Psoas abscess: the spine as a primary source of infection.

Study Design: Case report, literature review, discussion.
Objectives: To emphasize the role of the spine as primary source of infection for psoas abscess.
Summary of Background Data: Spine-associated psoas abscesses increase with more frequent invasive procedures of the spine and recurring tuberculosis in industrialized countries. Diagnosis is often delayed by misinterpretation as arthritis, joint infection, or urologic or abdominal disorders.
Methods: We present six cases of psoas abscesses associated with spinal infections that were treated in our hospital from January to December 2001. Diagnostic and treatment concepts are discussed.
Results: Our data emphasize the importance of the spine as primary source of infection and suggest an increase in the incidence of secondary psoas abscess. Treatment includes open surgical drainage and antibiotic therapy. In patients with high operative risk and uniloculated abscess, a CT-guided percutaneous abscess drainage can be sufficient. It is essential to combine abscess drainage with causative treatment of the primary infectious focus. Related to the spine, this includes treatment of spondylodiscitis or implant infection after spinal surgery. Usually, several operations are necessary to eradicate bone and soft-tissue infection and restore spinal stability. Continuous antibiotic therapy over a period of 2-3 weeks after normalization of infectious parameters is recommended.
Conclusion: The spine as primary source of infection for secondary psoas abscess should always be included in differential diagnosis. Because the prognosis of psoas abscess can be improved by early diagnosis and prompt onset of therapy, it needs to be considered in patients with infection and back or hip pain or history of spinal surgery.