Background: The debate continues with a limited number of publications describing outcomes in patients with vestibular schwannoma (VS) treated with planned subtotal resection (STR) plus stereotactic radiosurgery (SRS). Here we present our experience. Methods: This is a retrospective review of 22 patients with VS Koos grade III and IV who were treated with STR followed by SRS. Tumor volumes, facial nerve function, hearing preservation, and the presence of trigeminal neuropathy were noted. Spearman's rank test was used to correlate facial nerve grade with postoperative tumor residual tumor volume. Results: Tumor control was achieved in all patients with a mean follow-up of 28 months. No patient required other treatment beyond the original surgery and adjuvant SRS during this period. After a mean postoperative period of 28 months, 19/22 patients had excellent (House-Brackmann I or II) facial nerve function grading. Improved facial nerve function was positively correlated with larger residual tumor volume (rs = 0.63). Kaplan-Meier curve showed around 80% probability for regaining facial nerve function after initial deterioration. Four patients reported postoperative facial numbness at the side of surgery, with 3 cases showing improvement within a month. Temporary postoperative caudal cranial nerve dysfunction was observed in 2 patients. Conclusion: Hybrid strategy of STR and adjuvant SRS provides patients with large VS excellent tumor control and a good clinical outcome.

Keywords:
Vestibular schwannoma, Acoustic neuroma, Subtotal resection, Radiosurgery, Gamma Knife
1.
Propp JM, McCarthy BJ, Davis FG, Preston-Martin S: Descriptive epidemiology of vestibular schwannomas. Neuro Oncol 2006;8:1-11.
2.
Arlt F, Trantakis C, Seifert V, Bootz F, Strauss G, Meixensberger J: Recurrence rate, time to progression and facial nerve function in microsurgery of vestibular schwannoma. Neurol Res 2011;33:1032-1037.
3.
Matthies C, Samii M: Management of 1,000 vestibular schwannomas (acoustic neuromas): clinical presentation. Neurosurgery 1997;40:1-9; discussion 9-10.
4.
Arthurs BJ, Fairbanks RK, Demakas JJ, Lamoreaux WT, Giddings N, Mackay AR, et al: A review of treatment modalities for vestibular schwannoma. Neurosurg Rev 2011;34:265-277; discussion 277-279.
5.
Flickinger JC, Kondziolka D, Niranjan A, Maitz A, Voynov G, Lunsford LD: Acoustic neuroma radiosurgery with marginal tumor doses of 12 to 13 Gy. Int J Radiat Oncol Biol Phys 2004;60:225-230.
6.
Schwartz MS, Kari E, Strickland BM, Berliner K, Brackmann DE, House JW, et al: Evaluation of the increased use of partial resection of large vestibular schwannomas: facial nerve outcomes and recurrence/regrowth rates. Otol Neurotol 2013;34:1456-1464.
7.
Pollock BE, Link MJ, Bauch CD: Patient outcomes after vestibular resection and stereotactic radiosurgery. Neurosurgery 2006;58:77-85.
8.
Milligan BD, Pollock BE, Foote RL, Link MJ: Long-term tumor control and cranial nerve outcomes following Gamma knife surgery for larger-volume vestibular schwannomas. J Neurosurg 2012;116:598-604.
9.
Talfer S, Dutertre G, Conessa C, Desgeorges M, Poncet J-L: Surgical treatment of large vestibular schwannomas (stages III and IV). Eur Ann Otorhinolaryngol Head Neck Dis 2010;127:63-69.
10.
Han JH, Kim DG, Chung H-T, Paek SH, Park C-K, Kim C-Y, et al: Hearing preservation in patients with unilateral vestibular schwannoma who undergo stereotactic radiosurgery: reinterpretation of the auditory brainstem response. Cancer 2012;118:5441-5447.
11.
Fuentes S, Arkha Y, Pech-Gourg G, Grisoli F, Dufour H, Régis J: Management of large vestibular schwannomas by combined surgical resection and Gamma Knife radiosurgery. Prog Neurol Surg 2008;21:79-82.
12.
Iwai Y, Yamanaka K, Ishiguro T: Surgery combined with radiosurgery of large acoustic neuromas. Surg Neurol 2003;59:283-289.
13.
Daniel R, Tuleasca C, George M, Schiappacasse L, Zeverino M, Maire R, et al: Combined approach for the management of large vestibular schwannomas: planned subtotal resection followed by Gamma Knife surgery in a series of 20 consecutive cases. Neurochirurgie 2014;60:331-332.
14.
Yang S-Y, Kim DG, Chung H-T, Park S-H, Paek SH, Jung H-W: Evaluation of tumour response after Gamma Knife radiosurgery for residual vestibular schwannomas based on MRI morphological features. J Neurol Neurosurg Psychiatry 2008;79:431-436.
15.
van de Langenberg R, Hanssens PEJ, van Overbeeke JJ, Verheul JB, Nelemans PJ, de Bondt B-J, et al: Management of large vestibular schwannoma. Part I. Planned subtotal resection followed by Gamma Knife surgery: radiological and clinical aspects. J Neurosurg 2011;115:875-884.
