Visible light navigation for C1/C2 fixation and a rare complication related to C2 lamina fracture: case report.

Background: Os odontoideum is a rare craniocervical osseous anomaly leading to instability and cord compression that may require surgical stabilization. The increased precision and expedited workflow from visible light navigation allows for C1 lateral mass screw placement through the posterior arch while reducing dissection and venous bleeding compared to traditional entry at the arch-lateral mass junction. Case Description: A 57-year-old male presented with progressive myelopathy due to os odontoideum and C1/2 instability. Posterior C1-C2 fusion was performed via C1 through-the-arch screws and bilateral C2 laminar screws, with the assistance of visible light navigation (7D FLASH Navigation). Five weeks postoperatively, he developed progressive right arm pain and weakness. Computed tomography/magnetic resonance imaging (CT/MRI) demonstrated the lateral mass screws to be Conclusions: This is the first report of visible light navigation being used for posterior C1/C2 fixation. Navigation, however, cannot compensate for inadequate bony dimensions for screw placement with risk of subsequent mechanical failure. C2 lamina width should be evaluated prior to consideration of laminar screw insertion.