Background: Primary acquired nasolacrimal duct obstruction (PANDO) is a common cause of epiphora in adults, standard surgery for blockage of the lacrimal outflow tract is the dacryocystorhinostomy (DCR). The majority of studies have analyzed the lacrimal system of whites anatomically and presented guidelines for endonasal DCR. It has been our experience that DCR procedures for Asians are more difficult than for whites and we reasoned that the difficulty might be attributable to the anatomic differences in the intranasal structures between the races. Before we started doing endoscopic endonasal DCR in Mongolia, there was no hospital doing this surgery and there was lack of study done on anatomy of lacrimal fossa and DCR surgery result among Mongolians are our rationale of study. Goal: To study the effect of anatomical variance of lacrimal sac fossa on dacryocystorhinostomies performed by the endoscopic endonasal approach. Methods: 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). This study was approved by the Ethics Committee of Mongolian National University of Medical Sciences. 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. Standard Lac-Q questionnaire was used to compare satisfaction of the surgery in both groups. All statistical tests were two-sided, and a p-value of <0.05 was considered to be statistically significant. Statistical analysis was performed using STATA for Windows version 11.2. 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). Postoperative assessment was performed for 6 months. Patients who underwent endonasal group reported a 11.0-point improvement (IQR, 9.0–16.5). 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 have a high surgical success rate and good result on reduce of symptoms and improvement in quality of life by using the Lac-Q standard questionnaire.

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.

Introduction: Primary acquired nasolacrimal duct obstruction (PANDO) is a common cause of epiphora in adults, standard surgery for blockage of the lacrimal outflow tract is the dacryocystorhinostomy (DCR). The majority of studies have analyzed the lacrimal system of whites anatomically and presented guidelines for endonasal DCR. It has been our experience that DCR procedures for Asians are more difficult than for whites and we reasoned that the difficulty might be attributable to the anatomic differences in the intranasal structures between the races. Before we started doing endoscopic endonasal DCR in Mongolia, there was no hospital doing this surgery and there was lack of study done on anatomy of lacrimal fossa and DCR surgery result among Mongolians are our rationale of study. Goal: To study the effect of anatomical variance of lacrimal sac fossa on dacryocystorhinostomies performed by the endoscopic endonasal approach. Material and 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). This study was approved by the Ethics Committee of Mongolian National University of Medical Sciences. 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. Standard Lac-Q questionnaire was used to compare satisfaction of the surgery in both groups. All statistical tests were two-sided, and a p-value of <0.05 was considered to be statistically significant. Statistical analysis was performed using STATA for Windows version 11.2. 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). Postoperative assessment was performed for 6 months. Patients who underwent endonasal group reported a 11.0-point improvement (IQR, 9.0–16.5). 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 have a high surgical success rate and good result on reduce of symptoms and improvement in quality of life by using the Lac-Q standard questionnaire.