A new technique for mandibular osteotomy

Sagittal split osteotomy (SSO) is a surgical technique largely employed for mandibular mobilizations in orthognatic procedures. However, the traditional design of buccal osteotomy, located at the junction of mandibular ramus and body, may prevent more extensive sliding between the bone segments, particularly on the advance, laterality and verticality of the mandibular body. The author proposes a new technical and conceptual solution, in which osteotomy is performed in a more distal region, next to the mental formamen. Technically, the area of contact between medullary-cancellous bone surfaces is increased, resulting in larger sliding rates among bone segments; it also facilitates the use of rigid fixation systems, with miniplates and monocortical screws. Conceptually, it interferes with the resistance arm of the mandible, seen as an interpotent lever of the third gender

Evaluation of the bending strength of rigid internal fixation with absorbable and metallic screws in mandibular ramus sagittal split osteotomy: in vitro study Avaliação da resistência à flexão da fixação interna rígida, com parafusos absorvíveis e metálicos, na osteotomia sagital do ramo mandibular: estudo in vitro

The aim of this study was to evaluate, in vitro, the bending strength of internal fixation with absorbable and metallic screws in mandibular ramus sagittal split osteotomy in sheep hemimandibles. The screws were inserted as lag screws, with an inverted "L" configuration, and the set was submitted to bending strength tests. The load and displacement of the peak and final load averages were, respectively, 18.45 kgf, 8.19 mm and 14.38 kgf for Group I, and 16.67 kgf, 6.73 mm and 13.98 kgf for Group II. The results were submitted to statistical analysis by Student’s t test and by the Pearson correlation analysis. The groups showed no statistically significant differences, indicating the feasibility of both for osteosynthesis in mandibular ramus sagittal split osteotomies.<br>O objetivo deste estudo foi avaliar, in vitro, a resistência à flexão da fixação interna, através do uso de parafusos absorvíveis e metálicos, na osteotomia sagital do ramo em hemimandíbulas de carneiros. Os parafusos foram inseridos como "lag screw", com configuração em "L" invertido e o conjunto submetido ao teste de resistência à flexão. As médias da carga e do deslocamento do pico e da carga final do Grupo I foram de 18,45 kgf, 8,19 mm e 14,38 kgf, e do Grupo II de 16,67 kgf, 6,73 mm e 13,98 kgf, respectivamente. Os resultados foram submetidos à análise estatística pelo teste t de Student e pela análise de correlação de Pearson. Os grupos exibiram diferenças estatisticamente não significativas, indicando a viabilidade de ambos para a osteossíntese em osteotomias sagitais do ramo mandibular