Study design: We studied baseline magnetic resonance images of 155 patients with intermittent neurogenic claudication and lumbar spinal stenosis (LSS). Magnetic resonance imaging (MRI) and patient data were gathered from participants of a randomized trial.
Objective: It is believed that the narrowness of the lumbar spinal canal correlates to the severity of complaints and that it may be a good predictor of clinical outcome if treated. However, this hypothesis has never been (prospectively) tested.
Summary of background data: MRI is an important tool to confirm the diagnosis of LSS as a cause for intermittent neurogenic claudication.
Methods: Three raters were asked to evaluate the magnetic resonance images (Schizas scale). Symptom severities at baseline and 1-year follow-up were quantified. The radiological scores were correlated with clinical baseline and outcome scores to assess diagnostic and prognostic value of MRI findings at baseline.
Results: There was good agreement on the clinically relevant level of LSS (kappa range 0.57-0.64). MRI assessment of grading of compression (kappa 0.33-0.46) did not correlate with baseline MRDQ nor with outcome based on postoperative change in MRDQ (P = 0.61). However, both absence of epidural fat and presence of tortuous caudal nerves on magnetic resonance images (kappa 0.53-0.72 and 0.67-0.70) in patients with LSS were relatively good predictors for satisfactory recovery after surgery (P = 0.03 and P < 0.01).
Conclusion: The grading of compression on the preoperative MRI is neither ambiguous nor correlating to severity of clinical condition. It does, furthermore, not have the ability to predict the outcome after 1 year if surgically treated.
Level of evidence: 2.