Measurement of Mandibular Angle for Universal Wedge Osteotomy in Vascularised Fibula Reconstruction

Abstract

Background: Precise osteotomies from vascularised fibula flap, during mandibular reconstruction, ensure proper adaptation to replicate the mandible contour and the angle between osteotomies (or the reverse mandibular angle) is what brings about accurate adaptation for improved form and function. Therefore, we present a cheap and simple technique were a 3D information is transferred from a panoramic image using a cardboard paper, to a mandibular angle osteotomy cut to achieve adequate adaptation and contouring of the reconstruction.  

Materials and methods: Consecutive panoramic images taken at the radio diagnosis sub-unit, of the dental center of my institution, were retrieved from the database. The panoramic image files were converted to a DICOM file using MicroDicom DICOM Viewer 3.7.7 (2020), (free online tool). Digital measurement of the mandibular angle was undertaken using Miele - LXIV DICOM viewer workstation for macr. GPI-3.0 license (free online tool). Angle measured was between a line drawn from the two outermost points on the posterior border of the condyle and vertical ramus, and another line drawn between the two lowermost points on the horizontal ramus and body/parasymphysis. The reverse mandibular angle was 1800 minus the measured mandibular angle.  

Results: A total of 101 panoramic images were selected for analysis, out of which 196 angles were measured of which 70 were males and 31 were females. The median age for all subjects was 27 years. The mean female mandibular right angle was 122.220 and the left angle was 121.510 while the mean male right mandibular angle was 122.320 and the left angle was 122.770 (p<0.042). The mean reverse mandibular angles was 580.  

Conclusion: Through measurement of 196 mandibular angles from corresponding panoramic images, we put forward an ideal wedge osteotomy cut angle of 580 transferred to the fibula through a disposable sterile cardboard paper, to reconstruct the horizontal and vertical mandibular rami for all patients