To evaluate the surgical outcomes of lateral mass C1-pedicle C2 screws combined with allografts in C1-C2 unstable fracture caused by trauma. Subjects and method: A prospective study, describing cases of C1-C2 unstable fractures caused by trauma operated at Neurosurgery Department of Danang Hospital from 1 - 2012 to 8 - 2018. | Evaluation of surgical outcomes of lateral mass C1-pedicle C2 screws combined with allografts in C1-C2 unstable fractures caused by trauma