title: Risk factors for medical complication after spine surgery: a multivariate analysis of 1,591 patients.
abstract: BACKGROUND
  Several studies have examined the occurrence of medical complication after spine surgery. However, many of these studies have been done using large national databases. Although these allow for analysis of thousands of patients, potentially influential covariates are not accounted for in these retrospective studies. Furthermore, the accuracy of these retrospective data collection in these databases has been called into question.
  
  
  OBJECTIVE
  Using multivariate analysis on a prospectively collected data registry to determine significant risk factors for medical complication after spine surgery.
  
  
  METHODS
  Retrospective multivariate analysis of prospectively collected registry data. The registry is a prospectively collected database of all patients who underwent spine surgery in our two institutions from January 1, 2003 to December 31, 2004.
  
  
  METHODS
  Extensive demographic and medical information were prospectively recorded as described previously by Mirza et al. Complications were defined in detail a priori, and they were prospectively recorded for at least 2 years after surgery. We analyzed risk factors for medical complication after spine surgery using univariate and multivariate analyses.
  
  
  RESULTS
  We analyzed data from 1,591 patients who met out inclusion criteria. The cumulative incidences of complication after spine surgery per organ system are as follows: cardiac, 8.4%; pulmonary, 13%; gastrointestinal, 3.9%; neurological, 7.35%; hematological, 10.75%; and urological complications, 9.18%. The occurrence of cardiac or respiratory complication after spine surgery was significantly associated with death within 2 years (relative risk, 4.11 and 10.76, respectively). Surgical invasiveness and age were significant risk factors for complications in five of the six organ systems evaluated. Individual organ system-specific elative risk values with 95% confidence intervals and p values are listed in Tables 3 and 4.
  
  
  CONCLUSIONS
  Risk factors identified in this study can be beneficial to clinicians and patients alike when considering surgical treatment of the spine. Future analyses and models that predict the occurrence of medical complication after spine surgery may be of further benefit for surgical decision making.
authors.affiliation: Department of Orthopedics and Sports Medicine, University of Washington Medical Center, Seattle, WA 98195, USA. mjl3000@uw.edu
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Lee
authors.forename: Mark A
authors.initials: MA
authors.lastname: Konodi
authors.forename: Amy M
authors.initials: AM
authors.lastname: Cizik
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Bransford
authors.forename: Carlo
authors.initials: C
authors.lastname: Bellabarba
authors.forename: Jens R
authors.initials: JR
authors.lastname: Chapman
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D019637:Orthopedic Procedures / Q000009:adverse effects*; D011183:Postoperative Complications / Q000453:epidemiology*; D012307:Risk Factors; D013131:Spine / Q000601:surgery*; D055815:Young Adult