Segmental torso masses and joint torques produced by gravity in the adolescent scoliotic spine

Keenan, Bethany E., Izatt, Maree T., Askin, Geoffrey N., Pettet, Graeme J., Labrom, Robert D., Pearcy, Mark J., & Adam, Clayton J. (2013) Segmental torso masses and joint torques produced by gravity in the adolescent scoliotic spine. In Goh, James & Lim, ChweeTeck (Eds.) Proceedings of the 15th International Conference on Biomedical Engineering (ICBME 2013), IFMBE and Biomedical Engineering Society (Singapore), Singapore, p. 23.

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Abstract

Introduction Calculating segmental torso masses in Adolescent Idiopathic Scoliosis (AIS) patients allows the gravitational loading on the scoliotic spine during relaxed standing to be estimated.

Methods Low dose CT data was used to calculate vertebral level-by-level torso masses and spinal joint torques for 20 female AIS patients (mean age 15.0 ± 2.7 years, mean Cobb angle 53 ± 7.1°). ImageJ software (v1.45 NIH USA) was used to threshold the T1 to L5 CT images and calculate the segmental torso volume and mass for each vertebral level. Masses for the head, neck and arms were taken from published data.1 Intervertebral joint torques in the coronal and sagittal planes at each vertebral level were found from the position of the centroid of the segment masses relative to the joint centres (assumed to be at the centre of the intervertebral disc). The joint torque at each level was found by summing torque contributions for all segments above that joint.

Results Segmental torso mass increased from 0.6kg at T1 to 1.5kg at L5. The coronal plane joint torques due to gravity were 5-7Nm at the apex of the curve; sagittal torques were 3-5.4Nm.

Conclusion CT scans were in the supine position and curve magnitudes are known to be smaller than those in standing.2 Hence, this study has shown that gravity produces joint torques potentially of higher than 7Nm in the coronal plane and 5Nm in the sagittal plane during relaxed standing in scoliosis patients. The magnitude of these torques may help to explain the mechanics of AIS progression and the mechanics of bracing. This new data on torso segmental mass in AIS patients will assist biomechanical models of scoliosis.

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ID Code: 65263
Item Type: Conference Paper
Refereed: Yes
Additional URLs:
Keywords: Adolescent Idiopathic Scoliosis, Anthropometric Data, Body Segment Parameters, Computed Tomography, Scoliosis Progression, Torso Segment Masses, Gravity
ISBN: 9789810783655
Subjects: Australian and New Zealand Standard Research Classification > ENGINEERING (090000) > BIOMEDICAL ENGINEERING (090300) > Biomechanical Engineering (090302)
Australian and New Zealand Standard Research Classification > MEDICAL AND HEALTH SCIENCES (110000) > CLINICAL SCIENCES (110300) > Orthopaedics (110314)
Divisions: Current > Schools > School of Chemistry, Physics & Mechanical Engineering
Current > Institutes > Institute of Health and Biomedical Innovation
Current > Schools > School of Mathematical Sciences
Current > QUT Faculties and Divisions > Science & Engineering Faculty
Copyright Owner: Copyright 2013 Biomedical Engineering Society (Singapore)
Deposited On: 11 Dec 2013 00:22
Last Modified: 03 Jul 2014 03:06

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