Lumbar extraforaminal stenosis

All patients had congenital lumbosacral anomalies with various degrees of fixation between the last formed level and the pelvis. In all cases, affected roots were compressed between the transverse process of the last lumbar segment and the sacral ala. MR using coronal plane imaging demonstrated the root impingement directly in the far lateral zone in all patients. However, sagittal and axial images were unable to define the EF stenoses in all patients. The results of this study show that a transitional vertebra is a cause of EF stenosis and that MR images using coronal plane are useful in the assessment of EF stenosis ¹⁾.