Latent psoas abscess after anterior spinal fusion.

This case is presented to emphasize that late infection should be considered in all postoperative patients as a cause of pain. A psoas abscess may remain dormant for many years after an anterior spinal procedure. It should be considered in the differential diagnosis of back pain and lumbar radiculopathy after anterior spinal fusion. The lumbar nerve plexus lies within the psoas muscle, and referred pain patterns may occur in the lumbar nerve distribution. In this case, dysesthesias occurred in the distribution of the genitofemoral nerve. The diagnosis and treatment of a psoas abscess has been greatly aided by use of CT and ultrasound. Either of these modalities may be used for directed percutaneous drainage of the abscess. The presence of metal fixation devices necessitates removal of the hardware in order to ensure eradication of the infection.