Baastrup's disease correlating with diffuse lumbar paraspinal atrophy: a case report.

Baastrup's disease ("kissing spine") is an x-ray finding that has been considered a possible cause of low back pain (LBP) since the 1930s. Its etiology is unknown, and there are no reports of muscle or soft tissue changes associated with it. This case report concerns a 57-year-old man with chronic LBP, stiffness, and indurated skin over the back. He had classic sclerotic changes between the spinous processes on x-ray, which is consistent with Baastrup's disease. Computed tomography (CT) and electromyography were performed. CT showed profound fatty replacement of the paraspinal musculature. An electromyography report showed severe isolated paraspinal denervation. This case suggests that diffuse fatty replacement of the paraspinal muscles, perhaps due to a compartment syndrome or other vascular event, may have a role in the pathogenesis of Baastrup's disease.