Evaluation of Bone Formation After Sagittal Split Ramus Osteotomy With Bent Plate Fixation Using Computed Tomography

Abstract

Purpose. The purpose of this study was to evaluate bone formation between the proximal and distal segments after a sagittal split ramus osteotomy (SSRO) with bent plate fixation.Subjects and Methods. The subjects were 23 patients (46 sides) who underwent bilateral SSRO setback surgery. They were divided into titanium and absorbable plate groups. A 3-7 mm gap was made between the proximal and distal segments and a bent plate was fixed with 4 screws in each side of the mandible. The square of ramus (RmS), the antero-posterior length (RmA-RmP), and the medio-lateral width (RmM-RmL) of the ramus at the horizontal plane under the mandibular foramen were assessed preoperatively, immediately after surgery, and 1 year postoperatively by computed tomography (CT).Results. There were no significant differences between the titanium and absorbable plate groups over time. RmS after 1 year was larger than pre-operatively in both groups (P<0.0001). RmA-RmP significantly increased immediately after surgery and significantly decreased after 1 year in both groups (P<0.0001). RmA-RmP after 1 year was significantly larger than the preoperative value in both groups (P<0.0001). RmM-RmL showed a similar tendency to the antero-posterior length, but was not significant. Conclusion.The gap between the proximal and distal segments can fill with new bone after SSRO with both titanium and absorbable plates, even with few bony contacts between segments.

Effect of self-setting α-tricalcium phosphate between segments for bone healing and hypoaesthesia in lower lip after sagittal split ramus osteotomy

“…In this study, 2-dimensional CT evaluation could give valid results clinically as well as our previous studies that described regarding mandibular ramus morphology including inferior alveolar nerve after SSRO (Nakagawa et al, 2003;Hashiba et al, 2008;Ueki et al, 2009) and pterygoid plate in maxilla (Ueki et al, 2009), although the 3-dimensional reconstruction was used in the other previous studies (Ueki et al 2008;Ueki et al, 2009;Ueki et al, 2010). In this study, ramus square in the Biopex group was significantly larger than the control group immediately after surgery and after 1 year.…”

Osseous healing after a sagittal splitting ramus osteotomy

“…Some studies have reported a postoperative relapse of the original deformity when SSRO is followed by rigid fixation of bone fragments using screws and a plate 20,23,26 . Few reports have investigated remodelling and osseous healing in the cleavage between the bone fragments 23 .…”

“…Few reports have investigated remodelling and osseous healing in the cleavage between the bone fragments 23 . There are few clinical reports regarding the use of computed tomography (CT) to visualize bone formation between the fragments after SSRO for patients with jaw deformity 26 . The authors observed osseous healing in the cleavage space between the bone fragments 1 year after SSRO surgery and remodelling in the cleavage space continued from a previous study 14 .…”

An experimental study of use of absorbable plate in combination with self-setting α-tricalcium phosphate for orthognathic surgery

“…However, a concave outline was observed in some cases in the study, although the square of ramus increased significantly. 19 If healing of the periosteal membrane at the incision area is complete, it can prevent invasion of mucosal endothelial cells into the gap between segments.…”