Comparison of Egj Distensibility Changes During Poem and Heller Myotomy Using Intraoperative Endoflip

Ezra N Teitelbaum, MD, Lubomyr Boris, BS, Fahd O Arafat, MD, Frederic Nicodeme, MD, Peter J Kahrilas, MD, John E Pandolfino, MD, Nathaniel J Soper, MD, Eric S Hungness, MD

Northwestern University

Introduction: Peroral esophageal myotomy (POEM) is a novel endoscopic 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 tool, the endoscopic functional lumen imaging probe (EndoFLIP), allows for real-time evaluation of EGJ physiology intraoperatively. Using impedance planimetry, the EndoFLIP balloon-tipped catheter measures both esophageal lumen anatomy and intra-balloon pressure. EGJ distensibility is calculated by dividing the cross-sectional area of the EGJ at its narrowest point by intra-balloon pressure.

Methods: Distensibility was measured with EndoFLIP intraoperatively in patients undergoing POEM and LHM using balloon distension volumes of 30ml, 40ml, and 50ml. Separate measurements were taken after each operative step to evaluate each component’s specific effect on EGJ physiology. Both procedures were performed under general anesthesia with endotracheal intubation and paralysis. During POEM, measurements were taken after: 1) induction of anesthesia, intubation, and paralysis, 2) submucosal tunnel creation, and 3) myotomy. During LHM, after: 1) induction of anesthesia, intubation, and paralysis, 2) insufflation of pneumoperitoneum, 3) crural opening and hiatal dissection, 4) myotomy, 5) partial fundoplication, and 6) deinsufflation.

Results: 8 POEM patients and 8 LHM patients underwent intraoperative EndoFLIP measurements. Baseline distensibilities were similar between patients undergoing POEM and LHM. At a balloon distension volume of 30ml, POEM resulted in an overall increase in mean distensibility (pre 2 ±2.5 vs. post 8.6 ±2.5mm2/mmHg; p<.001). Taken individually, creation of the submucosal tunnel caused an increase in distensibility (from 2 ±2.5 to 4.6 ±2.7mm2/mmHg; p=.02), as did myotomy (from 4.6 ±2.7 to 8.6 ±2.5mm2/mmHg; p<.01). Changes were similar using 40 and 50ml distension volumes, except that the increase in distensibility after myotomy was not significant with 50ml (5.4 ±4 to 6.5 ±1mm2/mmHg; p=.14). At an EndoFLIP distension volume of 30ml, LHM also resulted in an overall increase in mean distensibility (pre 1.5 ±1 vs. post 6.1 ±4mm2/mmHg; p=.02). For LHM, neither insufflation of pneumoperitoneum nor hiatal dissection effected EGJ distensibility. Myotomy caused a significant increase in distensibility (from 1.5 ±.9 to 4.5 ±.8mm2/mmHg; p<.001). Partial fundoplication (Toupet in 5 cases, Dor in 3) resulted in a trend towards decreased distensibility (from 4.5 ±.8 to 3.3 ±1.4mm2/mmHg; p=.07), and final deinsufflation of pneumoperitoneum caused an increase in distensibility (from 3.3 ±1.4 to 6.1 ±4mm2/mmHg; p<.05). Changes were similar using 40 and 50ml distension volumes, except that the decrease in distensibility after partial fundoplication was significant with 50ml (from 4.6 ±1.3 to 3.4 ±1mm2/mmHg; p=.02). Overall increases in distensibility as a result of POEM and LHM were similar (30ml distension volume: 6.7 ±1.6 vs. 4.6 ±4.1mm2/mmHg; p=NS, 40ml: 6.7 ±2 vs. 5.6 ±3.2mm2/mmHg; p=NS, 50ml: 5.7 ±1 vs. 4.7 ±2.4mm2/mmHg; p=NS).

Conclusions: POEM and LHM result in similar increases in EGJ distensibility intraoperatively. During LHM, the steps of myotomy and final deinsufflation increase distensibility, whereas partial fundoplication may decrease distensibility. During POEM, both submucosal tunnel creation and myotomy increase distensibility. Further study is needed to correlate intraoperative EndoFLIP measurements with postoperative symptomatic and physiologic outcomes.

Session: Podium Presentation

Program Number: S065

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