An Algorithmic Approach Including Local Antibiotic Delivery for Spine Infection Treatment: Outcomes at One Institution

Introduction Spine infections represent a heterogeneous group of conditions with variable management strategies and no widely accepted standardized treatment algorithm. Local antibiotic delivery using biodegradable calcium sulfate beads has demonstrated efficacy in other orthopedic infections but remains underreported in spine infection management. This study evaluates the safety and effectiveness of an institutional algorithm incorporating antibiotic-impregnated calcium sulfate beads. Methods A retrospective review of 119 consecutive patients who underwent surgical management for spine infections between 2016 and 2020 was performed. All patients were treated using a standardized institutional protocol consisting of aggressive debridement, instrumented stabilization when indicated, local antibiotic delivery via calcium sulfate beads, and systemic antimicrobial therapy. Primary outcomes included infection resolution and treatment failure (defined as recurrence or sepsis-related death). Secondary outcomes included risk factors for failure, bead-related adverse effects, and microbiologic profiles. Univariate logistic regression was used to assess associations with treatment failure. Results Infection resolution was achieved in 81.5% of patients. Treatment failure occurred in 18% of cases, including 16 recurrences and 6 sepsis-related deaths. Acute kidney injury (AKI) and acute liver injury (ALI) were significantly associated with treatment failure. The most commonly used antibiotic combination was vancomycin and tobramycin. Polymicrobial infections were most frequent (38%). Transient hypercalcemia occurred in 7% of patients and was significantly associated with increased bead volume, though all cases resolved without intervention. No significant increase in treatment failure was observed with hardware retention or number of debridements. Conclusions An algorithmic approach incorporating antibiotic-impregnated calcium sulfate beads is associated with high rates of infection resolution and low systemic toxicity in spine infection management. Careful patient selection and limitation of bead volume are important to reduce adverse effects. Patients with AKI or ALI may require closer monitoring and more aggressive treatment strategies. Further prospective studies are warranted to validate these findings.