Surgical site infection rate in spine surgery, incidence, and risk factors: a ten-year retrospective cohort review in a developing neurosurgical centre.

Background/objective: Surgical site infection (SSI) is the third common complication in spinal surgery and often results in poor clinical outcomes, prolonged hospital stays, and additional costs. This study estimated the incidence of SSI and identified risk factors in spine surgeries done within 10 years.

Methodology: This was a retrospective cohort review of all patients who had spine surgery between January 2014 and December 2023. Patients' hospital records were retrieved, and relevant biodata and clinical information were obtained and entered into the Statistical Product and Service Solutions version 25. The incidence of SSI was computed and presented as a percentage, and a multivariable analysis to assess risk factors for SSI was done using the chi-square test and Fisher's exact test. The level of significance was set at a p-value < 0.05 and a 95% Confidence Interval.

Results: The incidence of SSI was 11.7%; (24/206), predominantly caused by Staphylococcus Aureus (37.5%,P = 0.01) and largely (70%) occurred among patients admitted ≤ 48 h before surgery. The majority were superficial incisional SSIs (19/24,79.2%). They occurred commonly among patients operated for spondylotic disease (13/67,19.4%) and bacterial spondylitis (one out of the two patients) compared to the other spinal pathologies (p = 0.042). Similarly, infection rates were significantly higher in surgeries performed at the lumbar (14/63,22.2%) and thoracolumbar junction (4/31, 12.9%) compared to the cervical and thoracic spine (p = 0.009). This was found to increase the odds of developing SSI by 2.2 times (odds ratio: 2.20;CI:1.38-3.47, P = 0.001), The median duration of hospital stay was 36.5 days for patients with SSIs versus 23 days for patients without SSI (p = 0.008).

Conclusion: This study found a relatively high incidence of SSI, which was predominantly superficial incisional SSI, caused by Staphylococcus Aureus, particularly among patients admitted within 48 h before surgery. Significant risk factors for these infections are patients operated on for spondylotic disease and those who had lumbar or thoracolumbar spine surgeries.