Goal of the Study?
In this cross-sectional study from the European Spine Journal 1 the authors’ primary goal was to describe the relationship between MRI findings in patients planned for degenerative Lumbar Spinal Stenosis (LSS) surgery and examine if any association exists between MRI findings and patient’s disability and pain attributes.
Why are they doing this study?
Degenerative Lumbar Spinal Stenosis (LSS) is predominantly caused by the arthrosis of the facet joints, ligament hypertrophy and degenerative changes of the intervertebral disks. These changes increase with age and can lead to narrowing of the spinal canal, nerve root compression and symptoms of neurogenic claudication with radiating pain or numbness in the legs, aggravated by standing and walking. The diagnosis of symptomatic LSS is based on clinical symptoms and stenosis of the spinal canal as visualized on the MRI. Patients with symptoms of LSS can present a wide variety of radiological findings of uncertain clinical reference. The authors believe that this is the first study to investigate several MRI parameters among LSS patients.
What was done?
All patients had MRI findings and symptoms consistent with LSS and were referred to an orthopedic or neurosurgical outpatient clinic. In total 2,227 patients were referred but only 437 met the eligibility criteria and were included. Eligible patients’ MRI’s were analyzed by orthopedic surgeons and musculoskeletal radiologists using several MRI metrics. Based on these metrics each patient was classified into either moderate or severe changes. After the MRI analysis, the patients completed a self-administered questionnaire that used three different symptom severity metrics.
- Norwegian version of the Oswestry Disability Index (ODI), which is a ten-question survey focusing on lower back pain symptoms
- Zurich Claudication Questionnaire is a disease-specific questionnaire designed to access patient’s walking capacity, neurogenic claudication and patient satisfaction
- Numeric Rating Scale which has a 10 point scale targeted at the pain symptoms of the back and leg.
What did they find?
MRI evaluations showed a high proportion of severe LSS changes when investigating spinal morphology. Over 70% of the patients rated severe on the Schizas grading system; over 80% rated severe using both the Dorsal Sac Cross-Sectional Area and the fatty infiltration of the multifidus muscle. Disk degeneration using the Pfirrmann scale was severe on almost 60% of the patients. Despite the MRI analysis showing a high proportion of severe LSS changes, there was no or very weak association with the three self-administered disability and pain questionnaires. Statistical analysis on patient characteristics indicated that gender influenced disability and pain scores to a larger extent than the degree of MRI findings. In fact, being female gives a nearly threefold larger impact on ODI pain scores than MRI radiological parameters.
Why do these findings matter?
Given the lack of statistical significance on the association of MRI findings and pain characteristics, the authors suggest that physicians should not overly emphasize the radiological signs of degenerative changes when giving medical advice to patients with LSS.
At Dynamic Disc Designs, we have developed models to help clinicians bridge the discrepancies between radiological findings of degenerative lumbar spinal stenosis and the clinical presentation of degenerative spinal stenosis. Small changes in spinal canal dynamics are often not picked up by MRI and need further education. Our Lumbar Spinal Stenosis helps this clinical problem.