Modified external revision-DCR in previous failed endonasal, transcanalicular or external-DCR: technical strategy and teaching Pearls for success.

Objective: To report perioperative findings of patients with multiple failed-dacryocystorhinostomy (DCR) and to determine the success rate of revision external (rEx-DCR) performed by a modified technique. Methods: Thirty-one eyes of 31 patients (19 women, 12 men) with recurrent dacryocystitis or epiphora following at least one previous failed-DCR were assessed regarding the time from initial surgery to recurrence and revision surgery, type of primary surgery (endoscopic, transcanalicular, Ex-DCR), recurrence number, stent usage and the success rate. Relief of epiphora and positive dye test were established as functional and anatomical successes, respectively. Results: The mean age was 43.0 years (8-78), with a mean follow-up period of 21.4 months (6-46). The mean reoperation number was 1.4 (1-5). The mean time from initial surgery to recurrence was 15.2 months (1-55) and to rEx-DCR, 19.8 months (4-65). Untouched medial canthal ligament was observed in 28 (90.3%), improper rhinostomy location in 26 (83.8%), inadequate osteotomy size in 25 (80.6%), single-anterior-flap-only in 5 (16.1%), membranous ostial scar formation in four (12.5%) and no flap in three (9.6%) patients. The success rate was 93.5%, which was lower than our primary modified Ex-DCR (99.1%). Conclusions: The most common reasons for recurrence were small and unsuitable osteotomy locations with intact medial canthal ligaments. "Double-mucosal flap" approach with an anterior sacco-mucosal complex suspension increases the functional success rate, and stent implantation is not obligatory if canalicular problems or small/ atrophic sacs do not exist. The knowledge of technical strategy and teaching pearls improves the success rates of primary and revision surgeries. Abbreviations: DCR = dacryocystorhinostomy, Ex-DCR = external DCR, EE-DCR = endoscopic endonasal DCR, TC-LA-DCR = transcanalicular laser-assisted DCR.