TOPOGRAPHICAL, ANATOMICAL AND GEOMETRIC CHARACTERISTICS SEGMENTAL DEFECTS OF THE MANDIBLE ACCORDING TO MULTISLICE COMPUTED TOMOGRAPHY

The mandible is the only movable bone of the facial bones, and is characterized by a unique anatomical structure and internal structure that provides the function of chewing, swallowing, speaking and it has a complex geometric configuration. The aim of present study was to evaluate topography and geometric shape of acquired mandibular defects and to develop objective diagnostic parameters for their preoperative assessment using multislice computed tomography, computer simulation and 3-D visualization. The material of this study was 60 patients with postoperative and post-traumatic defects of the mandible. To determine the geometric correspondence of defects of the mandible and standard bone autografts from the iliac crest and fibula on standardized mid-anatomical computer models (CAD) of the iliac and fibula bones, by virtual osteotomy, formed 3-D models of autografts to a given volume topographic and anatomical principles of their collection. Then the geometric parameters of the grafts was compared with the parameters of the jaw defects. The achieved shape will only conditionally approach the contour of the mandible, without reproducing its natural curvature. Compensation for these discrepancies is possible through the use of patient-specific anatomical fixators. Our standardized algorithm for determining the geometric parameters of the defect makes the measurement technique reproducible and easy to compare. The obtained values have a specific clinical and biological meaning. Conclusion. One of the possible ways to compensate for geometric inconsistencies is the use of combined patient-specific designs containing elements of the endoprosthesis and individualized fixator. When choosing the optimal type of bone graft, it is necessary to take into account its geometric correspondence of the defect, determined according to our proposed algorithm, as well as biomechanical and biological characteristics of the graft and recipient area.