A Comparison of Five Animal Models for Acute Intervertebral Disc Herniation Research

Area of Science:

• Biomechanical Engineering
• Orthopedic Research
• Animal Modeling

Background:

• Animal models are crucial for studying spinal disc herniation due to reduced variability and cost compared to human specimens.
• A consensus on the optimal animal model for replicating human disc herniation remains elusive, necessitating comparative studies.

Purpose of the Study:

• To compare the intervertebral disc herniation mechanisms across five distinct animal models under a standardized mechanical load.
• To identify the most suitable animal models for investigating specific types of disc herniation, such as annulus fibrosus failure or endplate junction failure.

Main Methods:

• Isolated intervertebral discs from five cadaveric animal models (bovine tail, bovine lumbar, ovine lumbar, porcine lumbar, porcine cervical) were subjected to a standardized shear-compressive load.
• A complex load simulating herniation was applied until failure or displacement limit, followed by microstructural analysis to determine failure modes.

Main Results:

• All tested animal models exhibited clinically relevant herniation features, including annulus fibrosus tearing, vertebral body fracture, and nucleus pulposus extrusion.
• Porcine cervical, bovine lumbar, and porcine lumbar discs showed high rates of radial nucleus pulposus movement.
• Ovine lumbar discs frequently displayed vertebral body fracture, while bovine tail discs exhibited sequential annulus fibrosus tears.

Conclusions:

• Porcine cervical, bovine lumbar, and porcine lumbar discs are suitable for annulus-failure herniation research, with porcine cervical discs being potentially optimal.
• Ovine lumbar discs are appropriate for studying endplate junction failure, and bovine tail discs are suitable for implant-related studies.