Comparison of Pain-reducing Effect After Selective Nerve Root Block According to the Type of Lumbar Foraminal Stenosis

Study Design: This was a nonrandomized controlled cohort study (level 3). Objective: This study was designed to compare the differences in clinical features among patients with various degrees of lumbar foraminal stenosis (LFS), and the therapeutic effect of selective nerve root block (SNRB). Summary of Background Data: Symptomatic improvement rate was lower in grade IV (0.377) than in other grades (1T: 0.612, 2:0.527, 3:0.551), with statistical significance ( P =0.03). Patients and Methods: A total of 233 patients with radiating pain, concurrent with neurological and radiologic findings, were assigned to receive SNRB for at least 1 level, and screened for ≥6 months. The degree of foraminal stenosis was classified by perineural fat obliteration, and the degree of radiating pain was assessed by visual analog scale. After SNRBs were performed, symptomatic improvement was assessed after 2, 12, and 24 weeks after injection. Results: There were no significant differences in visual analog scale with regard to the degree of stenosis. Improvements were significantly higher after 2 weeks ( P =0.030), and there were no significant differences in symptomatic improvement rates over time except LFS grade 1V. At 2 weeks after injection, there was no significant difference in the extent of symptomatic improvement between the grades. At 12 and 24 weeks after injection, patients with LFS grade 1T, 2, 3 showed significantly higher symptomatic improvement rates than patients with LFS grade 1V. Conclusions: Among the patients with LFS, SNRB reduced pain by 51% after 2 weeks. At after 12 weeks, SNRBs were more effective in patients with LFS grade 1T, 2, 3, compared with patients with grade 1V. All patients showed persistent symptomatic relief, whereas those with grade 1T showed a reduced degree of symptomatic relief after 2 weeks.