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Corresponding Author

Mahmoud Nafady, MD.

Subject Area

Degenerative, Imaging, Lumbosacral spine

Document Type

Original Study

Abstract

Background Data: Lumbar canal stenosis (LCS) is a common sequela of degenerative spine disorders. LCS is a narrowing in the spinal canal and/or neural foramina. A positive sedimentation sign (SS) was defined as the absence of nerve root sedimentation in at least one axial MRI scan at a level above or below, disregarding the location of the scan within the level and its proximity to the maximal stenosis. The only exception is the two nerve roots leaving the dural sac one segmental level below the stenosis.

Purpose: This study aims to assess the diagnostic significance of the nerve root SS in patients with symptomatic LCS.

Study Design: A prospective cohort study.

Patient and Methods: The AP diameter of the lumbar canal from levels L1-L5 was measured using a film scale in T2 axial and sagittal views to diagnose central stenosis. A 1.5 Tesla magnet closed magnetic resonance imaging (MRI) was used for assessment. Nerve root SS was assessed in an MRI of the lumbar spine in patients with symptomatic LCS. Statistical analysis of data obtained on 75 patients on the significance of SS in detecting LCS was conducted. Low back pain (LBP) and LCS were also assessed.

Results: In total, 55 patients had LCS, including 51 patients with positive SS and four patients with negative SS. Twenty patients had LBP and/or sciatica without radiological LCS, including 19 patients with negative SS and one with positive SS. As a radiological sign for detecting LCS, the nerve root SS had a sensitivity of 98.1%, while its specificity was 82.6%.

Conclusion: The data in this study suggest a high sensitivity and specificity of nerve root SS as a radiological sign for the detection of LCS. SS has a valuable role in diagnosing LCS in patients with degenerative spine disease. However, positive SS requires additional pathological and radiological signs for the clinical diagnosis of LCS.

Keywords

Lumbar canal stenosis, sedimentation sign, low back pain, magnetic resonance imaging, nerve root

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