title: Incidental dural tear in lumbar spinal decompression and discectomy: analysis of a nationwide database.
abstract: BACKGROUND
  An incidental dural tear (DT) is one of the most common intraoperative complications in lumbar spine surgery. The purpose of this study was to report the incidence of DT in lumbar spinal decompression (LSD) and lumbar discectomy (LD), risk factors, and patient outcomes on a national level.
  
  
  METHODS
  Clinical data were obtained from the Nationwide Inpatient Sample for 2009. Patients who underwent LSD for lumbar spinal stenosis and LD for lumbar disc herniation were identified and divided into those with and without DT, according to the International Classification of Diseases, 9th revision, Clinical Modification codes. Patient and healthcare system-related demographic data were retrieved. The incidence of DT and patient outcomes were analyzed. Multiple logistic regression analysis was performed to identify the risk factors for DT.
  
  
  RESULTS
  The incidence of DT was 6.3 % (4,255/67,982) in LSD and 1.9 % (2,564/136,482) in LD. Multivariate analysis revealed that significant risk factors for DT were hypertension and surgery in a teaching hospital for LSD, and older age and male gender for LD. DT was associated with significantly higher overall in-hospital complications (16.4 vs. 8.6 % for LSD, 9.1 vs. 8.0 % for LD). DT increased in-hospital mortality rate for LSD (0.7 vs. 0.1 %), however, not for LD (0.4 vs. 0.2 %). DT was associated with significantly longer hospital stay for LSD (4.6 vs. 3.0 days), however, not for LD (3.24 vs. 3.16 days). DT significantly increased hospital costs ($52,783 vs. $40,454 for LSD, and $32,307 vs. $27,787 for LD).
  
  
  CONCLUSIONS
  The incidence of DT was higher in LSD (6.3 %) than in LD (1.9 %), based on a national database. The effect of DT on in-hospital morbidity and mortality and health care burdens was more significant in LSD than in LD.
authors.affiliation: Department of Orthopedic Surgery, NYU Hospital for Joint Diseases, 301 East 17th St, New York, NY, 10003, USA, hiroyoshihara55@yahoo.co.jp.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Yoshihara
authors.forename: Daisuke
authors.initials: D
authors.lastname: Yoneoka
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016208:Databases, Factual; D019299:Decompression, Surgical; D017586:Diskectomy; D004388:Dura Mater / Q000293:injuries*; D005260:Female; D006801:Humans; D015994:Incidence; D007405:Intervertebral Disc Displacement / Q000601:surgery*; D007431:Intraoperative Complications / Q000453:epidemiology* / Q000628:therapy*; D008159:Lumbar Vertebrae; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D013130:Spinal Stenosis / Q000601:surgery*; D014481:United States; D055815:Young Adult