Clinical question: stenosis? Signs and Symptoms: degenerative spondylosis. Nonenhanced lumbar MRI:T11-T12 through L2-L3 are unremarkable other than mild bilateral facet and ligamentum flavum hypertrophy.L3-L4 demonstrate mild disc dessication and moderate bilateral ligamentum flavum and facet hypertrophic changes. There is resultant moderate left and mild right neural foraminal compromise and mild central spinal stenosis.L4-L5 demonstrate moderate degenerative disc disease and loss of disc height, significant bilateral facet and ligamentum flavum with resultant grade one anterolisthesis. There is a left lateral ventral epidural defect at this level with T1 hyperintense, T2 isointense and T2 STIR hyperintense signal intensity. The finding measures approximately at 7.5 x 10 mm in transaxial dimensions (axial T2 series 8 image 29). There is resultant subtle mass effect and posterior displacement of the thecal sac to the left of midline. Although the finding could represent an extruded disc fragment it appears to be contiguous with the left L4 nerve root which also appears mildly thickened which raises the possibility of an extradural intracanalicular schwannoma as a cause as well. Follow-up exam post contrast only images is recommended for better assessment and differentiation. This finding is best appreciated on axial T2 series 8 images 27 through 30 and on all sagittal series on images 13 and 14.There is moderate bilateral neural foraminal and mild central spinal stenosis.L5-S1 demonstrate mild disc disease and mild to moderate bilateral facet and ligamentum flavum hypertrophy. No spinal stenosis however significant left and moderate right neural foraminal compromise secondary to hypertrophic changes of posterior elements are detected.
1.Mild to moderate disc disease however disproportionate extensive hypertrophic changes of posterior elements of the mid to lower lumbar spine as detailed.2.Degenerative changes at L3-L4 results in mild central spinal stenosis and neural foraminal compromise.3.There is a left lateral well demarcated ventral epidural defect posterior to lower L4 vertebral body with apparent continuity with the thickened left L4 nerve root in the left neural foramina. It demonstrate mild mass effect on the thecal sac. This finding although could represent an extruded disc fragment possibility of a intracanicular extradural schwannoma should also be considered. Recommend follow-up with postcontrast only images for further assessment/differentiation.4.Degenerative changes at L4-L5 with disproportionate significant facet and ligamentum flavum hypertrophy results in mild central spinal stenosis and bilateral neural foraminal compromise. Please see detailed report per level above.