Use of Magnetic Resonance Imaging to Identify Outcome Predictors of Caudal Epidural Steroid Injections for Lower Lumbar Radicular Pain Caused by a Herniated Disc

OBJECTIVE: We used lumbar magnetic resonance image (MRI) findings to determine possible outcome predictors of a caudal epidural steroid injection (CESI) for radicular pain caused by a herniated lumbar disc (HLD). METHODS: Ninety-one patients with radicular pain whose MRI indicated a HLD were enrolled between September 2010 and July 2013. The CESIs were performed using ultrasound (US). A responder was defined as having complete relief or at least a 50% reduction of pain as assessed by the visual analog scale (VAS) and functional status on the Roland Morris Disability Questionnaire (RMDQ); responder (VAS n=61, RMDQ n=51), and non-responder (VAS n=30, RMDQ n=40). MRI findings were analyzed and compared between the two groups with regard to HLD level, HLD type (protrusion or exclusion), HLD zone (central, subarticular, foraminal, and extraforaminal), HLD volume (mild, moderate, or severe), relationship between HLD and nerve root (no contact, contact, displaced, or compressed), disc height loss (none, less than half, or more than half ), and disc degeneration grade (homogeneous disc structure or inhomogeneous disc structure-clear nucleus and height of intervertebral disc). RESULTS: A centrally located herniated disc was more common in the responder group than that in the non-responder group. Treatment of centrally located herniated discs showed satisfactory results. (VAS p=0.025, RMDQ p=0.040). Other factors, such as HLD level, HLD type, HLD volume, relationship to nerve root, disc height loss, and disc degeneration grade, were not critical. CONCLUSION: The HLD zone was significant for pain reduction after CESI. A centrally located herniated disc was a predictor of a good clinical outcome.

Compressive Radial Neuropathy Developed Under a Fibrotic Band Associated With Rhabdomyolysis and Successfully Treated With Surgery

A 34-year-old male patient visited the emergency room with complaint of right wrist drop and foot drop. The day before, he was intoxicated and fell asleep in a room containing barbeque briquettes; After waking up, he noticed that his right wrist and foot were dropped. Upon physical examination, his right wrist extensor, thumb extensor, ankle dorsiflexor, and big toe extensor showed Medical Research Council (MRC) grade 1 power. The initial laboratory tests suggested rhabdomyolysis induced by unrelieved pressure on the right side during sleep. Right foot drop was improved after conservative care and elevated muscle enzyme became normalized with hydration therapy with no resultant acute renal failure. However, the wrist drop did not show improvement and a hard mass was palpated on the follow-up physical examination. Ultrasonography and magnetic resonance imaging studies were conducted and an abnormal mass in the lateral head of the tricep was detected. Axonopathy was suggested by the electrodiagnostic examination. A surgical decompression was done and a fibrotic cord lesion compressing the radial nerve was detected. After adhesiolysis, his wrist extensor power improved to MRC grade 4. Herein, we describe a compressive radial neuropathy associated with rhabdomyolysis successfully treated with surgery and provide a brief review of the related literature.