Study design:

Systematic review and meta-analysis.

Objective:

To determine a pooled incidence rate for deep SSI, and compare available evidence for deep surgical site infection (SSI) management among instrumented spinal fusions.

Summary of background data:

Deep SSI is a common complication of instrumented spinal surgery associated with patient morbidity, poorer long-term outcomes, and higher healthcare costs.

Methods:

We systematically searched Medline and Embase, and included studies with an adult patient population undergoing posterior instrumented spinal fusion of the thoracic, lumbar or sacral spine, with a reported outcome of deep SSI. The primary outcome was the incidence of deep SSI. Secondary outcomes included persistent deep SSI following initial debridement, mean number of debridements, and microbiology. Subsequent meta-analysis combined outcomes for surgical-site infection using a random-effects model and quantified heterogeneity using the χ2 test and the I2 statistic. Additionally, qualitative analysis of management strategies was reported.

Results:

Of 9087 potentially eligible studies, we included 54 studies (37 comparative, 17 non-comparative). The pooled SSI incidence rate was 1.5% (95% CI, 1.1% to 1.9%) based on 209,347 index procedures. Up to 25% of patients (95% CI 16.8% to 35.3%), had a persistent infection. These patients require an average of 1.4 (range: 0.8-1.9) additional debridements. Infecting organisms were commonly gram-positive and among them, staphylococcus aureus was the most frequent (46%). Qualitative analysis suggests implant retention, especially for early deep SSI management. Evidence was limited for other management strategies.

Conclusions:

The pooled incidence rate of deep SSI post-thoracolumbar spinal surgery is 1.5%. The rate of recurrence and repeat debridement is at least 12%, up to 25%. Persistent infection is a significant risk, highlighting the need for standardized treatment protocols. Our review further demonstrates heterogeneity in management strategies. Large-scale prospective studies are needed to develop better evidence around deep SSI incidence and management in the instrumented thoracolumbar adult spinal fusion population.