Anatomy of lacrimal sac fossa affecting success rate in endoscopic and external dacryocystorhinostomy surgery in Mongolians

Abstract

To study the affect of anatomical variance of lacrimal sac fossa on dacryocystorhinostomies (DCR) performed by the traditional external (EX-DCR) approach or an endoscopic (EN-DCR) endonasal approach. A total of 292 consecutive cases with primary nasolacrimal obstruction underwent DCR surgery. Orbital computed tomography scan was used to measure lacrimal sac fossa and other related structures and Lac-Q questionnaire was used to compare surgery result. Maxillary portion of lacrimal sac fossa is thicker in failed surgery group than successful surgery group (P<0.05). Lateral nasal structures (uncinate process, operculum of the middle turbinate, agger nasi) are dominantly adjusting to lacrimal sac fossa in failed surgery group (P<0.05). Patients who underwent EX-DCR has a 6.0-point and EN-DCR group 11.0-point improvement (P<0.016) in Lac-Q questionnaire. Patients who have a thick frontal process of the maxilla and uncinate process, operculum of the middle turbinate, ethmoid cells adjusting to lacrimal fossa are prone to have recurrence of nasolacrimal duct obstruction after DCR surgery. The EN-DCR and the EX-DCR approach have an equivalent surgical success rate but improvement in quality of life by using the Lac-Q questionnaire is greater in the endoscopic group when compared with the external.

Morphometric Evaluation of the Lacrimal Sac Fossa in Anatolian Population Using Multidetector Computed Tomography

“…Japanese: upper, 4.6 mm; lower, 6.30 mm) (10,11). Purevdorj et al (2021) reported that thicker maxillary bone at the lacrimal sac fossa might lead to decreased success rates for endoscopic and external DCR interventions (23). In this study, midpoint thickness was higher at upper and lower planes in males.…”

Clinical Efficacy of Orbital Computed Tomographic Assessment in Determination of the Optimal Length of the Jones Tube in Endo CDCR

“…Previous studies have evaluated the lacrimal sac fossa length and morphology using orbital CT, suggesting a potentially consistent anatomical reference for endo DCR/CDCR including opercula of the middle turbinate and the uncinate process. 12,13,22 Furthermore, the lacrimal sac fossa bone should be removed to its complete depth to ensure proper ostium formation. Therefore, a comprehensive understanding of the anatomy of the lacrimal sac fossa may influence the success rate in Endo DCR/CDCR.…”

“…Preoperative orbital CT assessment can be a valuable tool to achieve a better understanding of the anatomy of main endonasal and nasolacrimal system landmarks, leading to safe and proper removal of the nasal mucosa and creation of sufficiently sized ostium and correctly placed osteotomy. Previous studies have evaluated the lacrimal sac fossa length and morphology using orbital CT, suggesting a potentially consistent anatomical reference for endo DCR/CDCR including opercula of the middle turbinate and the uncinate process 12,13,22 . Furthermore, the lacrimal sac fossa bone should be removed to its complete depth to ensure proper ostium formation.…”

Computed tomographic assessment of the lacrimal sac fossa in southwest population of Iran

“…Different studies showing that there is a variability in the LSF morphology and intranasal space between the different ethnic groups age and sex [7][8][9][10]. Generally, the lacrimal bone proportion of the lacrimal fossa appears to be higher in Indians, compared to other racial groups such as the Caucasians, Koreans, or black African [10][11][12][13].…”