Use of antibiotic-impregnated beads in the treatment of lumbosacral surgical site infection: A retrospective case series.

Background: Different adjuvant local-antibiotic techniques are described in management of surgical-site infections (SSIs). Antibiotic-laden polymethyl methacrylate (PMMA) spacers have been used in peri-prosthetic infections. However, their role in treatment of spinal SSIs is not well-recognised. Methods: After approval from Institutional Review Board, we retrospectively evaluated the data of patients aged≥18 years, who were treated for SSIs of lumbo-sacral region (2010-2019). Among them, those who underwent treatment with the placement of cement beads (temporarily/permanently) were identified. This approach was utilised for post-surgical spondylodiscitis patients with significant, associated infection or abscess involving the paraspinal musculature. Only those with≥2 years' follow-up, were included.Patient demographic details, site of infection, details regarding laboratory/radiological investigations, management-protocol followed, pathogen grown, antibiotics used (their dosage and duration of use), complications encountered and outcome were recorded. Results: 13 patients [4 males, age:57.3 ± 12.4 years] were included. Seven had co-morbidities. One had upper-lumbar involvement, one sacral and others had lower-lumbar (L4/distally) disease. While 7 had recent-onset infection (≤2 months since primary surgery), 6 had chronic infection. In 2, 8, 2, and 1 patients, primary surgery was microdiscectomy, TLIF, PLF, and adult-deformity surgery, respectively.Nine underwent two-staged intervention and 4 underwent single procedure. Eleven had PMMA beads, while 2 underwent calcium sulphate bead insertion. Culture grew E coli in 3, Pseudomonas in 2; and E fecalis, K pneumoniae, MSSA and MRSA in one patient each. In 4 patients, beads were not removed. All patients underwent 2 weeks of parenteral antibiotics, followed by 8-12 weeks of oral medications. There was complete remission in all patients, except one who required additional VAC therapy. Conclusion: Local antibiotic-laden bead application is an effective adjuvant strategy (along with debridement and systemic antibiotics) for the treatment of spinal SSI, where there is substantial infection involving the paraspinal musculature. It is cost-effective and often necessitates second procedure for bead removal.