Condylar resorption and functional outcome after unilateral sagittal split osteotomy

Objective. The objective of this study was to evaluate the radiological and functional results of unilateral sagittal split osteotomy (USSO) of the mandible. Study design. Between January 2001 and December 2008, 26 patients underwent USSO to correct laterognathia (isolated USSO in 3 patients and Le Fort I osteotomies in combination with USSO in 23 patients). Radiographs of 23 patients were evaluated for signs of condylar resorption or loss of ramus height; 16 patients were clinically examined and the movement of both condyles was measured with a nontouch device. Results. Unilateral condylar resorption was observed in 1 patient and bilateral signs of resorption with loss of ramus height were observed in a further patient. Mouth opening and protrusion were significantly reduced after surgery (6.06 +/- 6.91 mm, P = .005/0.63 +/- 0.89 mm, P = .020). The selected surgical site, whether left or right, had no influence on laterotrusion or retrusion (P > .05), but patients operated on the right side showed higher values of protrusion on the left side than patients who were operated on the left (mean difference: 3.13 +/- 1.24 mm; P = .038). Conclusions. USSO appears to be a procedure that can be used in orthognathic surgery, if applied to a certain extent. In this study, there was no evidence of adverse results in terms of condylar resorption or functional outcome when compared with the results of regular bilateral sagittal split osteotomy (BSSO) reported in the literature. To our best knowledge this is the first study in the literature investigating the impact of USSO in orthognathic surgery. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2011; 112:315-321)