An unusual cause of low back pain. Osteomyelitis of the spinous process

STUDY DESIGN: A case report of osteomyelitis of the spinous process. OBJECTIVE: To describe the diagnosis and successful treatment of a patient with spinous process osteomyelitis. SUMMARY OF BACKGROUND DATA: Spinous process osteomyelitis is exceedingly rare and may be misdiagnosed as paraspinal muscle strain, discitis, or vertebral body osteomyelitis. The clinical presentation of spinous process osteomyelitis is subtle, laboratory findings are nonspecific, and radiographs are often normal. METHODS: The diagnosis, treatment, and outcome of two patients with spinous process osteomyelitis (an adult and a child) with insidious, nonspecific lumbar pain and fever are reviewed. RESULTS: Magnetic resonance imaging with and without gadolinium enhancement demonstrated increased signal of the spinous process with paraspinous musculature enhancement, a finding consistent with spinous process osteomyelitis. Biopsy results demonstrated the presence of staphylococcus aureus in the child and no organisms in the adult. Treatment with intravenous antibiotics led to resolution in both cases. CONCLUSIONS: The use of magnetic resonance imaging technology permitted the early and accurate diagnosis of spinous process osteomyelitis.