Objective: To evaluate the accuracy in determining the degree of lumbar spinal stenosis in patients utilizing lumbar spine magnetic resonance imaging (MRI) with axial loading as compared to conventional lumbar spine MRI with clinical correlation. To assess the difference in the dural cross sectional area (DCSA) between lumbar spine MRI with axial loading and conventional lumbar spine MRI.

Materials and Methods: Thirteen patients with clinically diagnosed lumbar spinal stenosis, which comprised of three males and ten females, aged 20 to 80 years, and that had the severity of their stenosis clinically and radiologically graded by history taking, physical examination, and by performing both conventional and axial loaded MRI were included in this study.

Results: The present study found a statistically significant difference (p<0.05) after applying load at all lumbar levels. The L4-L5 level showed the greatest reduction at 12.8%, followed by L3-L4 and L2-L3, in which the DCSA was reduced by 11.2% and 9.0%, respectively. Comparing the clinical severity and degree of each lumbar spinotic level and the maximum severity per person, the results showed that the most accuracy was at the L3-L4 level followed by L5-S1 and L2-L3 levels. No accuracy between clinical severity and the degree of lumbar spinal stenosis at L1-L2 and L4-L5 levels were shown, suggesting that more than the DCSA change influence the clinical severity. To gain further insights, following up patients and a study with more patients are needed. The maximum severity by DCSA measurement, both pre- and post-loading, of individual patients compared with clinical severity showed concordance for three patients. No significant difference in accuracy was found between pre- and post-loading.

Conclusion: Changes in the DCSA of lumbar spinal stenosis after loading MRI was statistically significant especially at the moderate and severe stenotic levels particularly at the L3-4 level and L5-S1 level.

Keywords: Lumbar spine MRI; Axial loading; Lumbar spinal stenosis

DOI: 10.35755/jmedassocthai.2022.10.13679

Received 22 November 2021 | Revised 14 June 2022 | Accepted 22 June 2022