Effect of Intrawound Vancomycin Powder on the Pathogen Spectrum and Antimicrobial Susceptibility of Postoperative Infections in Elective Lumbar Fusion

This is a secondary microbiological analysis of a randomized trial of 292 patients undergoing elective posterior lumbar interbody fusion, comparing standard IV antibiotics alone versus IV antibiotics plus 1g of intrawound vancomycin powder. Among the 22 patients who developed any surgical site infection, gram-positive organisms still dominated in both groups (87.5% control vs 100% vancomycin, p=1.000), all tested isolates remained fully vancomycin-susceptible, and rates of non-wound infections like UTIs were similar between groups (5.3% vs 4.3%, p=0.788).

AI summary · from the full text · reviewed by Pukhraj Gaheer, Medical Student, Queen's University before publishing

Why it mattersMany spine surgeons already use intrawound vancomycin powder for SSI prophylaxis, and this trial addresses a lingering safety worry from retrospective data that it might shift infections toward resistant or gram-negative organisms.

Presenting this at rounds? Start here

• ?If gram-positive organisms and preserved vancomycin susceptibility remain the norm regardless of intrawound vancomycin use, should empiric antibiotic choice for suspected post-fusion SSI change at all based on prophylaxis history?
• ?Given the very small number of culture-positive infections in this cohort, how much weight should surgeons place on this reassurance when deciding whether to continue routine intrawound vancomycin powder in lumbar fusion?