Lumbar intervertebral disc cyst as a cause of radiculopathy.
BACKGROUND
Lumbar radiculopathy is commonly caused by degenerative conditions such as a herniated disc or lumbar spinal stenosis. Less common etiologies include intraspinal extradural masses such as synovial cysts and gas-containing ganglion cysts. Intraspinal extradural cysts that communicate with the intervertebral disc are a rare entity and thus, an uncommon cause of lumbar radiculopathy. There are only ten cases of an intervertebral disc cyst reported in the literature.


OBJECTIVE
To document the first reported case of an intervertebral disc cyst in North America. Two series of Japanese patients with intervertebral disc cyst confirmed radiographically and intraoperatively have recently been reported.


METHODS
A case report of an intervertebral disc cyst at L4-5 causing an L5 radiculopathy.


METHODS
Japanese Orthopaedic Association score for low back pain.


METHODS
The patient and the authors involved in the patient's management were interviewed. All medical records, radiographic imaging studies, intraoperative findings, and pertinent literature were also reviewed.


RESULTS
Preoperative magnetic resonance imaging (MRI) scan demonstrated a well-localized cyst compressing the ventral aspect of the thecal sac at L4-L5. Discography and subsequent computed tomographic (CT) scanning demonstrated the cyst communicating with an intervertebral disc herniation via an annular rupture. Decompressive discectomy and surgical excision of the disc cyst from the spinal canal resulted in complete recovery and resolution of the preoperative radiculopathy. Clinical improvement was documented using the JOA scoring system. Patient's preoperative score was 4/15, and postoperative score was 15/15.


CONCLUSIONS
Although exceedingly rare, an intervertebral disc cyst should remain in the differential diagnosis of any extradural intraspinal mass ventral to the thecal sac. Diagnosis of an intervertebral disc cyst requires recognition of this uncommon entity and a high index of suspicion. Discography and post-discography computerized tomography (CT) scan confirm the diagnosis. Operative treatment includes decompression, and excision of the cyst and is reserved only for cases in which the cyst results in clinical symptoms unresponsive to nonoperative management.
Department of Orthopaedic Surgery, Hospital for Joint Diseases, Orthopaedic Institute, 301 East 17th Street, 4th Floor, New York, NY 10003, USA.
Gerard K
GK
Jeong
John A
JA
Bendo
D000328:Adult; D003560:Cysts / Q000150:complications* / Q000175:diagnosis / Q000601:surgery; D003937:Diagnosis, Differential; D017586:Diskectomy; D006801:Humans; D007405:Intervertebral Disc Displacement / Q000150:complications* / Q000601:surgery; D008159:Lumbar Vertebrae; D008279:Magnetic Resonance Imaging; D008297:Male; D011843:Radiculopathy / Q000209:etiology*; D014057:Tomography, X-Ray Computed