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Chapter Summary
• Context: Primary spinal infections are relatively uncommon but carry high potential for vertebral destruction, deformity, instability, and neurological deficit. Early recognition is challenging because initial clinical presentations are frequently non-specific: persistent axial pain may precede fever, neurological signs, or clear radiographic abnormalities by weeks. Pathophysiology also varies by age due to differences in intervertebral disc vascularity between children and adults. Infection typically arises from hematogenous dissemination, direct inoculation, or contiguous spread, involving common pyogenic bacteria, opportunistic microorganisms, and specific granulomatous pathogens, notably spinal tuberculosis. This chapter integrates epidemiology, predisposing factors, clinical presentations, laboratory markers, imaging modalities, microbiological identification, and the AO Spine classification. Management is predominantly non-operative, but neurological deficits, progressive deformity, biomechanical instability, epidural abscesses, or medical failure warrant surgical debridement, decompression, and stabilization.
• Chapter Objective: Understand the pathophysiology, epidemiology, clinical presentation, and diagnostic workflow of primary spinal infections; differentiate non-specific pyogenic infections from tuberculous spondylitis; properly utilize laboratory tests, microbiological sampling, and imaging; and identify clinical scenarios where medical therapy suffices versus those requiring surgical debridement, decompression, and mechanical stabilization.
• Pathophysiology and predisposing factorsHematogenous seeding is the primary pathway in spondylodiscitis. In children, persistent vascular channels favor direct disc infection; in adults, the process usually begins in the subchondral bone of the vertebral body and secondarily spreads into the intervertebral disc space. Chronic systemic illness, immunosuppression, advanced age, intravenous drug use, malignancy, and invasive procedures increase host vulnerability. Among pyogenic bacteria, Staphylococcus aureus remains the predominant pathogen.
• Clinical presentation and classificationPersistent back or neck pain is the most frequent symptom, whereas systemic fever is absent in a significant proportion of patients. This dissociation frequently causes diagnostic delays. The chapter presents the AO Spine classification system, which categorizes infection based on anatomical location, infection severity, neurological status, and patient clinical modifiers, integrating structural disease extent with patient vulnerability.
• Multimodal diagnosisInflammatory markers (ESR, CRP) assist in initial suspicion and therapeutic monitoring, but cannot independently confirm or exclude infection. Blood cultures can isolate the pathogen and guide targeted antibiotic therapy. Plain radiographs may remain normal in early disease. CT characterizes osseous destruction and guided biopsy targets, while contrast-enhanced MRI is the reference standard for assessing soft-tissue extent, disc involvement, and neural compression. Table 58.1 compares diagnostic performance, and Figures 58.2 through 58.4 illustrate scintigraphy, CT, and PET-CT.
• Management of non-specific pyogenic infectionsIn the majority of patients, initial management comprises pathogen-directed antibiotic therapy and mechanical bracing. Clinical, biochemical, and radiological trajectories determine treatment response. Surgery is indicated in cases of medical failure, progressive neurological deficit, neural compression, spinal deformity, mechanical instability, or refractory intractable pain. Surgical goals include debriding devitalized tissue, draining abscesses, and restoring spinal stability.
• Spinal tuberculosisTuberculosis of the spine (Pott disease) exhibits an insidious course and can cause extensive bone destruction, kyphotic deformity, and large cold abscesses prior to severe symptoms. Figure 58.5 exemplifies multi-level vertebral destruction associated with a massive cold collection. Microbiological and histopathological confirmation should be actively pursued, but anti-tubercular therapy should not be delayed in strongly suggestive presentations. Prolonged multi-drug anti-TB regimens form the therapeutic core. Surgery is reserved for cord compression, severe kyphosis, or instability.
• Clinical Application: Spinal infection must be considered in the differential diagnosis of persistent back pain, particularly when predisposing factors exist. Normal body temperature or normal leukocyte count should not rule out spondylodiscitis. In the diagnostic workup, blood cultures and inflammatory markers guide initial care, but contrast-enhanced MRI is mandatory to assess neural structures and disease extent. When non-invasive cultures are negative, percutaneous image-guided biopsy should be performed prior to empiric antibiotics whenever clinically safe. Clinical response must be monitored with serial CRP, ESR, and repeat imaging when progression is suspected. Intractable pain, progressive neurological deficit, or severe bone destruction represents structural failure requiring surgical consultation. In tuberculous spondylitis, treatment balances microbiological eradication with structural realignment and spinal stabilization.
