Radiological classification of lumbar neuroforaminal and lateral recess stenosis according to Lee et al55 and Hasegawa et al.57
| Zone | Location | Range of Distance |
| Zone 1 | Entry | From dura to pedicle |
| Zone 2 | Middle | From medial pedicle wall to center pedicle |
| Zone 3 | Exit | From center pedicle to the lateral border of the facet joint |