TY - JOUR
T1 - Pedicle growth asymmetry as a cause of adolescent idiopathic scoliosis
T2 - A biomechanical study
AU - Huynh, Anne Marie
AU - Aubin, Carl Eric
AU - Rajwani, Talib
AU - Bagnall, Keith M.
AU - Villemure, Isabelle
N1 - Funding Information:
Acknowledgments This work was supported by the Canadian Institutes of Health Research (CIHR), the CIHR Training Program in Mobility and Posture Disorders, the Alberta Provincial CIHR Training Program in Bone and Joint Health, the Réseau Provincial de Recherche en Adaptation-Réadaptation, and the Alberta Heritage Foundation for Medical Research. The scientific and technical assistance of Josée Carrier is gratefully acknowledged.
PY - 2007/4
Y1 - 2007/4
N2 - Over the last century the neurocentral junction (NCJ) has been identified as a potential cause of adolescent idiopathic scoliosis (AIS). Disparate growth at this site has been thought to lead to pedicle asymmetry, which then causes vertebral rotation and ultimately, the development of scoliotic curves. The objectives of this study are (1) to incorporate pedicle growth and growth modulation into an existing finite element model of the thoracic and lumbar spine already integrating vertebral body growth and growth modulation; (2) to use the model to investigate whether pedicle asymmetry, either alone or combined with other deformations, could be involved in scoliosis pathomechanisms. The model was personalized to the geometry of a nonpathological subject and used as the reference spinal configuration. Asymmetry of pedicle geometry (i.e. initial length) and asymmetry of the pedicle growth rate alone or in combination with other AIS potential pathogenesis (anterior, lateral, or rotational displacement of apical vertebra) were simulated over a period of 24 months. The Cobb angle and local scoliotic descriptors (wedging angle, axial rotation) were assessed at each monthly growth cycle. Simulations with asymmetrical pedicle geometry did not produce significant scoliosis, vertebral rotation, or wedging. Simulations with asymmetry of pedicle growth rate did not cause scoliosis independently and did not amplify the scoliotic deformity caused by other deformations tested in the previous model. The results of this model do not support the hypothesis that asymmetrical NCJ growth is a cause of AIS. This concurs with recent animal experiments in which NCJ growth was unilaterally restricted and no scoliosis, vertebral wedging, or rotation was noted.
AB - Over the last century the neurocentral junction (NCJ) has been identified as a potential cause of adolescent idiopathic scoliosis (AIS). Disparate growth at this site has been thought to lead to pedicle asymmetry, which then causes vertebral rotation and ultimately, the development of scoliotic curves. The objectives of this study are (1) to incorporate pedicle growth and growth modulation into an existing finite element model of the thoracic and lumbar spine already integrating vertebral body growth and growth modulation; (2) to use the model to investigate whether pedicle asymmetry, either alone or combined with other deformations, could be involved in scoliosis pathomechanisms. The model was personalized to the geometry of a nonpathological subject and used as the reference spinal configuration. Asymmetry of pedicle geometry (i.e. initial length) and asymmetry of the pedicle growth rate alone or in combination with other AIS potential pathogenesis (anterior, lateral, or rotational displacement of apical vertebra) were simulated over a period of 24 months. The Cobb angle and local scoliotic descriptors (wedging angle, axial rotation) were assessed at each monthly growth cycle. Simulations with asymmetrical pedicle geometry did not produce significant scoliosis, vertebral rotation, or wedging. Simulations with asymmetry of pedicle growth rate did not cause scoliosis independently and did not amplify the scoliotic deformity caused by other deformations tested in the previous model. The results of this model do not support the hypothesis that asymmetrical NCJ growth is a cause of AIS. This concurs with recent animal experiments in which NCJ growth was unilaterally restricted and no scoliosis, vertebral wedging, or rotation was noted.
KW - Biomechanical modeling
KW - Growth modulation
KW - Idiopathic scoliosis
KW - Neurocentral junction
KW - Spine
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U2 - 10.1007/s00586-006-0235-4
DO - 10.1007/s00586-006-0235-4
M3 - Article
C2 - 17031702
AN - SCOPUS:34247187462
SN - 0940-6719
VL - 16
SP - 523
EP - 529
JO - European Spine Journal
JF - European Spine Journal
IS - 4
ER -