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 [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Considerando a variável anatomia como um possível fator de risco para o desenvolvimento de fraturas indesejadas após a osteotomia sagital do ramo mandibular (OSRM), este estudo avaliou a influência da espessura óssea sob o padrão de fratura entre os seguimentos proximal (contendo o côndilo) e distal (contendo o processo alveolar) após a OSRM. Para tanto, foram selecionadas tomografias pré e pós-operatórias de 31 pacientes (62 OSRM) com deformidade dento-esquelética-facial com tratamento ortodôntico-cirúrgico prévio. As tomografias foram analisadas utilizando o software Dolphin 3D 11.8. Nos exames pré-operatórios considerou-se 4 medidas da espessura óssea no sentido vestíbulo-lingual, em áreas pré determinadas da OSRM: Região A - 1,5 milímetros (mm) 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 6 mm da base inferior da mandíbula. Nos exames pós-operatórios, analisou-se o padrão de fratura gerado, classificando-o em I (Hunsuck verdadeiro), II (cortical posterior), III (através do canal mandibular) ou IV(fratura indesejada), conforme classificação de Plooij et al. Após teste de normalidade, os dados foram analisados pelo teste estatístico não paramétrico de Kruskal-Wallis seguido do pós-teste de Dunn. Encontrou-se 35 fraturas com padrão tipo I; 01 fratura tipo II; 19 tipo III e 07 padrão IV. O tipo I obteve as maiores médias de espessura nas 4 regiões analisadas, em contrapartida o padrão IV apresentou as menores médias. A variável espessura óssea foi estatisticamente significante apenas para a mensuração A analisado entre os padrões de fratura tipo I e IV. Dessa forma, conclui-se que mandíbulas menos espessas na região do ramo mandibular são mais propensas as fraturas indesejadas e que na metodologia empregada as espessuras nos locais B, C e D não influenciaram o padrão de separação após a OSRM.
Considering the variable anatomy as a possible risk factor for the development of undesirable fractures after bilateral sagittal split osteotomy (BSSO). This study evaluates the split pattern after BSSO and its correlation with the bone thickness. Pre and postoperative computed tomographies of 31 patients (62 BSSO) 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 milimeter (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.
Considering the variable anatomy as a possible risk factor for the development of undesirable fractures after bilateral sagittal split osteotomy (BSSO). This study evaluates the split pattern after BSSO and its correlation with the bone thickness. Pre and postoperative computed tomographies of 31 patients (62 BSSO) 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 milimeter (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.