Spine - Stenosis

Essential Radiology of the degenerative lumbar spine: updating concepts.

Authors: I. García Duitama, S. Carbullanca Toledo, J. Ares, A. Solano, A. Agustí; Barcelona/ES

DOI: 10.1594/ecr2018/C-1693

DOI-Link: https://dx.doi.org/10.1594/ecr2018/C-1693

https://epos.myesr.org/posterimage/esr/ecr2018/142641/mediagallery/753259

Qualatative grading of lumbar spinal stenosis to Schizas classification. Mild stenosis: there is dural sac area reduction with sufficient CSF surrounding the rootlets. Moderate stenosis: dural sac reduction and almost complete loss of perineural CSF. Rootlets are still visible. Severe stenosis: no rootlets nor CSF can be individualized. Dark dural sac on MRI. Posterior epidural fat present. Extreme stenosis: severe estenosis with loss of posterior epidural fat.


The lateral recess is delimited between the more medial margin of the superior facet process (or ligamentum flavum if hypertrophic) and the vertebral posterior wall or herniated disc. Lateral recess stenosis produces descending root impingement (red dots in diagram), generating radiculopathy in the inferior level (i.e; L4-5 lateral recess stenosis, L5 symptoms).

Mild stenosis: partial perineural fat obliteration due to ligamentum flavum hypertrophy or disc/osteophytic protrusion. Moderate stenosis: complete perineural fat obliteration. Severe stenosis: nerve root collapse or deformation in the foraminal zone due to extrinsic compression.