Training in peroral endoscopic myotomy (POEM) for esophageal achalasia

Peroral endoscopic myotomy (POEM) has been developed in the context of natural orifice transluminal endoscopic surgery (NOTES) as a minimally invasive endoscopic treatment for symptomatic esophageal achalasia, which is a chronic progressive benign disease with severe morbidity and difficult management. Since September 2008, POEM has been successfully performed in more than 200 consecutive patients with symptomatic achalasia at the Digestive Disease Center of Showa University, Northern Yokohama Hospital, Yokohama, Japan, with excellent short- and long-term results and absence of serious complications. International experience of POEM within clinical studies is also promising. According to these results, POEM is considered as a safe procedure that can be applied to all achalasia patients. However, the low incidence of achalasia (0.3%-1% per 100,000 population), in combination with the potential serious complications related to the technically demanding POEM procedure, has made training difficult. There is therefore an urgent need for an animal model for training to decrease the learning curve. Further, there are other ethical and training issues to address. The pig is the most appropriate animal model for training in POEM due to its anatomy being similar to that of humans. The porcine esophagus has the advantage of easy mobilization due to absence of tight junctions to surrounding organs. A non-survival porcine model would be a simple, inexpensive, and reproducible animal model for training in POEM, without the need for concern about complications. A possible training process might first involve observation of POEM performed by specialists, then training on non-survival and survival porcine models, followed by training in humans under specialist guidance and finally, performance of POEM in humans.