While there are many causes which are understood to lead to disk degeneration, loss of nutrition of the disk is the final common pathway1. Disk nutrition is fundamentally influenced by dynamic compression frequency2 which corresponds to the frequency at which the spinal segments move in a normal day. The effect of reduced movement is seen in disks adjacent to fused or immobilized segments which have been reported to degenerate at an increased rate3. Finite element modeling has predicted that after 200 cycles of dynamic compression at 0.1 Hz, even disks with impermeable end-plates would have a 33% increase in oxygen concentration in the nucleus, a 22% increase in the annulus fibrosis, and a significant decrease in lactate concentration, especially in the annulus2. However, it is not possible to relate these predictions to humans because normal values of spine movement frequency have not previously been reported. In the thoracic spine, disk degeneration has been reported to be strongly associated with hyperkyphosis4. Given that disk degeneration is related to reduced movement frequency, it is possible that hyperkyphosis and altered movement frequency are interrelated. The aim of this study was to ascertain how often normal adults move their thoracic spine and whether there is a relationship between movement frequency and the degree of thoracic kyphosis.
Perriman, D., Scarvell, J., Hughes, A., Lueck, C., Neeman, T., Ashman, B., & Smith, P. (2012). Movement Frequency of the Thoracic Spine—Implications for Thoracic Disk Degeneration. Global Spine Journal, 2(1_suppl, 2012), 60-61. https://doi.org/10.1055/S-0032-1319919