Risk factors for a bad split during sagittal split osteotomy.

One of the operative complications during sagittal split osteotomy (SSO) in orthognatic surgery is a bad split, meaning an undesired fracture of the mandible during osteotomy. The aim of this study was to find out if there is a relation between the occurrence of bad splits during SSO and the presence of third molars, the patient's age, or the surgeon's experience. Clinical notes of 110 consecutive patients who had had a total of 220 SSOs using the Obwegeser/Dal Pont technique were evaluated and divided into three groups: 1 missing third molar (n=168); 2 retained or impacted third molar that was removed during the SSO (n=23); and 3 third molar left in place during SSO (n=29). There were a total of 12 (6%) bad splits. 9 (5%) in group 1, two (9%) in group 2, and one (3%) in group 3. There were no significant differences between groups 1-3, in particular the surgeon's qualification had no influence on the incidence. Older patients seemed more at risk of a bad split than younger ones.