O-arm Navigation-assisted Excision of Cervical Osteoid Osteoma Adjacent to the Vertebral Artery: Technical Note and Case Report.

INTRODUCTION: Osteoid osteoma is a benign osteoblastic tumor that rarely involves the cervical spine. Lesions arising from the cervical pedicle adjacent to the vertebral artery present significant diagnostic and surgical challenges due to the complex regional anatomy and risk of neurovascular injury. Although radiofrequency ablation is an established treatment modality, surgical excision remains an important option when lesions are located close to critical neurovascular structures. CASE REPORT: A 20-year-old male presented with persistent nocturnal right-sided lower cervical pain for 8 months, which showed temporary relief with non-steroidal anti-inflammatory drugs. The patient failed prolonged conservative management. Computed tomography (CT) demonstrated a well-defined nidus with surrounding reactive sclerosis involving the right C7 pedicle, while magnetic resonance imaging revealed associated marrow edema and inflammatory soft-tissue changes. Due to the lesion's proximity to the vertebral artery, the patient underwent navigation-guided excision using an intraoperative three-dimensional imaging system (O-arm® Intraoperative Imaging System, Medtronic, Minneapolis, MN, USA) through a posterior cervical approach. Intraoperative navigation enabled precise localization and complete excision of the nidus while preserving adjacent stabilizing structures and avoiding injury to surrounding neurovascular elements. Post-operative CT confirmed complete tumor removal, and histopathological examination established the diagnosis of osteoid osteoma. The patient experienced immediate pain relief and remained symptom-free without recurrence or neurological deficit during follow-up. CONCLUSION: O-arm-based intraoperative navigation facilitates safe and accurate excision of cervical pedicular osteoid osteoma located adjacent to the vertebral artery. The technique allows complete nidus removal while minimizing unnecessary bone resection, preserving cervical stability, and reducing the risk of neurovascular complications. Navigation-assisted excision represents a valuable treatment option for osteoid osteomas situated in anatomically challenging regions of the cervical spine.