An Algorithmic Approach Including Local Antibiotic Delivery for Spine Infection Treatment: Outcomes at 1 Institution

Multiple treatment strategies for spine infections exist, including systemic antibiotic therapy alone or in conjunction with debridement surgeries. However, data on algorithmic approaches tailored to infection type and severity are limited. Furthermore, local antibiotic delivery using a dissolvable calcium sulfate carrier, which has been shown to be effective in treating other orthopedic infections, has been sparsely reported in spine infection treatment.

A retrospective analysis of 119 surgically managed spine infection cases (2016-2020) was performed to determine (1) the proportion of patients achieving infection resolution with institutional protocols incorporating calcium sulfate biodegradable beads, (2) risk factors for treatment failure, (3) prevalence of bead-associated adverse effects, and (4) microbiological profiles of treated infections. Patients were treated according to institutional protocols, including aggressive debridement, instrumented stabilization when instability is present, local antibiotic bead placement, and chronic, systemic antimicrobial therapy. Univariate logistic regression assessed associations between patient, operative, and infection characteristics with treatment failure odds.

Tobramycin/vancomycin-loaded calcium sulfate biodegradable beads were the most common type used. Among 119 patients, 81.5% achieved infection resolution without recurrence. Sixteen patients experienced infection recurrence, and 6 patients died of sepsis. Acute kidney injury and acute liver injury were significantly associated with treatment failure. A significant association was observed between calcium sulfate bead volume and risk of transient hypercalcemia, though all cases resolved without bead removal. The most commonly treated infections were polymicrobial.

This study suggests that calcium sulfate antibiotic beads, when incorporated into an algorithmic approach, facilitate successful infection eradication with minimal systemic toxicity. Careful patient selection and dose limitation are essential to mitigate potential adverse effects.

The use of biodegradable calcium sulfate beads in an algorithmic treatment approach achieves successful infection eradication with little evidence of antibiotic bead-induced systemic toxicity. Bead volume should be minimized to reduce hypercalcemia risk. Patients with acute kidney injury or acute liver injury may require more aggressive treatment.

Level 4 (therapeutic study).