16.
Yang H-C, Kano H, Awan NR, Lunsford LD, Niranjan A, Flickinger JC, et al: Gamma Knife radiosurgery for larger-volume vestibular schwannomas. Clinical article. J Neurosurg 2011;114:801-807.
17.
Veterans T, Hospital G, Sciences B, Bing C, Chwan S, Hospital M: Intracapsular decompression or radical resection followed by Gamma Knife surgery for patients harboring a large vestibular schwannoma. J Neurosurg 2012;117:69-77.
18.
Brokinkel B, Sauerland C, Holling M, Ewelt C, Horstmann G, van Eck ATCJ, et al: Gamma Knife radiosurgery following subtotal resection provides tumor growth control and excellent clinical outcomes in vestibular schwannoma. J Clin Neurosci 2014, DOI: 10.1016/j.jocn.2014.03.037.
19.
General TV, Veterans T, Hospital G: Microsurgery for vestibular schwannoma after Gamma Knife surgery: challenges and treatment strategies. J Neurosurg 2014;121:150-159.
20.
Park K-J, Kano H, Iyer A, Liu X, Niranjan A, Flickinger JC, et al: Salvage Gamma Knife stereotactic radiosurgery followed by bevacizumab for recurrent glioblastoma multiforme: a case-control study. J Neurooncol 2012;107:323-333.
21.
Iwai Y, Ishibashi K, Watanabe Y, Uemura G, Yamanaka K: Functional preservation after planned partial resection followed by Gamma Knife radiosurgery for large vestibular schwannomas. World Neurosurg 2015;84:292-300.
22.
Anaizi AN, Gantwerker E a., Pensak ML, Theodosopoulos PV: Facial nerve preservation surgery for Koos grade 3 and 4 vestibular schwannomas. Neurosurgery 2014;75:671-677.
23.
Nonaka Y, Fukushima T, Watanabe K, Friedman AH, Sampson JH, Mcelveen JT, et al: Contemporary surgical management of vestibular schwannomas: analysis of complications and lessons learned over the past decade. Neurosurgery 2013;72:103-115; discussion 115.
24.
Bloch D: The fate of the tumor remnant after less-than-complete acoustic neuroma resection. Otolaryngol Head Neck Surg 2004;130:104-112.
25.
Anderson BM, Khuntia D, Bentzen SM, Geye HM, Hayes LL, Kuo JS, et al: Single institution experience treating 104 vestibular schwannomas with fractionated stereotactic radiation therapy or stereotactic radiosurgery. J Neurooncol 2014;116:187-193.
26.
Benghiat H, Heyes G, Nightingale P, Hartley A, Tiffany M, Spooner D, et al: Linear accelerator stereotactic radiosurgery for vestibular schwannomas: a UK series. Clin Oncol (R Coll Radiol) 2014;26:309-315.
27.
Lo W-L, Yang K-Y, Huang Y-J, Chen W-F, Liao C-C, Huang Y-H: Experience with Novalis stereotactic radiosurgery for vestibular schwannomas. Clin Neurol Neurosurg 2014;121:30-34.
28.
Lunsford LD, Niranjan A, Flickinger JC, Maitz A, Kondziolka D: Radiosurgery of vestibular schwannomas: summary of experience in 829 cases. J Neurosurg 2005;102:195-199.
29.
Murphy ES, Suh JH: Radiotherapy for vestibular schwannomas: a critical review. Int J Radiat Oncol Biol Phys 2011;79:985-997.
30.
Pollock BE, Lunsford LD, Kondziolka D, Sekula R, Subach BR, Foote RL, Flickinger JC: Vestibular schwannoma management. Part II. Failed radiosurgery and the role of delayed microsurgery. J Neurosurg 1998;89:949-955.
31.
Lownie SP, Drake CG: Radical intracapsular removal of acoustic neurinomas. Long-term follow-up review of 11 patients. 1991;74:422-425.
32.
San V: Gamma Knife radiosurgery for vestibular schwannoma: clinical results at long-term follow-up in a series of 379 patients. J Neurosurg 2014;121:123-142.
33.
Pollock BE, Link MJ, Bauch CD: Patient outcomes after vestibular resection and stereotactic radiosurgery. Neurosurgery 2006;58:77-85.
34.
Regis J, Pellet W, Delsanti C, Dufour H, Roche PH, Thomassin JM, Zanaret M, Peragut JC: Functional outcome after Gamma Knife surgery or microsurgery for vestibular schwannomas. J Neurosurg 2002;97:1091-1100.
35.
Betka J, Zvěřina E, Balogová Z, Profant O, Skřivan J, Kraus J, et al: Complications of microsurgery of vestibular schwannoma. Biomed Res Int 2014;2014:315952.
36.
Chen L, Chen L, Liu L, Ling F, Yuan X, Fang J, et al: Vestibular schwannoma microsurgery with special reference to facial nerve preservation. Clin Neurol Neurosurg 2009;111:47-53.
37.
Samii M, Gerganov VM, Samii A: Functional outcome after complete surgical removal of giant vestibular schwannomas. J Neurosurg 2010;112:860-867.
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2016
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