Clin Endosc.  2013 Jan;46(1):54-58. 10.5946/ce.2013.46.1.54.

Peroral Endoscopic Myotomy for Treating Achalasia in an Animal Model: A Feasibility Study

• Bang BW
• Choi YC
• Kim HG
• Kwon KS
• Shin YW
• Lee DH
• Kim JM

• KMID: 1792640
• DOI: http://doi.org/10.5946/ce.2013.46.1.54

Abstract

BACKGROUND/AIMS
Laparoscopic Heller myotomy with antireflux procedure is considered to be a standard treatment for achalasia. Recently, peroral endoscopic myotomy (POEM) was developed and performed on patients with achalasia. However, there is no report on POEM use in South Korea. The aim of this study was to evaluate the technical feasibility of POEM in a porcine model.
METHODS
POEM was performed on two mini pigs. We performed upper endoscopy under general anesthesia. A submucosal tunnel was created and the circular muscle layer was incised using several knives. The mucosal entry was closed using resolution clips. We performed a follow-up endoscopy and sacrificed the pigs 2 weeks after the POEM. The myotomy site was evaluated grossly and histologically.
RESULTS
POEM was successfully performed on the two mini pigs. No injuries to any abdominal or mediastinal structures occurred. Two weeks after the POEM, the esophageal mucosa healed without any endoscopic evidence of complications. Necropsy revealed that the circular muscle layer was completely lost and replaced with fibrotic tissue.
CONCLUSIONS
We found that POEM is a technically feasible method which can be performed on an animal model. However, to ensure safe use on patients with achalasia, further studies on technical methods and long-term follow-up examinations are required.

Keyword

Esophagus; Esophageal achalasia; Endoscopy; Animal models; Feasibility studies

MeSH Terms

Anesthesia, General
Animals
Dietary Sucrose
Endoscopy
Esophageal Achalasia
Esophagus
Feasibility Studies
Follow-Up Studies
Humans
Models, Animal
Mucous Membrane
Muscles
Republic of Korea
Swine
Dietary Sucrose

Figure

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  Fig. 1 The process of peroral endoscopic myotomy. (A) Creation of the submucosal tunnel. A 2-cm transverse mucosal incision was made on the mucosal surface to create an entry into the submucosal space 10 cm from the gastroesophageal junction (GEJ). (B) Submucosal tunnel. A long submucosal tunnel was created 10 cm above the GEJ to 3 cm below the GEJ. (C) Endoscopic myotomy. The inner circular muscle was incised under direct visualization using several knives. (D) Completion of endoscopic myotomy. The circular muscle bundles were cleanly dissected (arrows).

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  Fig. 2 Endoscopic finding 2 weeks after the peroral endoscopic myotomy. Endoscopy revealed a small scar at the mucosal entry site (arrow).

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  Fig. 3 Gross and histologic findings of the esophagus. (A) Gross examination revealed that myotomy site was relatively whitish, thin, and retracted (arrow) compared to the surrounding circular muscle. (B) Histologic evaluation showed that the circular muscle layer was discontinuous and replaced with fibrotic tissue (arrowhead) at the myotomy site (Masson's trichrome stain, ×12.5).

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