Facet joint synovial cysts are abnormal fluid-filled cystic formations that develop from a degenerative process of the facet joints. Spinal epidural lipomatosis is a process of excessive accumulation of fat in the epidural space. Conjoined nerve root (CNR) anomaly refers to an anatomical variation in which two adjacent nerve roots share a common dural sleeve. The aforementioned three rare pathologies cause the same pathological process of stenosis, therefore compressing the nervous structures.
A 45-year-old female patient was admitted to the Department of Neurosurgery with severe low back and radicular pain, and numbness along her left leg. Antalgic posture, painful paravertebral muscle tenderness, L4 radiculopathy, and L5 and S1 dermatome hypoesthesia on the left as well as positive straight leg raising sign (Laseque) were present upon examination. CT and MRI scanning showed stenosis on L4-L5 level caused by bilateral synovial cyst formation.
Microsurgical decompression by foraminotomy at L4-L5 level on the left with dissection of the synovial cyst and epidural lipomatosis was performed. In the course of the operation CNR anomaly was discovered. The complete decompression alleviated the symptoms and after 3 uneventful postoperative days the patient was discharged.
Spinal stenosis causing compression upon nervous structures is a process that could be caused by a number of conditions. The incidence of rare pathologies and anomalies or even the more rarely occurring combination of them must be considered on daily basis in the clinical practice in order to make the correct diagnosis and plan the best possible treatment for the patient.
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