The Lever-Action Drill Technique: A Universal Approach to Facilitate Efficient Tunneling in Peroral Endoscopic Myotomy

CASE REPORT In peroral endoscopic myotomy, extension of the submucosal tunnel and myotomy 2 cm beyond the gastroesophageal junction toward the gastric side has been regarded as the standard approach.1,2 However, novice operators often fail to extend the submucosal tunnel sufficiently when strong resistance is encountered due to the lower esophageal sphincter (LES) or a curved submucosal tunnel. Rotation during endoscopic overtube advancement embodies 2 universal principles—axial stability and friction reduction—which together facilitate smoother progression through the soft and narrow intestinal lumen. By applying these principles, we developed the Lever-Action Drill (LAD) technique. The term drill refers not to excavation but to screw-like rotational advancement. The LAD technique was employed within the submucosal tunnel. Following each submucosal dissection, the rigid portion of the endoscope is manipulated like a lever, using the mouthpiece as a fulcrum, by pushing the lever with slight forward insertion (Figure 1). Pushing the rigid portion caused the tip of the endoscope to rotate to the right, and releasing the pushing force of the right hand, while slightly pulling back the endoscope to remove any slack, allowed it to naturally rotate to the left, the right hand to return to the neutral position (Figures 1 and 2). This series of movements constitutes the LAD technique.Figure 1.: Images showing the right hand movements required for the lever-action drill technique. (A) This is the neutral right hand position. (B) The terminal point of the lever push with slight forward insertion is initiated using the mouthpiece as the fulcrum. (C) Releasing the pushing force of the right hand, while slightly pulling back the endoscope to remove any slack, allowed the right hand to return to the neutral position.Figure 2.: Images showing the right hand movements and endoscopic views in the lever-action drill technique. (A) This is the neutral position of the right hand and the endoscopic view. (B) Pushing the rigid portion causes the tip of the endoscope to rotate to the right.The lever principle comes into play, and the tip of the endoscope rapidly repeats right and left torsional movements with minimal force. These torsional forces reduce friction while maintaining axial stability, enhancing the straight advancement of the endoscope. On the esophageal side, the lever action is often sufficient when gentle and shallow. At the LES and on the gastric side, the lever action is often stronger and deeper, because the tunnel is longer and there is resistance at the LES (Video 1). {"href":"Single Video Player","role":"media-player-id","content-type":"play-in-place","position":"float","orientation":"portrait","label":"Video 1","caption":"The video presents peroral endoscopic myotomy performed using the lever-action drill technique.","object-id":[{"pub-id-type":"doi","id":""},{"pub-id-type":"other","content-type":"media-stream-id","id":"1_9yidsx9c"},{"pub-id-type":"other","content-type":"media-source","id":"Kaltura"}]} LAD technique may facilitate tunneling during peroral endoscopic myotomy. However, its applicability may be limited in cases with severe fibrosis, where reduced submucosal distensibility increases the risk of incidental mucosotomies during the tunneling phase. Careful case selection and cautious handling are therefore required when using this technique in fibrotic lesions. DISCLOSURES Author contributions: S. Abiko wrote the manuscript. Y. Nishikawa, Y. Tamaru, K. Ushikubo, K. Shigeta, K. Yamamoto, I. Tanaka, M. Tanabe, N. Theodore Valencia Raymundo, M. Onimaru, H. Inoue and N. Sakamoto edited the manuscript. S. Abiko is the article guarantor. Acknowledgments: We are very grateful to the wonderful staff in the endoscopic room, outpatient care, and ward of Showa Medical University Koto Toyosu Hospital. Financial disclosure: H. Inoue is an advisor for Olympus Corporation and Top Corporation. He has also received educational grants from Olympus Corporation and Takeda Pharmaceutical Co. The other authors declare no conflict of interest for this article. Informed consent was obtained for this case report.