The surgical correction of mandibular protraction, retraction, and fractures of the ascending rami

Abstract

Summary Corrective surgery of the mandible should fulfill certain definite mechanical and functional requirements that deal with three essential considerations: 1. Anatomic restoration and symmetry of this bone as a whole. 2. Proper functional position of the temporomandibular joints. 3. The maintenance or restoration of proper dental occlusion. The principles involved are discussed and illustrated. The history and present position of surgery applied to prognathism and micrognathism are defined and analyzed from the standpoints of technical objections and advantages. Transection of the ascending rami through a direct surgical approach is advocated as the method of choice. The blind method of performing this operation in current use has some serious objections and falls far short of achieving a proper end-result. The surgical and mechanical requirements of transposition of the mandible are discussed and illustrated. A prescribed position and direction of osteotomy of the ascending rami is indicated in every case. The position of osteotomy should be constant within a central area of three-sixteenths of an inch. The direction of osteotomy should be predetermined by the angle and mass of mandibular deformity and by the type of malrelationship of the dental arches. A direct surgical approach offers the only means of meeting these requirements. An operative procedure for the correction of mandibular protraction and retraction is presented. It consists of a direct surgical approach that permits visible osteotomy in the proper direction and in the area suitable for transection of the vertical rami. The method of performance is described and illustrated. A supplementary operation to complete the cosmetic correction of microgenia is described and illustrated. The application of the surgical approach devised for the correction of prognathism and microgenia to osteosynthesis of certain fractures of the ascending rami is discussed.