Cervical conjoined nerve root anomalies: prevalence and impact on posterior cervical surgery

Anomalous nerve roots (ANRs) are well described in the lumbosacral spine but are rarely reported in the cervical region. The aim of this study was to evaluate the incidence, clinical characteristics, and surgical outcomes of cervical ANRs, with particular emphasis on conjoined nerve roots, in a single-center clinical series.

A retrospective analysis was conducted of patients who underwent posterior cervical discectomy for cervical disc herniation at our institution between 2010 and 2025. A total of 113 posterior cervical procedures were performed, and seven patients were found to have surgically confirmed cervical ANRs. For these patients, demographic data, clinical presentation, radiological findings, intraoperative observations, and postoperative outcomes were reviewed. Surgical interventions included posterior cervical microdiscectomy and endoscope-assisted discectomy.

Among the 113 patients who underwent posterior cervical discectomy, cervical ANRs were identified intraoperatively in seven patients, yielding an incidence rate of 6.19%. These patients included four women (57.1%) and three men (42.9%), with a mean age of 46.0 years (range: 35-54 years). Motor deficits were observed in five patients (71.4%) and sensory deficits were present in four patients (57.1%). Radiologically, cervical disc herniation was identified in all cases, most frequently at the C6-C7 level (71.4%).

Cervical ANRs are rare yet likely underrecognized anatomical variants that can pose diagnostic and intraoperative challenges. Awareness of their potential presence, careful preoperative imaging evaluation, and meticulous surgical technique are essential to minimize complications and optimize surgical outcomes.