Long-Term Effects of a Lumbosacral Ventral Root Avulsion Injury on Axotomized Motor Neurons and Avulsed Ventral Roots in a Non-Human Primate Model of Cauda Equina Injury

Neuroscience, 2013 · DOI: 10.1016/j.neuroscience.2013.06.054 · Published: October 10, 2013

Simple Explanation

This study investigates the long-term effects of a specific spinal cord injury (ventral root avulsion) in monkeys, mimicking injuries to the lower spinal cord in humans. The researchers looked at the damage to nerve cells and roots after this type of injury, to better understand the potential for future treatments. They found that nerve cells die off and roots undergo changes that could affect how well they can be repaired later on.

Study Duration

6-10 months

Participants

Four adult male rhesus monkeys

Evidence Level

Level II, Experimental Study

Key Findings

1
A lumbosacral VRA injury resulted in retrograde motoneuron loss and astrocytic glial activation in the ventral horn.
2
The Wallerian degeneration of motor axons in the avulsed ventral roots was followed by a repopulation of the avulsed roots by small myelinated and unmyelinated fibers.
3
The small axons may represent sprouting or axonal regeneration by primary afferents or autonomic fibers.

Research Summary

Ventral root avulsion injury in the rhesus macaque resulted in a marked loss of axotomized motoneurons and an astroglial reaction in the ventral horn. The avulsed ventral roots undergoing initial Wallerian degeneration exhibited long-term changes, including the presence of a large number of small myelinated and unmyelinated axons The repopulation of the avulsed ventral roots by small myelinated fibers of presumed peripheral origin may affect the utility of the roots for late replantation procedures.

Practical Implications

Understanding Cauda Equina Injury

Provides insights into the long-term consequences of cauda equina injuries, informing clinical management and expectations.

Implications for Nerve Repair

Highlights the potential challenges in late replantation procedures due to the repopulation of avulsed roots by non-motor fibers.

Future Research Directions

Suggests the need for further investigation into the origin and functional significance of the small myelinated fibers that repopulate avulsed ventral roots.

Study Limitations

1
Small sample size (n=4)
2
Study conducted on rhesus macaques; results may not be directly transferable to humans
3
Focus on morphological changes; limited functional assessment

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