Abdolreza Medghalchi - Eye Research Center, Department of Eye, Amiralmomenin Hospital, School of Medicine, Guilan University of Medical Sciences, Rasht, Iran.
Yousef Alizadeh - Eye Research Center, Department of Eye, Amiralmomenin Hospital, School of Medicine, Guilan University of Medical Sciences, Rasht, Iran.
Maryam Dourandeesh - Eye Research Center, Department of Eye, Amiralmomenin Hospital, School of Medicine, Guilan University of Medical Sciences, Rasht, Iran.
Sima Fallah Arzpeima - Poursina Hospital, School of Medicine, Guilan University of Medical Sciences, Rasht, Iran
Reza Soltani Moghadami - Eye Research Center, Department of Eye, Amiralmomenin Hospital, School of Medicine, Guilan University of Medical Sciences, Rasht, Iran.
Mitra Akbari - Eye Research Center, Department of Eye, Amiralmomenin Hospital, School of Medicine, Guilan University of Medical Sciences, Rasht, Iran.
Sara Khadem - Eye Research Center, Department of Eye, Amiralmomenin Hospital, School of Medicine, Guilan University of Medical Sciences, Rasht, Iran.
Ehsan Kazemnezhad Leyli - Associate Professor of Biostatistics Department of Biostatistics, School of Health Road Trauma Research Center Guilan University of Medical Sciences

Backgrounds: External dacryocystorhinostomy (DCR) failure is sometimes due to pathologies located within the nasal cavity. Preoperative computerized tomography (CT) scan is useful in the assessment of nasolacrimal drainage and adjacent anatomical structures; however, it is not routinely performed before DCR. The present study evaluates abnormal findings in CT scans of patients with nasolacrimal duct obstruction (NLDO) and its effect on changing treatment approaches.Methods: This prospective descriptive cross-sectional study included ۱۶۲ patients with NLDO. All the patients underwent a supine axial CT scan. Patients with signs of rhinosinusitis, sinus mucositis, nasal septal deviation, nasal polyps or masses, and turbinate deformities were referred to an otolaryngologist. The rest of the patients underwent external DCR. The demographics and radiologic characteristics of the patients undergoing CT scans and their effect on changing treatment approaches were evaluated. Results: The study participants included ۱۶۲ patients with a mean±SD age of ۶۲.۵±۱۴.۰ years (age range of ۳۵-۹۳ years). The percentage of endonasal DCR in cases with an abnormal nasal cavity on CT scan was almost ۳۰% higher compared to those without this problem (۵۹.۶% vs. ۳۰.۲%). Septum deviation and turbinate deformity led to ۳.۶-fold and ۳.۹-fold changes in the surgical approach, respectively.ConclusionA significant association existed between the sinonasal pathologies in patients with NLDO and changing surgical approaches. It is believed that a preoperative CT scan is necessary to detect such pathologies and manage them appropriately.

nasolacrimal duct obstruction, dacryocystorhinostomy, computerized tomography, endoscopic dacryocystorhinostomy, external dacryocystorhinostomy