Introduction: Surgical Site Infection (SSI) in spinal surgery at the James Cook University Hospital was investigated and compared with the published rates of 1 – 12%. Variables of instrumentation, laminar air flow, duration of operation, and blood units transfused in the first 48 hours were examined.

Methods: 556 spinal operations were carried out in 2005–6. 147 of these involved the use of instrumentation. Infections were defined as positive wound or blood cultures. The duration of surgery, presence of laminar air flow and units of blood transfused were recorded. Statistical analysis was performed using Fishers exact test.

Results: 9 cases of SSI were identified in the 147 instrumented spinal operations in comparison to zero in the 409 non-instrumented patients (p < 0.0001).

The mean duration of surgery was 4 hours 19mins. The results for operation duration < 5hours vs. operation duration > 5hours (3/96 vs 6/51) were not statistically significant. (p=0.065)

Of the 147 instrumented spinal operations, 8 of the infected were performed in a laminar air flow system and 1 without (not statistically significant, p=0.69).

The results for blood transfusion < 2units vs. blood transfusion ≥2 units (4/85 vs 5/62) were not significant (P=0.49).

Conclusion: The rate of SSI at the James Cook University Hospital in instrumented spinal surgery was 6%.

SSI in spinal surgery was heavily influenced by instrumentation, but was not reduced by laminar airflow. Duration of operation and number of units of blood transfused were not significant factors.