Purpose: To investigate the accuracy of the preoperative evaluation in identifying a membranous obstruction of the distal canaliculus and the success rate of an external dacryocystorhinostomy (DCR) when membranectomy of the canalicular obstruction is also performed.
Design: Retrospective, interventional case series.
Methods: The surgical records of the lacrimal cases operated at Moorfields Eye Hospital between January 1997 and December 1999 were reviewed. All the patients with evidence of a membranous block of the canalicular opening into the sac identified and excised during the course of a standard DCR procedure with silastic intubation and a minimum follow-up period of 12 months were selected for this study. The records were analyzed for preoperative evaluation with syringing and probing, surgical details, outcome, and complications.
Results: In 59 (85%) cases a functional anastomosis was established after tube removal. Additionally, 5 cases (7%) had patent system but required later ectropion repair and considered successful. Only 4 (6%) patients needed further lacrimal surgery, and one was referred to the ENT department for nasal polyps. The silastic tube was removed at a mean period of 6 weeks (SD = 4; range, 2-24 weeks), and the mean follow-up period was 13 months (SD = 3; range, 12-29 months). The preoperative evaluation failed to identify the membranous obstruction in 30 (43%) cases, which were correctly diagnosed intraoperatively.
Conclusions: In our series the anatomic success rate of 92% after DCR with membranectomy is comparable to the outcome of the DCR procedure. The distal canalicular membranous obstruction is an anatomic factor that may lead to surgical failure if not identified and excised.