Zhou J, Wang R, Huo X, Xiong W, Kang L, Xue Y.

Spine (Phila Pa 1976). 2020;45(3):208-216.
doi:10.1097/BRS.0000000000003218

Summary by Jennifer Z. Mao, MBA

Surgical site infection (SSI) is a common, preventable health-associated complication that has a wide range of reported incidences in the spine literature.¹ SSI is the third most common complication after spine surgery, and a frequent reason for readmission.^2,3 SSI can lead to poor outcomes and additional costs.⁴ Risk factors for developing a SSI include diabetes, obesity, hypertension, transfusion, CSF leak and increased duration of surgery. Although many studies have reported the incidence and risk factors of SSI after spine surgery, no meta-analysis has been conducted. The purpose of the study conducted by Zhou et al. was to investigate the literature on the incidence of SSI following spine surgery and examine the microorganisms of spinal SSI.^5-10

The authors conducted a systematic search of English articles across three databases for studies reporting SSI after spine surgery. The meta-analysis included 22,475 patients from 27 studies. The overall pooled incidence of SSI using a random-effects model was 3.1% (95% CI 2.3 – 4.3%). The incidence in the thoracic spine (3.7%) was marginally higher than cervical (3.4%) and lumbar spine (2.7%). The incidence of superficial (1.4%) and deep (1.7%) infections were comparable. Anterior surgical approaches demonstrated a lower incidence than posterior approaches (2.3% vs. 5.0%). Minimally invasive surgery (1.5%) had a lower SSI incidence than open surgery (3.8%). SSI rates were higher with instrumentation than without (4.4% vs. 1.4%). There was a lower incidence of SSI when vancomycin powder was applied during the surgery (1.9%) compared to without (4.8%). In the elderly population, the incidence was 3.6%, but was only 2.5% in those younger than 60 years old. Patients with normal BMI had an incidence of 3.3%; for those >25 kg/m² the incidence was 2.9%. The incidence of SSI was 3.6 times less in those who were in surgery for less than 3 hours (1.3%) compared to those who were in surgery for more than 3 hours (4.7%). The most common microorganism was Staphylococcus aureus and other members of the Staphylococcus species:^11,12 Staphylococcus aureus (37.9%), Staphylococcus epidermidis (22.7%), methicillin-resistant Staphylococci (23.1%).

The results of the study are useful in estimating the probability of SSI development after spine surgery. However, the study poses some limitations. There was substantial heterogeneity within the overall incidence, which varied from 0.2 to 16.1%. Not all included studies were designed for incidence statistics, and diagnostic criteria for SSI were not consistent across all studies. The authors believe this may lead to a degree of bias.

References:

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2. Napolitano F, Tomassoni D, Cascone D, Di Giuseppe G, Group TCW. Evaluation of hospital readmissions for surgical site infections in Italy. European Journal of Public Health. 2017;28(3):421-425.
3. Zhou J, Wang R, Huo X, Xiong W, Kang L, Xue Y. Incidence of Surgical Site Infection After Spine Surgery: A Systematic Review and Meta-analysis. Spine (Phila Pa 1976). 2020;45(3):208-216.
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