Retrospective radiological analysis to establish anatomical variation in angulation between medial canthus and the middle turbinate, for optimal positioning of Lester Jones Lacrimal bypass tubes in treatment of Epiphora

Abstract

Purpose To determine the optimum angle for placement of Lester Jones lacrimal bypass tube using fixed radiological markers on CT scan head with axial and coronal cuts, as well as analysing the anatomical variation and range of angulation between individuals within our local population. Methods A retrospective radiological study conducted on a randomly selected sample of 384 adult patients in a UK Teaching Hospital. The angle between the medial canthus and the middle turbinate was measured on CT scans of the head using fixed radiological anatomical landmarks and analysed using the IMPAX software. Patients with orbital or nasal fractures, as well as those with history of surgical procedures involving the facial bones, were excluded. The accuracy of our measurements was validated using three dimensional (3D) CT head reconstruction technology. Results Analysis of the results showed a range of angulation between 28–45 degrees, with a mean angle of 36.99 ± 4.78 SD. There was no significant correlation found when comparing the different age groups using the One Way ANOVA test. Furthermore, a non-significant correlation was found between males and females when their mean angles were compared using the independent t-test. Conclusion Our study showed that the ideal angle for insertion of Lester Jones tube would be between 30–45 degrees, with a mean of 37 degrees. No significant correlation was found between the age of the patient and the ideal angle of insertion of Lester Jones tube. Moreover, no significant difference was found in the angle measurements between males and females.