Risk Factors for Surgical Site Infections and the Effects of Betadine Irrigation and Intrawound Vancomycin Powder on Infection Rates in Spine Tumor Surgery.

Background Surgical site infection (SSI) following spine tumor surgery results in delays in radiation therapy and the initiation of systemic treatment. The study aims to assess risk factors for SSI in malignancy-related spinal infections and rates of infection observed in a single center with the use of betadine irrigation (BI) and intrawound vancomycin powder (IVP).  Methods Spine tumor patients managed from 11/2012 to 11/2023 were identified using a surgical database (JotLogs, Efficient Surgical Apps, Portland, Maine). Inclusion criteria were patients receiving BI and IVP and alive at 30 days post-op. Exclusion criteria were patients not receiving a combination of BI and IVP due to allergies and mortality within 30 days of surgery. Patient demographics, histology, history of pre-operative and post-operative radiation treatment history, tumor location, procedure type, number of procedures per patient, SSI, wound culture results, and mortality were collected. Results One hundred two patients undergoing 130 procedures had an SSI rate of 3.85% (5/130). There were 18.6% primary and 81.4% metastatic tumors. Demographics were average age 59.5 years old (range 7-92), 60.8% male, 39.2% female, White 88.2%, Black 9.8%, and others 2%. Pre-operative radiation therapy was significantly associated with the risk of SSI (p=0.005). Percutaneous instrumentation did not lead to a significant difference in infection rates (p=0.139). There was no significant difference in infection rates between primary and metastatic tumors (p=0.58). Multivariable regression analysis revealed pre-operative radiation (OR: 18.1; 95%CI: 1.9-172.7; p=0.009) as the statistically significant independent risk factor. Conclusions Pre-operative radiation therapy remains a risk factor for SSI. However, percutaneous instrumentation did not lead to SSI, and there was no significant difference in infection rates between primary and metastatic tumors. SSI rate was 3.85% in patients who had a combination of BI and IVP in spine tumor surgery.