Synovial chondromatosis presenting with lumbar radiculopathy.

STUDY DESIGN: A case report of lumbar synovial chondromatosis with radiculopathy.

OBJECTIVE: To report a case of synovial chondromatosis of a lumbar facet joint that extended into the spinal canal and compromised the lumbar nerve root and raised spinal surgeons' awareness of the possibility of this unusual clinical problem.

SUMMARY OF BACKGROUND DATA: Synovial chondromatosis is an uncommon disorder characterized by the formation of multiple cartilaginous nodules in the synovium of a facet joint. It most commonly affects large joints. Synovial chondromatosis in the spine is rare and there is no previous report of associated lumbar radiculopathy.

METHODS: A 24-year-old woman presented with low back pain and right sciatica lasting 5 months. There was no objective weakness. Computed tomography scans showed multiple calcified nodules anterior and medial to the right apophyseal joint of L5-S1 and extending into the spinal canal. Magnetic resonance imaging showed a lobulated, heterogeneous enhancing extradural mass arising from the anteromedial aspect of the right L5-S1 facet joint. The lesion was removed in multiple pieces with curette after exposure of the corresponding intervertebral space through a conventional interlaminar approach. The histologic examination showed nodules of hyaline cartilage beneath the synovial cell lining.

RESULTS: The patient was completely free of low back pain and right sciatica 5 days after the surgery. All neurologic tests were normal from that point onwards.

CONCLUSION: Synovial chondromatosis may compromise lumbar nerve roots when it extends into the spinal canal from the facet joint. Although synovial chondromatosis of the lumbar spine is rare, it should be included in the differential diagnosis of radiculopathy.