Cauda Equina Syndrome After Intradiscal Electrothermal Therapy

Intradiscal electrothermal therapy (IDET) has become increasingly popular for the management of low back pain. First described by Saal and Saal in 2000,1 the device was approved by the Food and Drug Administration in March 1998 for the coagulation and decompression of disc material. The procedure is recommended for those patients with degenerative disc disease who complain of nonspecific pain in the lumbar spine, but do not have significant disc herniation or nerve root compression and who have a normal neurologic examination. IDET is proposed to be a safe procedure, yet a single case report describes cauda equina syndrome after the procedure.2 Herein, I report another case of cauda equina syndrome following the IDET procedure. The patient was a 65-year-old female referred to me for pain medicine consultation 12 months after the IDET. Prior to the procedure, the patient had chronic nonspecific lumbar spine pain. A pre-IDET computerized tomography scan did not show a lumbar disc herniation, but she did have an annular disruption at the L4-5 disc. Magnetic resonance imaging was not done because of her pacemaker. Pre-IDET neurologic examination was within normal limits. She had no history of bowel or bladder dysfunction. Provocative discography revealed pain at the L3-4 and L4-5 levels. She subsequently underwent IDET at the L3-4 and L4-5 discs. The IDET 17-gauge introducer needles and thermal catheters (SpineCath, Oratec Interventions, Inc, Menlo Park, CA) were placed with fluoroscopic guidance. The electrode was heated to 90° centigrade over 18 minutes and maintained for 4 minutes. During the procedure, she complained of transient burning pain in both lower extremities. The physician performing the procedure again ascertained proper needle and catheter placement with lateral and anterior-posterior fluoroscopic views. Following the procedure, the patient complained of weakness in both lower extremities, and had neurogenic bowel and bladder as well as saddle anesthesia. She was treated aggressively with steroids administered intravenously, but had no significant change in acute symptoms. Postprocedural electrophysiologic studies demonstrated the following: an inability to obtain an F-wave latency in the right peroneal nerve, denervation of L5 and S1 nerve roots bilaterally, and denervation of L4 and L5 nerve roots on the right. Twelve months later, she continues to complain of burning pain in both lower extremities, but has return of bowel and bladder function. She currently is being treated with anticonvulsants, amitriptyline, and hydrocodone. This is the second reported case of cauda equina syndrome following the IDET procedure that I am aware of. It is concerning that neither case was reported by the treating physician. The IDET procedure is relatively new, and complications possibly related to it may not be readily reported because of potential litigation. It is recommended that any complications possibly associated with IDET be reported to a referenced journal or the manufacturer so that any pattern of adverse outcome can be evaluated by scientific and/or manufacturer investigation.