Removal of nucleus pulposus from the intervertebral disc – the use of chymopapain enhances mechanical removal with rongeurs: a laboratory study

<p>Abstract</p> <p>Background</p> <p>A laboratory study was conducted, on cadaveric sheep spines to develop an effective procedure for removing as much nucleus as possible from an intervertebral disc with minimal disruption to the annulus. The results of many studies involving removal of nucleus, including chemonucleolysis, using chymopapain, have been published but we are not aware of any previous quantitative studies on procedures for removing as much nucleus as possible from the disc.</p> <p>Methods</p> <p>All procedures were performed via a 3 mm trocar. Four procedures were compared: (I) unilateral approach using rongeurs alone, (II) bilateral approach using rongeurs alone, (III) unilateral approach using rongeurs followed by chymopapain and (IV) bilateral approach using rongeurs followed by chymopapain.</p> <p>Results</p> <p>The percentages of nucleus removed were: (I) 34%, (II) 41%, (III) 52% and (IV) 75%; there were significant differences between the four sets of results according to ANOVA.</p> <p>Conclusion</p> <p>Significantly more nucleus is removed using a bilateral than a unilateral approach; significantly more nucleus is removed if chymopapain is used in addition to rongeurs. A brush is useful in removing strands of nucleus loosened by chymopapain.</p

Assessment of non-contacting optical methods to measure wear and surface roughness in ceramic total disc replacements

This study presents a method for measuring the low volumetric wear expected in ceramic total disc replacements, which can be used to replace intervertebral discs in the spine, using non-contacting optical methods. Alumina-on-alumina ball-on-disc tests were conducted with test conditions approximating those of cervical (neck region of the spine) total disc replacement wear tests. The samples were then scanned using a three-dimensional non-contacting optical profilometer and the data used to measure surface roughness and develop a method for measuring the wear volume. The results showed that the magnification of the optical lens affected the accuracy of both the surface roughness and wear volume measurements. The method was able to successfully measure wear volumes of 0.0001mm3, which corresponds to a mass of 0.0001 mg, which would have been undetectable using the gravimetric method. A further advantage of this method is that with one scan the user can measure changes in surface topography, volumetric wear and the location of the wear on the implant surface. This method could also be applied to more severe wear, other types of orthopaedic implants and different materials

Effect of Axial Load on the Flexural Properties of an Elastomeric Total Disc Replacement

Study Design. Twelve Cadisc-L devices were subjected to flexion (0°–6°) and extension (0° to -3°) motions at compressive loads between 500 N and 2000 N at a flexural rate between 0.25°/s and 3.0°/s.\ud \ud Objective. To quantify the change in flexural properties of the Cadisc-L (elastomeric device), when subjected to increasing magnitudes of axial load and at different flexural rates.\ud \ud Summary of Background Data. The design of motion preservation devices, used to replace degenerated intervertebral discs, is commonly based on a low-friction, ball-and-socket-articulating joint. Recently, elastomeric implants have been developed that attempt to provide mechanical and motion properties that resemble those of the natural disc more closely.\ud \ud Methods. Twelve Cadisc-L devices (MC-10 mm-9° and MC-10 mm-12° size) were supplied by Ranier Technology Ltd (Cambridge, United Kingdom). The devices were hydrated and tested using a Bose spinal disc-testing machine (Bose Corporation, ElectroForce Systems Group, Eden Prairie, MN) in Ringer's solution at 37°C. A static load of 500 N was applied to a device and it was then subjected to motions of 0° to 6° to 0° (flexion) and 0° to -3° to 0° (extension) at a flexural rate of 0.25°/s, 0.5°/s, 1.0°/s, 1.5°/s, 2.0°/s, and 3.0°/s. Tests were repeated at 1000 N, 1500 N, and 2000 N.\ud \ud Results. Regression analyses showed a significant ($R^2$ > 0.99, $\rho$< 0.05) linear increase in bending moment and flexural stiffness with flexion and extension angles (at 1000 N and higher loads)—a significant ($R^2$> 0.994, $\rho$< 0.05) linear decrease in flexural stiffness in flexion and extension as flexural rate increased.\ud \ud Conclusion. The bending moment of the Cadisc-L increased linearly with flexion and extension angles at 1000 N and higher loads. Flexural stiffness increased with compressive load but decreased with flexural rate.\ud \u

