Novel Delivery of Cryoablation Through Transoral Surgical Approach for Atypical Presentation of Osteoid Osteoma of the C1 Lateral Mass: Technical Case Illustration.

Background and importance: Neurosurgical literature rarely explores cases of osteoid osteomas of the atlas. Traditionally, neurosurgeons performed en bloc surgical resection for refractory osteoid osteomas in the subaxial and lumbar spine, but minimally invasive ablation therapies have gained favor. Complete lesioning of the nidus, either by surgical or minimally invasive therapies, produces curative results with recurrence only developing after partial lesioning.

Clinical presentation: We discuss the case of a 16-year-old adolescent boy who presented with neck and occipital pain refractory to multimodal pain management. Prolonged workup demonstrated a subtle radiographic lesion of the left C1 lateral mass. Interventional radiologists attempted a posterior approach percutaneous computed tomography-guided radiofrequency ablation but aborted due to proximity of the vertebral artery. Surgeons then pursued an open transoral approach to provide a corridor for cyclical cryoablation therapy, which proceeded without complication. The patient was discharged on postoperative day one with remission of occipital pain at the 10-month follow-up. No clinical or radiographic evidence of instability appeared on postoperative cervical films.

Conclusion: No reports exist in the literature of an osteoid osteoma of C1 treated by an open anterior approach and with cryoablation. The transoral approach is a safe, effective method to access ventral pathologies of C1. The transoral approach may minimize blood loss and reduce the risk of craniocervical instability, allowing for preserved cervical mobility and improved patient outcomes. Surgeons may especially consider cryoablation when the nidus is within proximity to critical neural structures.