Fluoroscopy to document the extent of cardiomyotomy during peroral endoscopic myotomy.

myotomy during peroral endoscopic myotomy Peroral endoscopic myotomy (POEM) is being increasingly performed for the management of achalasia. One of the major technical challenges in performing POEM is assessing the extent of the submucosal tunnel, as this will determine the extent of the myotomy. The myotomy should extend 2–3cm beyond the lower esophageal sphincter, as an adequate cardiomyotomy is critical to achieve the high response rates observed with POEM [1,2]. Methods used to assess whether the submucosal tunnel has extended sufficiently beyond the lower esophageal sphincter include: measurement of insertion depth, resistance to the passage of the gastroscope at the lower esophageal sphincter, change in vasculature of the gastric cardia, injection of epinephrine, and double-endoscope transillumination [3]. We herein present a novel technique to accurately determine the extent of the submucosal tunnel using fluoroscopy and an endoclip. The submucosal tunnel is created as previously described [4]. The endoscope is removed from the submucosal tunnel and an endoclip is deployed immediately distal to the gastroesophageal junction on the wall opposite to the side where the submucosal tunnel has been created (●" Fig.1). The endoscope is then reinserted to the most distal aspect of the submucosal tunnel (●" Fig.2). A fluoroscopic image is obtained in the anterior– posterior axis using a C-arm (●" Fig.3). The distance between the endoclip and the endoscope tip can be calculated using the length of the endoclip as a scale. The lower esophageal sphincter is 1cm proximal to the gastroesophageal junction and this allows the length to be calculated of the extent of the submucosal tunnel below the lower esophageal sphincter. If the submucosal tunnel appears to extend less than 2–3cm below the lower esophageal sphincter then further tunneling can be performed. At the end of the procedure, the endoclip is left in position until it migrates spontaneously. We herein demonstrate a novel, yet simple and efficient, method of confirming the adequacy of the extent of the submucosal tunnel created during POEM.