Spinal Cord Stimulation Infection Rate and Risk Factors: Results From a United States Payer Database.

OBJECTIVE: Surgical site infections can cause negative clinical and economic outcomes. A recent international survey on Spinal Cord Stimulation (SCS) infection control practices demonstrated low compliance with evidence-based guidelines. This study defines infection rate for SCS implants and identifies infection risk factors.

MATERIALS AND METHODS: A retrospective analysis of the MarketScan® Databases identified patients with SCS implant (2009-2014) and continuous health plan enrollment for ≥12-months (12 m) preimplant. For logistic regression analysis, patients were enrolled for 12 m postimplant. Kaplan-Meier and Cox Proportional Hazard survival analyses assessed time to infection, with infection rate reported at 12 m postimplant. Logistic regression characterized risk factors based on demographics, comorbidities, and clinical characteristics.

RESULTS: In the logistic regression (n = 6615), 12 m device-related infection rate was 3.11%. Infection risk factors included peripheral vascular disease (OR, 1.784; 95% CI: 1.011-3.149; p = 0.0457) and infection in 12 m before implant (OR, 1.518; 95% CI: 1.022-2.254; p = 0.0386). The odds of patients experiencing an infection decreased by 3.2% with each additional year of age (OR, 0.968; 95% CI: 0.952-0.984; p < 0.0001). Survival analysis (n = 13,214) identified prior infection (HR, 1.770; 95% CI: 1.342-2.336; p < 0.0001) as a risk factor. Infection was less likely in older patients (HR, 0.974; 95% CI: 0.962-0.986; p < 0.0001). Expected risk factors including obesity, diabetes, and smoking were not identified as risk factors in this analysis. There was no significant difference between infection rate for initial and replacement implants.

CONCLUSIONS: The 3.11% SCS-related infection rate within 12 m of implant emphasizes the need for improved infection control practices. Research is needed to limit SCS infections in younger patients and those with infection history.