Original article Clinical endoscopy| Volume 94, ISSUE 3, P509-514, September 2021

Comparison of preoperative, intraoperative, and follow-up functional luminal imaging probe measurements in patients undergoing myotomy for achalasia

Published:March 01, 2021DOI:https://doi.org/10.1016/j.gie.2021.02.031

      Background and Aims

      The functional luminal imaging probe (FLIP) is a novel catheter-based device that measures esophagogastric junction (EGJ) distensibility index (DI) in real time. Previous studies have demonstrated DI to be a predictor of post-treatment clinical outcomes in patients with achalasia. We sought to evaluate EGJ DI in patients with achalasia before, during, and after peroral endoscopic myotomy (POEM) and laparoscopic Heller myotomy (LHM) and to assess the correlation of DI with postoperative outcomes.


      DI (defined as the minimum cross-sectional area at the EGJ divided by distensive pressure) was measured at 4 time points in patients undergoing surgical myotomy for achalasia: (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). Routine Eckardt symptom score, endoscopy, timed barium esophagram, and pH study were obtained 12 months postoperatively.


      Forty-six patients (35 POEM, 11 LHM) underwent FLIP measurements at all 4 time points. Preoperative and induction mean DI were similar for both groups (POEM, 1 vs .9 mm2/mm Hg; LHM, 1.7 vs 1.5 mm2/mm Hg). POEM resulted in a significant increase in DI (induction .9 vs postmyotomy 7 mm2/mm Hg, P < .001). There was a subsequent decrease in DI in the follow-up period (postmyotomy 7 vs follow-up 4.8 mm2/mm Hg, P < .01), but DI at follow-up was still significantly improved from preoperative values (P < .001). For LHM patients, DI also increased as a result of surgery (induction 1.5 vs postmyotomy 5.9 mm2/mm Hg, P < .001); however, the increase was smaller than in POEM patients (DI increase 4.4 vs 6.2 mm2/mm Hg, P < .05). After LHM, DI also decreased in the follow-up period, but this change was not statistically significant (5.9 vs 4.4 mm2/mm Hg, P = .29). LHM patients with erosive esophagitis on follow-up endoscopy had a significantly higher postmyotomy DI compared with those without esophagitis (9.3 vs 4.8 mm2/mm Hg, P < .05).


      EGJ DI improved dramatically as a result of both POEM and LHM, with POEM resulting in a larger increase. Mean DI decreased at intermediate follow-up but remained well above previously established thresholds for symptom recurrence. 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.

