Surgical site infection in spinal metastasis: incidence and risk factors

Abstract

Background: Surgical site infection (SSI) in spinal metastasis surgery represents the most common postoperative surgical complication with high morbidity and mortality.

Objective: This study aims to evaluate the incidence of SSI in spinal metastasis surgery and its risk factors.

Study design: This is a retrospective analysis of a prospectively collected data.

Methods: Preoperative, operative, and postoperative data were collected together with the modified Tokuhashi score and Frankel score at all time checkpoints. Surgical site infection was divided into superficial and deep SSI, as well as early (<90 days) and late SSI. Multiple logistic regression analysis was performed to identify independent risk factors, with p<.05 as significance threshold.

Results: A total of 297 patients were included, with an incidence of SSI of 5.1% (superficial SSI: 3.4%; deep SSI: 1.7 %). Cervicothoracic surgery was associated with the highest incidence of SSI, whereas cervical surgery had the lowest incidence. Smoking, higher number of spinal metastasis, elevated body mass index (BMI), and higher ASA (American Society of Anesthesiologist) score were the preoperative factors associated with increased risk of SSI. Increased intraoperative blood loss and increased number of fixed vertebra increased the SSI incidence. SSI increased hospital stay by a mean of 12 days. When all these variables are analyzed in a multiple regression model, only surgical time≥4 hours and ASA≥3 were found to be independent risk factors for the occurrence of SSI.

Conclusion: This paper represents the largest series of spinal metastasis with a mean incidence of SSI of 5.1%. Smoking, higher BMI, higher number of spinal metastasis, higher ASA score, higher number of fused vertebra, intraoperative bleeding≥2000 mL, and neurologic deterioration are risk factors for SSI occurrence. Only ASA≥3 and operative duration≥4 hours are independent risk factors for this complication occurrence. Finally, SSI occurrence is associated with increased hospital stay, increased 30-day mortality rate, and decreased survival rates.

Keywords: Acute infection; Debridement; Fixation; Spinal metastasis; Surgery; Surgical site infection.