Characterization of symptomatic lumbar foraminal stenosis by conventional imaging

The preoperative identification of lumbar foraminal stenosis (LSFS) is important because a lack of recognition of this clinical entity is often associated with failed back surgery syndrome. Although magnetic resonance imaging (MRI) is widely used, and is considered by many as an appropriate tool for studying spine pathologies, there is limited data to suggest that MRI examinations are sufficiently sensitive or specific for the diagnosis of LSFS. There is a paucity of literature on the diagnostic performance of the combination of conventional diagnostic imaging methods. The purpose of this study is to determine the characteristics of conventional diagnostic imaging for symptomatic lumbar foraminal stenosis.

The characteristics of conventional diagnostic imaging of LSFS (X-ray, computed tomography (CT) and MRI) were assessed in 68 patients in whom the site of the stenosis was confirmed by means of selective decompression surgeries.

Measurement of the foraminal width and height on CT imaging of the diseased side was significantly less than that on the intact side in the LSFS group. The grading scale for facet joint arthritis on the diseased side was significantly higher than that on the intact side in the LSFS group. The prevalence of the vacuum phenomenon and stage of intervertebral disk (IVD) pathology were higher in the L5-S1 spine of the LSFS group (95.2%) compared with the lumbar spinal canal stenosis (LCS) group (21.1%). MRI study revealed that the prevalence of Type 3 Modic changes was significantly higher in the LSFS group (39.3%) compared with the LCS group (7.7%).

Our study demonstrates combination of conventional imaging techniques, to improve the detection of symptomatic foraminal stenosis.