"Spinolith": case report of a loose body in the spinal canal

Case report. A hitherto unreported finding of a bony loose body found lying in the spinal canal causing spinal canal stenosis is presented.

A 68-year-old, fit man presented with a history of progressive neurologic claudication and neurologic deficit in both his lower limbs. Clinical examination revealed excellent range of movements in his lumbar spine and bilaterally normal straight leg raising. He had no significant pain in his back. Neurologic examination showed affection of L5 and S1 dermatomes and myotomes bilaterally. Magnetic resonance imaging scan showed severe localized lumbar spinal stenosis at L4-L5. In the absence of any obvious pathology on the scan, it was presumed that the stenosis was the result of infolding of the redundant ligamentum flavum. His walking distance and neurologic deficit continued to deteriorate, although sphincters were not involved. He underwent a posterior spinal decompression of L4-L5. On performing the laminectomy an ovoid and well-defined pearly white loose body was discovered lying loose in the spinal canal causing stenosis. Histologically, the loose body consisted of trabecular bone with areas of cartilage. The patient made a speedy recovery after surgery and was back to his previous level of activity within a month.

Several different types of foreign body have been identified in the spinal canal. However, this case of an autologous loose body in the spinal canal causing symptomatic canal stenosis is unique. Because the authors could not identify the source of this loose body, they have termed it "spinolith."