Clinico-anatomical classification of the processus condylaris mandibulae for traumatological purposes

Mandible condyle fracture has been reported to constitute 9-45 % (Asprino and Consani, 2006), 14.1 % (Bataineh, 1998), 25-50 % (Silvennoinen, Iizuka, 1992), 32 % (Chrcanovic et al., 2004), and 38 % (Brasileiro and Passeri, 2006) of all mandible fractures (Kozakiewicz and Swiniarski, 2013). Small bone segments, limited available space for application of the fixation material and limited visibility of the operative field are common difficulties. To guarantee satisfactory treatment effects, anatomical reduction and proper fracture stability are necessary. The use of 3-4 screws in the upper section (proximal segment) provides adequate immobilization, which can be easily achieved when the condyle is low and wide. However, if the condyle is slender, it is not technically possible to fix 2 plates and 4 screws for osteosynthesis. Selection of the appropriate fixative material that will provide adequate rigidity during the healing period while simultaneously allowing proper construction of the lateral silhouette of the processus condylaris mandibulae to fix the plate remains a key consideration. The aim of this study was to evaluate clinico-anatomical classification of the condyle of mandible posture for traumatological purposes. Five hundred computer tomography virtual models were created, from which 11 measurements were made, and 2 indexes were calculated. Assessment of types based on the ratio of the condyle height index revealed a dichotomous division into high and short condyles. Statistically associated with the division, the Width_neck_basal (the width of the bone at the level of semilunar notch measured by a frontal projection perpendicular to line "A", as described by Neff (Neff et al., 2014)) measurement allowed the creation of the following clinico-anatomical classification: -slender-type condyles have a Width_neck_basal in the range of 4-8.5mm; -squad-type condyles have a Width_neck_basal in the range of 11.5-19.5mm. Patients with a Width_neck_basal value in the 8.5-11.5mm range cannot be classified using this method, and a different method to assess the lateral condylar silhouette must be used. The proposed clinic-anatomical classification method avoids the problems associated with incorrect osteosynthesis plate selection. Assignment to a group can be obtained by making one measurement (the Width_neck_basal). In that way, the optimal fixing material can be selected by the surgeon before the operation commences, with great intraoperation time savings.