title: Operative Duration and Risk of Surgical Site Infection in Neurosurgery.
abstract: BACKGROUND
  The association of surgical duration with the risk of surgical site infection (SSI) has not been quantified in neurosurgery. We investigated the association of operative duration in neurosurgical procedures with the incidence of SSI.
  
  
  METHODS
  We performed a retrospective cohort study involving patients who underwent neurosurgical procedures from 2005 to 2012 and were registered in the American College of Surgeons National Quality Improvement Project registry. To control for confounding, we used multivariable regression models and propensity score conditioning.
  
  
  RESULTS
  During the study period there were 94,744 patients who underwent a neurosurgical procedure and met the inclusion criteria. Of these patients, 4.1% developed a postoperative SSI within 30 days. Multivariable logistic regression showed an association between longer operative duration with higher incidence of SSI (odds ratio [OR], 1.18; 95% confidence interval [CI], 1.16-1.20). Compared with procedures of moderate duration (third quintile, 40th-60th percentile), patients undergoing the longest procedures (>80th percentile) had higher odds (OR, 2.07; 95% CI, 1.86-2.31) of developing SSI. The shortest procedures (<20th percentile) were associated with decreased incidence of SSI (OR, 0.72; 95% CI, 0.61-0.83) compared with those of moderate duration. The same associations were present in propensity score adjusted models and models stratified by subgroups of cranial, spinal, peripheral nerve, and carotid procedures.
  
  
  CONCLUSIONS
  In a cohort of patients from a national prospective surgical registry, longer operative duration was associated with increased incidence of SSI for neurosurgical procedures. These results can be used by neurosurgeons to inform operative management and to stratify patients with regard to SSI risk.
authors.affiliation: Section of Neurosurgery, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, USA; The Dartmouth Institute for Health Policy and Clinical Practice, Lebanon, New Hampshire, USA. Electronic address: kbekelis@gmail.com.
authors.forename: Kimon
authors.initials: K
authors.lastname: Bekelis
authors.affiliation: Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts, USA.
authors.forename: Shannon
authors.initials: S
authors.lastname: Coy
authors.affiliation: Section of Neurosurgery, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, USA.
authors.forename: Nathan
authors.initials: N
authors.lastname: Simmons
mesh_terms: D017677:Age Distribution; D015331:Cohort Studies; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000706:statistics & numerical data*; D061646:Operative Time; D012042:Registries; D012189:Retrospective Studies; D012307:Risk Factors; D017678:Sex Distribution; D013530:Surgical Wound Infection / Q000175:diagnosis* / Q000453:epidemiology*; D014481:United States / Q000453:epidemiology
keywords: NSQIP; Neurosurgery; Operative duration; Surgical site infection