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 – 3 cm 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 re-inserted 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 1 cm 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 – 3 cm 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.
Fig. 1 Endoscopic view showing the endoclip being deployed on the wall opposite to the submucosal
tunnel immediately distal to the gastroesophageal junction.
Fig. 2 Endoscopic view as the endoscope is inserted to the most distal aspect of the submucosal
tunnel prior to performing the myotomy.
Fig. 3 Fluoroscopic image showing the endoscope positioned in the submucosal tunnel. The
tip of the endoscope is 3 cm distal to the endoclip (arrow) and hence 4 cm below the
lower esophageal sphincter. At this point, further tunneling is unnecessary and the
myotomy can commence.
We herein demonstrate a novel, yet simple and efficient, method of confirming the
adequacy of the extent of the submucosal tunnel created during POEM.
Endoscopy_UCTN_Code_TTT_1AO_2AN
