Relief of Low Back Pain After Posterior Decompression for Lumbar Spinal Stenosis.

STUDY

DESIGN

A retrospective study.

OBJECTIVE

The aim of this study was to confirm that decompression for lumbar spinal stenosis (LSS) relieves low back pain (LBP) as adequately as it relieves leg pain and to identify predictors for inadequate LBP relief.

SUMMARY OF BACKGROUND DATA: Although decompression for LSS is generally thought to yield worse results for LBP than for leg pain, some studies have reported similar improvements in pain scores between LBP and leg pain. To treat LBP or take measures to prevent inadequate LBP relief, reliable predictors for LBP relief should be identified.

METHODS

We retrospectively reviewed 175 patients who underwent posterior element-preserving decompression and evaluated the relief of LBP and leg pain using numeric rating scales (NRSs). Associations between demographic, clinical, or imaging parameters and LBP relief at 1 and 4 years were analyzed by stepwise linear regression analyses. The imaging parameters included Modic change type 1, disc degeneration, foraminal stenosis, vertebral slipping (within Grade 1), scoliosis (<15°) and lordosis.

RESULTS

The mean improvements in LBP and leg pain NRS scores from baseline were 5.22 and 4.70 points (P = 0.064, paired t test) at 1 year and 5.12 and 4.62 points (P = 0.068) at 4 years, respectively. Poor LBP scores at 4 years were significantly associated with long-lasting LBP (beta = 0.31, P < 0.0001) and moderate or severe arm symptoms with cervical spinal cord compression or intramedullary hyperintense signal on T2-weighted MRI (beta = 0.22, P = 0.0014). The imaging parameters of the lumbar spine failed to show clear associations with poor LBP scores at 4 years, although Modic change type 1 showed a significant association with poor LBP scores at 1 year (beta = 0.28, P < 0.0001).

CONCLUSION

Posterior decompression relieves LBP as well as leg pain. Long-lasting LBP and concurrent symptomatic cervical myelopathy are important predictors for inadequate LBP relief. There were no reliable imaging parameters predictive of inadequate LBP relief.Level of Evidence: 4.