Cervical Synovial Cyst Causing Cervical Radiculomyelopathy: Case Report and Review of the Literature

Study Design Case report. Objective Synovial cysts in the subaxial cervical spine are rare and are most commonly reported at the cervicothoracic junction. Only six cases of symptomatic C5-C6 synovial cysts have been reported in the literature; the condition is usually treated with decompressive laminectomy. We present a patient with a synovial cyst arising from the C5-C6 facet joint, associated with spondylolisthesis, and causing radiculomyelopathy. The patient was treated with a posterior excision of the cyst, decompressive laminectomy, and fusion. Methods A 67-year-old man had vertebral canal stenosis at C5-C6 secondary to a synovial cyst and spondylolisthesis with symptoms and signs of radiculopathy and myelopathy. Surgical management involved C5-C6 posterior decompressive laminectomy and excision of the cyst and C4-C6 instrumented fusion with lateral mass screws and rods. A literature review of symptomatic cervical synovial cysts is presented. Results The imaging studies identified grade I spondylolisthesis and a 3.3 × 4.3-mm extradural lentiform-like mass associated with focal compression of the spinal cord and exiting the C6 nerve root. After the surgery, the patient had an immediate full recovery and was asymptomatic by the 6-month examination. No operative complications were reported. The histologic report confirmed the presence of a synovial cyst. Conclusions C5-C6 is an unusual localization for symptomatic synovial cysts. Similar cases reported in the literature achieved excellent results after cyst excision and decompressive laminectomy. Because spondylolisthesis plus laminectomy are risk factors for segmental instability in the cervical spine, we report a case of a C5-C6 facet synovial cyst successfully treated with posterior laminectomy and C4-C6 fusion.