Dr. Sam Veres, a biomedical engineer and Associate Dean of Science at Saint Mary’s University, has won the prestigious ISSLS Prize in Basic Sciencefor 2020 from the International Society for the Study of the Lumbar Spine.
The winning paper, co-written with student Tyler Herod (MASc in Biomedical Engineering at Dalhousie), is titled “Beyond microstructure: Circumferential specialization within the lumbar intervertebral disc annulus extends to collagen nanostructure, with counterintuitive relationships to macroscale material properties.”
The work focuses on intervertebral discs, which are a component of the skeletal system that is not yet fully understood, despite being critically important to everyday living. These thin soft tissue discs interposed between adjacent vertebrae are what provide the spine with flexibility, allowing us to bend and twist.
Intervertebral discs support mechanical load in a similar way to an exercise ball or car tire, explained Dr. Veres. “When compressed, the pressure generated within the centre of an intervertebral disc resists the compressive load, while the periphery or annulus of the disc is stretched in tension, restraining the pressurized interior from escaping.”
A herniation, or slipped disc, occurs when the stretched disc ruptures, allowing the pressurized centre of the disc to escape—with painful, debilitating consequences for the patient. Disc herniations often occur posteriorly, and their proximity to the spinal cord makes this especially problematic. Herniated nuclear material from within a disc can cause pain by mechanically compressing or chemically irritating the spinal cord or its enveloping membrane, the dura.
“What struck us as odd about the posterior annulus is not that failure often occurs here, but that the rates of microdamage accumulation in this area—the small tears, clefts, and fissures that start to develop within the first few decades of life—are not remarkably higher compared to other less loaded regions of the annulus,” said Dr. Veres. “We suspected that the posterior annulus may possess structural differences to other regions on a smaller structural scale.”
To test their theory, Dr. Veres and Tyler tested the lumbar spines of sheep to study the structural organization of collagen molecules using a thermo-mechanical technique known as hydrothermal isometric tension analysis.
“In general, our results showed that the collagen fibres of the intervertebral disc annulus are much stronger than previously thought—more than double the strengths previously reported,” said Dr. Veres.
“Interestingly, despite being composed of fibres with greater intermolecular connectivity, the posterior annulus was significantly weaker than the anterior annulus,” he said. “These results show that a previously unknown regional variation exists in the fundamental load-bearing structural makeup of the intervertebral disc annulus.”
Currently the standard treatment for herniated discs is to remove the discs and fuse the two adjacent vertebrae to become a single column of bone; successful, well-established techniques for repairing discs don’t yet exist.
“Our work is just one piece in a much larger attempt by the spinal research community to understand normal function and failure within intervertebral discs, in order to inform how to better care for and perhaps one day repair or replace these critical elements of our skeletal system,” said Dr. Veres.
Dr. Sam Veres’s Research
Biomedical engineer Dr. Veres uses a multidisciplinary approach, using knowledge and techniques from engineering, physics, chemistry, biology, and medicine to improve understanding of tissue development, normal function, aging, injury, and repair. His work has provided fundamental insights into the structural changes that occur in mechanically overloaded soft tissues, and work continues on the development of new therapies for treatment of tendons, ligaments, and the intervertebral discs of the lower back.
The award-winning work was funded by a grant from the Natural Sciences and Research Council of Canada (NSERC). The Veres Group is part of a tissue development, damage and repair research collaborative located at Saint Mary’s University and Dalhousie University.
The Group specializes in investigating interactions between structure and function in the load-bearing tissues of the human body, and how these relationships change in health and disease.
The ISSLS Prize for Lumbar Spine Research
The ISSLS Prize program is sponsored by the European Spine Journal. Three prizes of $20,000 each are awarded annually based on scientific merit in the areas of basic science, bioengineering, and clinical science. Papers submitted for the competition must be original, full article manuscripts, not previously published or submitted for publication. The prize also comes with an invitation to present the winning paper in Australia in 2020.