Polymethyl methacrylate (PMMA) and Wood's Metal are fixation media for biomechanical testing; however, the effect of each potting medium on the measured six degree-of-freedom (DOF) mechanical properties of human lumbar intervertebral discs is unknown. The first aim of this study was to compare the measured 6DOF elastic and viscoelastic properties of the disc when embedded in PMMA compared to repotting in Wood's Metal. The second aim was to compare the surface temperature of the disc when potted with PMMA and Wood's Metal. Six human lumbar functional spinal units (FSUs) were first potted in PMMA, and subjected to overnight preload in a saline bath at 37 °C followed by five haversine loading cycles at 0.1 Hz in each of 6DOF loading directions (compression, left/right lateral bending, flexion, extension, left/right axial rotation, anterior/posterior, and lateral shear). Each specimen was then repotted in Wood's Metal and subjected to a 2-h re-equilibrating preload followed by repeating the same 6DOF tests. Outcome measures of stiffness and phase angle were calculated from the final loading cycle in each DOF and were expressed as normalized percentages relative to PMMA (100%). Disc surface temperatures (anterior, left/right lateral) were measured during potting. Paired t-tests (with alpha adjusted for multiple DOF) were conducted to compare the differences in each outcome parameter between PMMA and Wood's Metal. No significant differences in stiffness or phase angle were found between PMMA and Wood's Metal. On average, the largest trending differences were found in the shear DOFs for both stiffness (approximately 35% greater for Wood's Metal compared to PMMA) and phase angle (approximately 15% greater for Wood's Metal). A significant difference in disc temperature was found at the anterior surface after potting with Wood's Metal compared to PMMA, which did not exceed 26 °C. Wood's Metal is linear elastic, stiffer than PMMA and may reduce measurement artifact of potting medium, particularly in the shear directions. Furthermore, it is easier to remove than PMMA, reuseable, and cost effective.
Skip Nav Destination
Article navigation
Technical Briefs
Effect of Potting Technique on the Measurement of Six Degree-of-Freedom Viscoelastic Properties of Human Lumbar Spine Segments
Dhara B. Amin,
Dhara B. Amin
Biomechanics and Implants Research Group,
School of Computer Science,
Engineering and Mathematics,
e-mail: dhara.amin@flinders.edu.au
School of Computer Science,
Engineering and Mathematics,
The Medical Device Research Institute
,GPO Box 2100
,Adelaide, South Australia 5001
, Australia
e-mail: dhara.amin@flinders.edu.au
Search for other works by this author on:
Isaac M. Lawless,
Isaac M. Lawless
Biomechanics and Implants Research Group,
School of Computer Science,
Engineering and Mathematics,
e-mail: isaac.lawless@flinders.edu.au
School of Computer Science,
Engineering and Mathematics,
The Medical Device Research Institute
,GPO Box 2100
,Adelaide, South Australia 5001
, Australia
e-mail: isaac.lawless@flinders.edu.au
Search for other works by this author on:
Dana Sommerfeld,
Dana Sommerfeld
Institute of Biomechanics,
e-mail: dana.sommerfeld@tuhh.de
TUHH Hamburg University of Technology
,Denickestr. 15
,Hamburg 21073
, Germany
e-mail: dana.sommerfeld@tuhh.de
Search for other works by this author on:
Richard M. Stanley,
Richard M. Stanley
Biomechanics and Implants Research Group,
School of Computer Science,
Engineering and Mathematics,
e-mail: richard.stanley@flinders.edu.au
School of Computer Science,
Engineering and Mathematics,
The Medical Device Research Institute
,GPO Box 2100
,Adelaide, South Australia 5001
, Australia
e-mail: richard.stanley@flinders.edu.au
Search for other works by this author on:
Boyin Ding,
Boyin Ding
School of Mechanical Engineering,
e-mail: boyin.ding@adelaide.edu.au
The University of Adelaide
,Engineering South, L1
,Adelaide, SA 5005
, Australia
e-mail: boyin.ding@adelaide.edu.au
Search for other works by this author on:
John J. Costi
John J. Costi
1
Biomechanics and Implants Research Group,
School of Computer Science,
Engineering and Mathematics,
e-mail: john.costi@flinders.edu.au
School of Computer Science,
Engineering and Mathematics,
The Medical Device Research Institute
,GPO Box 2100
,Adelaide, South Australia 5001
, Australia
e-mail: john.costi@flinders.edu.au
1Corresponding author.
