BACKGROUND:
Achalasia is a disorder of esophageal dysmotility characterized by dysfunctional peristalsis
and increased lower esophageal sphincter (LES) tone. Achalasia is further divided into three
subtypes using high-resolution manometry (HRM) following the Chicago Classification. Type I,
or classic achalasia, and Type II achalasia are both characterized by aperistalsis and
increased LES tone and are thought to be a spectrum of the same disease process with Type II
evolving into Type I.
Per-oral Endoscopic Myotomy (POEM) was first developed in 2008 as a treatment for achalasia.
The technique involves a trans-oral approach with a flexible endoscope. An endoscopic
incision is made in the esophagus and a submucosal tract is created towards the LES and
gastric cardia to expose the underlying muscle of the LES and distal esophagus. The inner
circular muscle is then dissected to create a myotomy and the tract is then closed with
endoscopic clips. By creating a myotomy, the increased LES tone is improved, allowing food to
pass into the stomach in order to relieve the dysphagia caused by achalasia.
Unlike Type III achalasia, where POEM myotomy length is determined by HRM, the standard
myotomy length in Type I/Type II achalasia is typically 8 cm. The rationale for the 8 cm
myotomy is derived from the Heller myotomy procedure which is a laparoscopic surgery approach
in which the teaching has been to perform at least a 5 cm myotomy in the esophagus and an
additional 2-3 cm myotomy in the gastric cardia. However, the purpose of the myotomy in POEM,
is to reduce the LES tone. The clinical efficacy of the procedure comes from the myotomy of
the high pressure zone within the LES, which is only 2-3cm in length. This is much shorter
than the current standard POEM myotomy length. There are a few potential pitfalls regarding
longer myotomy lengths in the esophagus and in the gastric cardia. A longer esophageal
myotomy may result in esophageal wall strain in the area weakened by esophageal myotomy
resulting in a blown out myotomy which is identified by the presence of a pseudo-diverticulum
endoscopically. Longer gastric cardia myotomy has been thought to lead to an increased rate
of gastroesophageal reflux in patients undergoing POEM. There are no data looking at shorter
myotomy lengths in POEM for Type I and Type II achalasia. Our anecdotal experience at
Northwestern when performing short myotomy during POEM has not resulted in any difference in
procedural efficacy.
STUDY ENDPOINTS:
Upon enrollment, patients will complete the Eckardt study questionnaire and the GERDQ
questionnaire on the initial visit. Enrolled subjects will complete POEM as per clinical
standard of care with the following specifications. Patients will be randomized to receive a
short myotomy of 4 cm or standard myotomy of 8 cm. Following POEM, patients will be followed
in clinic per standard of care and study questionnaires will be administered at follow-up
visits. The Eckardt Symptom score is validated for research use in achalasia and is the tool
with which we monitor success rates for treatment of achalasia. We will also monitor GERD
symptoms with the GERDQ questionnaire. The endpoints for this study following randomization
and completion of 30 POEM procedures are:
3, 12 and 24-months of follow-up to monitor Eckardt score for all 30 participants
3, 12 and 14-months of follow-up to monitor safety and GERD for all 30 participants
PROCEDURES INVOLVED:
Patients will be recruited from the pool of patients seen in esophageal clinics and endoscopy
centers at Northwestern's Digestive Health Center who are specifically consented to undergo
POEM for Type I or Type II achalasia and also in patients with EGJ outflow obstruction that
demonstrate features of achalasia. Involvement with the study will not determine or affect
eligibility or recommendation for POEM in the treatment of achalasia. Upon enrollment,
patients will complete all study questionnaires on the initial visit - these include our
GERDQ questionnaire and our Northwestern Esophageal Quality of Life Survey.
Following enrollment, 30 patients will be randomized to receive either a 4 cm or 8 cm
myotomy. Randomization will occur via computer randomization software. At the time of the
procedure, the endoscopist will be given the randomized grouping in an opaque envelope
(either 4 cm or 8 cm myotomy). Participants will then undergo Per-Oral Endoscopic Myotomy as
per standard of care with flexible endoscope using an anterior approach. The only difference
in the procedure will be the length of the muscle layer dissection (myotomy). Fifteen
subjects will undergo the standard 8 cm myotomy, which includes 7 cm myotomy of the esophagus
and 1 cm myotomy of the gastric cardia. Fifteen subjects will undergo a short 4 cm myotomy,
which includes 3 cm myotomy in the esophagus and a 1 cm myotomy of the gastric cardia. All
participants will undergo intra-operative functional monitoring as is standard of care at
Northwestern to ensure adequate response to myotomy. If the shorter myotomy is insufficient,
the patient can undergo standard-length myotomy.
Participants will be monitored as per standard care before, during and after POEM procedure.
Post-procedure follow-up for both groups will adhere to standard of care. Data will be
collected on a prospective data from EPIC electronic health care records. Data collected will
include demographic information, imaging results, functional studies (specifically EndoFlip
and HRM) as well as questionnaire data.