Australia’s Grains Farm Biosecurity Program – a national initiative in plant biosecurity awareness, education and best management practice.: Presentation

Sound biosecurity systems contribute to achieving sustainable agricultural and environmental systems, reducing the threat of introducing unwanted pests and supporting food safety and product integrity. Within Australia, the Grains Farm Biosecurity Program (GFBP) is a national initiative to assist in the development and implementation of improved biosecurity practice within its grain industry. Initiated in 2007, the extension focused program contributes to the industry’s risk mitigation activities, supports continued market access and promotes a partnership approach involving governments, industry and community. The program is funded through grower levies in partnership with state government agencies and Plant Health Australia. Using a variety of community engagement strategies, the GFBP has developed a wide range of tools to improve the management of and preparedness for, biosecurity risks in the Australian grains industry at the farm and industry level by highlighting risk pathways and activities throughout the supply chain and encouraging adoption of practices and strategies to mitigate risks. The GFPB also promotes and conducts surveillance for high priority pests especially in on-farm storage. Evaluations indicate an increased awareness of biosecurity risks, industry capacity and voluntary adoption of biosecurity best practices throughout the sector. The GFBP focus on biosecurity best practice through industry engagement has seen it contribute to safeguarding and maintaining Australia’s export reputation, with the program recently winning a national biosecurity award.Sound biosecurity systems contribute to achieving sustainable agricultural and environmental systems, reducing the threat of introducing unwanted pests and supporting food safety and product integrity. Within Australia, the Grains Farm Biosecurity Program (GFBP) is a national initiative to assist in the development and implementation of improved biosecurity practice within its grain industry. Initiated in 2007, the extension focused program contributes to the industry’s risk mitigation activities, supports continued market access and promotes a partnership approach involving governments, industry and community. The program is funded through grower levies in partnership with state government agencies and Plant Health Australia. Using a variety of community engagement strategies, the GFBP has developed a wide range of tools to improve the management of and preparedness for, biosecurity risks in the Australian grains industry at the farm and industry level by highlighting risk pathways and activities throughout the supply chain and encouraging adoption of practices and strategies to mitigate risks. The GFPB also promotes and conducts surveillance for high priority pests especially in on-farm storage. Evaluations indicate an increased awareness of biosecurity risks, industry capacity and voluntary adoption of biosecurity best practices throughout the sector. The GFBP focus on biosecurity best practice through industry engagement has seen it contribute to safeguarding and maintaining Australia’s export reputation, with the program recently winning a national biosecurity award

Viscoelastic properties of bovine knee joint articular cartilage : dependency on thickness and loading frequency

BackgroundThe knee is an incongruent joint predisposed to developing osteoarthritis, with certain regions being more at risk of cartilage degeneration even in non-osteoarthrosed joints.At present it is unknown if knee regions prone to cartilage degeneration have similar storage and/or loss stiffness, and frequency-dependent trends, to other knee joint cartilage. The aim of this study was to determine the range of frequency-dependent, viscoelastic stiffness of articular cartilage across the bovine knee joint. Such changes were determined at frequencies associated with normal and rapid heel-strike rise times.MethodsCartilage on bone, obtained from bovine knee joints, was tested using dynamic mechanical analysis (DMA). DMA was performed at a range of frequencies between 1 and 88 Hz (i.e. relevant to normal and rapid heel-strike rise times). Viscoelastic stiffness of cartilage from the tibial plateau, femoral condyles and patellar groove were compared.ResultsFor all samples the storage stiffness increased, but the loss stiffness remained constant, with frequency. They were also dependent on cartilage thickness. Both the loss stiffness and the storage stiffness decreased with cartilage thickness. Femoral condyles had the thinnest cartilage but had the highest storage and loss stiffness. Tibial plateau cartilage not covered by the meniscus had the thickest cartilage and lowest storage and loss stiffness.ConclusionDifferences in regional thickness of knee joint cartilage correspond to altered frequency-dependent, viscoelastic stiffness