Electromyographic abnormalities in redundant nerve root syndrome of the cauda equina.

This report documents the seventh patient with redundant nerve root syndrome of the cauda equina in which electromyographic abnormalities were reported. A 79-year-old woman developed low back pain radiating into the left lower extremity. Electromyography (EMG) revealed partial denervation of the left medial gastrocnemius muscle. Metrizamide myelography disclosed a complete block of the spinal canal at the L3 vertebral level, and a coiled nerve root was present behind the L2 vertebral body. Computed tomography showed marked spondylotic narrowing of the spinal canal at the L3 to L4 vertebral level, and spinal stenosis at the L4 to L5 vertebral level. An L3 laminectomy revealed nodular bony overgrowth and ligamentous hypertrophy compressing the dura. Postoperatively, the patient experienced significant pain relief and increased ambulation ability. Electromyographic abnormalities in the left medial gastrocnemius muscle were still present at three- and six-month follow-up.