Deep spinal infection in instrumented spinal surgery: diagnostic factors and therapy.

AIM: Postoperative surgical site infections (SSI) are complication of spinal surgery. These complications may lead to a poor outcome with neurological deficits, spinal deformity and chronic pain. The purpose of this study is to explore the statistical value of diagnostic parameters and the proper therapy. METHOD: We retrospectively reviewed 550 patients who underwent spinal instrumentation at our department from January 2011 to December 2015. The SSI was present in 16 patients out of 550 operated. Diagnostic criteria of SSI were the positivity of the surgical wound swab or blood culture, the clinical findings, positivity of laboratory tests and radiological elements. All patients had peri-operative antibiotic prophylaxis. Diagnostic laboratory findings were compared with a homogeneous control group of 16 patients and analyzed by univariate statistical analysis with Chi-square test for the discrete variables. P<0,05 was considered statistically significant. RESULTS: Matching the SSI patients with a group of control, fever was not statistically significant for diagnosis as number of leukocytes, neutrophils and lymphocytes. On the contrary values of ESR and CRP were statistically significant with p <0, 01. The hardware was removed only in 3 patients (18%) out of 16 SSI patients. CONCLUSION: In this study the statistically significant parameters to diagnose SSI are ESR and CRP values. The leucocytes count, number of lymphocytes and presence of fever integrates the data of ESR and CRP with no statistical significance. Most patients with SSI reach clinical healing with favorable outcome by means of target antibiotic therapy without hardware removal.