P13. Efficacy and limitations of continuous local antibiotic perfusion for patients with surgical site infection after instrumented spinal surgery; a retrospective multicenter study

Background Context

Surgical site infection (SSI) is one of the most serious postoperative complications following spinal instrumented surgery. We previously reported the potential of continuous local antibiotic perfusion (CLAP) to retain the implants for SSI after spinal instrumented surgery (J Clin Neurosci, 2021). Nonetheless, the effectiveness and limitations of CLAP for patients with SSI after spinal instrumented surgery remain unclear.

Purpose

To elucidate the efficacy and limitations of CLAP for patients with SSI after spinal instrumented surgery.

Study Design/Setting

A retrospective multicenter case series study.

Patient Sample

A total of 40 patients treated with CLAP for SSI after spinal instrumented surgery were included in the present study.

Outcome Measures

The ratio of implant retention was calculated. We examined factors including age, sex, presence of diabetes, type of surgery (primary or revision), surgical level (cervical or thoracolumbar), number of fused vertebrae, pathogen causation, duration from diagnosis to CLAP installation, and temporal changes in white blood cell count (WBC; x10³/μL) and C-reactive protein (CRP) based on blood test results.

Methods

Patients were categorized into 2 groups: a favorable outcome group of 28 patients where SSI was promptly controlled after CLAP and a poor outcome group of 12 cases where additional surgery was required or resulted in fatal outcomes after CLAP. The correlation between the two groups was assessed and risk factors contributing to poor outcomes after CLAP were analyzed.

Results

Among the 40 patients, implants have been removed before CLAP installation in 12 cases. Except for these cases, CLAP achieved successful control of SSI with implant retention in 25 out of 28 patients (89%). Only two patients experienced uncontrolled SSI even after CLAP, resulting in the removal of all implants. Across all cases, a significant improvement in both WBC and CRP levels was observed one week after CLAP (p<.01). In the poor outcome group, the proportion of elderly patients aged over 75 years was significantly higher (p=.01), antibiotic-resistant pathogens were detected more frequently (p=.022), and the WBC value at 1 week after CLAP (poor group: 7.7±2.4, favorable group: 5.8±1.6) was significantly elevated (p=.013) compared to the favorable group. Multivariate analysis showed the above three parameters were the independent risk factors contributing to poor outcomes after CLAP.

Conclusions

CLAP proved effective in achieving a high rate of implant retention for controlling SSI after spinal instrumented surgery. However, poor outcomes following CLAP were associated with factors such as advanced age, antibiotic-resistant pathogens, and inadequate improvement in WBC values one week after CLAP.

FDA Device/Drug Status

This abstract does not discuss or include any applicable devices or drugs.