Peroral endoscopic myotomy for sigmoid-type achalasia: the myotomy length and ways to facilitate the procedure

We read with great interest the case by Unn et al. [1] entitled “Use of a long, stiff, overtube placed by a colonoscope to facilitate the POEM procedure for a 36-year history of achalasia with 13-cm esophageal dilation.” The procedure involved the use of an overtube to facilitate peroral endoscopic myotomy (POEM) in a patient with severe sigmoid-type achalasia, in whom a flexible gastroscope could not be used to reach the cardia.

We have a comment regarding the myotomy length: the myotomy length in the patient was 4 cm (2 cm above and 2 cm below the cardia), which may not be sufficient for long-term efficacy. Following the tenets of Heller myotomy, POEM length is at least 6 cm (2 cm in the esophagus, 2 – 3 cm in the lower esophageal sphincter [LES], 2 cm in the cardia), and averages 8 – 10 cm. The International Per Oral Endoscopic Myotomy Survey suggested an 8 – 10 cm myotomy for typical nonspastic achalasia (Chicago classification I, II) and a longer myotomy for patients with spastic disorders (e. g. type III) [2]. The Chicago classification of the patient in the current case was not stated, and it is unclear as to why the myotomy length was only 4 cm; follow-up is necessary for assessment of the long-term efficacy.

In addition to the method described by Unn et al., several modifications can facilitate POEM for sigmoid-type achalasia [3] [4]. First, we should choose a relative straight path for the submucosal tunnel, with few turns. During tunnel creation, submucosal injection of a mixed solution containing indigo, from the esophageal cavity into the submucosal cavity, can be used to preset the tunnel route in order to ensure a straight tunnel into the proximal stomach. Second, the submucosal tunnel should be wide enough, even up to a half of the circumference of the esophagus, in order to bypass the site of most serious esophageal twisting. Third, myotomy can be performed 0 – 1 cm below the tunnel entry to shorten the tunnel length. A shorter tunnel length may be preferred if difficulty is encountered when creating the submucosal tunnel, or in cases of tortuosity. Fourth, in case of extreme difficulty in making a safe submucosal passage when traversing the LES, myotomy can be started prematurely, or concurrent myotomy and tunneling can be performed in order to gain access to the distal esophagus and proximal gastric wall. In the reported case, the gastroscope could not reach the cardia without the aid of the overtube; it is possible that the cardia could have been reached if the site was loosened by concurrent myotomy and tunneling.

• References

• 1 Unn K, Chhorn P, Rivory J et al. Use of a long, stiff, overtube placed by a colonoscope to facilitate the POEM procedure for a 36-year history of achalasia with 13-cm esophageal dilation. Endoscopy 2016; 48: E172-173
• 2 Stavropoulos SN, Modayil RJ, Friedel D et al. The International Per Oral Endoscopic Myotomy Survey (IPOEMS): a snapshot of the global POEM experience. Surg Endosc 2013; 27: 3322-3338
• 3 Hu JW, Li QL, Zhou PH et al. Peroral endoscopic myotomy for advanced achalasia with sigmoid-shaped esophagus: long-term outcomes from a prospective, single-center study. Surg Endosc 2015; 29: 2841-2850
• 4 Lv L, Liu J, Tan Y et al. Peroral endoscopic full-thickness myotomy for the treatment of sigmoid-type achalasia: outcomes with a minimum follow-up of 12 months. Eur J Gastroenterol Hepatol 2016; 28: 30-36