Bilateral synovial cyst of the thoracic spine causing paraparesis

Abstract Spinal synovial cysts are degenerative extradural lesions mostly found in the lumbar region, and more rarely at cervical or thoracic levels and in a bilateral presentation. We report a patient with a history of progressive paraparesis associated with bilateral cervicothoracic synovial cysts, causing spinal canal narrowing and cord compression, ultimately resulting in myelopathy. A review of the literature summarizes previous reports on this topic. Surgical excision of the extradural mass, decompression of the spinal canal and instrumented fusion were performed, improving lower limb deficit and gait. Post-surgical MRI showed evidence of complete cyst resection, and good arthrodesis consolidation with adequate sagittal balance. Surgical excision is indicated in case of medical treatment failure or increasing symptom severity. Given the strong pathophysiological link between synovial cysts and spinal instability, concomitant instrumented fusion may help improve outcome.