Influence of Intercanthal Distance Variation in Locating Lacrimal Sac during Endonasal Dacryocystorhinostomy

Abstract

Introduction: Endoscopic endonasal dacryocystorhinostomy is one of the leading modalities for the treatment of distal lacrimal system obstruction. Knowledge of an accurate position of lacrimal sac in the lateral nasal wall is crucial to perform this surgery and to obtain favorable long-term results. This study is an attempt to define the position of lacrimal sac in the lateral nasal wall in relation to axilla of middle turbinate which is a well-accepted anatomical landmark on the lateral nasal wall to perform endonasal dacryocystorhinostomy; in extension, a variation in the inner intercanthal distance of the subject was correlated with any variation in the distance between the axilla of middle turbinate and lacrimal sac.

Methods: An observational cross-sectional study was conducted on thirty patients with epiphora. Patients were evaluated with lacrimal syringing and those with distal lacrimal system obstruction were included in the study. Inner intercanthal distance was measured using vernier caliper. All patients underwent endoscopic endonasal dacryocystorhinostomy and intraoperative measurement between the axilla of middle turbinate and midpoint of lacrimal sac in the anteroposterior dimension was recorded.

Results: Females predominantly presented with epiphora. The average anteroposterior distance of lacrimal sac from the axilla of middle turbinate in the lateral nasal wall was found to be 7.06mm with a range of 6mm to 8mm. Intercanthal distance in our study population had a range of 26mm to 38mm with a mean of 31.46mm. Statistically significant correlation could not be established between the inner intercanthal distance and position of lacrimal sac in relation to the axilla of middle turbinate.

Conclusion: The lacrimal sac can be located 6mm to 8mm anterior to the axilla of middle turbinate. However, it does not correlate with varying inner intercanthal distance. The knowledge of accurate position of lacrimal sac in the lateral nasal wall is important to perform an endoscopic endonasal dacryocystorhinostomy and to obtain good long-term results.