Analysis and Measurement of the Lumbar Spinal Canal Dimension using Magnetic Resonance Imaging / 대한정형외과학회잡지

ABSTRACT

PURPOSE: It is very difficult to measure the spinal canal dimension in elderly patients because of disc degeneration and facet joint hypertrophy. The purpose of this study is to determine reference values of the spinal canal dimension in a population of normal Korea subjects and to evaluate other measurement methods of the spinal canal dimension that correlate to normal spinal canal dimensions determined using Magnetic Resonance Imaging (MRI). MATERIALS AND METHODS: We studied 100 patients who had mild symptoms and had normal MRI findings from 2475 outpatients that had undergone lumbar MRI from November 2002 to May 2004. The dimension of the spinal canal and dural sac was measured at the center of intervertebral discs L3/4, L4/5 and L5/S1. The dimension of the spinal canal and vertebral body was measured and was compared at the transverse plane perpendicular to the spinal canal that transected L4, L5 and the S1 pedicle. RESULTS: For the sequence of L3/4, L4/5 and L5/S1, the mean spinal canal dimensions were 249.38+/-38.30 mm2, 253.04+/-48.62 mm2 and 288.46+/-57.62 mm2, respectively. For the sequence of L4, L5 and S1, the mean spinal canal dimensions were 279.78+/-42.36 mm2, 301.50+/-54.26 mm2 and 355.10+/-60.65 mm2, respectively. The correlation coefficient was high at 0.913 for the L3/4 and L4 interpedicular transverse plane. The correlation coefficient for L4/5 and L5 was 0.905, and the correlation coefficient for L5/S1 and S1 was 0.845. CONCLUSION: The lumbar spinal canal dimension measured at the intervertebral disc level in a population of normal Korean subjects is expected to be useful as reference data. The transpedicular plane perpendicular to the spinal canal can give information for estimating the spinal canal dimension at the disc level.