# Schizas — Schizas morphological grading of lumbar central canal stenosis

> Grades degenerative lumbar central canal narrowing at each level by cauda-equina rootlet, CSF and posterior epidural-fat morphology on axial T2 MRI. It does not grade foraminal stenosis, diagnose symptomatic lumbar stenosis or select surgery by itself.

**Situação:** vigente · **Órgão:** Coluna · **Órgão emissor:** Schizas et al. / spine imaging literature · **Versão:** 2010 original morphology; current clinical-correlation limits · **Ano:** 2010

## Procedência e vigência
- Família: léxico
- Tipo de lógica: flat
- Modalidade: MRI
- Fonte primária: Schizas C, Theumann N, Burn A, et al.. Qualitative grading of severity of lumbar spinal stenosis based on the morphology of the dural sac on MR images (2010) — https://pubmed.ncbi.nlm.nih.gov/20671589/
- Última verificação: 2026-07-24
- Última checagem: 2026-08-12

## Lógica de decisão
Grade every relevant lumbar level from axial T2 morphology. Keep central, lateral-recess and foraminal disease separate, preserve ungradable and adjacent-grade states, and never use the grade alone to diagnose symptomatic stenosis or choose surgery.

## Categorias

| Código | Rótulo | Critérios | Conduta | Risco | Localizador | Verificado |
| --- | --- | --- | --- | --- | --- | --- |
| A1 | Grade A1, no/minor stenosis, rootlets dorsal occupying less than half the sac | On an adequate axial T2 image through the evaluated lumbar central canal level, cerebrospinal fluid remains clearly visible and the cauda-equina rootlets lie dorsally while occupying less than half of the dural-sac area. | Report A1 at the named lumbar level and describe lateral-recess, foraminal and causative degenerative findings separately. This morphology alone neither establishes symptomatic lumbar stenosis nor determines conservative, injection or surgical care. | A1 belongs to broad grade A (no or minor central stenosis in the original morphology). Grade has weak/inconsistent correlation with symptoms and postoperative outcome, so it cannot exclude a clinically responsible dynamic or noncentral lesion. | Schizas et al. 2010, DOI 10.1097/BRS.0b013e3181d359bd, Figure 1 and p. 1920: dorsal rootlets occupying less than half of dural sac; Yang et al. 2023, PMC10039594, Results/Discussion for limited symptom and outcome correlation. | ✓ |
| A2 | Grade A2, rootlets dorsal in horseshoe configuration | On axial T2 MRI, cerebrospinal fluid remains clearly visible and the rootlets lie dorsally in contact with the dura in a horseshoe configuration. The horseshoe morphology, not a numeric area cutoff, distinguishes A2. | Report A2 per level with image adequacy and the separate compartmental findings. A1-A4 are morphological subtypes within broad grade A and must not be converted into different treatment tiers without clinical correlation. | A2 does not predict pain, walking tolerance, neurologic deficit or surgical benefit. Static supine morphology can underrepresent dynamic narrowing, and reader training affects reproducibility. | Schizas et al. 2010, DOI 10.1097/BRS.0b013e3181d359bd, Figure 1 and p. 1920 for dorsal rootlets touching dura in a horseshoe; Ko et al. 2020, PMC7252624, reliability analysis; JOA guideline DOI 10.1016/j.jos.2022.03.013 for clinical-imaging correlation. | ✓ |
| A3 | Grade A3, rootlets dorsal occupying more than half the sac | On axial T2 MRI, cerebrospinal fluid remains clearly visible and the rootlets lie dorsally while occupying more than half of the dural-sac area. If occupancy near one half cannot be judged, report A1-versus-A3 uncertainty. | Use A3 as a per-level central-canal morphology and document symptoms, neurologic findings and responsible-level concordance outside the score. It does not prescribe surveillance, injection or decompression. | The increased rootlet occupancy is a morphology descriptor rather than a validated patient-level prognosis. Symptoms can be severe with lesser morphology or absent with greater narrowing, and the scale does not evaluate foraminal disease. | Schizas et al. 2010, DOI 10.1097/BRS.0b013e3181d359bd, Figure 1 and p. 1920 for dorsal rootlets occupying more than half; Yang et al. 2023, PMC10039594, correlation analyses and limitations. | ✓ |
