2021 Young Investigator Award Winner: Anatomic Gradients in the Microbiology of Spinal Fusion Surgical Site Infection and Resistance to Surgical Antimicrobial Prophylaxis.

STUDY DESIGN: Retrospective hospital-registry study. OBJECTIVE: To characterize the microbial epidemiology of surgical site infection (SSI) in spinal fusion surgery and the burden of resistance to standard surgical antibiotic prophylaxis. SUMMARY OF BACKGROUND DATA: SSI persists as a leading complication of spinal fusion surgery despite the growth of enhanced recovery programs and improvements in other measures of surgical quality. Improved understandings of SSI microbiology and common mechanisms of failure for current prevention strategies are required to inform the development of novel approaches to prevention relevant to modern surgical practice. METHODS: Spinal fusion cases performed at a single referral center between January 2011 and June 2019 were reviewed and SSI cases meeting National Healthcare Safety Network criteria were identified. Using microbiologic and procedural data from each case, we analyzed the anatomic distribution of pathogens, their differential time to presentation, and correlation with methicillin-resistant Staphylococcus aureus screening results. Susceptibility of isolates cultured from each infection were compared with the spectrum of surgical antibiotic prophylaxis administered during the index procedure on a per-case basis. Susceptibility to alternate prophylactic agents was also modeled. RESULTS: Among 6727 cases, 351 infections occurred within 90 days. An anatomic gradient in the microbiology of SSI was observed across the length of the back, transitioning from cutaneous (gram-positive) flora in the cervical spine to enteric (gram-negative/anaerobic) flora in the lumbosacral region (correlation coefficient 0.94, P < 0.001). The majority (57.5%) of infections were resistant to the prophylaxis administered during the procedure. Cephalosporin-resistant gram-negative infection was common at lumbosacral levels and undetected methicillin-resistance was common at cervical levels. CONCLUSION: Individualized infection prevention strategies tailored to operative level are needed in spine surgery. Endogenous wound contamination with enteric flora may be a common mechanism of infection in lumbosacral fusion. Novel approaches to prophylaxis and prevention should be prioritized in this population.Level of Evidence: 3.

Evaluation of Appropriate Venous Thromboembolism Prophylaxis in Patients With Orthopaedic Trauma With Symptom-Driven Vascular and Radiographic Studies.

OBJECTIVE: To evaluate venous thromboembolism (VTE) prophylaxis adherence and effectiveness in orthopaedic trauma patients who had vascular or radiographic studies showing deep vein thromboses or pulmonary emboli. DESIGN: Retrospective review. SETTING: A level I trauma center that independently services a 5-state region. PATIENTS: Four hundred seventy-six patients with orthopaedic trauma who underwent operative treatments for orthopaedic injuries and had symptom-driven diagnostic VTE studies. INTERVENTION: The medical records of patients treated surgically between July 2010 and March 2013 were interrogated using a technical tool that electronically captures thrombotic event data from vascular and radiologic imaging studies by natural language processing. MAIN OUTCOME MEASUREMENTS: Patients were evaluated for hospital guideline-directed VTE prophylaxis adherence with mechanical or chemical prophylaxis. Patient demographics, associated injuries, mechanism of injury, and symptoms that led to imaging for a VTE were also assessed. RESULTS: Of the 476 orthopaedic patients who met inclusion criteria, 100 (mean age 52.3 median 52, SD 18.3, 70% men) had positive VTE studies. Three hundred seventy-six (age 47.3, SD 17.3, 69% men) had negative VTE studies. Of the 100 patients with VTE, 63 deep vein thromboses, and 49 pulmonary emboli were found. Eight-five percent of all patients met hospital guideline-VTE prophylaxis standards. CONCLUSION: The study population had better than previously reported VTE prophylaxis adherence, however, patients still developed VTEs. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.