| Variable | No. | % |
| Intraoperative complications | ||
| No | 26 | 86.7 |
| Yes | 4 | 13.3 |
| Total | 30 | 100.0 |
| Bleeding | 4 | 100.0 |
| Dural tear | 0 | - |
| Nerve root injury | 0 | - |
| Total | 4 | 100.0 |