Sumotm System Facilitates Mucosotomy and Submucosal Tunnel Creation for Per-oral Esophageal Myotomy (POEM)

Objective:
The POEM procedure for achalasia is a complex therapeutic flexible endoscopic technique, requiring extensive practice to learn. Initial experience with the POEM demonstrates that it has the potential to become the therapeutic procedure of choice in the future. However, in order for this to be achieved, the procedure needs to be simple, safe and easily replicated. One potential area of difficulty that has been noted in the early experience is the tendency for the initial submucosal tunnel to spiral in the esophageal wall. We hypothesized that the SuMOtm system (Apollo Endosurgery, Austin, Texas.) would better facilitate the creation of a straight haemostatic submucosal tunnel and the insertion of the endoscope into the tunnel as compared with current techniques, when performing a POEM procedure.
Methods:
The SuMOtm system was initially designed for endoscopic submucosal dissection and includes a 22 gauge injection needle with a 6mm tip, an adjustable tunneling balloon and an electrosurgical cutting device. The SuMOtm tunneling balloon measures 12-15mm in diameter and 7 cm when fully inflated. It expands proximal to distal with the ability to control the rate and extent of inflation while creating a haemostatic submucosal tunnel. We used the injection needle and the balloon during the POEM procedure under an IRB approved protocol.
The mucosotomy site was marked and a submucosal wheal was raised using the 22 gauge needle. Mucosotomy was made using electrocautery and the submucosal plane was entered. The tunneling balloon was inserted in the submucosal plane and inflated to create a linear submucosal tunnel in a controlled fashion. The balloon was removed and the procedure was performed as previously described.
Results:
Four POEM procedures incorporated the SuMOtm system. When compared with 4 other case-matched patients with a similar tunnel length the SuMOtm system shortened the duration for creation of the tunnel in the esophageal body and seemed to facilitate creation of a straight, hemostatic tunnel in the esophagus. In the region of the gastro-esophageal junction (GEJ), the balloon caused an uncontrolled myotomy in three of the four patients forcing conversion to conventional POEM techniques. There were no full thickness esophageal perforations or intraoperative sequelae. One of the patients with the inadvertent myotomy developed an intraluminal hematoma presenting with hematemisis 10 days postoperatively. She was observed and recovered without intervention other than a diagnostic endoscopy.
Conclusions:
The SuMOtm system represents a significant advance in technology that may facilitate the faster creation of a straighter submucosal tunnel while performing a POEM. This would enable shortening the learning curve and standardizing a major component of this procedure. Although this technology works well in the esophageal body, care should be taken when applying it across the GEJ junction as our experience demonstrates.