Post Operative Infection following Multi-level Posterior Lumbar Spinal Instrumentation in the Vancomycin Powder Era

Introduction: Since the early 2010s, the use of prophylactic vancomycin powder has become commonplace in spine surgery, with many surgeons attributing low surgical site infection (SSI) rates (1-2%) to its application. However, some studies have challenged these estimates, and there remains ongoing debate within the neurosurgical community regarding the true efficacy of prophylactic vancomycin powder use.

Methods: The TriNetX Research Network was queried to identify adult patients who underwent posterior spinal instrumentation at more than three levels with a preoperative diagnosis of lumbar spinal stenosis or spondylolisthesis. Postoperative wound infections requiring incision and drainage were identified through corresponding procedural and diagnostic codes within 90 days of the index surgery. The patient population was divided into two cohorts: (1) those who underwent surgery between January 1, 2003, and December 31, 2013, and (2) those who underwent surgery between January 1, 2014, and December 31, 2023. Propensity matching was performed based on age at surgery, gender, race, and selected comorbidities. The primary outcome was the incidence of incision and drainage for postoperative wound infections. The secondary outcome was a composite rate of postoperative infection.

Results: A total of 30,362 patients met the inclusion criteria (mean age at surgery: 63.8 years [SD, 11.0]; 13,054 [42.99%] male), with 26,225 (86.37%) undergoing surgery between 2014 and 2023, and 4,137 (13.63%) between 2003 and 2013. After propensity matching, each cohort contained 4,135 patients, with no significant differences in age at surgery, gender, race, or selected comorbidities between the two groups. Among these propensity-matched cohorts, patients who underwent surgery between 2014 and 2023 had significantly lower odds of requiring incision and drainage (OR = 0.553) and of developing postoperative infections (OR = 0.489).

Conclusion : This large-scale, retrospective, propensity-matched analysis indicates that the likelihood of developing a postoperative infection or requiring incision and drainage following multi-level posterior lumbar spinal instrumentation is approximately 50% lower during the era of vancomycin powder use compared to the period before its widespread adoption. These findings suggest that prophylactic vancomycin powder may be an effective strategy to reduce postoperative infections in patients undergoing multi-level posterior lumbar spinal instrumentation, potentially enhancing surgical outcomes and lowering healthcare-associated costs.