title: Factors affecting the success of external dacryocystorhinostomy.
abstract: OBJECTIVE
  To assess the success rate of external dacryocystorhinostomy (Ext-DCR) and factors affecting it in a university hospital.
  
  
  METHODS
  In a retrospective interventional non-comparative case series, records of 276 Ext-DCRs in 274 patients in a 9-year period were reviewed. 'Complete success' was defined as patent system on irrigation (objective) and absence of symptoms (subjective). Patent system on irrigation with minimal postoperative symptoms was considered as partial success. The chi-square and Fisher's exact tests with 95% confidence interval (CI) were used to analyze the data (SPSS release version 9.0, Chicago).
  
  
  RESULTS
  The age range was 3-84 years (mean: 41.5, SD: 17.7). The majority of the patients (66.7%) were female. The most common presumed etiology was primary acquired nasolacrimal duct obstruction (PANLDO) (227/276, 82.2%). A silicone tube was inserted in 111 patients (40.2%). Follow-up was from 6 to 89 months (mean: 11.5, SD: 10.4). Overall complete success rate was 89.1% (246/276). It was 92% (209/227) in PANLDO, 72.7% (16/22) in congenital NLDO (P: 0.01, 95% CI: 0.024-0.030), 71.4% (10/14) in traumatic NLDO (P: 0.001, 95% CI: 0.012-0.017), 90% (9/10) in previous failed DCR (P: 0.6, 95% CI: 1), and two out of three patients with previous nasal/sinus surgery. Gender, type of presenting symptoms, duration of preoperative symptoms, silicone tube insertion in PANLDO, and associated canalicular stenosis did not have a significant effect on the success.
  
  
  CONCLUSIONS
  Ext-DCR is an effective and highly successful procedure for the treatment of NLDO regardless of the etiology.
authors.affiliation: Ocular Adnexal Unit, Rassoul Akram Hospital, Iran University of Medical Sciences, Tehran, Iran. bahmanik@yahoo.com
authors.forename: Mohsen Bahmani
authors.initials: MB
authors.lastname: Kashkouli
authors.forename: Mohammad
authors.initials: M
authors.lastname: Parvaresh
authors.forename: Mehdi
authors.initials: M
authors.lastname: Modarreszadeh
authors.forename: Masih
authors.initials: M
authors.lastname: Hashemi
authors.forename: Bijan
authors.initials: B
authors.lastname: Beigi
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016009:Chi-Square Distribution; D002648:Child; D002675:Child, Preschool; D003608:Dacryocystorhinostomy / Q000379:methods*; D005260:Female; D006785:Hospitals, University; D006801:Humans; D007767:Lacrimal Duct Obstruction / Q000175:diagnosis; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012189:Retrospective Studies; D016896:Treatment Outcome