A two centimeter submucosal lesion arising from muscularis mucosae is identified in the distal esophagus.

An osmotic agent, consisting in a Voluven based solution with indigo carmine, is injected in the submucosal space at the level in which the mucotomy is planned.

The needle is exchanged for an endoscopic knife and a longitudinal mucotomy of 15 to 20 mm long is created.

A submucosal tunnel is created from a point 5 cm proximal to the lesion. It is extended the distally until the tumor is identified, using a combination of blunt dissection and coagulation.
Mucosal thermal damage must be prevented so repeated injections in the submucosal space contribute to better exposure.
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.

A pearl-white submucosal tumor is identified during the dissection. The lesion is dissected from the submucosal space and larger feeding vessels are coagulated with coagulation forceps and then sectioned. The distal attachment provides proper traction in order to assist the dissection.
Once the tumor is completely free it is extracted through the mouth by aspirating it into the distal attachment. Larger specimens may require the use of a Roth net.
Finally the specimen is sent to histology assessment. In this case the biopsy informed an esophageal leiomyoma.

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 to six clips are used in a standard procedure.
This is a very important step of the procedure, since a clip misplacement may result in esophageal leakage.