A Biomechanical Analysis of Muscle Force Changes After Bilateral Sagittal Split Osteotomy

A basic procedure affecting maxillofacial geometry is the bilateral sagittal split osteotomy. During the surgery, the bony segments are placed in a new position that provides the correct occlusion. Changes in the geometry of the mandible will affect the surrounding structures and will have a significant impact on the functioning of the masticatory system. As a result of the displacement of the bone segment, the biomechanical conditions change, i.e., the load and the position of the muscles. The primary aim of this study was to determine the changes in the values of the muscular forces caused by mandible geometry alteration. The study considered the translation and rotation of the distal segment, as well as rotations of the proximal segments in three axes. Calculations were performed for the unilateral, static loading of a model based on rigid body mechanics. Muscles were modeled as spring elements, and a novel approach was used to determine muscle stiffness. In addition, an attempt was made, based on the results obtained for single displacements separately, to determine the changes in muscle forces for geometries with complex displacements. Based on the analysis of the results, it was shown that changes in the geometry of the mandibular bone associated with the bilateral sagittal split osteotomy will have a significant effect on the values of the masticatory muscle forces. Displacement of the distal segment has the greatest effect from −21.69 to 26.11%, while the proximal segment rotations affected muscle force values to a less extent, rarely exceeding 1%. For Yaw and Pitch rotations, the opposite effect of changes within one muscle is noticed. Changes in muscle forces for complex geometry changes can be determined with a high degree of accuracy by the appropriate summation of results obtained for simple cases.

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Ultrasonic vertical osteotomy of the distal segment for safe elimination of interference between the proximal and distal segments in bilateral sagittal split osteotomy for mandibular asymmetry

British Journal of Oral and Maxillofacial Surgery ◽

10.1016/j.bjoms.2012.05.012 ◽

2013 ◽

Vol 51 (7) ◽

pp. e192-e194 ◽

Cited By ~ 6

Author(s):

Toshinori Iwai ◽

Jiro Maegawa ◽

Shinjiro Aoki ◽

Iwai Tohnai

Keyword(s):

Distal Segment ◽

Mandibular Asymmetry ◽

Sagittal Split Osteotomy ◽

Bilateral Sagittal Split Osteotomy

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Biomechanical Analysis of the Forces Exerted during Different Occlusion Conditions following Bilateral Sagittal Split Osteotomy Treatment for Mandibular Deficiency

Applied Bionics and Biomechanics ◽

10.1155/2019/4989013 ◽

2019 ◽

Vol 2019 ◽

pp. 1-10 ◽

Cited By ~ 1

Author(s):

Yuan-Han Chang ◽

Man-Yee Chan ◽

Jui-Ting Hsu ◽

Han-Yu Hsiao ◽

Kuo-Chih Su

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

High Stress ◽

Biomechanical Analysis ◽

Von Mises Stress ◽

Intermaxillary Fixation ◽

Element Analysis ◽

Sagittal Split Osteotomy ◽

Bilateral Sagittal Split Osteotomy ◽

External Forces

The bilateral sagittal split osteotomy (BSSO) technique is commonly used to correct mandibular deficiency. If the patient is exposed to excessive external forces after the procedure, occlusal changes or nonunion may occur. However, previous studies only focused on single external forces on the mandible and did not conduct relevant research on the forces exerted by different occlusion conditions. The main purpose of this study was to use finite element analysis methods to determine the biomechanics of four common occlusion conditions after BSSO surgical treatment. This study constructed a finite element analysis computer model of a miniplate implanted in the lower jaw. The structure of the model consisted of the mandible, miniplate, and screws. In addition, external forces were applied to the superficial masseter, deep masseter, medial pterygoid, anterior temporalis, middle temporalis, and posterior temporalis muscles to simulate the incisal clench, intercuspal position (ICP), right unilateral molar clench (RMOL), and right group function occlusion conditions. Subsequently, this study observed the effects of these conditions on the miniplate, screws, and mandible, including the von Mises stress values. The results showed that all of the different occlusion conditions that this study evaluated placed high stress on the miniplate. In the ICP and RMOL occlusion conditions, the overall mandibular structure experienced very high stress. The screw on the proximal segment near the bone gap experienced high stress, as did the screw on the buccal side. According to the present analysis, although the data were not directly obtained from clinical practice, the finite element analysis could evaluate the trend of results under different external forces. The result of this study recommended that patients without intermaxillary fixation avoid the ICP and RMOL occlusion conditions. It can be used as a pilot study in the future for providing clinicians more information on the biomechanics of implantation.

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Assessment of rigidity and strength of selected osteosyntheses after bilateral sagittal split osteotomy

Physiotherapy ◽

10.2478/v10109-009-0020-0 ◽

2008 ◽

Vol 16 (2) ◽

Author(s):

Przemyslaw Stróżyk ◽

Agnieszka Szust ◽

Rafal Nowak

Keyword(s):

Sagittal Split Osteotomy ◽

Bilateral Sagittal Split Osteotomy

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Subjective perception of paraesthesia of the lower lip after bilateral sagittal split osteotomy at a district general hospital

British Journal of Oral and Maxillofacial Surgery ◽

10.1016/j.bjoms.2018.02.017 ◽

2018 ◽

Vol 56 (6) ◽

pp. 490-495 ◽

Cited By ~ 1

Author(s):

E. Mackinnon ◽

K. Bajaj ◽

D. Tighe ◽

M. Williams

Keyword(s):

General Hospital ◽

District General Hospital ◽

Subjective Perception ◽

Lower Lip ◽

Sagittal Split Osteotomy ◽

Bilateral Sagittal Split Osteotomy

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Knee Muscle Force Estimating Model Using Machine Learning Approach

The Computer Journal ◽

10.1093/comjnl/bxaa160 ◽

2020 ◽

Author(s):

Anurag Sohane ◽

Ravinder Agarwal

Keyword(s):

Machine Learning ◽

Random Forest ◽

Muscle Force ◽

Vastus Lateralis ◽

Input Parameter ◽

Research Work ◽

Cost Effective ◽

Coefficient Of Determination ◽

Muscle Forces ◽

Knee Muscle

Abstract Various simulation type tools and conventional algorithms are being used to determine knee muscle forces of human during dynamic movement. These all may be good for clinical uses, but have some drawbacks, such as higher computational times, muscle redundancy and less cost-effective solution. Recently, there has been an interest to develop supervised learning-based prediction model for the computationally demanding process. The present research work is used to develop a cost-effective and efficient machine learning (ML) based models to predict knee muscle force for clinical interventions for the given input parameter like height, mass and angle. A dataset of 500 human musculoskeletal, have been trained and tested using four different ML models to predict knee muscle force. This dataset has obtained from anybody modeling software using AnyPyTools, where human musculoskeletal has been utilized to perform squatting movement during inverse dynamic analysis. The result based on the datasets predicts that the random forest ML model outperforms than the other selected models: neural network, generalized linear model, decision tree in terms of mean square error (MSE), coefficient of determination (R2), and Correlation (r). The MSE of predicted vs actual muscle forces obtained from the random forest model for Biceps Femoris, Rectus Femoris, Vastus Medialis, Vastus Lateralis are 19.92, 9.06, 5.97, 5.46, Correlation are 0.94, 0.92, 0.92, 0.94 and R2 are 0.88, 0.84, 0.84 and 0.89 for the test dataset, respectively.

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