| A4 | Grade A4, rootlets central occupying most of the sac | On axial T2 MRI, cerebrospinal fluid remains clearly visible and the rootlets lie centrally while occupying the majority of the dural-sac area. Central position differentiates A4 from the dorsal A1-A3 patterns. | Report the A4 morphology at its exact level and preserve separate lateral-recess and foraminal assessments. Do not infer a distinct intervention threshold merely because A4 is the last A subtype. | A4 is not an ordinal treatment step between A3 and B; all A subtypes retain visible cerebrospinal fluid. It cannot independently establish symptom causality, future deterioration or likely surgical response. | Schizas et al. 2010, DOI 10.1097/BRS.0b013e3181d359bd, Figure 1 and p. 1920 for central rootlets occupying most of the sac; Yang et al. 2023, PMC10039594, outcome-correlation limitations. | ✓ |
| B | Grade B, moderate, rootlets fill the sac but still individualizable | Moderate central stenosis morphology: rootlets occupy the entire dural sac but remain individually recognizable, with some residual cerebrospinal-fluid signal producing a grainy appearance. Loss of individual rootlet recognition moves the boundary toward C/D. | Report grade B per lumbar level, the degenerative cause, and other stenotic compartments. Clinical diagnosis and care require symptom pattern, examination and concordance; B alone does not favor or exclude surgery. | The original cohort grouped A/B as less associated with conservative-treatment failure than C/D, but it was small and clinically selected. Later work shows limited correlation with symptoms and postoperative outcomes, so this is not an individual risk estimate. | Schizas et al. 2010, DOI 10.1097/BRS.0b013e3181d359bd, Figure 1, pp. 1920-1922 for individualized rootlets, grainy CSF and cohort associations; Yang et al. 2023, PMC10039594, Results/Discussion for modern correlation limits. | ✓ |
| C | Grade C, severe, no rootlets seen, posterior epidural fat present | Severe central stenosis morphology: no individual rootlets are recognizable and no cerebrospinal-fluid signal is visible, producing a homogeneous gray sac, while posterior epidural fat remains visible. Posterior fat is the required C-versus-D discriminator. | Surface grade C and any neurologic red flags promptly, but choose care only after clinical syndrome, examination, responsible level, comorbidity and patient goals are integrated. C is not an automatic decompression indication. | C/D were strongly associated with conservative-treatment failure in the original selected cohort (reported odds ratio 29.8), but grade was unrelated to baseline disability or surgical result there, and modern studies find weak or no outcome correlation. Do not individualize that cohort odds ratio. | Schizas et al. 2010, DOI 10.1097/BRS.0b013e3181d359bd, Figure 1 and pp. 1920-1923 for absent CSF/rootlet recognition, retained posterior fat, odds ratio and outcome limits; Yang et al. 2023, PMC10039594, correlation and surgical-outcome analyses. | ✓ |
| D | Grade D, extreme, no rootlets and no posterior epidural fat | Extreme central stenosis morphology: no individual rootlets and no cerebrospinal-fluid signal are recognizable, and posterior epidural fat is also no longer visible. If posterior fat cannot be evaluated technically, report C-versus-D uncertainty rather than guessing. | Report grade D at the named level and communicate urgent neurologic findings directly, while retaining clinical decision-making outside the score. D alone does not determine emergency status, decompression, fusion or prognosis. | D is the most compressed morphology in this scale and shared the original C/D association with failed conservative care, but neither the original nor later evidence validates a deterministic symptom or surgical-outcome prediction from grade D alone. | Schizas et al. 2010, DOI 10.1097/BRS.0b013e3181d359bd, Figure 1 and pp. 1920-1923 for absent rootlets/CSF/posterior fat and cohort limitations; Ko et al. 2020, PMC7252624, reader reliability; Yang et al. 2023, PMC10039594, clinical and outcome limits. | ✓ |

