POEM and Surgical Myotomy for Achalasia Show Comparable Functional Luminal Imaging Probe Measurement Results at 1 Year

The functional luminal imaging probe (FLIP) measures the distensibility index (DI) at the gastroesophageal junction (GEJ). This is a measure of GEJ compliance, which has been demonstrated to be lower in patients with achalasia. Previous studies have shown that intraoperative FLIP measurements can potentially predict postmyotomy (either surgical or endoscopic) symptomatic outcomes, but long-term follow-up results are not available. The authors of this study conducted a single-center prospective study to compare the DI in patients with achalasia before, during, and after myotomy (laparoscopic Heller myotomy [LHM] or peroral endoscopic myotomy [POEM]). 

A total of 46 patients with achalasia were enrolled in the study; 35 underwent POEM and 11 underwent LHM. FLIP measurements were obtained 4 times: preoperatively, after anesthesia induction, immediately after the myotomy procedure, and 12 months postoperatively. In the POEM group, the mean DI at these time points were 1, 0.9, 7, and 4.8 mm^2/mm Hg, respectively. In the LHM group, the mean DI at the same time points were 1.7, 1.5, 5.9, and 4.4 mm^2/mm Hg, respectively.

Both groups had comparable DI trends: DI measurements were similar before and during myotomy, the DI increased significantly immediately after the procedure, and the DI decreased slightly at 12 months (albeit still higher than the preoperative measurements). A significantly greater intraoperative change in the DI occurred with POEM (+6.2 mm^2/mm Hg) than LHM (+4.4 mm^2/mm Hg) (P<.05), but this difference was not maintained at 12 months (4.8 mm^2/mm Hg [POEM] vs LHM 4.4 mm^2/mm Hg [LHM]; P=.62). Both groups had similar significant improvements in Eckhardt symptom scores from baseline to 12-month follow-up (preoperative, 7; 12-month follow-up, 2; P<.001). The authors also noted that patients who developed erosive esophagitis after LHM had a higher DI (9.3 mm^2/mm Hg) compared to patients without erosive esophagitis after LHM (4.8 mm^2/mm Hg). The same difference did not occur in the POEM group.