Introducing Standing Weight-bearing MRI in the Di-agnostics of Low Back Pain and Degenerative Spinal Disorders.

This PhD thesis is based on three scientific papers. In 2011 the Parker Institute the department of rheumatology introduced standing weight-bearing MRI (G-Scan, ESAOTE, Genova, Italy) in the diagnostic of low back pain patients. Unfortunately, we experienced a substantial risk of fainting (orthostatic syncope) during standing pMRI. In paper 1 we present in an observational study that the risk of fainting (19%) during standing pMRI could almost be eliminated by the use of an external pneumatic compression device (2%). The lumbar lordosis in the standing position is a significant contributor to positional changes in the morphology in the lumbar spine. In paper 2, we present in an observational study that changes in lumbar lordosis angle (ΔLA) between the conventional supine and standing position were independent of pain and the degenerative disc score. Before a full introduction of standing pMRI in clinical practice, it is important to know if the interpretation of positional changes in common degenerative findings has a sufficient reproducibility. In paper 3, we present in a reliability study that the pMRI evaluation has a fair to substantial reliability, although positional changes in the lumbar spine's morphology from the supine to the standing seems a less reliable outcome. There are currently no international evidence-based recommendations for the use of standing pMRI, and we have limited knowledge about how to interpret these positional changes in the lumbar spine into a clinical context. Therefore, further research is warranted to test the precision (sensitivity and specificity) in prospective longitudinal studies or RCTs. However, from a clinical perspective it seems logical to scan patients with low back pain in the position worsening their symptoms - typically the upright position. Therefore, standing pMRI may provide a higher diagnostic specificity and additional benefit to low back pain patients in the future.