Short Vs Standard Length Myotomy in Achalasia

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:

1. 3, 12 and 24-months of follow-up to monitor Eckardt score for all 30 participants
2. 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.