The modifications of the sagittal ramus split osteotomy: a literature review.

Background: In 1953, the sagittal ramus split osteotomy was introduced by Obwegeser. For many years, and in some countries still, this technique has defined the term oral and maxillofacial surgery.
Methods: The basic design of the sagittal ramus split surgical procedure evolved very quickly. The original operation technique by Obwegeser was shortly after improved by Dal Pont's modification. The second major improvement of the basic technique was added by Hunsuck in 1967. Since then, the technical and biological procedure has been well defined. Resolution of the problems many surgeons encountered has, however, taken longer. Some of these problems, such as the unfavorable split or the damage of the inferior alveolar nerve, have not been satisfactorily resolved.
Results: Further modifications, with or without the application of new instruments, have been introduced by Epker and Wolford, whose modification was recently elaborated by Böckmann. The addition of a fourth osteotomy at the inferior mandibular border in an in vitro experiment led to a significant reduction of the torque forces required for the mandibular split.
Conclusions: The literature was reviewed, and the last modifications of the successful traditional splitting procedure are presented narrowly. It indicates the better the split is preformatted by osteotomies, the less torque force is needed while splitting, giving more controle, a better predictability of the lingual fracture and maybe less neurosensory disturbances of the inferior alveolar nerve.