J Korean Assoc Oral Maxillofac Surg.  1997 Nov;23(4):561-580.

A CLINICAL STUDY ON PROGNOSIS OF INTRAORAL VERTICAL RAMUS OSTEOTOMY FOR MANDIBULAR SET-BACK IN THE MANDIBULAR PROGNATHISM

• Park HS

Abstract

Intraoral Vertical Ramus Osteotomy(IVRO) is a typical osteotomy procedure to setback the mandible for the prognathic patients and has many advantages functionally and morphologically, however, available data to predict the progressive prognosis on the functional rehabilitation of the mandible and the morphological change of the rami of the mandible after IVRO has been less reported. This is a prospective study for the progressive changes on the functional rehabilitation and the morphology of the rami of the mandible after IVRO for the Korean Prognathisms. 38 patients were studied for the functional rehabilitation and 21 patients were for the morphological change. Maxillo-Mandibular Fixation(MMF) was maintained for two weeks after IVRO and active physiotherapy was applied by means of Park's Protocol for next two weeks. Progressive change of the range of motion after release of MMF at maximum mouth opening, protrusion, lateral excursion(right and left) was recorded daily for 15days, and also recorded at 1st, 3rd, 6th, 12th, 18th months on the flow charts in the group for functional rehabilitation study. Nine measurements were measured to check morphological changes of the rami of the mandible at Immediate, 1, 3, 6 and 12 months postoperative period on Panex, P-A and Lateral Cephalometrics. The results were obtained as followings : 1. Mandibular function was returned rapidly during early 5 days after release of MMF, and reached to the almost normal range within 15days. And then slowly and progressively increased more and more afterward. 2. Recovery rate of the mandibular function after IVRO was depended upon the forcible application of a well-oriented protocol for active physiotherapy during early stage(within 15 days) after release of MMF. 3. Evidences of cortex-to-cortex healing between proximal and distal segments of the Mandible(CNS, CA, DOA on Panex) were definitely observed. They were changed slowly from immediate to 3 months but changed remarkably from 3 to 6 months of postoperative period, and then showed continuous but very slow changes afterward. 4. Vertical lengths of the proximal segments(RL, LL) were reduced remarkably from immediate to 3 month of postoperative period, and more slowly reduced from 3 to 6th month period, and then constantly reduced afterward as mimic rate. 5. Transverse distance between proximal segments(TL) was reduced rapidly within one month postoperatively and showed more slow and stable changes until one year follow-up period. 6. The gap between proximal and distal segments was disappeared rapidly within 6 month postoperatively, and then reduced very slowly afterward. 7. The change of Gonial angle(GA) was rapidly increased within one month of postoperative period and then increased very slowly afterward. In summary, mandibular function was returned to almost normal within two weeks after release of MMF, and osseous union was completely established between the proximal and distal segments without any complications in spite of early functional movement of the mandible without fixation between fragments. Morphological changes on the rami of the mandible was remarkable within 3 month period of postoperative and then continuously remodeled until one-year follow-up period. The application of a forcible and well-oriented protocol of active physiotherapy immediate after release of MMF may be the most important factor for prognosis of rehabilitation and morphological changes in IVRO.

MeSH Terms

Follow-Up Studies
Humans
Mandible
Mouth
Osteotomy*
Postoperative Period
Prognathism*
Prognosis*
Prospective Studies
Range of Motion, Articular
Reference Values
Rehabilitation