L5 nerve root duplication in the setting of MRI-depicted L5-S1 disk herniation

Lumbosacral nerve root anomalies are rare anatomic variations with a predilection for the lumbosacral spine. Among these, conjoined nerve roots are the most common with other rare variants such as nerve root duplication occurring far less frequently. While these anatomic variations are exceedingly rare, their presence has significant clinical ramifications. Undiagnosed lumbosacral nerve root anomalies are at risk for iatrogenic injury, may contribute to wrong-site surgery and contribute to continued postoperative symptoms. Herein, we present a case of a 74 year-old female with diskogenic back pain and L5 radiculopathy found to have a duplicated L5 nerve root intraoperatively. Interestingly, the L5-S1 disk was found to be normal and unlikely to contribute to her presentation. She underwent L5-S1 laminectomy and L5 foraminotomy with resolution of her L5 radicular symptoms postoperatively.