Study design: Case-control observational study.
Objective: Determination of dimensional changes in the lumbar spines of athletes between supine and stand-up position in MRI, concerning the lordosis, spinal canal cross-sectional area (SCCA), dural sac cross-sectional area (DSCA), sagittal dural sac diameter (SDSD), the lateral recess and the neural foramina.
Summary of background data: The development of positional MRI allows the examination of spine segments under a true weight-bearing situation.
Methods: About 35 athletes (20m/15f, Ø: 28a) were examined using a 0.25 T open MRI-Scanner (G-Scan, ESAOTE, Italy). In all cases, axial and sagittal SE-T1 + SSE-T2 images were recorded in supine and true standing position. All measurements were performed using MEDIMAGE software (Vepro AG, Germany). The blinded measurements were performed 3 times by 2 independent examiners. Sagittal images were used to determine the lordosis and the narrowing of the left/right foramen at all levels between L1/2 and L5/S1. Axial images were used to determine the SDSD, the SCCA and the DSCA at L3/4, L4/5, L5/S1, and narrowing of the left/right recessus lateralis of L4, L5 and S1.
Results: The lordosis showed a significant increase of 6.3 degrees (14%) from supine to true standing position (P < 0.001). The SDSD is significantly smaller in true standing position, than in supine position at the level of L3/4 and L4/5 (P < 0.001). Narrowing of the foramen occurred in true standing position in 13.4% at L4/L5 and in 26.7% at level L5/S1. No significant differences were observed at the recessus lateralis, the SCCA and the DSCA.
Conclusion: The measurement method in supine and true standing position is excellent for depicting the anatomical regions relevant for spinal canal stenosis in healthy individuals. Measuring the lumbar lordosis angle in both positions is an important requirement for interpreting the relevant anatomical regions. Of particular importance here is the DSCA and the SDSD.