Single-blinded randomized controlled trial comparing the effect of underwater versus carbon dioxide insufflation during peroral endoscopic myotomy on postprocedural pain (with video) - 02/09/26

Doi : 10.1016/j.gie.2026.06.066

Dennis Yang, MD ^1,^⁎ , Peter V. Draganov, MD ², Maham Hayat, MD ¹, Abdullah Abbasi, MD ¹, Saurabh Chandan, MD ¹, Sagar J. Pathak, MD ¹, Muhammad K. Hasan, MD ¹, Carlos Bertran-Rodriguez, MD ¹, Zubair Khan, MD ¹, Abdul Sattar Shariq Mohammed, MD ¹, Varan Perananthan, MD ³, Maria Gmehlin, PA-C ³, Kathryn Swenson, NP ³, Kevin P. Buller, MS ³, Kenneth F. Binmoeller, MD ⁴, Louis Michel Wong Kee Song, MD ³

¹ Center for Interventional Endoscopy, AdventHealth, Orlando, Florida, USA

² Division of Gastroenterology, Hepatology, and Nutrition, University of Florida, Gainesville, Florida, USA

³ Mayo Clinic, Rochester, Minnesota, USA

⁴ California Pacific Medical Center, San Francisco, California, USA

^∗ Corresponding author: Dennis Yang, MD, Center for Interventional Endoscopy, Box 167, 601 E Rollins St, Orlando, Florida 32779, USA. Center for Interventional Endoscopy Box 167 601 E Rollins St Orlando Florida 32779 USA

Sous presse. Épreuves corrigées par l'auteur. Disponible en ligne depuis le Wednesday 02 September 2026

Abstract

Background and Aims

Underwater endoscopic techniques have gained traction given their potential advantages. The aim of this multicenter randomized trial was to compare the effect of saline solution–immersion “underwater” peroral endoscopic myotomy (U-POEM) versus carbon dioxide insufflation during peroral endoscopic myotomy (CO ₂ -POEM) on postprocedural pain.

Methods

Consecutive patients with achalasia subtype I and II were randomized in a 1:1 ratio to U-POEM or CO ₂ -POEM during the study period between February 2025 and November 2025. Pain was assessed using the validated Numeric Pain Rating Scale (NPRS) on a scale of 0 (none) to 10 (most severe). The primary outcome was immediate postprocedural pain. Secondary outcomes included postprocedural pain at different times, requirement of analgesics, and clinical response (defined as a post-POEM Eckardt score < 3).

Results

Thirty-six patients were randomized to U-POEM ( n = 18) and CO ₂ -POEM ( n = 18). Technical and clinical success rates were 100% in both groups with no immediate or delayed adverse events. There were no differences in dissection speed or procedural time between the 2 groups. The immediate post-POEM mean NPRS score was significantly lower in the U-POEM versus CO ₂ -POEM group (1.6 ± 1.6 vs 3.3 ± 2.6; 95% CI, 0.23-3.16; P = .02). Compared with CO ₂ -POEM, patients who underwent U-POEM reported less moderate-to-severe pain (16.7% vs 55.5%; 95% CI, 0.04-0.64; P = .04) and a lower number required opioids for postoperative pain management (5.5% vs 50%; 95% CI, 0.11-0.68; P = .007). Mean NPRS score remained lower in the U-POEM versus CO ₂ -POEM group at 72 hours after the procedure (1.13 ± 1.36 vs 2.26 ± 1.78; 95% CI, 0.06-2.20; P = .04).