Anterior screw fixation for odontoid fracture: clinical results in 45 cases.

Clinical results of anterior screw fixation in 45 patients with odontoid fractures were reviewed retrospectively. The patients were 36 males and 9 females, with fractures classified as 35 type II and 10 type III. There were 34 fresh and 11 old fractures. Neurological complications were present in 16 patients and 18 had associated injuries. All patients underwent single screw fixation. Postoperative immobilization, external support, and surgical trauma were minimal. In one patient a screw extruded from the dens and immediate posterior fusion was necessary. The overall rate of fracture union was 93% (41 out of 44 fractures). Fracture resolution averaged 5.2 months. There were two delayed unions and three nonunions, the causes of which were preoperatively established nonunion, severe osteoporosis, and inaccurate screw placement. Out of 11 old cases, 8 went on to union. Ninety-six percent of the patients recovered neurologically. The overall complication rate, including a misplaced screw, a retropharyngeal wall injury, and three nonunions, was 11%. Head rotation was preserved in 90% of the patients with fracture union according to clinical measurements. Anterior screw fixation is an excellent treatment for fresh type II and cephalad type III odontoid fractures, carrying a high union rate, preservation of the C1-2 motion segment, and minimal surgical trauma; it can be applied even to some old cases. Precise patient selection in regard to patient age, bone density, and time elapsed since injury as well as preoperative anatomical reduction and meticulous surgical technique with fine fluoroscopy are essential to avoid complications and nonunions.