Intraoral vertico-sagittal ramus osteotomy: modification of the L-shaped osteotomy

The sagittal split ramus osteotomy and intraoral vertical ramus osteotomy carry the potential risk of postoperative nerve paralysis, bleeding, and fracture and dislocation of the condyle. In 1992, Choung first described the intraoral vertico-sagittal ramus osteotomy for the purpose of avoiding postoperative dislocation of the condyle. However, there is still potential for damaging the inferior alveolar nerve and maxillary artery with this technique. The authors have developed a modified technique to minimize these risks. An evaluation of surgical experience and patient outcomes with the use of this technique is presented herein. One hundred twenty-two sides in 97 Japanese patients diagnosed with a jaw deformity were analyzed. This technique includes a horizontal osteotomy that is performed at a higher position than in the original Choung procedure. Intraoperatively, there was no unexpected bleeding from the operative site. Proximal segment dislocation from the glenoid fossa was observed on one side (0.82%). Non-union of the osteotomy was not observed in any patient. Intraoperative fracture of the coronoid process occurred in 2.46%, but none necessitated treatment of the fracture. Nerve dysfunction was found in 2.46% at the 12-month postoperative follow-up. The modified technique presented herein was developed to reduce postoperative nerve dysfunction and intraoperative hemorrhage.