EVALUATION OF SLING FIBERS AND TWO PENETRATING VESSELS (TPVS) FOR GUIDING EXTENT OF THE TUNNEL AND MYOTOMY DURING POSTERIOR POEM IN A WESTERN COHORT

Aims It has been described by Tanaka et al, that the TPVs are a good landmark to end submucosal tunneling and guide myotomy to spare the sling fibers (inner oblique muscle fibers) during posterior POEM.

Our aim was to study and characterize the presence of the TPVs in a western cohort of patients undergoing posterior POEM

Methods Clinical, anatomical and technical endoscopic data were collected prospectively from all consecutive cases of posterior POEM performed by one endoscopist looking for the TPV between November 2018 and November 2019.

TPVs were defined as those branches from the left gastric artery found in posterior wall of gastric cardia, with first vessel immediately after passing GEJ and the second a few centimeters distally, as described by Tanaka et al.

Gastroesophageal junction landmarks used were: distance+narrowing area followed of expansion of submucosal space, presence of spindle veins or double scope transilumination.

Intraprocedural X-ray was also used in cases of sigmoid esophagus.

Results 18 posterior POEM were performed, 47% males, mean age 57 (27-80). Technical and clinical success were 100% (minimum 30 days follow-up) without major complications.

Cases included 4 sigmoid esophagus, 3 with previous Heller, 5 with previous balloon dilation, 6 cases of type 3 achalasia. Mean procedural time 69 minutes (43-112).

TPVs were identified in 14 cases (77%).

The first vessel was immediately to 1 cm distal to the narrow GEJ, at 5 or 6 o´clock, and the second vessel usually 2cm distal, at 5 or 4 o´clock. Sling fibers,when identified, were seen as internal oblique fibers running longitudinal at the left side of the TPVs.

Conclusions TPVs seem to be easy to identify in a western population.

They seem to be good indicator of the optimal distal extent of posterior POEM, and to guide myotomy to preserve gastric oblique fibers, potentially reducing the incidence of postPOEM reflux.