The Short Term Results of Selective Nerve Root Block in Spinal Stenosis by Contrast Pattern

STUDY DESIGN: Retrospective study. OBJECTIVES: To observe the short term effect of selective nerve root block (sNRB) depending on the contrast pattern and spinal canal size. SUMMARY OF LITERATURE REVIEW: A number of studies have demonstrated that sNRB is quite effective not only for patients with herniated intervertebral discs but also for those with spinal stenosis. MATERIALS AND METHODS: The Visual Analog Scale(VAS) score was collected before and after the procedure from 217 subjects with lumbar spinal stenosis and underwent sNRB. Two types were classified after observing the contrast's spreading pattern, Type I contrast reaching the spinal canal and Type II not reaching the spinal canal. Efficacy of the treatment for each type was also compared. In addition, the spinal canal size was classified into three categories. Treatment efficacy depending on the contrast pattern was also compared in each category. RESULTS: When divided into two types based on the contrast pattern, type I showed a more significant reduction in VAS score according to T-test although both types showed a decrease in VAS score after the procedure. In regards to spinal canal dimension, both types showed decreased VAS scores after the procedure in patients with spinal canal size larger than 172.2mm2; however, there were no changes in VAS score before and after the procedure for those with spinal canal size smaller than 73mm2. CONCLUSIONS: There was a short term effect of selective nerve root block (sNRB) in patients with spinal stenosis regardless of their contrast pattern, type I group showing a stronger correlation. In regards to spinal canal dimension, patients with larger spinal canal sizes not only showed a significant decrease in VAS score after selective nerve root block (sNRB) but also showed differences depending on the contrast pattern. On the contrary, there was no significant difference in VAS score before and after selective nerve root block (sNRB) in patients with small spinal canal sizes, and there was also no difference in the outcome depending on the contrast pattern in patients with small spinal canal sizes. Therefore, when performing selective root nerve block (sNRB), the operator should remember to manipulate the angle and position of the spinal needle when injecting the appropriate drug after confirming that the contrast material reached the spinal canal. The operator should also consider surgical management when performing selective nerve root block (sNRB) in patients with severe central spinal stenosis.

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

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.