Sudden Bilateral Foot Drop Due to Dorsally Unilateral Migration of the Herniated Lumbar Disc: A Case Report

BACKGROUND: Due to the anatomical characteristics of the anterior epidural space, dorsal migration of material from herniated lumbar disc is quite rare. Also, bilateral foot drop due to unilateral dorsal migration of disc herniation is extremely rare. This report presents a case of sudden bilateral foot drop caused by the unilateral dorsal migration of material from a herniated lumbar disc. CASE DESCRIPTION: A 51-year-old male presented with sudden onset severe leg pain with bilateral foot drop. The patient was referred to our emergency department by a local clinic. Neurological examination showed bilateral ankle and big toe dorsiflexion weakness grade 1. There was no perianal anesthesia, anal sphincter weaknesses, or voiding difficulty. Apart from essential hypertension, this patient’s medical history was unremarkable. Magnetic resonance imaging showed that intervertebral disc material in the dorsal extradural space at the L3-4 level had compressed the dural sac from the left side to the center. We performed an emergency operation. The pathologic result revealed fibrous cartilaginous materials. After the operation, the leg pain was markedly resolved. At postoperative three months, the patient showed improvement of foot drop. CONCLUSION: We recommended emergent mass removal, which produced a favorable outcome.