Intraoperative Discovery of a Conjoined Nerve Root During Transforaminal Lumbar Interbody Fusion: A Case Report

Case This case report describes a rare intraoperative discovery of a conjoined nerve root (CNR) at L4-L5 in a 74-year-old male undergoing L4-S1 TLIF for chronic lower back pain and radiculopathy. Although preoperative MRI showed stenosis and spondylolisthesis, it did not reveal the CNR, which was identified during the osteotomy when the L4 nerve root was seen merging with the L5 root across the disc space. The surgeon proceeded with caution, protecting the nerve root during cage placement, and the patient experienced complete symptom resolution postoperatively, returning to daily activities within three weeks. Conclusion Transforaminal lumbar interbody fusion (TLIF) is used to treat spinal cord and nerve root compression. Anatomical anomalies like CNRs can complicate spinal procedures. This case highlights the limitations of imaging in detecting CNRs and emphasizes the importance of intraoperative awareness to avoid injury to anomalous nerve roots or other anatomical variants.