The purpose of this study was to determine if the Disc Unloader brace was effective in reducing intradiscal pressure. There is a strong correlation between lumbar paraspinal activity and intradiscal pressure. We used ten healthy volunteers to measure lumbar paraspinal activity at L5 using a quantitative EMG system. After doing reliability and reproducibility testing which showed margin of error of 7%, ten volunteers were measured for quantitative EMG activity at the L5 paraspinal level in full lumbar flexion without the Disc Unloader brace three times and averaged. The same quantitative EMG testing was done in full flexion with the Disc Unloader brace on at the L5 paraspinal level three times and averaged. For five of the ten patients, we performed the test first with the Disc Unloader brace on whereas for the rest of the five, the test was performed first without the brace on. There were 7 females and 3 males with average age of 39 (range 26-46). The average area under the curve score was 173 ± 27.1 microvolts at the L5 paraspinal for the ten healthy subjects without the Disc Unloader brace on. The average area under the curve score was 102 ± 19.6 microvolts at the L5 paraspinal for ten healthy subjects with the Disc Unloader brace on. There was a statistically significant (p<0.05) reduction in quantitative paraspinal activity of 41% with the Disc Unloader brace on. We conclude that the Disc Unloader brace is effective in reducing quantitative EMG lumbar paraspinal myoelectric activity and therefore intradiscal pressures.

Keywords: Low back pain, orthosis, quantitative EMG