Synovial cyst in the cervical spine is a very rare pathology that develops from the facet joint. When a synovial cyst emerges into the surrounding space, it can compress the nervous tissue and cause neurological symptoms. In the cervical area there is additionally the risk of spinal cord compression comparing to the more common presentation of synovial cysts in the lumbar spine.

A literature review identified 35 studies with 89 previously reported cases of surgically treated subaxial cervical juxtafacet cysts (JFCs) ¹⁾.

Retroodontoid synovial cyst

Numerous theories have been established to explain the pathogenesis of synovial cyst. Biomechanical alterations of the spine play a significant role in the development of synovial cyst. However, the etiology is still unclear ²⁾.

At given cervical spinal levels, synovial cysts probably share clinical features with disc herniation and stenosis.

A rare case of a synovial cyst in the lower cervical spine presented as Brown Séquard syndrome

No previous report has been issued in the English literature on a synovial cyst presenting with Brown-Séquard syndrome. Neurologic function recovered completely after complete removal of the cyst and expansive laminoplasty ³⁾.

Uschold et al. advocate for early decompression rather than prolonged conservative treatment, for pre- and postoperative dynamic imaging, and for fusion in selected cases as an initial surgical consideration ⁴⁾. ⁵⁾.

A cervical synovial cysts from the left facet joint grew into the spinal canal and compressed the C8 nerve root which led to root compressing symptoms. Interestingly Breckwoldt et al. found this synovial cyst with congenital fusion and identified only nine similar cases in the literature. The cyst was removed surgically and the patient discharged without complications ⁶⁾.