title: A systematic review of preoperative predictors for postoperative clinical outcomes following lumbar discectomy.
abstract: Sciatica is often caused by a herniated lumbar intervertebral disc. When conservative treatment fails, a lumbar discectomy can be performed. Surgical treatment via lumbar discectomy is not always successful and may depend on a variety of preoperative factors. It remains unclear which, if any, preoperative factors can predict postsurgical clinical outcomes.
  
  
  
  This review aimed to determine preoperative predictors that are associated with postsurgical clinical outcomes in patients undergoing lumbar discectomy.
  
  
  
  This is a systematic review.
  
  
  
  This systematic review of the scientific literature followed the Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines. MEDLINE and PubMed were systematically searched through June 2014. Results were screened for relevance independently, and full-text studies were assessed for eligibility. Reporting quality was assessed using a modified Newcastle-Ottawa Scale. Quality of evidence was assessed using a modified version of Sackett's Criteria of Evidence Support. No financial support was provided for this study. No potential conflict of interest-associated biases were present from any of the authors.
  
  
  
  The search strategy yielded 1,147 studies, of which a total of 40 high-quality studies were included. There were 17 positive predictors, 20 negative predictors, 43 non-significant predictors, and 15 conflicting predictors determined. Preoperative predictors associated with positive postoperative outcomes included more severe leg pain, better mental health status, shorter duration of symptoms, and younger age. Preoperative predictors associated with negative postoperative outcomes included intact annulus fibrosus, longer duration of sick leave, worker's compensation, and greater severity of baseline symptoms. Several preoperative factors including motor deficit, side and level of herniation, presence of type 1 Modic changes and degeneration, age, and gender had non-significant associations with postoperative clinical outcomes.
  
  
  
  It may be possible for certain preoperative factors to be targeted for clinical evaluation by spine surgeons to assess the suitability of patients for lumbar discectomy surgery, the hope being to thereby improve postoperative clinical outcomes. Prospective cohort studies are required to increase the level of evidence with regard to significant predictive factors.
authors: Ottawa Combined Adult Spinal Surgery Program (OCASSP), The Ottawa Hospital, 1053 Carling Ave, Ottawa, ON, Canada K1Y 4E9.
authors: Courtney A
authors: CA
authors: Wilson
authors: Ottawa Combined Adult Spinal Surgery Program (OCASSP), The Ottawa Hospital, 1053 Carling Ave, Ottawa, ON, Canada K1Y 4E9; Clinical Epidemiology Program, Ottawa Hospital Research Institute, 725 Parkdale Ave, Ottawa, ON, Canada K1Y 4E9.
authors: Darren M
authors: DM
authors: Roffey
authors: Division of Orthopaedic Surgery, University of Ottawa, 1053 Carling Ave, Ottawa, ON, Canada K1Y 4E9.
authors: Donald
authors: D
authors: Chow
authors: Ottawa Combined Adult Spinal Surgery Program (OCASSP), The Ottawa Hospital, 1053 Carling Ave, Ottawa, ON, Canada K1Y 4E9; Clinical Epidemiology Program, Ottawa Hospital Research Institute, 725 Parkdale Ave, Ottawa, ON, Canada K1Y 4E9; Division of Neurosurgery, University of Ottawa, 1053 Carling Ave, Ottawa, ON, Canada K1Y 4E9.
authors: Fahad
authors: F
authors: Alkherayf
authors: Ottawa Combined Adult Spinal Surgery Program (OCASSP), The Ottawa Hospital, 1053 Carling Ave, Ottawa, ON, Canada K1Y 4E9; Clinical Epidemiology Program, Ottawa Hospital Research Institute, 725 Parkdale Ave, Ottawa, ON, Canada K1Y 4E9; Division of Orthopaedic Surgery, University of Ottawa, 1053 Carling Ave, Ottawa, ON, Canada K1Y 4E9. Electronic address: ewai@ottawahospital.on.ca.
authors: Eugene K
authors: EK
authors: Wai
mesh_terms: D000328:Adult; D017586:Diskectomy / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008159:Lumbar Vertebrae / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000453:epidemiology*; D057234:Preoperative Period
keywords: Lumbar disc herniation; Lumbar discectomy; Outcome; Predictor; Sciatica; Surgery