| Level of stenosis | ||
| L4, 5 | 45 | (83%) |
| L5, S1 | 21 | (39%) |
| L3, 4 | 14 | (26%) |
| Number of levels | ||
| One | 25 | (46.3%) |
| Two | 20 | (37%) |
| Three | 9 | (16.7%) |