To investigate postoperative outcomes of endonasal dacryocystorhinostomy (DCR) using lacrimal sac flap and silastic sheet in patients with acquired nasolacrimal duct obstruction.

From November 2009 until December 2010, endonasal DCR with lacrimal sac flap was performed in 26 eyes (group 1) and conventional DCR without flap in 28 eyes (group 2). The anatomic and functional success rates and complications were analyzed and compared between the 2 groups.

The anatomical success rate was 96.2% in group 1 and 85.7% in group 2. The functional success rate was 100% in group 1 and 92.9% in group 2. The success rate was higher in group 1 than in group 2, although not being statistically significant. Granuloma was found in 15.4% of patients in group 1 and 32.1% of patients in group 2. Synechia or membranous obstruction was not found in group 1, whereas synechia developed in 14.3% of patients in group 2.

Endonasal DCR with lacrimal sac flap showed a greater success rate and lower formation of granuloma than conventional endonasal DCR without flap because of reduced inflammation and granulation tissue formation around retained bony spicles.