C2 nerve root sectioning in C1-C2 arthrodesis: a single-surgeon series of 31 patients.

PURPOSE: C1-C2 instability can result from trauma, degenerative changes, neoplasms, or congenital abnormalities. Atlantoaxial stabilization is a complex surgical procedure due to the unique anatomy of C1 and C2 and the wide range of motion of this segment. This study evaluates the safety and utility of C2 nerve root sectioning to facilitate visualization of the C1 screw entry point, reducing the risk of intraoperative neurological and vascular injury.

METHODS: We retrospectively reviewed a single-surgeon (CM) series of 31 patients undergoing C1-C2 arthrodesis between 2009 and 2025, with intraoperative sectioning of the C2 nerve roots. Demographic, clinical, and surgical data were collected, including age, sex, diagnosis, operative time, use of neuronavigation, vascular injury, postoperative neurological deficits, and C2-related symptoms. The Harms technique involved bilateral C1 lateral mass screws and C2 pedicle screw fixation. C2 nerve roots were sectioned distal to the dural sac after placement of a metal clips, in order to improve intraoperative visualization and control venous bleeding.

RESULTS: No patients developed C2 numbness, hypoesthesia, or occipital anesthesia following C2 roots sectioning and no intraoperative vascular injuries or postoperative neurological deficits occurred. Postoperative CT confirmed optimal screw placement in all cases. The most frequent causes of instability were post-traumatic type II odontoid fractures, followed by odontoid fractures involving the C2 body and C1, neoplastic lesions, cranio-cervical junction cyst, and degenerative instability.

CONCLUSION: C2 nerve roots sectioning during C1-C2 arthrodesis is safe and provides optimal exposure of the C1 screw entry point, reducing intraoperative risks, with no C2-related deficits or numbness observed in our series of 31 patients.