To investigate if adding a lumbar pillow in supine position during magnetic resonance imaging (MRI) is superior to standing positional MRI for diagnosing lumbar spinal stenosis (LSS).
Summary of Background Data.
The upright standing position and especially extension of the lumbar spine seem to worsening symptoms of LSS. However, it is unclear whether a forced lumbar extension by a pillow in the lower back during conventional supine MRI may improve the diagnostics of LSS compared with standing MRI.
Patients suspected for LSS and referred to conventional MRI were included to an additional positional MRI scan (0.25T G-Scan) performed in: (1) conventional supine, (2) standing, (3) supine with a lumbar pillow in the lower back. LSS was evaluated for each position in consensus on a 0 to 3 semi-quantitative grading scale. Independently, L2-S1 lordosis angle, spinal cross-sectional diameter (SCSD), dural cross-sectional diameter (DCSD), and dural cross-sectional diameter (DCSA) were measured. The smallest dural diameter was defined as stenosis level and the largest control level for comparison.
Twenty-seven patients (60.6 years; ±9.4) were included. The lordosis angle increased significantly from supine to standing (3.2° CI: 1.2–5.2) and with the lumbar pillow (12.8° CI: 10.3–15.3). One-way analysis of variance (ANOVA) showed significant differences between positions (P < 0.001). When compared with the supine position, pairwise comparisons showed decreased SCSD, DCSD, DCSA, and increasing semi-quantitative grading, during both standing and supine with the lumbar pillow. A difference in the semi-quantitative grades was only found between standing and supine with a lumbar pillow, and the scan with a lumbar pillow was significantly more painful.
Standing MRI and supine MRI with a lumbar pillow resulted in equal changes in the lumbar spine, although standing MRI may be more sensitive in the assessment of patients suspected for LSS.
Level of Evidence: 2