A retrospective comparison of endonasal KTP laser dacryocystorhinostomy versus external dacryocystorhinostomy

We retrospectively reviewed all primary external dacryocystorhinostomies (DCRs) and endonasal KTP laser DCRs performed for epiphora as a result of nasolacrimal duct obstruction in our unit between 1993 and 2000. Forty-nine patients underwent an external approach and 76 endonasal laser procedures were performed. The success rate of the external group was 94% with a mean follow-up of 9 months. In contrast, the endonasal group's success rate was 64% with a mean follow-up of 12 months. This difference reached statistical significance (P = 0.0002). However, when including revision procedures, the success rate in the endonasal group increased from 64% to 82%. The success rate in the endonasal group improved from 50% in the first 38 cases to 79% in the last 38 cases (P = 0.0084), thereby demonstrating a learning curve. Our study confirms external DCR as the 'gold standard' for a successful outcome. However, the endonasal technique has significant advantages, including being a quicker procedure with less morbidity, no cutaneous scar, and being more amenable to a bilateral procedure, daycase surgery and local anaesthetic. We are persisting with the endonasal technique because of its advantages but have moved towards more 'cold steel' techniques in an effort to improve results and emulate other series. In conclusion, for nasolacrimal duct obstruction, the endonasal technique is our approach of choice, with revision surgery if necessary, and the external technique is held in reserve.