| Markwalder grade | Technique | p-value | Sig. | |||
| Fenestration group | Non-fenestration group | |||||
| No. | % | No. | % | |||
| Before operation | ||||||
| Grade 0 | 0 | 0% | 0 | 0% | >0.05 | NS |
| Grade 1 | 0 | 0% | 1 | 10% | >0.05 | NS |
| Grade 2 | 5 | 50% | 3 | 3% | >0.05 | NS |
| Good | 5 | 50% | 4 | 40% | >0.05 | NS |
| Grade 3 | 5 | 50% | 6 | 50% | >0.05 | NS |
| Grade 4 | 0 | 0% | 0 | 0% | >0.05 | NS |
| Bad | 5 | 50% | 6 | 60% | >0.05 | NS |
| After operation | ||||||
| Grade 0 | 2 | 20% | 1 | 10% | >0.05 | NS |
| Grade 1 | 1 | 10% | 2 | 20% | >0.05 | NS |
| Grade 2 | 7 | 70% | 7 | 70% | >0.05 | NS |
| Good | 10 | 100% | 10 | 100% | >0.05 | NS |
| Grade 3 | 0 | 0% | 0 | 0% | >0.05 | NS |
| Grade 4 | 0 | 0% | 0 | 0% | >0.05 | NS |
| Bad | 0 | 0% | 0 | 0% | >0.05 | NS |