Fractures of the odontoid process. Treatment with anterior screw fixation.

Seventeen cases of Anderson and D'Alonzo Type II and "shallow" Type III fractures of the odontoid, treated by anterior screw fixation, were reviewed and compared with previously published series of fractures treated nonoperatively, treated with posterior C1-C2 arthrodeses, and with anterior screw fixation series. Although the nonunion rate (12%) and major complication rate (24%) in the present series were higher than those previously reported, the combined rates of all anterior screw fixation series were comparable to those of posterior C1-C2 arthrodesis studies. Three of the complications presented occurred in cases that in retrospect were inappropriate for the use of this technique. These included a verified nonunion and 2 individuals with markedly osteoporotic bone and unfavorable fracture type. Because of the difficulty involved in mastering anterior screw fixation of the dens, its use should be limited to experienced spine surgeons with the appropriate surgical facilities.