Juxtafacet Cysts as a Cause of Low Back Pain

A case of persistent low back pain occurring in association with facet joint synovial cysts is presented. A history of low back pain and negative plain radiographs illustrate the nonspecific nature of the problem these cysts cause. Magnetic resonance imaging (MRI) clearly demonstrates the presence of lumbar facet joint cysts. Our patient underwent a L5-S1 laminectomy prior to presenting with a new episode of low back pain. Workup, including computed tomography (CT) scan and MRI, confirmed the presence of bilateral synovial cysts at the L4-5 level. Our patient exhibited a partial clinical improvement after surgical excision of bilateral facet joint cysts.

Intraspinal synovial or ganglion cysts of the facet joints are rarely diagnosed. They originate from the synovium of the facet articulation. They can be a source of low back pain¹ and present an important diagnostic and therapeutic challenge. Their presence can be easily overlooked using standard radiological techniques² which may only demonstrate nonspecific degenerative changes such as disc space narrowing and osteophytes. If the patient undergoes surgery and the cyst is not identified preoperatively, the patient may be left with persistent back pain. Computed tomography scan and myelogram have been shown to demonstrate cystic lesions with calcified walls typical of facet joint cysts.^3,4 In our case MRI definitively identified what was suspected on the CT scan. It is proposed that MRI is also a valuable, if not better imaging technique of the identification of these cysts.