Search for other works by this author on:
Dhara B. Amin
Biomechanics and Implants Research Group,
School of Computer Science,
Engineering and Mathematics,
e-mail: dhara.amin@flinders.edu.au
School of Computer Science,
Engineering and Mathematics,
The Medical Device Research Institute
,GPO Box 2100
,Adelaide, South Australia 5001
, Australia
e-mail: dhara.amin@flinders.edu.au
Isaac M. Lawless
Biomechanics and Implants Research Group,
School of Computer Science,
Engineering and Mathematics,
e-mail: isaac.lawless@flinders.edu.au
School of Computer Science,
Engineering and Mathematics,
The Medical Device Research Institute
,GPO Box 2100
,Adelaide, South Australia 5001
, Australia
e-mail: isaac.lawless@flinders.edu.au
Dana Sommerfeld
Institute of Biomechanics,
e-mail: dana.sommerfeld@tuhh.de
TUHH Hamburg University of Technology
,Denickestr. 15
,Hamburg 21073
, Germany
e-mail: dana.sommerfeld@tuhh.de
Richard M. Stanley
Biomechanics and Implants Research Group,
School of Computer Science,
Engineering and Mathematics,
e-mail: richard.stanley@flinders.edu.au
School of Computer Science,
Engineering and Mathematics,
The Medical Device Research Institute
,GPO Box 2100
,Adelaide, South Australia 5001
, Australia
e-mail: richard.stanley@flinders.edu.au
Boyin Ding
School of Mechanical Engineering,
e-mail: boyin.ding@adelaide.edu.au
The University of Adelaide
,Engineering South, L1
,Adelaide, SA 5005
, Australia
e-mail: boyin.ding@adelaide.edu.au
John J. Costi
Biomechanics and Implants Research Group,
School of Computer Science,
Engineering and Mathematics,
e-mail: john.costi@flinders.edu.au
School of Computer Science,
Engineering and Mathematics,
The Medical Device Research Institute
,GPO Box 2100
,Adelaide, South Australia 5001
, Australia
e-mail: john.costi@flinders.edu.au
1Corresponding author.
Manuscript received May 22, 2014; final manuscript received January 12, 2015; published online February 20, 2015. Assoc. Editor: James C. Iatridis.
J Biomech Eng. May 2015, 137(5): 054501 (8 pages)
Published Online: May 1, 2015
Article history
Received:
May 22, 2014
Revision Received:
January 12, 2015
Online:
February 20, 2015
Citation
Amin, D. B., Lawless, I. M., Sommerfeld, D., Stanley, R. M., Ding, B., and Costi, J. J. (May 1, 2015). "Effect of Potting Technique on the Measurement of Six Degree-of-Freedom Viscoelastic Properties of Human Lumbar Spine Segments." ASME. J Biomech Eng. May 2015; 137(5): 054501. https://doi.org/10.1115/1.4029698
Download citation file:
Get Email Alerts
Cited By
In Memoriam: Shmuel Einav, 1942–2022
J Biomech Eng (August 2022)
A Review of Head Injury Metrics Used in Automotive Safety and Sports Protective Equipment
J Biomech Eng (November 2022)
Related Articles
Effects of Anterior Shear Displacement Rate on the Structural Properties of the Porcine Cervical Spine
J Biomech Eng (September,2010)
Biomechanical In Vitro Test of a Novel Dynamic Spinal Stabilization System Incorporating Polycarbonate Urethane Material Under Physiological Conditions
J Biomech Eng (January,2020)
The Effects of Bone Microstructure on Subsidence Risk for ALIF, LLIF, PLIF, and TLIF Spine Cages
J Biomech Eng (March,2019)
Synthetic Soft Tissue Characterization of the Mechanical Analogue Lumbar Spine
J. Med. Devices (June,2008)
Related Proceedings Papers
Related Chapters
Novel and Efficient Mathematical and Computational Methods for the Analysis and Architecting of Ultralight Cellular Materials and their Macrostructural Responses
Advances in Computers and Information in Engineering Research, Volume 2
Microstructure Evolution and Physics-Based Modeling
Ultrasonic Welding of Lithium-Ion Batteries
Pressure Testing
Process Piping: The Complete Guide to ASME B31.3, Third Edition