title: Reoperation rate after surgery for lumbar herniated intervertebral disc disease: nationwide cohort study.
abstract: METHODS
  Retrospective cohort study using national health insurance data.
  
  
  OBJECTIVE
  To provide a longitudinal reoperation rate after surgery for lumbar herniated intervertebral disc (HIVD) disease, and to compare the reoperation rates of surgical methods.
  
  
  BACKGROUND
  Herniated intervertebral disc disease is the most common cause of lumbar spinal surgery. Despite improved surgical techniques and instrumentation, reoperation cannot be avoided. The reoperation rates were in the range of 6% to 24% in previous studies. A population-based study is less subject to bias; hence, a nationwide longitudinal analysis was warranted.
  
  
  METHODS
  A national health insurance database was used to identify a cohort of patients who underwent first surgery for herniated intervertebral disc disease in 2003 and 18,590 patients were selected. Individual patients were followed for at least 5 years through their encrypted unique resident registration number. The primary endpoint was any type of second lumbar surgery. After adjusting for confounding factors, 5 surgical methods (fusion, laminectomy, open discectomy, endoscopic discectomy, and nucleolysis [including mechanical nucleus decompression]) were compared. Open discectomy was used as the reference method.
  
  
  RESULTS
  Open discectomy was the most common procedure (68.9%) followed by endoscopic discectomy (16.1%), laminectomy (7.9%), fusion (3.9%), and nucleolysis (3.2%). The cumulative reoperation rate was 5.4% at 3 months, 7.4% at 1 year, 9% at 2 years, 10.5% at 3 years, 12.1% at 4 years, and 13.4% at 5 years. The reoperation rates were 18.6%, 14.7%, 13.8%, 12.4%, and 11.8% after laminectomy, nucleolysis, open discectomy, endoscopic discectomy, and fusion, respectively. Compared with open discectomy, the reoperation rate was higher after laminectomy at 3 months, whereas the other surgical methods had similar rates.
  
  
  CONCLUSIONS
  The cumulative reoperation rate after 5 years was 13.4% and half of the reoperations occurred during the first postoperative year. With the exception of laminectomy, the reoperation rates of the other procedures were not different from that of open discectomy.
authors.affiliation: Department of Neurosurgery, Seoul National University Hospital and Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Chi Heon
authors.initials: CH
authors.lastname: Kim
authors.forename: Chun Kee
authors.initials: CK
authors.lastname: Chung
authors.forename: Choon Seon
authors.initials: CS
authors.lastname: Park
authors.forename: Boram
authors.initials: B
authors.lastname: Choi
authors.forename: Min Jung
authors.initials: MJ
authors.lastname: Kim
authors.forename: Byung Joo
authors.initials: BJ
authors.lastname: Park
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D015897:Comorbidity; D016208:Databases, Factual; D017586:Diskectomy / Q000379:methods / Q000706:statistics & numerical data*; D004724:Endoscopy / Q000379:methods / Q000706:statistics & numerical data*; D005260:Female; D005500:Follow-Up Studies; D006509:Hepatitis B / Q000453:epidemiology; D006801:Humans; D007348:Insurance, Health; D007404:Intervertebral Disc Chemolysis / Q000706:statistics & numerical data*; D007405:Intervertebral Disc Displacement / Q000453:epidemiology / Q000601:surgery* / Q000628:therapy; D007796:Laminectomy / Q000706:statistics & numerical data*; D008159:Lumbar Vertebrae / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D010024:Osteoporosis / Q000453:epidemiology; D010437:Peptic Ulcer / Q000453:epidemiology; D016016:Proportional Hazards Models; D012008:Recurrence; D012086:Reoperation / Q000706:statistics & numerical data; D056910:Republic of Korea / Q000453:epidemiology; D012189:Retrospective Studies; D012307:Risk Factors; D013123:Spinal Fusion / Q000706:statistics & numerical data*; D013130:Spinal Stenosis / Q000453:epidemiology; D055815:Young Adult