Graduation Year


Document Type




Degree Granting Department

Biomedical Engineering

Major Professor

Wesley M. Johnson, Ph.D.

Committee Member

Thomas B. Freeman, M.D.

Committee Member

William E. Lee III, Ph.D.


Intradiscal pressure, Pressure transducer, Nucleus pulposus, Lumbar spine, Biomechanics, Spinal load


Introduction. To test the effects of torsion torques on intradiscal pressure and disc height in human lumbar specimens.

Methods. Six human lumbar cadaveric functional spine units (FSU) were loaded in the neutral position with 600 N compression. Nucleus pressure measurements were obtained at 0 Nm, 0.5 Nm, 1.0 Nm and 2 Nm torsion torque. Posterior elements were removed and pressure measurements were repeated at the same torsion torques for the disc body unit (DBU). The pressure in the nucleus was measured by pulling a pressure probe through the disc along a straight path in the midsagittal plane.

Results. There was no statistically significant difference of nucleus pressure or intervertebral disc height with different torsion torques among or between the FSU's and DBU's. However, a disc height increase ranging from 0.13 mm to 0.16 mm occurred with the insertion of a 1.85 mm diameter cannula. Conclusions. Small torsion torques showed no significant difference in intradiscal pressures or disc heights. Disc height increases were seen with the insertion of the cannula that could lead to methods of disc height restoration.