Abstract
A 62-year-old man who had been treated for lumbar canal stenosis developed right buttock pain after he was injured by falling off a bicycle. Findings on radiography, computed tomography, magnetic resonance imaging, and bone scintigraphy were normal except for slight narrowing of the right L4/5 intervertebral foramen. The Freiberg and Pace tests were both positive. Right sciatic nerve block (parasacral) and right L4 nerve root block resulted in marked alleviation of the right buttock pain, but no obstruction of the contrast medium was noted in the L4/5 intervertebral foramen. Piriformis muscle resection was performed with a diagnosis of piriformis syndrome, resulting in immediate relief of the right buttock pain, and the patient was discharged without recurrence. Piriformis syndrome requires differentiation from conditions including lumbar spinal disorders and tumoral diseases of the pelvic region. The disorder in this patient was diagnosed based on physical findings and the results of multiple nerve blocks, and pain was relieved by surgery.
