Dynamic measurement of intraosseous pressures in lumbar spinal vertebrae with reference to spinal canal stenosis.

Dynamic measurements of intraosseous pressures in lumbar vertebrae were performed to determine the effects of positional change on lumbar vertebral circulation. The data collected are applicable to the question of spinal canal stenosis. The measurements were made in 23 patients, 12 of whom had spinal canal stenosis and 11 of whom had spondylosis deformans. The pressures within the spinous processes of L3 and L5 were measured continuously while the patients were prone, lying in the lateral position, and standing. The pressures ranged from approximately 10 to 30 mm Hg in the prone position and showed substantial changes with changes in position. In each subject, they were lowest in the prone, intermediate in the lateral, and highest in the standing position.