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Published on: May 8, 2012
A method to obtain surface strains of soft tissues using a laser scanning device
Frank Heuer1, Uwe Wolfram, Hendrik Schmidt
1Institute of Orthopaedic Research and Biomechanics, University of Ulm, Helmholtzstr. 14, 89081 Ulm, Germany. frank.heuer@uni-ulm.de
Journal of Biomechanics
|July 16, 2008
Summary
A novel 3D laser scanning system accurately measures surface strains on musculoskeletal and soft tissues. This technology aids in understanding tissue mechanics and validating biomechanical models.
Area of Science:
- Biomechanics
- Biomedical Engineering
- Medical Imaging
Background:
- Understanding the mechanical behavior of musculoskeletal and soft tissues under load is crucial for diagnosing conditions and developing treatments.
- Current methods for measuring tissue strain may have limitations in accuracy and scope.
- Accurate strain data is essential for validating computational models used in biomechanics.
Purpose of the Study:
- To develop and validate a 3D laser scanning device for quantifying surface strains on biological tissues.
- To assess the accuracy and limitations of the developed system across various loading conditions.
- To demonstrate the system's application in analyzing complex biological structures like intervertebral discs.
Main Methods:
- A 3D laser scanning device was engineered for high-resolution surface digitization of tissues.
- Image processing algorithms were developed for image registration, displacement mapping, and surface strain calculation.
- Validation was performed using a test cylinder under rigid rotation and a silicon cylinder under compression.
- The system's accuracy was evaluated for vertical, shear, and circumferential strain measurements.
- The method was applied to measure surface strain on a human lumbar intervertebral disc during flexion and extension.
Main Results:
- The system achieved high accuracy, with errors of +/-0.10% strain (vertical) and +/-0.16% strain (shear/circumferential) in zero-strain validation.
- Accuracy was best for small strains; errors increased with higher strains (>5%), showing slight underestimation (0.54% error at 7.22% vertical strain).
- Employing sub-steps for strain measurements improved accuracy, reducing the error for 7.22% vertical strain to 0.41%.
Conclusions:
- A robust 3D laser scanning method for measuring soft tissue surface strains has been successfully introduced.
- The system provides valuable data for understanding the mechanical loading and behavior of musculoskeletal structures.
- This technology can significantly contribute to the validation of finite-element models in biomechanics and tissue engineering.
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