      Graphical abstract


      CSA (cross-sectional area), DI (distensibility index), EGJ (esophagogastric junction), FLIP (functional luminal imaging probe), HRM (high-resolution manometry), LES (lower esophageal sphincter), LHM (laparoscopic Heller myotomy), POEM (peroral endoscopic myotomy), TBE (timed barium esophagram)
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        • Pandolfino J.E.
        • Gawron A.J.
        Achalasia: a systematic review.
        JAMA. 2015; 313: 1841-1852
        • Mari A.
        • Abu Backer F.
        • Amara H.
        • et al.
        Achalasia: updates on diagnosis and management from the last decade [in Hebrew with English abstract].
        Harefuah. 2018; 157: 668-671
        • Vaezi M.F.
        • Pandolfino J.E.
        • Vela M.F.
        ACG clinical guideline: diagnosis and management of achalasia.
        Am J Gastroenterol. 2013; 108 (quiz 50): 1238-1249
        • Tuason J.
        • Inoue H.
        Current status of achalasia management: a review on diagnosis and treatment.
        J Gastroenterol. 2017; 52: 401-406
        • Teitelbaum E.N.
        • Dunst C.M.
        • Reavis K.M.
        • et al.
        Clinical outcomes five years after POEM for treatment of primary esophageal motility disorders.
        Surg Endosc. 2018; 32: 421-427
        • Moonen A.
        • Annese V.
        • Belmans A.
        • et al.
        Long-term results of the European achalasia trial: a multicentre randomised controlled trial comparing pneumatic dilation versus laparoscopic Heller myotomy.
        Gut. 2016; 65: 732-739
        • Werner Y.B.
        • Hakanson B.
        • Martinek J.
        • et al.
        Endoscopic or surgical myotomy in patients with idiopathic achalasia.
        N Engl J Med. 2019; 381: 2219-2229
        • Carlson D.A.
        Functional lumen imaging probe: the FLIP side of esophageal disease.
        Curr Opin Gastroenterol. 2016; 32: 310-318
        • Rohof W.O.
        • Hirsch D.P.
        • Kessing B.F.
        • et al.
        Efficacy of treatment for patients with achalasia depends on the distensibility of the esophagogastric junction.
        Gastroenterology. 2012; 143: 328-335
        • Carlson D.A.
        • Hirano I.
        Application of the functional lumen imaging probe to esophageal disorders.
        Curr Treat Options Gastroenterol. 2017; 15: 10-25
        • Smeets F.G.
        • Masclee A.A.
        • Keszthelyi D.
        • et al.
        Esophagogastric junction distensibility in the management of achalasia patients: relation to treatment outcome.
        Neurogastroenterol Motil. 2015; 27: 1495-1503
        • Pandolfino J.E.
        • de Ruigh A.
        • Nicodeme F.
        • et al.
        Distensibility of the esophagogastric junction assessed with the functional lumen imaging probe (FLIP) in achalasia patients.
        Neurogastroenterol Motil. 2013; 25: 496-501
        • Teitelbaum E.N.
        • Boris L.
        • Arafat F.O.
        • et al.
        Comparison of esophagogastric junction distensibility changes during POEM and Heller myotomy using intraoperative FLIP.
        Surg Endosc. 2013; 27: 4547-4555
        • Campagna R.A.J.
        • Carlson D.A.
        • Hungness E.S.
        • et al.
        Intraoperative assessment of esophageal motility using FLIP during myotomy for achalasia.
        Surg Endosc. 2020; 34: 2593-2600
        • Teitelbaum E.N.
        • Soper N.J.
        • Pandolfino J.E.
        • et al.
        Esophagogastric junction distensibility measurements during Heller myotomy and POEM for achalasia predict postoperative symptomatic outcomes.
        Surg Endosc. 2015; 29: 522-528
        • Su B.
        • Callahan Z.M.
        • Novak S.
        • et al.
        Using impedance planimetry (EndoFLIP) to evaluate myotomy and predict outcomes after surgery for achalasia.
        J Gastrointest Surg. 2020; 24: 964-971
        • Kahrilas P.J.
        • Bredenoord A.J.
        • Fox M.
        • et al.
        The Chicago classification of esophageal motility disorders, v3.0.
        Neurogastroenterol Motil. 2015; 27: 160-174
        • Campagna R.A.J.
        • Hungness E.S.
        Treatment of idiopathic achalasia with per-oral esophageal myotomy.
        Tech Gastrointest Endosc. 2018; 20: 114-119
        • Vaziri K.
        • Soper N.J.
        Laparoscopic Heller myotomy: technical aspects and operative pitfalls.
        J Gastrointest Surg. 2008; 12: 1586-1591
        • Boeckxstaens G.E.
        • Annese V.
        • des Varannes S.B.
        • et al.
        Pneumatic dilation versus laparoscopic Heller’s myotomy for idiopathic achalasia.
        N Engl J Med. 2011; 364: 1807-1816
        • Sawas T.
        • Ravi K.
        • Geno D.M.
        • et al.
        The course of achalasia one to four decades after initial treatment.
        Aliment Pharmacol Ther. 2017; 45: 553-560
        • Zaninotto G.
        • Costantini M.
        • Portale G.
        • et al.
        Etiology, diagnosis, and treatment of failures after laparoscopic Heller myotomy for achalasia.
        Ann Surg. 2002; 235: 186-192
      1. Holmstrom AL, Campagna RAJ, Cirera A, et al. Intraoperative use of FLIP is associated with clinical success following POEM for achalasia. Surg Endosc. Epub 2020 Jul 6

        • Ngamruengphong S.
        • von Rahden B.H.
        • Filser J.
        • et al.
        Intraoperative measurement of esophagogastric junction cross-sectional area by impedance planimetry correlates with clinical outcomes of peroral endoscopic myotomy for achalasia: a multicenter study.
        Surg Endosc. 2016; 30: 2886-2894
        • Su B.
        • Callahan Z.M.
        • Kuchta K.
        • et al.
        Use of impedance planimetry (Endoflip) in foregut surgery practice: experience of more than 400 cases.
        J Am Coll Surg. 2020; 231: 160-171
      2. Holmstrom AL, Campagna RAJ, Alhalel J, et al. Intraoperative FLIP distensibility during POEM varies according to achalasia subtype. Surg Endosc. Epub 2020 Jul 6

      Linked Article

      • Myotomy and EndoFLIP: repeated measurements require a different statistical test
        Gastrointestinal EndoscopyVol. 95Issue 4
        • Preview
          With great interest, we read the study comparing preoperative, intraoperative, and follow-up functional luminal imaging probe measurements in patients undergoing myotomy for achalasia cardia.1 In that study, the esophagogastric junction distensibility index (EGJ-DI) was measured at 4 time points (preoperative, induction, postmyotomy, and follow-up) in patients undergoing peroral endoscopic myotomy (POEM) and laparoscopic Heller myotomy (LHM). The authors concluded that the preoperative and induction mean EGJ-DIs were similar, with a significant increase in DI after POEM.
        • Full-Text
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      • Functional lumen imaging probe and Heller myotomy: solves the dysphagia issue, but the resulting GERD is still a mystery
        Gastrointestinal EndoscopyVol. 94Issue 3
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          The practice of esophagology has advanced significantly over the past few decades as the now widespread use of high-resolution esophageal manometry (HRM), 24-hour pH-impedance testing, and 48- to 96-hour wireless pH monitoring have transformed the way in which we evaluate patients with esophageal diseases. One of the newest tools used by esophagologists is the functional lumen imaging probe (FLIP), which over the past few years has become (1) increasingly used, especially in academic medical centers, and (2) increasingly investigated to enable a better understanding of all of its potential applications in diagnosing, treating, and monitoring esophageal diseases.
        • Full-Text
        • PDF