Post-operative spondylodiscitis.

Postoperative spine infections (PSIs) are a frequent and dreaded complication of spine surgery. Although different studies have been published, the prevalence of PSIs is thought to be about 5% for most spine surgical procedures. Different risk factors have been identified for PSIs. Among the others, extensive soft tissue dissection, longer operative time, soft tissue devitalization, and use of surgical instrumentation have been associated with higher risks of infection. Direct inoculation during surgery is the common infection route for PSIs. Gram-positive cocci (such as Staphylococcus aureus, Staphylococcus epidermidis and beta-hemolytic streptococci) are the most common pathogens. Gram-negative bacteria also play a role in PSIs and may be associated with systemic illness and multisystem organ failure. A high level of suspicion is of paramount importance in early diagnosis of PSIs. Clinical symptoms of PSIs may be subtle and the infection may become apparent only in its late stages. Early diagnosis is the most important prognostic factor for PSIs. Although blood tests (i.e. ESR, CRP, and white blood cell count) and imaging studies (most commonly MRI) can be useful, it must be clear to the clinician that diagnostic modalities, either tissue biopsy or blood cultures, are of the utmost importance for diagnosing PSIs and devising a correct antibiotic therapy. Antibiotic therapy with early bracing (or bed rest) is the most commonly used treatment method for PSIs. Nevertheless, a more aggressive surgical treatment may be required in some patients. The goals of surgical treatment are to help the eradication of the infection, provide an adequate wound closure, and maintain spine column mechanical stability.