Predictors of nasolacrimal duct intubation failure for primary acquired nasolacrimal duct obstruction——A CT dacryocystography study

Abstract Background: Whether to choose nasolacrimal duct intubation or dacryocystorhinostomy (DCR) for primary acquired nasolacrimal duct obstruction (PANDO) therapy is an important question in clinic practice. The purpose of this study is to find the potential lacrimal sac characteristics which can be used for the predictors of unsuccessful intubation for PANDO based on computed tomography-dacryocystography (CT-DCG). Methods: In this retrospective comparative observational study, we included PANDO patients who had a history of failed intubation for nasolacrimal duct obstruction as intubation failure group, and PANDO patients without intubation history as control group. We analyzed the lacrimal sac height, lacrimal sac width and obstruction site based on CT-DCG, all measured based on several reference levels on axial sections (upper, intermediate, lower level, common canaliculus level and lowermost contrast level), which were defined according to the contrast and the bony structure. Results: A total of 114 sides of PANDO were studied, including 36 sides in intubation failure group the other 78 sides in control group. The intubation failure group showed smaller lacrimal sac height (11.69±4.59 mm) and width (2.28±1.97 mm, intermediate level) than control group (14.13±2.92 mm, 3.32±2.02 mm, P = 0.005 and 0.012, respectively). Intubation failure group showed higher obstruction site than control group (P = 0.009). Conclusions: A small lacrimal sac and a high obstruction site are predictors of nasolacrimal duct intubation failure for PANDO. For PANDO patients with small lacrimal sac or high obstruction position, DCR is more recommended than intubation.