Lumbar spinal canal stenosis grading systems by Lee and Schizas

Case contributed by Francis Deng
Diagnosis not applicable


Visual grading of lumbar spinal canal stenosis based on axial T2-weighted MRI

Lee classification

  • Grade 0: no stenosis: no obliteration of the anterior cerebrospinal fluid space
  • Grade 1: mild stenosis: mild obliteration of the anterior cerebrospinal fluid space and all cauda equina clearly separated from each other
  • Grade 2: moderate stenosis: moderate obliteration of the anterior cerebrospinal fluid space and some cauda equina aggregation
  • Grade 3: severe stenosis: severe obliteration of the anterior cerebrospinal fluid space, marked compression of the dural sac, and the entire cauda equina appearing as one bundle

Schizas classification

  • Grade A: no or minor stenosis
    • A1: rootlets lying dorsally and occupying less than half of the dural sac area.
    • A2: rootlets lying dorsally with a horseshoe configuration
    • A3: rootlets lying dorsally and occupying more than half of the dural sac area
    • A4: rootlets lying centrally and occupying the majority of the dural sac area
  • Grade B: moderate stenosis: rootlets occupying the entire dural sac, but rootlets can still be individualized
  • Grade C: severe stenosis: no recognizable rootlets with complete effacement of cerebrospinal fluid space, but epidural fat is present posteriorly
  • Grade D: extreme stenosis: no recognizable rootlets and no epidural fat posteriorly

Case Discussion

Authors: Yeon-jee Ko, Eugene Lee, Joon Woo Lee, Chi Young Park, Jungheum Cho, Yusuhn Kang, Joong Mo Ahn.

Original file: (published in PLOS ONE)

Modifications: The original figures were divided, cropped, and captioned separately.

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