The effect of incremental distal gastric myotomy lengths on EGJ distensibility during POEM for achalasia

Abstract

Background During peroral esophageal myotomy (POEM) for the treatment of achalasia, the optimal distal gastric myotomy length is unknown. In this study we used a functional lumen imaging probe (FLIP) to intraoperatively measure the effect of variable distal myotomy lengths on esophagogastric junction (EGJ) distensibility. Methods EGJ distensibility index (DI) (minimum cross-sectional area divided by intra-bag pressure) was measured with FLIP after each operative step. Each patient's myotomy was performed in four increments from proximal to distal: 1) an esophageal myotomy (from 6cm proximal to the EGJ, to 1cm proximal to it), 2) a myotomy ablating the lower esophageal sphincter (LES) complex (from 1cm proximal to the EGJ, to 1cm distal to it), 3) an initial gastric extension (from 1cm distal to the EGJ, to 2cm distal), and 4) a final gastric extension (from 2cm distal to the EGJ, to 3cm distal). Results Measurements were performed in 16 achalasia patients during POEM. POEM resulted in an overall increase in DI (pre 1.2 vs. post 7.2 mm2/mmHg, p<.001). Initial creation of the submucosal tunnel resulted in a 3-fold increase in DI (1.2 vs. 3.6 mm2/mmHg, p<.001). When the myotomy was then performed in a stepwise fashion from proximal to distal, the initial esophageal myotomy component had no effect on DI. Subsequent myotomy extension across the LES complex resulted in an increase in DI, as did the initial gastric myotomy extension (to 2cm distal to the EGJ). The final gastric myotomy extension (to 3cm distal) had no further effect. Conclusions During POEM, creation of the submucosal tunnel prior to myotomy resulted in a marked improvement in EGJ physiology. Myotomy extension across the LES complex and to 2cm onto the gastric wall resulted in normalization of EGJ distensibility, whereas subsequent extension to 3cm distal to the EGJ did not increase compliance further.

Peroral Endoscopic Myotomy for Treating Achalasia and Esophageal Motility Disorders

“…33 Intraprocedural application of EndoFLIP to POEM was highly predictive of postoperative symptomatic outcomes. 34,35 Along with the improvement of manometric profiles of EGJ, Figure 3. Endoscopic myotomy of circular muscle bundle begins from 2-3 cm distal to the mucosal entry and extends to 2-3 cm distal to the esophagogastric junction.…”

Functional Lumen Imaging Probe for the Management of Esophageal Disorders: Expert Review From the Clinical Practice Updates Committee of the AGA Institute

“…Several studies have demonstrated an immediate increase in EGJ-DI following POEM or Heller myotomy (associated with a slight decrease following fundoplasty creation) 16–20 . Further, intra-operative FLIP may provide a method to ‘tailor’ the myotomy +/− fundoplasty to help improve dysphagia (i.e.…”

Functional lumen imaging probe in gastrointestinal motility diseases

“…Pandolfino et al indicated that successfully treated achalasia patients had significantly higher EGJ‐DI than untreated patients. Intraoperative distensibility measurement using FLIP was first reported by Perretta et al Subsequent studies further confirmed that the CSA of the EGJ and the LES‐DI significantly increased after a Heller myotomy or POEM . Measuring distensibility with FLIP intraoperatively offers the possibility to assess the efficacy of LES myotomy in real time, which potentially predicts a patient's clinical response to therapy .…”