Before starting the procedure, an extensive lavage of the esophageal lumen is required. Small debris can be aspirated through the working channel of the scope. Larger ones, can be advanced to the stomach or extracted through the mouth with a Roth net.
After assuring that the esophagus is clean, an accurate measurement of the level of the gastroesophageal junction is crucial to plan where to start the submucosal tunnel and the myotomy.
A conic shaped cap is used to favor tunnel access and blunt dissection.
An osmotic agent is injected in the submucosal space at the level in which the mucotomy is planned.
We prefer using a Voluven based solution with indigo carmine, because it lasts more than saline but is less expensive than sodium hyaluronate
The needle is exchanged for an endoscopic knife.
A longitudinal mucotomy of 15 to 20 mm long is created.
A submucosal tunnel is created from the level of the mucotomy an extended distally about 2 to 3 cm beyond the gastroesophageal junction, using a combination of blunt dissection and coagulation with the endoscopic knife.
The plane of the dissection must be right next to the muscle layer in order to prevent mucosal thermal damage. Repeated injections of the submucosal space contribute to better exposure and is very important as the tunnel approaches the sphincter, which tends to narrow.
Small vessels are often encountered in the esophagus submucosal space, that can be sectioned with the same knife. On the other hand, vessels tend to be larger as you approach to the gastric submucosa, that may require the use of coagulation forceps to prevent bleeding.
The myotomy is started 2 to 3 cm distal to the mucotomy.
Our group prefers the use of a triangular tip knife which provides adequate traction of the circular muscle fibers.
It is to be emphasized the relevance of preventing mucosal thermal injury when performing the myotomy.
A selective section of the inner circular fibers is attempted. However, as recognized in the video, the longitudinal fibers regularly tend to separate completely resulting in a full thickness myotomy.
Finally, after assuring adequate hemostasis, a gentamicin based solution is instilled into the tunnel.
The esophageal mucosa is closed with endoscopic clips starting from the distal end of the defect. On average five clips are used in a standard procedure.
Some groups have enunciated the possibility of using Apollo endo-suture to close the defect, but in our opinion, this is not cost-effective.
This is a very important step of the procedure, since a clip misplacement may result in esophageal leakage.
When the POEM is completed, a smooth passage through the gastroesophageal junction is noted.