Report of an Isolated L5 Radiculopathy Caused by an L2-3 Disc Herniation and Review of the Literature

Intervertebral disc herniation is a common cause of radiculopathy. Disc herniations occurring in the lumbar spine typically affect the nerve root exiting under the pedicle of the vertebral body, one level caudal. However, in rare cases, a disc herniation can cause remote isolated radicular symptoms. The authors present the case of a 70-year-old male who presented with an acute, new-onset, left-sided foot drop, low back pain, and a classic L5 monoradiculopathy. Imaging revealed a large, left-sided paracentral extruded L2-3 disc and the absence of any pathology at the L4/5 level. Although the patient’s clinical presentation and imaging did not classically correlate, it was felt that the L2-L3 disc was the etiology of the patient’s L5 radiculopathy and a left L2-3 microsurgical discectomy was performed. At the six-week follow-up, his foot drop was near normal, sensation was intact with minimal paresthesias, and he remained pain-free. At the one-year follow-up, he experienced full resolution of his foot drop and remained symptom-free. Although rare, disc herniations may cause isolated, remote, painful mononeuropathies not related to the direct level of nerve root compression and should be considered along with other etiologies of peripheral neuropathies.