Comparison of failed and successful dacryocystorhinostomy by using computed tomographic dacryocystography findings.

PURPOSE To compare the spiral computed tomographic dacryocystography (CT-DCG) findings of failed and successful dacryocystorhinostomies (DCR) and to detect the possible causes of failure before reoperation. METHODS Eighteen patients with failed and 15 patients with functional DCR were examined by spiral CT-DCG, a combination of contrast dacryocystography and spiral computed tomography. Radiologists, who were blinded to the clinical status of the patients, measured the diameter of the osteotomy window, evaluated its position relative to the lacrimal sac, and documented any abnormal findings around the osteotomy, which may contribute to the failure of DCR. RESULTS Location of the osteotomy window was inappropriate in 83% (15/18) of unsuccessful cases and in 7% (1/15) of successful cases and the difference was statistically significant (p<0.01). Presence of the ethmoid air cells medial to the ostium was detected to have a significantly higher frequency in the unsuccessful DCR group (78%, 14/18) than in the successful group (20%, 3/15) (p<0.01). The antero-posterior diameter of bony ostium was less than 15 mm in 94% (17/18) of failed DCR cases, but in only 60% (9/15) of successful DCR cases, and the difference was statistically significant (p<0.05). Some additional findings that may contribute to the failure were noted in failed cases. There were ethmoid sinusitis in three, concha bullosa in two, nasal polyposis in two, mass in medial canthus in one, and extensive granulation tissue around the rhinostomy in one of the failed cases. CONSLUSIONS. CT-DCG is a valuable imaging tool to evaluate DCR failures before reoperation. In this series, CT-DCG showed that small size and inappropriate position of osteotomy, and also extension of ethmoid air cells medial to the lacrimal sac, were frequently seen causative factors of DCR failure. (Eur J Ophthalmol 2005; 15: 523-9).