Bulging or protruding intervertebral discs occupies the intervertebral foramen and nerve roots are compressed.
The cross-sectional area of nerve root fibers is reduced, fiber bundles gathered together and interrupted at the affected side, with no branching. Dr. Xin Tian and colleagues from the Second Hospital of Hebei Medical University in China was the first to use diffusion tensor tractography to reveal spinal nerve root function. A scoring system of nerve root morphology was used to quantitatively assess nerve root morphology and functional alteration after intervertebral disc degeneration.
Results from this study, published in the Neural Regeneration Research
(Vol. 8, No. 33, 2013), suggest that diffusion tensor magnetic resonance imaging-based tractography can be used to quantitatively evaluate nerve root function according to the area and morphology of fiber bundles of nerve roots.