Prolonged Surgical Drain Retention May Be Protective Against Surgical Site Infection in Patients with Traumatic Spine Injuries Undergoing Posterior Spinal Fusion

Introduction: Surgical site infections (SSIs) are common following spinal surgery. Multiple independent risk factors have been identified including obesity, multiple levels of fusion and diabetes for conferring increased risk of SSI. There have been several studies investigating the association between postoperative surgical site drain use and SSI in elective spine surgery. However, no studies have evaluated trauma patients undergoing spinal fusion, who are known to have elevated risk of SSI.

Methods: Records of 149 patients undergoing PSF following traumatic spinal injury at our level 1 safety-net trauma center between 2016-2021 were collected. Trauma patients undergoing PSF by a single surgeon were retrospectively reviewed. A log rank test was used to test for associations between duration of surgical drain usage and incidence of SSIs. Additionally, a Cox proportional hazards model was used as an adjusted model.

Results: The overall infection rate was 13% and the average drain was placed for 4.32 days (IQR: 3-5). When controlling for age, sex, BMI, smoker status and diabetic status in a multivariate analysis, male sex (HR 0.188; CI 5%: 0.068; CI 95%: 0.518; p = 0.001) and drain placement > 6 days (HR 0.057; CI 5%: 0.006; CI 95%: 0.539; p = 0.013) was associated with decreased SSI. Multivariate analysis also revealed increased risk of SSI associated with patients whose BMI > 30 (HR 1.076; CI 5%: 1.014; CI 95%: 1.142; p = 0.015), and in whom > 5 vertebral levels were fused during the operation (HR 3.943; CI 5%: 1.378; CI 95%: 11.282; p = 0.011).

Conclusion : Prolonged surgical drain retention (> 6 days) and male sex may be associated with decreased rates of SSIs. Patients with BMI > 30 and those who underwent > 5 levels of spinal fusion were found to have significantly increased rates of SSIs.