Lumbar Extradural Synovial Cyst a Cause of Cauda Equina Syndrome: A Case Report

Synovial cysts (SC) of the spine are defined as cystic swelling of the synovial sheaths commonly occurs in the lumbar region. Most of the patients with lumbar synovial cysts (LSC) usually occur in their fifth to sixth decade of life with a female predominance. The aetiology of LSC is still unclear however strongly associated with spinal instability, facet joint arthropathy and degenerative spondylolisthesis. These can cause myeloradiculopathy due to compression to the spinal cord or the peripheral nerve roots. LSC which not response to conservative therapy should be treated surgically. Surgical excision and decompression with or without fusion and spinal instrumentation remains controversial. This fact collaborates with the aim of this report presentation of an elderly women with LSC complicated with progressive cauda equina syndrome with no history of trauma or associated symptoms. Urgent Magnetic resonance imaging (MRI) was done in our clinic and revealed a single extradural LSC at L4 level and causes L4/5 spinal canal stenosis. We performed complete excision biopsy and posterior instrumentation with decompression for this patient. The neurological status of the patient was immediately improved and no recurrence symptoms on follow-up after one year postoperatively.