### Citações por categoria
- **A1**: Schizas C, Theumann N, Burn A, et al.. Qualitative grading of severity of lumbar spinal stenosis based on the morphology of the dural sac on MR images (2010) — https://pubmed.ncbi.nlm.nih.gov/20671589/ · Schizas et al. 2010, DOI 10.1097/BRS.0b013e3181d359bd, Figure 1 and p. 1920: dorsal rootlets occupying less than half of dural sac; Yang et al. 2023, PMC10039594, Results/Discussion for limited symptom and outcome correlation.
- **A2**: Schizas C, Theumann N, Burn A, et al.. Qualitative grading of severity of lumbar spinal stenosis based on the morphology of the dural sac on MR images (2010) — https://pubmed.ncbi.nlm.nih.gov/20671589/ · Schizas et al. 2010, DOI 10.1097/BRS.0b013e3181d359bd, Figure 1 and p. 1920 for dorsal rootlets touching dura in a horseshoe; Ko et al. 2020, PMC7252624, reliability analysis; JOA guideline DOI 10.1016/j.jos.2022.03.013 for clinical-imaging correlation.
- **A3**: Schizas C, Theumann N, Burn A, et al.. Qualitative grading of severity of lumbar spinal stenosis based on the morphology of the dural sac on MR images (2010) — https://pubmed.ncbi.nlm.nih.gov/20671589/ · Schizas et al. 2010, DOI 10.1097/BRS.0b013e3181d359bd, Figure 1 and p. 1920 for dorsal rootlets occupying more than half; Yang et al. 2023, PMC10039594, correlation analyses and limitations.
- **A4**: Schizas C, Theumann N, Burn A, et al.. Qualitative grading of severity of lumbar spinal stenosis based on the morphology of the dural sac on MR images (2010) — https://pubmed.ncbi.nlm.nih.gov/20671589/ · Schizas et al. 2010, DOI 10.1097/BRS.0b013e3181d359bd, Figure 1 and p. 1920 for central rootlets occupying most of the sac; Yang et al. 2023, PMC10039594, outcome-correlation limitations.
- **B**: Schizas C, Theumann N, Burn A, et al.. Qualitative grading of severity of lumbar spinal stenosis based on the morphology of the dural sac on MR images (2010) — https://pubmed.ncbi.nlm.nih.gov/20671589/ · Schizas et al. 2010, DOI 10.1097/BRS.0b013e3181d359bd, Figure 1, pp. 1920-1922 for individualized rootlets, grainy CSF and cohort associations; Yang et al. 2023, PMC10039594, Results/Discussion for modern correlation limits.
- **C**: Schizas C, Theumann N, Burn A, et al.. Qualitative grading of severity of lumbar spinal stenosis based on the morphology of the dural sac on MR images (2010) — https://pubmed.ncbi.nlm.nih.gov/20671589/ · Schizas et al. 2010, DOI 10.1097/BRS.0b013e3181d359bd, Figure 1 and pp. 1920-1923 for absent CSF/rootlet recognition, retained posterior fat, odds ratio and outcome limits; Yang et al. 2023, PMC10039594, correlation and surgical-outcome analyses.
- **D**: Schizas C, Theumann N, Burn A, et al.. Qualitative grading of severity of lumbar spinal stenosis based on the morphology of the dural sac on MR images (2010) — https://pubmed.ncbi.nlm.nih.gov/20671589/ · Schizas et al. 2010, DOI 10.1097/BRS.0b013e3181d359bd, Figure 1 and pp. 1920-1923 for absent rootlets/CSF/posterior fat and cohort limitations; Ko et al. 2020, PMC7252624, reader reliability; Yang et al. 2023, PMC10039594, clinical and outcome limits.

## Referências cruzadas
- _fronteira compartilhada_ → [Pfirrmann — Pfirrmann grading of lumbar disc degeneration](https://radcommons.laudos.ai/systems/pfirrmann.md) — Degenerative lumbar MRI: Schizas grades central canal stenosis, Pfirrmann grades disc degeneration.

## Histórico de versões

| Data | Evento | Detalhe | Situação |
| --- | --- | --- | --- |
| 2010-10-01 | published | Morphological grading of lumbar spinal stenosis published in Spine. | confirmed |


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> Conteúdo de referência reescrito. Confira a publicação primária vigente. Não é dispositivo médico nem substitui o julgamento clínico. O radiologista responsável pelo laudo permanece o autor e o responsável.

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