Observation of Osseous Healing after Sagittal Splitting Ramus Osteotomy (SSRO)

• Published in: Nihon Gaku Henkeishō Gakkai zasshi Vol. 18; no. 4; pp. 259 - 267
• Main Authors: TATEISHI, CHIZU, KOMORI, TAKAHIDE, FURUDOI, SHUNGO, UCHIDA, RYOKO, SHIBUYA, YASUYUKI, YOKOO, SATOSHI, HASEGAWA, TAKUMI
• Format: Journal Article
• Language: Japanese
• Published: THE JAPANESE SOCIETY FOR JAW DEFORMITIES 2008
• Subjects: Osseous healing; Remodeling; Sagittal splitting ramus osteotomy (SSRO)
• ISSN: 0916-7048; 1884-5045; 1884-5045
• DOI: 10.5927/jjjd1991.18.259

The purpose of this study was to clarify the relationship between the cleavage of bone fragments and the stability of osseous healing after performing sagittal split ramus osteotomy (SSRO). The subjects were 11 patients with mandibular prognathism who underwent SSRO on both sides (22 rami). These rami were studied immediately after surgery, 6 months thereafter, and 1 year after surgery by computed tomography. The plane passing through the mandibular foramen was designated as the upper plane, while the plane passing through the root furcation of the first and second molars of the mandible was designated as the lower plane. Examining the cleavage at the anterior and posterior borders of distal and proximal bone fragments, the cleaved planes were classified into three types (smooth, stairway, concave) by a modification of the methods of Nemoto T, et al.(J Jpn Stomatol Soc 50: 227-241, 2001). Many of the concave type anterior borders changed to the stairway type between 6 months to 1 year after surgery, but few changed to the smooth type. Almost all of the stairway and concave type of posterior borders changed to the smooth type between 6 months to 1 year after surgery. Regarding the posterior borders at 1 year after surgery, the cleavage of distal and proximal bone fragments demonstrated stable osseous healing (smooth type) in cases in which the length and width between the bone fragments were large. In order to achieve a stable state of osseous healing at the anterior border, it is therefore important to consider the length between the bone fragments and delete the projection of the distal bone fragment. On the other hand, in order to achieve a stable state of osseous healing of the posterior border, it is important to carefully consider the width between the bone fragments. Sufficient bone contact is necessary for the cleavage of distal and proximal bone fragments in both the anterior and posterior border. The increased distance of the mandibular ramus due to the posterior movement of the SSRO and the clear absorption of the projection of both distal and proximal bone fragments was not observed from 6 months to 1 year after surgery. Therefore, the remodeling in the cleavage between the bone fragments is considered to play a major role in the osseous healing which occurs after SSRO.