Goal of the Study?
Low back-related leg pain is thought to be neuropathic in origin due to compromise of a nerve root(s) and is also commonly known as sciatica. In a study published in the Journal of Clinical Medicine 1 a group of authors looked to see if loading the spine during MRI imaging (axial loaded MRI) would help discern more specificity to the anatomical cause of the low back-related leg pain. These leg pain sufferers will often undergo recumbent MRI while their symptoms are in the vertical or axially loading posture.
Why are they doing this study?
Many cases of sciatica can be challenging to diagnose because of the complexity of the disc mechanics and physiology. There are many nuances of sciatica, and each case can bring its own set of complexities. Learning to determine the source(s) of sciatica more accurately can be helpful in its therapeutic management.
What was done?
Ninety patients were recruited for this retrospective observational study. The participant’ ages ranged from 21-89 years and were screened by an orthopedic surgeon to exclude those with hip and knee problems from the study. Participants were asked to fill out a self-evaluation including the visual analog scale along with a pain drawing. Each participant was evaluated by an attending physician and underwent an axial-loaded 1.5T MRI with added weight. As a comparison, each participant.
The investigators looked for these variables:
Cross-section of the dural sac
Lumbar spinal stenosis grade with axial loading
Disk herniation with axial loading
Size of herniated disc with axial loading
Size of hyperintensity zone with axial loading
Ligamentum flavum ‘type’ with axial loading
Intervertebral foraminal size with axial loading
Degenerative disc classification
Degenerative facet arthropathy
Edema of facet joint and effusion with axial loading
Synovial cyst area with axial loading
What did they find?
The authors found that axial-loading subjects played a significant role in extracting findings that would otherwise not be seen with conventional recumbent MRI. Specifically, they found facet joint edema, atypical ligamentum flavum, was associated with low back-related leg pain.
Why do these findings matter?
Often, sciatica patients undergo MRI to identify a cause. However, recumbent MRI does not tell the whole picture as patients often report a worsening of symptoms when they are axially loaded. This study helped reveal the changes in the loaded state and can help clinicians make informed decisions about the symptoms patients express in a clinical setting. Understanding that the facets are under more load and the ligamentum flavum can buckle inwards towards the spinal canal can help the clinician understand the anatomy when assessing patients. Notably, the authors summarized that these axial-loaded findings could offer a dynamic picture of the instability contributing to sciatica.
At Dynamic Disc Designs we have developed models to help demonstrate load related changes to the spine. We believe that our models not only help the patients understand their symptoms better so they can make the appropriate adjustments to improve their sciatica, but they also help in the context of the education of spine pain in general.