Rosamaira Bozzi, MD, Aviel Roy-Shapira, MD, Fabio Cattaneo, PhD, Domenico Cattaneo, MD. U.O.C. di Chirurgia ed Endoscopia Digestiva “Azienda dei Colli”.
Objective: A new method for trans-oral long submucsal myotomy – (POEM™) has been shown to be a relatively safe and effective method to treat achalasia. However, the procedure often results in severe gastroesophageal reflux(GERD). Recently, FDA approved a method for transoral stapled anterior fundoplication (SRS™) for the treatment of GERD. The SRS™ device incorporates an ultrasonic range finder, that measures tissue thickness. It enables a single operator to staple the fundus of the stomach to the esophagus 2-4 cm above the gastroesophageal junction, using two or three quintuplets of standard 4.8mm titanium “B” shaped surgical staples. The stapled anterolateral fundoplication restores the the gastroesophageal flap valve mechanism, creating an effective reflux barrieir. The objective of the experiment was to test the feasibility of combining the two procedures, in order to perform a transoral myotomy with anterior fundoplication, functionally equivalent to the standard laparoscopic operation for achalasia.
Description of the method: The experiment was performed in compliance with the Israeli Animal Welfare Act, on a swine model, under general anesthesia. A standard gastroscope was inserted into the stomach, and an overtube was slided into the mid-esophagus. A submucosal tunnel, starting about 5 cm above the GE junction and extending to 2 cm below it, was created, and the circular layer of esophageal muscle was incised using the POEM electrode. Following the myotomy, the SRS stapler was inserted through the overtube, and the fundus of the stomach was stapled over the myotomy, using three quintuplets of staples. Staples were placed on both sides of the myotomy, using the ultrasonic range finder to ensure that the staples were placed across both muscle layers. At the end of the procedure, the animal was sacrificied, the stomach with the distal esophagus were dissected out carefully, and inspected.
Results: The resulting fundoplication covered the distal 3 cm of the esophageal myotomy. No perforation was observed. The endoscopic and external apearance was similar to that of a standard anterior fundoplication. The staples were across both muscle layers.The submucosal myotomy was palpable accross the GE junction under the gastric flap.
Conclusions / Expectations: It is feasible to combine the two procedures, and add a transoral reflux barrier to the submucosal myotomy. If the aganglionic segment is short (<3cm) it is possible to cover all the myotomized esophagus with the fundus, which may reduce the risk of perforation. It is probably easier to ensure that the staples are placed across the full thickness of the esophageal wall, and that the stapled fundus covers the myotomy, if the stapling is done first, and the myotomy is started between the two topmost quintuplets. Further experiments are needed to optimize staple placement relative to the submucosal myotomy. Nevertheles, it is likely that the combined transoral operation may enable the operator to achieve an anatomic and functional result similar to the operation now recommended by both SAGES and the American Gastroenteroloists Association (AGA) for the treatment of achalasia: laparoscopic myotomy with anterior fundoplication (Dor-Thal). But transorally, without any incisions.