Author(s): Dallin Dodds, Ethan Ence
Mentor(s): Danni Porter, Anton Bowden
Institution BYU
To support healthy intervertebral discs, proper fluid flow through various spine components must be maintained. When spinal discs degenerate, the bony endplates of the vertebrae in contact with the disc typically calcify, compromising the permeability of the bony endplate and affecting the natural flow rate of essential spinal fluid to support the disc. Definitive literature on this flow rate is scarce, so this research aims to quantify that flow rate experimentally through young bovine and elderly human vertebral endplate samples. Permeability was measured using a calibrated column of water contained within a straight piping system which was instrumented with a sealed, embedded sample container. Water was constrained by the device to pass only through the vertebral endplate sample. Water column height, volumetric flow, and mass flow were measured continuously and video recorded. Based on our measurements, the permeability of bovine, bony vertebral endplate ranged between X and Y Darcy. As reported in literature, cortical bone permeability ranges from 10-20 to 10-23 Darcy. This data corroborates our measurements, as the bony vertebral endplate is expected to exhibit higher permeability due to its role in facilitating spinal fluid flow through spine components. Our eventual goal is to create an artificial bony endplate capable of duplicating the hydraulic permeability, mechanical stiffness, and strength of the healthy human vertebral bony endplate. The data reported in the present work is a key step towards that goal. Future testing will involve substituting water with light oil to determine the function of viscosity in the permeability of the bony vertebral endplate. This testing will inform how the flow rate of the bony vertebral endplate is affected by the viscosity of spinal fluid