| Variables | Group I | Group II | Group III |
|---|---|---|---|
| Ratio of central canal distance(%) | |||
| Group I | – | – | – |
| Group II | 0.001 | – | – |
| Group III | * | * | – |
| Ratio of interpedicular distance(%) | |||
| Group I | – | – | – |
| Group II | * | – | – |
| Group III | * | * | – |
| Ratio of spinal canal area(%) | |||
| Group I | – | – | – |
| Group II | 0.020 | – | – |
| Group III | * | 0.002 | – |
| Ratio of anterior height(%) | |||
| Group I | – | – | – |
| Group II | 0.684 | – | – |
| Group III | 0.003 | 0.153 | – |