TY - JOUR
T1 - Modeling the biomechanics of swine mastication - An inverse dynamics approach
AU - Basafa, Ehsan
AU - Murphy, Ryan J.
AU - Gordon, Chad R.
AU - Armand, Mehran
N1 - Funding Information:
This study was made possible, in part, by the Johns Hopkins Institute for Clinical and Translational Research (ICTR) which is funded in part by the National Center for Advancing Translational Sciences (NCATS), a component of the National Institutes of Health (NIH), and National Institutes of Health Roadmap for Medical Research. Its contents are solely the responsibility of the authors and do not necessarily represent the official view of the Johns Hopkins ICTR, NCATS or NIH [NCATS grant # UL1TR000424-06 ].
Funding Information:
We thank Dr. Ian Stavness of University of Saskatchewan and Ms. Michala Cadova of University of Zurich for their valuable insights regarding musculoskeletal modeling of mastication. We also thank Dr. Ali Nabavizadeh of Johns Hopkins School of Medicine for his help with understanding of swine anatomy of mastication and setting up the model. Also, we thank Capt. Gerald Grant and Dr. Peter Liacouras of Walter Reed National Military Medical Center for their collaborative efforts and providing the swine surface models used in this analysis. Funding was provided by the 2011 Basic Science Research grant from American Society of Maxillofacial Surgeons , 2012-14 Academic Scholar Award from American Association of Plastic Surgeons , the Accelerated Translational Incubator Program Award at Johns Hopkins University׳s Institute for Clinical and Translational Research (funded by National Institutes of Health (Grant no. UL1TR000424-06 )), Independent Research and Development grant from Johns Hopkins University Applied Physics Laboratory , and the Abell Foundation Award/ Johns Hopkins Alliance for Science and Technology Development . The above funding entities had no role in the study design, data collection, analysis of the data, writing of the manuscript, or the decision to submit the manuscript for publication.
PY - 2014/8/22
Y1 - 2014/8/22
N2 - A novel reconstructive alternative for patients with severe facial structural deformity is Le Fort-based, face-jaw-teeth transplantation (FJTT). To date, however, only ten surgeries have included underlying skeletal and jaw-teeth components, all yielding sub-optimal results and a need for a subsequent revision surgery, due to size mismatch and lack of precise planning. Numerous studies have proven swine to be appropriate candidates for translational studies including pre-operative planning of transplantation. An important aspect of planning FJTT is determining the optimal muscle attachment sites on the recipient[U+05F3]s jaw, which requires a clear understanding of mastication and bite mechanics in relation to the new donated upper and/or lower jaw. A segmented CT scan coupled with data taken from literature defined a biomechanical model of mandible and jaw muscles of a swine. The model was driven using tracked motion and external force data of one cycle of chewing published earlier, and predicted the muscle activation patterns as well as temporomandibular joint (TMJ) reaction forces and condylar motions. Two methods, polynomial and min/max optimization, were used for solving the muscle recruitment problem. Similar performances were observed between the two methods. On average, there was a mean absolute error (MAE) of <0.08 between the predicted and measured activation levels of all muscles, and an MAE of <7. N for TMJ reaction forces. Simulated activations qualitatively followed the same patterns as the reference data and there was very good agreement for simulated TMJ forces. The polynomial optimization produced a smoother output, suggesting that it is more suitable for studying such motions. Average MAE for condylar motion was 1.2. mm, which reduced to 0.37. mm when the input incisor motion was scaled to reflect the possible size mismatch between the current and original swine models. Results support the hypothesis that the model can be used for planning of facial transplantation.
AB - A novel reconstructive alternative for patients with severe facial structural deformity is Le Fort-based, face-jaw-teeth transplantation (FJTT). To date, however, only ten surgeries have included underlying skeletal and jaw-teeth components, all yielding sub-optimal results and a need for a subsequent revision surgery, due to size mismatch and lack of precise planning. Numerous studies have proven swine to be appropriate candidates for translational studies including pre-operative planning of transplantation. An important aspect of planning FJTT is determining the optimal muscle attachment sites on the recipient[U+05F3]s jaw, which requires a clear understanding of mastication and bite mechanics in relation to the new donated upper and/or lower jaw. A segmented CT scan coupled with data taken from literature defined a biomechanical model of mandible and jaw muscles of a swine. The model was driven using tracked motion and external force data of one cycle of chewing published earlier, and predicted the muscle activation patterns as well as temporomandibular joint (TMJ) reaction forces and condylar motions. Two methods, polynomial and min/max optimization, were used for solving the muscle recruitment problem. Similar performances were observed between the two methods. On average, there was a mean absolute error (MAE) of <0.08 between the predicted and measured activation levels of all muscles, and an MAE of <7. N for TMJ reaction forces. Simulated activations qualitatively followed the same patterns as the reference data and there was very good agreement for simulated TMJ forces. The polynomial optimization produced a smoother output, suggesting that it is more suitable for studying such motions. Average MAE for condylar motion was 1.2. mm, which reduced to 0.37. mm when the input incisor motion was scaled to reflect the possible size mismatch between the current and original swine models. Results support the hypothesis that the model can be used for planning of facial transplantation.
KW - Craniomaxillofacial Surgery
KW - Inverse dynamics
KW - Jaw biomechanics
KW - Swine mastication
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U2 - 10.1016/j.jbiomech.2014.05.019
DO - 10.1016/j.jbiomech.2014.05.019
M3 - Article
C2 - 24957923
AN - SCOPUS:84905250968
SN - 0021-9290
VL - 47
SP - 2626
EP - 2632
JO - Journal of Biomechanics
JF - Journal of Biomechanics
IS - 11
ER -