Table 3.
Clinical parameters and outcomes of vestibular schwannoma surgery before and after treatment paradigm change with the introduction of Cyber Knife (CK) radiosurgery
| Before CK (n = 73) 2001–2012 |
After CK (n = 22) 2013–2017 |
||
|---|---|---|---|
| Age (mean ± sd) | 53 ± 14 years | 52 ± 16 years | |
| Gender (male/female) | 30/43 | 7/15 | |
| Diameter (mean ± sd) | 25 ± 14 mm | 31 ± 9 mm | p < 0.05 |
| Volume (mean ± sd) | 10,400 ± 12,100 mm3 | 14,100 ± 11,400 mm3 | p < 0.05 |
| Size1 | |||
| Intrameatal | 6.6% (n = 4) | – | |
| Small | 11.5% (n = 7) | – | |
| Medium | 50.8% (n = 31) | 54.5% (n = 12) | |
| Large | 31.1% (n = 19) | 45.5% (n = 10) | |
| Koos grade (mean ± sd (range))2 | 3.32 ± 0.81 (1–4) | 3.95 ± 0.21 (3–4) | |
| Extent of resection | p < 0.01 | ||
| Gross total | 36.1% (n = 26) | 9.1% (n = 2) | |
| Near total | 47.2% (n = 34) | 90.9% (n = 20) | |
| Subtotal | 13.9% (n = 10) | – | |
| Partial | 2.8% (n = 2) | – | |
| Drilling3 | 58.3% (n = 42) | 9.1% (n = 2) | p < 0.001 |
| Complication4 | 15.1% (n = 11) | 4.5% (n = 1) | |
| Regrowth5 | 24.7% (n = 18) | 19.8% (n = 4) | |
| Facial nerve outcome6 | p < 0.05 | ||
| Good | 65.2% (n = 43) | 68.4% (n = 13) | |
| Moderate | 12.1% (n = 8) | 31.6% (n = 6) | |
| Poor | 22.8% (n = 15) | – | |
| Hearing class (mean ± SD) 7 | |||
| Preoperative | 2.5 ± 1.2 | 2.6 ± 1.5 | |
| Postoperative | 4.2 ± 1.3 | 4.3 ± 0.9 | |
| Change | 1.7 ± 1.4 | 2.0 ± 1.5 | |
Significant differences have been indicated according to the Mann-Whintey U and chi square test
1Size is determined according to largest diameter (small ≤ 15 mm < medium ≤ 30 mm < large)
2Koos grading of vestibular schwannoma: 1, intarmeatal; 2, extending to the cerebellopontine angle; 3, in contact with the brainstem; 4, compressing the brainstem
3Drilling in internal acoustic meatus
4Complication requiring re-operation
5Regrowth leading to reoperation or radiosurgery
6Facial nerve outcome at 12 months by House-Brackman grade (1–2 good, 3–4 moderate, 5–6 poor)
7Hearing is determined according to the WHO classification