Functional luminal imaging probe (FLIP) appears promising for calibration of partial fundoplication construction during laparoscopic Heller myotomy (LHM). These findings are based on the results of a study published in Gastrointestinal Endoscopy.

A team of investigators sought to evaluate esophagogastric junction (EGJ) distensibility index (DI) in patients with achalasia before, during, and after peroral endoscopic myotomy (POEM) and LHM, as well as to assess the association of DI with postoperative outcomes.

The 4 time points of DI measurement with FLIP, which were conducted on patients undergoing surgical myotomy for achalasia, are described by the authors as the following: (1) during outpatient preoperative endoscopy (preoperative DI), (2) at the start of each operation after the induction of anesthesia (induction DI), (3) at the conclusion of each operation (postmyotomy DI), and (4) at routine follow-up endoscopy 12 months postoperatively (follow-up DI).

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A total of 46 adult patients (35 POEM, 11 LHM) underwent FLIP measurements at all 4 time points. The study population consisted of 19 women (41%), median age was 53 years, and most patients had achalasia type II (63% vs 24% type I, 4% type III, and 9% variant).

Preop and induction mean DI were found to be similar among both groups (POEM: 1 mm2/mm Hg vs 0.9 mm2/mm Hg and LHM: 1.7 mm2/mm Hg vs 1.5 mm2/mm Hg). POEM yielded a significant increase in DI (induction 0.9 mm2/mm Hg vs postmyotomy 7mm2/mm Hg; P<.001).

During the follow-up period, there was a subsequent decrease in DI (postmyotomy 7 mm2/mm Hg vs follow-up 4.8 mm2/mm Hg; P<.01). However, DI at follow-up was still significantly improved from preop (P<.001). DI increased in LHM patients due to surgery (induction 1.5 mm2/mm Hg vs postmyotomy 5.9mm2/mm Hg; P<.001) but the increase was smaller compared to POEM patients (DI increase 4.4 mm2/mm Hg vs 6.2 mm2/mm Hg; P<.05). After LHM, during the follow-up period, DI decreased, but this change was not considered statistically significant (5.9 mm2/mm Hg vs 4.4 mm2/mm Hg; P=.29).

On follow-up endoscopy, LHM patients with erosive esophagitis had a significantly higher postmyotomy DI compared against those without esophagitis (9.3 mm2/mm Hg vs 4.8 mm2/mm Hg; P<.05).

This study has multiple limitations: all procedures were performed at a single institution, the included study population was of relatively small size, especially in the LHM group, incomplete physiologic follow-up was completed, and the possibility of selection bias was present. Lastly, some patients may not have adhered to the scheduled 12-month follow-up visit and request to obtain physiologic studies.

The study authors concluded, “Premyotomy EGJ DI was consistent across anesthetic settings and improved dramatically as a result of both POEM and LHM, with POEM resulting in a larger increase. At 12-month follow-up, DI decreased as compared with immediate postmyotomy measurements but remained well above previously published thresholds for treatment failure.” They added, “DI at the conclusion of LHM was predictive of erosive esophagitis in the postoperative period, which supports the potential use of FLIP for calibration of partial fundoplication construction during LHM.”

Disclosure: Multiple authors declared industry affiliations. Please refer to the original article for a full list of disclosures.


Holmstrom AL, Campagna RJ, Carlson DA, et al. Comparison of preoperative, intraoperative, and follow-up functional luminal imaging probe measurements in patients undergoing myotomy for achalasia. Gastrointest Endosc. Published online March 1, 2021. doi: 10.1016/j.gie.2021.02.031