Influência da anatomia óssea no padrão de separação da osteotomia sagital do ramo mandibular
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Data
2018-03-08
Autores
Cunha, Giovanni
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Este estudo avaliou o padrão da separação da osteotomia sagital do ramo mandibular, sob o aspecto lingual e a influência da espessura óssea correlacionando a esse padrão. Para tanto, foram selecionadas tomografias pré e pós-operatórias de 31 pacientes com deformidade dento-esquelética facial que haviam sido submetidos a tratamento ortodôntico-cirúrgico para correção de deformidade facial dento-esquelética. As tomografias foram analisadas utilizando o software Dolphin 3D 11.8. Foram avaliadas 62 osteotomias sagitais do ramo mandibular (OSRM). Nos exames tomográficos pré-operatórios foram consideradas 4 medidas de espessura no sentido vestíbulo lingual, em áreas pré determinadas da osteotomia: Região A - 1,5mm acima da língula mandibular, Região B - 1mm distante da borda anterior de ramo (Região A e B na altura da osteotomia medial), Região C - 5mm distalmente ao segundo molar e 5mm a partir da borda superior (região retromolar) Região D - região de entre as raízes distal e mesial do 1º e 2º molares inferiores, distando 5 mm da base inferior da mandíbula. Nos exames pós-operatórios, foi analisado o padrão de fratura gerada, classificado em padrão I, II, III ou IV, conforme classificação de Plooij et al. Os dados coletados foram analisados pelo teste estatístico de Kruskal-Wallis seguido do pós-teste de Dunn. Foram encontradas 35 fraturas com padrão tipo I; 01 fratura padrão tipo II; 19 do padrão tipo III e 07 fraturas de padrão tipo IV. O padrão I obteve as maiores médias de espessura nos 4 regiões analisadas, enquanto que o padrão IV apresentou as menores médias nas 4 medidas. A variável espessura óssea foi estatisticamente significante apenas para a mensuração A analisado entre os padrões de fratura tipo I e IV. Dessa forma, pode-se concluir que mandíbulas menos espessas na região do ramo mandibular apresentam maior probabilidade de fratura incorreta e que as espessuras nos locais B, C e D não influenciaram no padrão de separação resultante.
This study evaluates the split pattern after sagittal split ramus osteotomy and its correlation with the bone thickness. Pre and postoperative computed tomographies of 31 patients submitted to orthognathic surgery for corrections of dentofacial deformities were used in the study. Dicom images were analyzed using the software Dolphin 3D 11.8. In the preoperative tomographies 4 thickness measurements were considered: A - 1.5 mm above the lingula. B - 1mm from the anterior border of the ramus (A and B points at the height of the medial osteotomy cut). C - 5mm distally to the second molar and 5mm from the upper border of the mandible (retromolar region) D - In the region between the mesial and distal roots of the first and second mandibular molars. In the postoperative tomographies the exams were analyzed and classified according to the fracture pattern described in the literature, where I (true Hunsuk), II (posterior cortical of the branch), III (through the mandibular canal) and IV (bad split). The data were analyzed by the Kruskal-Wallis test followed by the Dunn post-test. Results showed 35 type I fractures, 01 type II fracture, 19 type III fractures and 07 type IV fractures. Type I presented the highest thickness average values for the four considered measurements, whereas type IV presented the lowest values for all measurements. The variable bone thickness was statistically significant only for point A, when the types I and IV were compared. Results allowed to conclude that mandibles with thinner mandibular rami are more prone to bad splits and that thickness at points B, C and D did not influence the fracture patterns.
This study evaluates the split pattern after sagittal split ramus osteotomy and its correlation with the bone thickness. Pre and postoperative computed tomographies of 31 patients submitted to orthognathic surgery for corrections of dentofacial deformities were used in the study. Dicom images were analyzed using the software Dolphin 3D 11.8. In the preoperative tomographies 4 thickness measurements were considered: A - 1.5 mm above the lingula. B - 1mm from the anterior border of the ramus (A and B points at the height of the medial osteotomy cut). C - 5mm distally to the second molar and 5mm from the upper border of the mandible (retromolar region) D - In the region between the mesial and distal roots of the first and second mandibular molars. In the postoperative tomographies the exams were analyzed and classified according to the fracture pattern described in the literature, where I (true Hunsuk), II (posterior cortical of the branch), III (through the mandibular canal) and IV (bad split). The data were analyzed by the Kruskal-Wallis test followed by the Dunn post-test. Results showed 35 type I fractures, 01 type II fracture, 19 type III fractures and 07 type IV fractures. Type I presented the highest thickness average values for the four considered measurements, whereas type IV presented the lowest values for all measurements. The variable bone thickness was statistically significant only for point A, when the types I and IV were compared. Results allowed to conclude that mandibles with thinner mandibular rami are more prone to bad splits and that thickness at points B, C and D did not influence the fracture patterns.
Descrição
Palavras-chave
Cirurgia ortognática, Osteotomia sagital do ramo mandibular, Tomografia computadorizada de feixe cônico espiral, Ortognathic surgery, Bilateral sagittal split osteotomy, Spiral cone-beam computed tomography.