Predictors of nasolacrimal duct intubation failure for primary acquired nasolacrimal duct obstruction: a computed tomography-dacryocystography (CT-DCG) study.

Background: Making a choice between nasolacrimal duct intubation and dacryocystorhinostomy (DCR) for primary acquired nasolacrimal duct obstruction (PANDO) is an important issue in clinical practice. This study aimed to determine the potential lacrimal sac characteristics that could be used as predictors of unsuccessful intubation for PANDO based on computed tomography-dacryocystography (CT-DCG).

Methods: In this retrospective comparative observational study, we included PANDO patients with a history of failed intubation for nasolacrimal duct obstruction as the intubation failure group and PANDO patients without a history of intubation as the 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 the PANDO were studied, including 36 in the intubation failure group and 78 in the control group. The intubation failure group showed a smaller lacrimal sac height (11.69±4.59 mm) and width (2.28±1.97 mm, intermediate level) than the control group (14.13±2.92, 3.32±2.02 mm, P=0.005 and 0.012, respectively). The intubation failure group had a higher obstruction site than the control group (P=0.009).

Conclusions: A small lacrimal sac and high obstruction site are predictors of nasolacrimal duct intubation failure in PANDO. For PANDO patients with a small lacrimal sac or a high obstruction position, DCR is recommended as opposed to intubation.