Anatomy of lacrimal sac fossa affecting success rate in dacryocystorhinostomy surgery

Abstract

Purpose: To study the affect of anatomical variance of lacrimal sac fossa on dacryocystorhinostomies performed by the traditional external approach and an endoscopic endonasal approach. Methods: A total of 292 consecutive cases of DCR were performed age between 16-75 years old who have primary nasolacrimal obstruction (ICD-H04.559). A total of 146 EX-DCR and 146 EN-DCR patients were identified. Full success was defined as no symptoms of tearing after surgery and anatomical patency with lacrimal irrigation. Standart Lac-Q questionnaire was used to compare satisfaction of the surgery in both groups. Results: There was no significant difference in age or gender distribution between the two groups. Frontal process of the maxillary bone is 4.41±1.96 mm in successful group and 4.97±1.04 in failed group (p<0.05). The uncinate process was attached to the lacrimal sac fossa in 80.1% of the all cases and 100% in surgery failed group (p<0.05). The variation that agger nasi cell adjacent to the lacrimal sac fossa was in 93.9%. The operculum of the middle turbinate was attached to the lacrimal sac fossa in 94.5% of the cases (p=0.76). The mean operative duration was 28.5 minutes for EX-DCR and 10.2 minutes for EN-DCR (P < 0.005, t test). Surgical success rate was achieved in 95.1% of EX-DCRs and 96.4% of EN-DCRs. The failure rate was 0.05% for EX-DCR and 0.03% for EN-DCR. There was no statistical significance between these outcomes with a two-sample test for equality of proportions with continuity correction (P= 0.75). Postoperative assessment was performed at 3 and 6 months. Patients who underwent external DCR reported a median 6.0-point improvement (interquartile range [IQR], 3.0–10.0) in total Lac-Q scores. A 11.0-point improvement (IQR, 9.0–16.5) was seen in the endonasal group (p<0.016). Conclusions: A thick frontal process of the maxilla and uncinate process, operculum of the middle turbinate, and ethmoid cells adjusting to lacrimal fossa are dominant in Mongolians. Patients who have these features are prone to have recurrence of nasolacrimal duct obstruction after DCR surgery. The EN-DCR and the traditional external approach have an equivalent surgical success rate. However EN-DCR and EXDCR reduce of symptoms and improvement in quality of life by using the Lac-Q standart questionnaire.