as well as at 8 weeks after laparoscopic myectomy. Furthermore, endoscopy and reflux testing were pathologic compared with control animals.
CONCLUSIONS: Laparoscopic partial myectomy results in complete sphincter insufficiency with only little procedure-related morbidity. This procedure allows for the experimental evaluation of surgical procedures on the gastroesophageal junction. Future modifications of surgical antireflux procedures can therefore be evaluated in an experimental setting prior to their clinical introduction.