Accuracy between virtual surgical planning and actual outcomes in orthognathic surgery by iterative closest point algorithm and color maps: A retrospective cohort study

Background: To evaluate the accuracy between actual outcomes and virtual surgical planning (VSP) in orthognathic surgery regarding the use of three-dimensional (3D) surface models for registration using iterative closest point (ICP) algorithm and generated color maps. Material and Methods: Construction of planning and postoperative 3D models in STL files format (M0 and M1, respectively) from CBCT of 25 subjects who had been submitted to bimaxillary orthognathic surgery was performed. M0 and M1 were sent to Geomagic software in semi-automatic alignment surface mesh order of M0 and M1 for registration using ICP algorithm to calculate mean deviation (MD, MD+, MD-, SD) and root mean square (RMS - 3D Error). Color maps were generated to assess qualitative congruence between M0 and M1. From deviation analysis, 3D Error was defined as accuracy measurement. To assess the reproducibility, the workflow was performed by two evaluators multiple times. t-tests were used to assess whether all means of MD, MD+, MD-, SD and 3D Error values would be ≤ - 2 mm and ≥ 2 mm. Results: High intra and inter evaluators correlation were found, supporting the reproducibility of the workflow. t-tests proved that all MDs and 3D Error values were > - 2 mm and < 2 mm. Conclusions: 3D error mean was within the standards of clinical success lower than 2 mm. ICP algorithm provided a reproducible method of alignment between 3D models and generated color maps to evaluate 3D congruence but did not answer all methodological parameters regarding the assessment of accuracy in orthognathic surgery

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Comparação de diferentes planejamentos em cirurgia ortognática para tratamento de assimetrias faciais: relato de casos / Comparison between planning in orthoganathic surgery for treating facial asymmetries: case reports

Introdução: a cirurgia ortognática envolve a correção de desarmonias funcionais e estéticas. A hiperplasia condilar (HC) unilateral resulta em crescimento mandibular acentuado, provocando assimetria facial. Para obter previsibilidade e sucesso nos resultados, é imprescindível planejamento preciso e adequado. Objetivo: descrever e comparar diferentes métodos de planejamento e seus resultados no pós-operatório no tratamento de pacientes com assimetria facial. Relato de caso: foram avaliados 03 casos orto-cirúrgicos (A, B e C) de pacientes adultos jovens, com média de idade de 22 anos, portadores de má oclusão esquelética de Classe III, com assimetria facial resultante de HC inativa. Foi realizada análise facial e empregou-se dois métodos de planejamento em cirurgia ortognática (convencional e virtual). O caso A foi planejado por meio de imagens bidimensionais (2D) e sequência cirúrgica iniciada pela maxila. O caso B foi planejado por imagens 2D associado ao recurso de simulação em protótipo. Por fim, o caso C foi planejado exclusivamente com imagens tridimensionais (3D) e simulação virtual, sendo que os casos B e C utilizaram sequência cirúrgica iniciada pela mandíbula. Foi utilizado o software Dolphin Imaging® em todos os planejamentos e os mesmos foram transferidos para os procedimentos cirúrgicos com auxílio dos guias em resina acrílica estereolitográfica. Conclusão: os planejamentos demonstraram eficácia em termos de previsibilidade e viabilidade para a correção das assimetrias faciais, sendo todos os resultados considerados satisfatórios por parte dos cirurgiões e dos pacientes. Houve tendência de melhores resultados quando da utilização de prototipagem, das imagens 3D e sequência operatória iniciada pela mandíbula, no planejamento.

Introduction: orthognathic surgery provides correction of functional and esthetic disharmony. Condylar hyperplasia induces in pronounced mandibular growth, resulting facial asymmetry. Planning is important to get predictable and successful on outcomes. Purpose: to describe and compare methods of planning and post-operative outcomes by reporting three cases associated with facial asymmetries. Case report: a total of 03 young adult patients (cases A, B and C), mean of age 22 years old, Class III skeletal malocclusion, and facial asymmetry after inactive condylar hyperplasia were evaluated. They were undergone facial analysis, two methods of planning in orthognathic surgery (conventional and virtual). Patient A was planned by bidimensional (2D) images and maxilla first sequence. Patient B was planned by 2D images associated with simulating on surface mesh prototyping. And, Patient C was solely planned by three-dimensional (3D) images and virtual surgical planning. Patients B and C used mandible first sequence. Dolphin Imaging software was used on each planning. Each planning was transferred to surgical procedures by assisting of the guides manufactured (acrylic resin and stereolithography). Patients were usually assessed during post-operative and were pleasured with outcomes. Conclusion: planning showed predictable and feasibility for facial asymmetries because outcomes were great. There was a propensity of better outcomes when surface mesh, 3D images and mandible first sequence were used at the treatment planning.

Efficacy of Gastric Aspiration in Reducing Postoperative Nausea and Vomiting After Orthognathic Surgery: A Double-Blind Prospective Study.

PURPOSE: To determine whether gastric aspiration performed after orthognathic surgery, in conjunction with a prophylactic protocol, could prevent postoperative nausea and vomiting (PONV). PATIENTS AND METHODS: Twenty-four consecutive patients treated at a single academic institution were included in this double-blinded randomized control trial and were divided into control (n = 12) and study (n = 12) groups. Patients underwent orthognathic surgery, and the same anesthetic protocol was used for the 2 groups. The only difference between groups was the performance of gastric aspiration in the study group. Patients were observed during the first postoperative day, and information concerning PONV was collected and statistically analyzed. RESULTS: The 2 groups were similar in age, gender, and medical history. There was no statistically relevant difference between the control and study groups in the overall incidence of PONV (33.3 vs 33.3%). However, there was a significant correlation between the presence of PONV after turbinectomy (P = .011) and patient dissatisfaction (P = .049). CONCLUSION: The results of this study could not associate the performance of gastric aspiration with a decrease in the incidence of PONV after orthognathic surgery.