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Anterior versus Posterior Myotomy during POEM for the Treatment of Achalasia: Systematic Review and Meta-Analysis of Randomized Clinical Trials

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Enrique Rodríguez de Santiago1,2, Noor Mohammed1,3, Anastassios Manolakis1,4, Yuto Shimamura1, Manabu Onimaru1, Haruhiro Inoue1

1) Digestive Diseases Center, Showa University, Koto-Toyosu Hospital, Tokyo, Japan
2) Gastroenterology and Hepatology Department, Hospital Universitario Ramón y Cajal. University of Alcala. Instituto Ramón y Cajal de Investigación Sanitaria, Madrid, Spain
3) Department of Gastroenterology, Leeds Teaching Hospitals NHS Trust, Leeds, United Kingdom
4) Department of Gastroenterology, Larissa University Hospital, Larissa, Greece

DOI: http://dx.doi.org/10.15403/jgld.2014.1121.281.pom

Background & Aims: The optimal orientation of the myotomy during peroral endoscopic myotomy (POEM) is unknown. This meta-analysis aims to compare anterior and posterior myotomy regarding clinical success and safety.
Methods: Pubmed, Embase, Cochrane Library, WOK, and clinicaltrials.gov were searched to identify randomized clinical trials (RCTs) comparing anterior and posterior myotomy during POEM for the treatment of achalasia. The primary outcome was clinical success. Secondary outcomes included postprocedural gastroesophageal reflux disease (GERD), adverse events (AEs), manometric findings, and procedure-related parameters. Random-effects models were used for the primary analysis.
Results: Four RCTs enrolling 488 patients were included. Overall clinical success 3-12 months after POEM was 97% (95% confidence interval [CI] 93-100%) and did not differ between anterior and posterior myotomy (Relative risk [RR] 0.98, 95%CI: 0.96-1.01; I2: 0%). Incidence of GERD after POEM based on 24-hour pH monitoring (RR 0.98, 95%CI: 0.75-1.28), endoscopy (RR 1.04, 95%CI: 0.78-1.38), and symptoms (RR 0.89, 95%CI: 0.55-1.42) was similar. Posterior myotomy was associated with fewer AEs (RR 0.63, 95%CI: 0.42-0.94), lower risk of mucosotomy (RR 0.42, 95%CI: 0.27-0.66) and shorter incision closure time (mean difference: -2.28 minutes, 95%CI: -3.46 to -1.10). Anterior myotomy was associated with a shorter length of hospitalization (mean difference: 0.31 days, 95%CI: 0.05-0.57), although the clinical relevance of this finding is negligible. No significant differences were found regarding manometric outcomes, total operation and myotomy time.
Conclusions: Anterior and posterior myotomy are equally effective for the treatment of achalasia, without significant differences in postprocedural GERD. Posterior POEM was associated with fewer AEs and a shorter incision closure time.
Key words: endoscopy − meta-analysis − myotomy − peroral endoscopic myotomy − POEM.
Abbreviation: AE: adverse event; GEJ: gastroesophageal junction; GERD: gastroesophageal reflux disease; HRM: high-resolution manometry; IRP: integrated relaxation pressure; LES: lower esophageal sphincter; LESP: lower oesophageal sphincter pressure; LHM: laparoscopic Heller myotomy; PICOT: population, intervention, comparison, outcomes, type of study; POEM: peroral endoscopic myotomy; RCT: randomized clinical trials.