Per-Oral Endoscopic Myotomy for Esophageal Swallowing Disorders

Currently the most commonly performed definitive treatment for symptomatic esophago-gastric
junction outflow obstruction is a laparoscopic esophageal myotomy (LEM). In this procedure
the outer longitudinal and inner circular muscle fibers of the distal esophagus and proximal
stomach are divided, releasing the spasm and resulting in an open lumen. Although this
procedure is effective in relieving troubles swallowing and in improving esophageal emptying,
it is often accompanied by the development of GERD (as the muscle division results in
incompetence of the antireflux barrier, the lower esophageal sphincter). For this reason a
laparoscopic esophageal myotomy is most often accompanied by a fundoplication, in which part
of the fundus of the stomach is folded around the distal esophagus and sutured in place,
recreating a flap-valve mechanism. (It is best to perform this at the time of the
laparoscopic myotomy as reoperation in that area is difficult). The fundoplication however
may be imperfect, and may result in some degree of outflow obstruction itself or fail to
control reflux. LEM results in 80% to 90% global patient satisfaction; but 10-20% continue to
experience moderate dysphagia and 10-35% will have GERD by esophageal pH testing.

Others have evaluated the possibility of surgically dividing the muscle fibers from within
the esophagus, using an endoscope rather than a laparoscope, in an animal model. The first
human experience was reported in Japan using a per-oral endoscope to (a) incise the mucosa in
the proximal esophagus as an entry point, (b) create a submucosal tunnel downwards, (c)
perform an esophageal myotomy of the distal esophageal circular muscle, and (d) close the
mucosal entry site with clips. The creation of the submucosal tunnel for some distance before
the myotomy is a safety measure, so that should the mucosal closure fail, native tissues will
appose and help seal any leak (rather like the Z-entry for a thoracentesis). Subsequent to
this initial report, multiple single-arm studies have reported that the technique is safe and
is associated with excellent medium-term relief of dysphagia..

In the POEM technique no fundoplication is performed. By the endoscopic creation of an
esophageal submucosal tunnel the inner circular muscle layer could be easily visualized and
in contrast to conventional laparoscopic esophageal myotomy, the authors described the
division of only this inner circular esophageal muscle layer leaving the outer longitudinal
muscle layer intact. The distal esophagus is exposed in LEM, hence disrupting the attachments
to the diaphragm. These attachments contribute to the overall antireflux mechanism. It is
hypothesized that by only dividing the inner circular muscle, and not disrupting the
contribution of the outer longitudinal muscle or the diaphragmatic attachments to the
antireflux mechanism, POEM may not have the same potential for reflux as a LEM. If this is
the case then an antireflux procedure may not be needed after the POEM procedure.

Inclusion Criteria:

- Patient with symptomatic achalasia or EGJ outflow obstruction with a motility study,
esophagram, and EGD consistent with EGJ outflow obstruction.

- Medical indication for surgical myotomy.

- Ability to undergo general anesthesia

- Age > 18 yrs. of age and <85 yrs. of age with ability to give informed consent

- Candidate for laparoscopic esophageal myotomy.

Exclusion Criteria:

- Previous chest radiotherapy.

- Eosinophilic esophagitis

- Barrett's esophagus

- Stricture of esophagus

- Malignant or premalignant esophageal lesion

- Contraindications for EGD.

- Unable to provide informed consent.

- Pregnancy