ABSTRACT
Objective: to present a case of a patient with "os odontoideum" treated by posterior occipitocervical fusion. Description: we report a case of a patient suffering posterior cervical pain, left brachialgia, lip numbness and paresthesias in the tip of the tongue. A compressive "os odonteideum" was found which was treated by a posterior approach. The patient did well showing symptoms relief. Intervention: the patient was operated through a posterior approach and an occipitocervical (2) fixation and arthrodesis with iliac bone graft were reformed. Conclusion: patients harboring compressive "os odontoideum" and / or C1-C2 instability associated or not to neurological symptoms should be surgically treated. The occipitocervical fixation and fusion through a posterior approach offered stability and allowed symptoms improvement in some cases