I can’t find a code for this procedure. I found 43130 (Diverticulectomy of hypopharynx or esophagus, with or without myotomy; cervical approach) but it doesn’t say endoscopic so I’m not sure if I should use it.
You are right to be cautious! CPT 43130 requires a skin incision so it should not be used for an endoscopic, or transoral, procedure. You should use an unlisted code, 43499 (Unlisted procedure, esophagus) for an endoscopic resection of a Zenker’s diverticulum.