Background: Peroral endoscopic myotomy (POEM) is a novel endoscopic surgical procedure for the treatment of achalasia. The comparative effects of POEM and laparoscopic Heller myotomy (LHM) on esophagogastric junction (EGJ) physiology are unknown. A novel measurement catheter, the functional lumen imaging probe (FLIP), allows for intraoperative evaluation of EGJ compliance by measuring luminal geometry and pressure during volume-controlled distensions.
Methods: Distensibility index (DI) (defined as the minimum cross-sectional area at the EGJ divided by pressure) was measured with FLIP intraoperatively in patients undergoing LHM and POEM. Separate measurements were taken after each operative step. During LHM, measurements were performed after: (1) induction of anesthesia, (2) insufflation of pneumoperitoneum, (3) hiatal dissection and esophageal mobilization, (4) myotomy, (5) partial fundoplication, and (6) deinsufflation. During POEM, they were performed after: (1) induction of anesthesia, (2) submucosal tunnel creation, and (3) myotomy.
Results: Eleven LHM and 14 POEM patients underwent intraoperative FLIP. Baseline DI was similar between groups. LHM resulted in an overall increase in mean DI (pre 1.4 vs. post 7.6 mm(2)/mmHg, using a 40-ml distension volume; p < 0.001). Insufflation of pneumoperitoneum and hiatal dissection did not affect DI. Myotomy caused an increase in DI. Partial fundoplication (6 Toupet, 5 Dor) caused a decrease in DI, and deinsufflation caused an increase in DI. POEM also resulted in an overall increase in mean DI (pre 1.4 vs. post 7.9 mm(2)/mmHg; p < 0.001). Measured individually, both submucosal tunnel creation and myotomy caused increases in DI. When overall changes were compared, there were no differences in the amount of DI increase between LHM and POEM.
Conclusions: POEM and LHM result in a similar improvement in EGJ distensibility intraoperatively. Further study is needed to correlate intraoperative FLIP measurements with postoperative symptomatic and physiologic outcomes.