Radiological classification
Ozer 2022
Stable group
- General:
- No motion on dynamic imaging
- The disc and annulus are calcified and fused to the upper and lower corpus vertebrae. Posterior facet joints are hypertrophic and severely degenerated. Fusion of articular facets is not a rare finding.
- Type I: Root trapped between upper and lower pedicles with a completely degenerated, non‑mobile disc.
- Type II: Degenerated disc with degenerative listhesis; root compressed between upper pedicle and lower vertebral body.
- Type III: Hypertrophic/calcified superior facet pushes root toward the corner between upper pedicle and posterior wall of the upper vertebral body.
- Type IV: Calcified, bulged disc fused to both vertebral bodies; root compressed between this calcified disc and hypertrophic facets.
Unstable group
- General
- Degenerative and mobile intervertebral disc that causes instability in any motion.
- Does not mean that there is listhesis in the level need further flex and ext xray to define instability
- Type I: Soft, bulging, mobile disc; root squeezed between disc bulge and posterior facets.
- Use flex and ext xray to define if there is motion.
- Type II: Mobile disc with degenerative listhesis and pseudodisc bulge; root compressed between pseudobulged disc and superior pedicle.
- Type III: Mobile disc without significant bulge; hypertrophic/calcified facet pushes root against upper pedicle–vertebral body corner.
- Type IV: Mobile bulging disc present but secondary; root mainly compressed between hypertrophic facet and a synovial cyst.
Lee 1988
- Entry zone
- Dura to pedicle
- Zone 1
- Stenosis due to hypertrophy of the superior articular face as the predominant pathology.
- Middle
- Medial pedicle wall to center pedicle
- Zone 2
- Stenosis due to an osteophytic process underneath the pars interarticularis
- Exit zone
- Center pedicle to lateral border of the facet joint
- Zone 3
- Stenosis due a subluxed and hypertrophic facet joint
Management
- For stable foraminal stenosis
- Decompression procedures were performed without instrumentation due to spontaneous fusion of the related spinal segment
- For unstable foraminal stenosis
- Might need stabilization if flex and ext xray shows instability