Double-scope POEM: A Prospective Randomized Controlled Trial

Kevin L Grimes, MD, Haruhiro Inoue, MD, PhD. Showa University Koto Toyosu Hospital

Introduction: This study aims to evaluate the utility of a second endoscope during Per-Oral Endoscopic Myotomy (POEM) to ensure adequate dissection onto the gastric cardia. Since its introduction in 2010, POEM has offered an alternative to laparoscopic Heller myotomy (LHM) for the treatment of achalasia. A recent study by Teitelbaum et al. demonstrated a significant improvement in gastroesophageal junction (GEJ) distensibility with a gastric myotomy length of at least 3cm. During POEM, however, it can be difficult to ensure adequate submucosal dissection has been performed. Currently, the most useful endoscopic markers are blue discoloration of the gastric mucosa on retroflex view and narrowing followed by expansion of the submucosal space. These markers may be inaccurate, however, particularly in patients with prior balloon dilation of the lower esophageal sphincter (LES). We hypothesize that use of a second endoscope will result in a more complete myotomy.

Methods and Procedures: Patients undergoing POEM were randomized into single-scope (control) and double-scope (treatment) groups by the OR scheduler, who was blinded to the purpose of the study. In the control group, POEM was performed in standard fashion. In the treatment group, a second endoscope was placed after completion of the myotomy. The dissecting scope was placed at the end of the submucosal tunnel and used to transilluminate, while the second endoscope obtained a retroflex view of the gastric cardia to evaluate for adequate myotomy length. Prospectively collected data included location and length of myotomy, length of any additional myotomy after insertion of the second endoscope, operative time, complications, and hospital length of stay. Treatment and control groups were compared using an unpaired t-test.

Results: To date, 36 patients have been randomized (23 treatment, 13 control). There were no significant demographic differences between groups. Mean procedure time was 16 minutes longer in the treatment group (94 vs. 78 min, p=0.15). Intra- and post-operative complication rates and hospital length of stay were similar. Use of the second endoscope resulted in additional gastric myotomy being performed in a significant number of cases (30% vs. 0%, p=0.01), with an average increase of 1.6cm (Table 1).

Conclusion: A second endoscope is useful for ensuring a complete gastric myotomy during POEM. With a minimal increase in procedure time and no increase in morbidity, it may be particularly useful in cases of sigmoid esophagus or otherwise altered anatomy that make identification of the GEJ difficult. Additional follow-up is needed to determine whether the additional gastric myotomy length results in differences in post-operative Eckardt scores or in the rate of symptom recurrence.

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