Improvement in Radicular Symptoms but Continued Facet Arthropathy and Axial Back Pain Following Rupture of a Facet Joint Synovial Cyst

Lumbar synovial cysts are benign fluid collections thought to form in a background of facet joint degeneration, allowing for fluid to leak from the joint capsule and form cysts in the synovium. Although often asymptomatic, patients with symptomatic synovial cysts will present with low back pain and possibly an associated radiculopathy. Clinicians can consider conservative management, epidural steroid injection, surgical intervention, or facet joint block with aspiration and rupture. This case describes a 59-year-old male facilities manager with intermittent low back pain for one year with worsening right-sided radicular symptoms secondary to a lumbar facet joint synovial cyst in the context of severe facet arthropathy and microinstability. The patient’s low back pain and radicular symptoms were refractory to conservative treatment. Imaging demonstrated a lumbar synovial cyst and subsequent management included transforaminal epidural steroid injection and facet joint block with cyst aspiration and rupture. The patient’s radicular pain resolved but axial lumbar pain returned after 3 weeks of relief. Follow-up imaging demonstrated decreased cyst size with fluid accumulation and joint space widening. Although the cyst was successfully decompressed with resolution of radicular pain, the underlying facet arthropathy remains contributing to persistent axial low back pain and potential for continued degenerative changes including cyst recurrence.