title: Effect of Perioperative Vitamin C Supplementation on Postoperative Pain and the Incidence of Chronic Regional Pain Syndrome: A Systematic Review and Meta-Analysis.
abstract: OBJECTIVE
  Postoperative pain can contribute to increased risk for complications and lengthened hospital stays. The objective was to analyze the effects of perioperative vitamin C supplementation on postoperative pain and the development of complex regional pain syndrome I (CRPS I) in patients undergoing surgical procedures.
  
  
  METHODS
  A systematic review of published literature was performed through April 2014. References from relevant studies were scanned for additional studies. Results were screened for relevance independently, and full-text studies were assessed for eligibility. Reporting quality was assessed using a modified Newcastle-Ottawa Scale.
  
  
  RESULTS
  The search strategy yielded 710 studies, of which 13 were included: 7 on postoperative pain and 6 on CRPS I. In the final analysis, 1 relevant study found a reduction in postoperative morphine utilization after preoperative vitamin C consumption, whereas another showed no difference in postoperative pain outcomes between the vitamin C and control groups. A meta-analysis of 3 applicable CRPS I studies showed a decrease in postoperative CRPS I after perioperative vitamin C supplementation (relative risk=2.25; τ²=0).
  
  
  CONCLUSIONS
  There is moderate-level evidence supporting the use of a 2 g preoperative dose of vitamin C as an adjunct for reducing postoperative morphine consumption, and high-level evidence supporting perioperative vitamin C supplementation of 1 g/d for 50 days for CRPS I prevention after extremity surgery. Additional studies are necessary to increase the level of evidence to determine the overall effectiveness and optimum dosage of vitamin C.
authors: *University of Ottawa Spine Program, The Ottawa Hospital §Faculty of Medicine, University of Ottawa Divisions of †Neurosurgery ∥Orthopaedic Surgery, The Ottawa Hospital ‡Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada.
authors: Suzan
authors: S
authors: Chen
authors: Darren M
authors: DM
authors: Roffey
authors: Charles-Antoine
authors: CA
authors: Dion
authors: Abdullah
authors: A
authors: Arab
authors: Eugene K
authors: EK
authors: Wai
mesh_terms: D000975:Antioxidants / Q000008:administration & dosage*; D001205:Ascorbic Acid / Q000008:administration & dosage*; D020918:Complex Regional Pain Syndromes / Q000453:epidemiology* / Q000601:surgery; D016206:Databases, Bibliographic / Q000706:statistics & numerical data; D006801:Humans; D015994:Incidence; D010149:Postoperative Pain / Q000517:prevention & control*; D011300:Preoperative Care
chemical_list: D000975:Antioxidants; D001205:Ascorbic Acid