Mechanism of disc rupture. A preliminary report

Spine (Phila Pa 1976). 1991 Apr;16(4):450-6. doi: 10.1097/00007632-199104000-00011.


Lumbar intervertebral disc herniation is thought to be related to senescent changes in the nucleus pulposus except in rare instances of trauma. This investigation provides the first in vitro model of disc prolapse that reliably ruptures discs under physiologically reasonable stress. Fourteen vertebral motion segments with intact posterior elements were loaded repetitively at 1.5 Hz in a combination of flexion (7 degrees), rotation (less than 3 degrees), and compression (1,334 N) for an average of 6.9 hours (range, 3.0-13.0 hours) in a materials testing machine. Loading was terminated when reaction force leveled off for more than 1 hour. Ten discs failed through annular protrusions, and four failed by nuclear extrusion through annular tears, supporting the hypothesis that intervertebral disc prolapse is peripheral in origin. The annulus fibrosus is the site of primary pathologic change.

MeSH terms

  • Humans
  • Intervertebral Disc Displacement / etiology*
  • Intervertebral Disc Displacement / pathology
  • Lumbar Vertebrae / pathology*
  • Magnetic Resonance Imaging
  • Materials Testing / instrumentation
  • Middle Aged
  • Rupture
  • Stress, Mechanical