Adequate Decompression of Adult Lumbar Intradural Lipoma without Dysraphism Using a Monopolar Stimulation Electrode for Intraoperative Monitoring: Case Report

Abstract

Adult non-dysraphic intradural spinal lipomas are rare entities. Here we report two cases of adult non-dysraphic intradural lumbar lipoma. Case 1: A 66-year-old man experienced gradual progression of sensory disturbance and numbness in the lower extremities bilaterally over the course of 2 years. Magnetic resonance imaging (MRI) suggested an intradural lipoma at T12 with no evidence of dysraphism. Adequate decompression and duraplasty were performed with intraoperative monopolar stimulation to elicit evoked electromyography responses. Case 2: A 54-year-old man with a 10-year history of lower back pain and gradual progression of weakness of the right lower extremity over the course of 2 years was referred to our hospital, where he presented with urinary disturbance. An MRI suggested intradural lipoma at L2 without evidence of dysraphism. Roentgenograms revealed L5 isthmic spondylolisthesis. Adequate resection, duraplasty, and L4-S posterior lumbar interbody fusion were performed with intraoperative monopolar stimulation monitoring. Both patients received pathological diagnoses of lipomas, and neurological symptoms improved postsurgically in both cases. Adequate resection is recommended for adult lumbar lipomas without dysraphism in order to achieve a good clinical outcome. The evoked electromyography response was a simple and useful intraoperative tool to demonstrate adequate decompression of adult non-dysraphic intradural spinal lipomas in both of these cases.