Lower spinal mobility and external immobilization in the normal and pathologic condition.

The study presented here used lateral flexion and extension roentgenograms to determine lumbosacral motion in healthy persons and in patients with spondylolisthesis. The lumbosacral corset, Jewett extension brace, and plastic thoracolumbosacral orthosis (TLSO) were then placed and repeat roentgenograms were done to see if effective immobilization could be obtained. Although individual variation existed, there appeared to be no significant difference in lower lumbar motion between the two groups studied, and the orthotics acted in a similar fashion on both the volunteers and the patients. The lumbosacral corset was unable to immobilize the L3-S1 levels. There was a statistically significant decrease in the average lateral disk space motion at L3-4 and L4-5 with the use of the Jewett brace and the TLSO (P less than .01); however, the motion was never completely eliminated. No brace could adequately immobilize the L5-S1 level, and some people demonstrated increased motion at this level while wearing the orthotics.