This week, in Spine Journal, an ISSLS prize winning study was published on the dynamics of the disc.
What these researchers looked at was how nutrient uptake differed when the disc was exposed to:
- stationary position
- a high-rate, low frequency force and
- a low-rate, low frequency force
Their objective was to quantify the effects of mechanical loading rate on disc fluid movement into healthy and degenerative discs in vivo.
This research looked to measure what kind of forces could possibly draw more fluid into the discs. Conventional thought believed that ‘pumping’ of the disc did not have an influence on nutrient transport into discs as some previous work on diffusion rates into discs did not show that it mattered whether discs were moving or not. (Jill Urban) But now, new researchers showed that it is possible to influence nutrient flow into these avascular discs and best accomplished in a slow moving and constant way.
What they found was quite profound but makes some common sense. They observed that discs responded best to low-rate, low frequency forces. They used New Zealand white rabbits to test using an oscillative force equal to 0-200N (0-44lbs) over a 2 second period–similar to intermittent traction. Interestingly, they also found that the degenerated discs took up the fluid quicker than normal discs.
This research should have a significant influence on how we understand spine. It will influence exercise programs and also guide strategies in manual therapies like mobilization and decompression techniques.
Dynamic Disc Designs develops dynamic disc models to help with patient education and showcase the dynamics of the intervertebral discs in the management and treatment of spinal related disorders.