Statewide Evaluation of Intra-wound Antibiotics in Spine Surgery Patients: A Report from the SCOAP-CERTAIN Collaborative
Anne Pugel, MD, Department of Surgery, University of Washington; Sara Khor, MS, Surgical Outcomes Research Center, University of Washington, Seattle, WA; Neal Shonnard, MD, Rainier Orthopedic Institute, Proliance Surgeons Inc, Puyallup, WA; Rod Oskouian, Jr, MD, Swedish Neuroscience Institute, Swedish Medical Center, Seattle, WA; Rajiv Sethi, MD, Department of Neurosurgery and Orthopaedics, Virginia Mason Medical Center, Seattle, WA; Group Health Physicians, Seattle, WA; Department of Health Services, University of Washington, Seattle, WA; Amy Cizik, MPH, Department of Orthopaedics and Sports Medicine, University of Washington, Seattle, WA; Michael Lee, MD, University of Chicago Medical Center, Chicago, IL; Samuel Bederman, MD, Department of Orthopaedic Surgery, University of California-Irvine, Orange, CA; E. Patchen Dellinger, MD, Department of Surgery, University of Washington, Seattle, WA; David Flum, MD, MPH, Department of Surgery, University of Washington, Seattle, WA
Surgical site infection (SSI) after spine surgery is classified as a never event but occurs up to 10% of the time, often with devastating consequences. Intra-wound antibiotics (IWA) have been proposed to reduce the incidence of spine SSI. Robust evidence to support IWA use is lacking.Hypothesis:
We hypothesize that rates of SSI will differ between patients who did and did not receive IWA.Methods:
We evaluated IWA use in a prospective cohort undergoing spine fusion surgery at 20 Washington State hospitals (July 2011-March 2014) participating in the Surgical Care and Outcomes Assessment Program Spine Program (Spine SCOAP). Patient, hospital, and operative covariates associated with SSI and IWA use during index hospitalizations were analyzed. Effects of IWA on SSI were examined using a random effects logistic model adjusting for patient and hospital characteristics. A propensity score matching analysis was also performed independently to confirm our findings.Results:
9646 cervical or lumbar fusions were completed during the study period (mean age 58, 90% white, 54% female). Nearly all (99%) received antibiotics on-time, and 97% were normothermic in the recovery room. Overall, the infection rate was 1.1%.Those with SSI were more likely to be non-white (22% vs 13%, p<0.01), older (64 vs 58 years, p<0.01), to have diabetes (32% vs 17%, p<0.01), and more frequently underwent lumbar versus cervical fusion (76% vs 52%, p<0.01). The unadjusted rate o SSI was 0.8% for those who received IWA and 1.5% for those who did not (OR: 0.56; p<0.01). The use of IWA varied widely across hospitals (10%-98.2%, p<0.01), but increased use of IWA was not correlated to SSI (r2=0.16). In the random-effects logistic model clustering by hospital, those who received IWA had a lower odds of SSI (OR 0.7, 95% CI 0.46-1.07; p=0.097), but this was not statistically significant. A separate propensity score analysis demonstrated no significant difference in SSI between those who did and did not receive IWA (1.01% vs 1.41%, p=0.12).Conclusions:
While unadjusted analyses indicate a nearly 50% reduction in SSI using IWA, once multivariate adjustment of patient, provider, and hospital characteristics was used the rate of SSI was not significantly lower. It remains to be determined if IWA should be promoted as a quality improvement intervention. A large trial is needed to determine the effectiveness of this treatment. Nearly 32,000 subjects would be needed to effectively study IWA given the low incidence of SSI and a 30% risk reduction.