Modified Sagittal Split Ramus Osteotomy

Especially on Internal Fixation of Segments by Angular Screwing Instrument System^® and Titanium Miniplate without Skin Incision

Abstract

The sagittal split osteotomy of the mandible is widely used for the correction of various dentofacial deformities in Japan but was some problems to apply it to Japanese women whose mandibular ramus are small and thin.
From these reasons, we developed a modified technique of the procedure that the mandibular ramus was cut by a reciprocating bone saw with minimal split, and osteotomized segments were fixed monocortically with titanium miniplate and screws placed by Angular screwing instrument^® on each side without skin incision.
Based on our experience of 30 cases treated by the procedure from September 1989 to December 1990, following merits are obtained.
1) Bone cut is safer and easier and cutting surfaces become flat and smooth because of minimal split.
2) Placement of miniplate and screws is made easily by Angular screwing instrument^® without skin incision.
3) A sharp angle at the second molar region made by bone cuttings allows the sufficient rigidity of the monocortical fixation between segments by one miniplate and screws.
6) Postoperative adaatation to the new occlusion is rapid because the duration of the maxillo-mandibular fixation decreases significantly.