[Synovial cyst of the intervertebral joint as cause of a lumboradicular syndrome].

Synovial cysts of various joints and tendon sheaths (knee, elbow, hip, proximal interphalangeal joints are well known. Cysts arising from the zygapophyseal joints however are rare, but not unknown. 3 patients with lumbosciatic pain, due to nerve root compression by a synovial cyst of the zygapophyseal joints are described. The age ranged from 54 to 77 years. There are 2 men and 1 woman. The symptoms and signs involved the fourth (1 patient) and fifth (1 patient) lumbal nerve root and the first sacral nerve root (1 patient). X-rays showed degenerative changes of the facet joints in 2 cases and spondylolisthesis in 1 case. Myelography revealed compression of the fifth lumbar and the first sacral nerve root, but did not allow to make the exact diagnoses. CT scans however made the diagnoses possible in all 3 cases. Treatment was surgical excision of the cyst in 2 cases, 1 patient showed pain relief after steroid-infiltration in the affected facet joint.