Endoscopic management of a duplicate nerve root-case report and technique.

Background: Nerve root anomalies (NRAs), including duplicate and conjoined exiting nerve roots, are uncommon lumbar anatomic variants that increase the risk of neural injury during foraminal and extraforaminal surgery. Fully endoscopic descriptions remain limited, with only a small number of prior reports. We present a case and technique note on the endoscopic management of a duplicate exiting nerve root with a concomitant far-lateral disc herniation through a transforaminal approach and build on the existing literature to describe a structured, reproducible intraoperative sequence for safe decompression. Case Description: A 69-year-old woman presented with right lower-extremity radicular pain and progressive foot drop following a far-lateral disc herniation at L4-L5. She underwent a right L4-L5 far-lateral endoscopic microdiscectomy via a transforaminal approach. A Type IIB duplicate right L4 exiting nerve root was identified on meticulous preoperative imaging review by the operating surgeon (not described on the radiology report) and confirmed intraoperatively within the neural foramen. A structured intraoperative sequence, adapting commonly taught endoscopic approaches but not formally published termed "rotating neural blockade", was employed, in which each limb of the duplicated root was sequentially protected, allowing for safe discectomy and foraminal decompression without neural injury. The patient's radicular pain and dorsiflexion weakness improved postoperatively. Conclusions: This case represents one of the first reports of fully endoscopic transforaminal management of a duplicate exiting nerve root and describes a reproducible intraoperative framework for safe decompression in the setting of a Type IIB NRA.