title: Bilateral lacrimal drainage obstruction and its association with secondary causes.
abstract: OBJECTIVE
  Etiologies of lacrimal obstruction requiring a dacryocystorhinostomy (DCR) have been reviewed previously but most commonly are thought to result from "primary acquired" nasolacrimal duct obstruction, a process of chronic inflammation in a narrowed duct. The authors have observed that secondary causes are frequently associated with bilateral lacrimal outflow disease. The purpose of this study is to investigate this relationship to help the clinician prioritize which patients to evaluate for secondary causes.
  
  
  METHODS
  This is a retrospective case-controlled review of patients who underwent bilateral DCR from 1986 to 2012 at this institution. They are compared with an age and gender-matched control group who underwent unilateral DCR. Statistical analysis was undertaken using the Pearson chi-square test for p value, except for age, which used the Wilcoxon rank sum test. Logistic regression was used for comparing prevalence of secondary issues in bilateral disease versus unilateral disease, with age as covariate.
  
  
  RESULTS
  Two hundred thirty-five patients underwent bilateral (91) or unilateral DCR (144). Twice as many patients undergoing bilateral DCR had an underlying secondary cause compared with the patients undergoing unilateral DCR. (38%, 19%, p= 0.001, odds ratio 2.59). In patients <50, the odds ratio of a secondary cause in bilateral disease would be 5.34 compared with patients older than 80. (p = 0.0002) Patients in the bilateral DCR group underwent revisions at more than twice the rate as patients in the unilateral DCR group (26%, 12%, p = 0.007).
  
  
  CONCLUSIONS
  Ophthalmologists should have a high index of suspicion for secondary conditions underlying bilateral lacrimal outflow obstruction, especially in patients <50. These patients should undergo laboratory workup and intraoperative biopsy. They should also be counseled regarding a higher failure rate.
authors.affiliation: Departments of *Ophthalmology and Visual Sciences, and †Otolaryngology-Head and Neck Surgery, University of Iowa Hospitals and Clinics, Iowa City, Iowa, U.S.A.
authors.forename: Rachel K
authors.initials: RK
authors.lastname: Sobel
authors.forename: Keith D
authors.initials: KD
authors.lastname: Carter
authors.forename: Richard C
authors.initials: RC
authors.lastname: Allen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D003608:Dacryocystorhinostomy; D005128:Eye Diseases / Q000150:complications; D005260:Female; D006801:Humans; D007223:Infant; D007767:Lacrimal Duct Obstruction / Q000175:diagnosis / Q000209:etiology*; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000150:complications; D008297:Male; D008875:Middle Aged; D009301:Nasolacrimal Duct / Q000473:pathology* / Q000601:surgery; D012189:Retrospective Studies; D055815:Young Adult