Intraoperative assessment of esophagogastric junction distensibility during per oral endoscopic myotomy (POEM) for esophageal motility disorders.

Background: Per oral endoscopic myotomy (POEM) is a novel treatment for esophageal motility disorders such as achalasia. To date, the extent of the myotomy has been determined based on the subjective assessment of the endoscopist. We hypothesized that the real-time measurement of esophagogastric junction (EGJ) distensibility using a novel functional lumen-imaging probe would enable objective evaluation of POEM.
Methods: Patients diagnosed with achalasia disorders electively underwent POEM. Using impedance planimetry with a transorally inserted functional lumen-imaging probe (EndoFLIP), cross-sectional areas (CSA) and distensibilities at the EGJ were measured intraoperatively immediately before and after the transoral myotomy (n = 4). All patients completed their 6-month follow-up and two patients had repeat distensibility tests at this time. Four healthy volunteers served as a control group.
Results: POEM was successfully performed in all patients (4/4). Premyotomy measurements (40-ml fill mode) showed a median diameter of 6.5 mm (range = 5.2-7.9 mm) at the narrowest location of the EGJ and was 10.1 mm (7.3-13.2 mm) following POEM. CSA increased from 41.5 mm(2) (20-49 mm(2)) to 86 mm(2) (41-137 mm(2)) at a similar median intraballoon pressure (40.3 vs. 38.6 mmHg). The increased EGJ distensibility (DI, 1.0 vs. 2.4 mm(2)/mmHg) was comparable to that of healthy volunteers (2.7 mm(2)/mmHg).
Conclusion: Functional lumen distensibility measures show that POEM can result in an immediate correction of the nonrelaxing lower esophageal sphincter, which appears similar to that of healthy controls. Intraoperative EGJ profiling may be an important tool to objectively guide the needed extent and completeness of the myotomy during POEM.