Efficacy and Limitations of Continuous Local Antibiotic Perfusion in Treating Surgical Site Infections Following Instrumented Spinal Surgery: A Retrospective Multicenter Study

Introduction: Surgical site infection (SSI) is one of the most serious postoperative complications following instrumented spinal surgery. We previously reported the potential of continuous local antibiotic perfusion (CLAP) to retain implants for patients with SSI following instrumented spinal surgery. We conducted a retrospective multicenter study to elucidate the efficacy and limitations of CLAP for patients with SSI following instrumented spinal surgery.

Methods: A total of 40 patients treated with CLAP for SSI after instrumented spinal surgery were included in this study. The implant retention rate was calculated. We investigated the influence of age, presence of diabetes, number of fused vertebrae, causative pathogens, duration from diagnosis to CLAP initiation, white blood cell (WBC) count (× 10³/μL), and C-reactive protein (CRP) level on the development of SSI after CLAP. Patients were divided into two groups: a favorable outcome group (n = 28), in which SSI was promptly controlled after CLAP, and a poor outcome group (n = 12), in which additional surgery was required or fatal outcomes occurred after CLAP. The relationship between these two groups was evaluated.

Results: In 13 of 40 patients, implants had already been removed before CLAP initiation. Excluding these cases, control of SSI with implant retention was achieved by CLAP in 22 of 27 patients (81%). In the poor outcome group, antibiotic-resistant pathogens were detected at a higher rate than in the favorable outcome group (p = 0.022), and the WBC counts at 1 week after CLAP were significantly increased compared with the favorable outcome group (poor outcome group 7.7 ± 2.4, favorable outcome group 5.8 ± 1.6; p = 0.013).

Conclusions: Application of CLAP enabled SSI control with a high rate of implant retention. However, detection of antibiotic-resistant pathogens and increased WBC count 1 week after initiating CLAP may predict poor control of SSI, even after CLAP.