Osteotomy length and postoperative stability in vertical subcondylar ramus osteotomy

Abstract

The osteotomy sites in 80 patients treated for mandibular prognathism by intraoral (IVSO) or extraoral (EVSO) vertical subcondylar ramus osteotomy and their relationships to postoperative mandibular stability were studied. A model study demonstrated that metric orthopantomographic measurements of the ramus showed insignificant variability of magnification and distortion. The relative osteotomy length and the bony overlapping area of the osteotomized fragments were evaluated on 6-week postoperative orthopantomograms. High correlation was found between the clinical estimate of osteotomy length and metric registrations. Bony overlapping area of the IVSO and the EVSO group did not reveal differences. The mandibular positional changes during the fixation/postfixation periods were analyzed on 6-week and 6-month postoperative lateral cephalograms. Significant correlations could not be demonstrated between postoperative stability and osteotomy length or overlapping bony area. Thus the osteotomy length appears to be factor of minor importance for postoperative stability.

Key Words:

• Clinical study
• mandibular prognathism
• maxillofacial surgery
• radiology

Additional information

Notes on contributors

Knut Tornes

Joyce Laing works in the Department of Child and Family Psychiatry, Playfield House, Cupar, Fife, and is a Consultant Art Therapist to Psychiatric Hospitals and Prisons and Chairwoman of the Scottish Society of Art and Psychology.