Management of large vestibular schwannoma. Part II. Primary Gamma Knife surgery: radiological and clinical aspects

Clinical article

Restricted access


In large vestibular schwannomas (VSs), microsurgery is the main treatment option. A wait-and-scan policy or radiosurgery are generally not recommended given concerns of further lesion growth or increased mass effect due to transient swelling. Note, however, that some patients do not present with symptomatic mass effect or may still have serviceable hearing. Moreover, others may be old, suffer from severe comorbidity, or refuse any surgery. In this study the authors report the results in patients with large, growing VSs primarily treated with Gamma Knife surgery (GKS), with special attention to volumetric growth, control rate, and symptoms.


The authors retrospectively analyzed 33 consecutive patients who underwent GKS for large, growing VSs, which were defined as > 6 cm3 and at least indenting the brainstem. Patients with neurofibromatosis Type 2 were excluded from analysis, as were patients who had undergone previous treatment. Volume measurements were performed on contrast-enhanced T1-weighted MR images at the time of GKS and during follow-up. Medical charts were analyzed for clinical symptoms.


Radiological growth control was achieved in 88% of cases, clinical control (that is, no need for further treatment) in 79% of cases. The median follow-up was 30 months, and the mean VS volume was 8.8 cm3 (range 6.1–17.7 cm3). No major complications occurred, although ventriculoperitoneal shunts were placed in 2 patients. The preservation of serviceable hearing and facial and trigeminal nerve function was achieved in 58%, 91%, and 86% of patients, respectively, with any facial and trigeminal neuropathy being transient. In 92% of the patients presenting with trigeminal hypesthesia before GKS, the condition resolved during follow-up. No patient- or VS-related feature was correlated with growth.


Primary GKS for large VSs leads to acceptable radiological growth rates and clinical control rates, with the chance of hearing preservation. Although a higher incidence of clinical control failure and postradiosurgical morbidity is noted, as compared with that for smaller VSs, primary radiosurgery is suitable for a selected group of patients. The absence of symptomatology due to mass effect on the brainstem or cerebellum is essential, as are close clinical and radiological follow-ups, because there is little reserve for growth or swelling.

Abbreviations used in this paper: GKS = Gamma Knife surgery; HB = House-Brackmann; VS = vestibular schwannoma.

Article Information

Address correspondence to: Rick van de Langenberg, M.D., Maastricht University Medical Center, Department of Otolaryngology, Head and Neck Surgery, PO Box 5800, 6202 AZ Maastricht, The Netherlands. email:

Please include this information when citing this paper: published online August 12, 2011; DOI: 10.3171/2011.6.JNS101963.

© AANS, except where prohibited by US copyright law.



  • View in gallery

    Axial contrast-enhanced T1-weighted MR images (A and B) obtained in a 47-year-old patient with a large (17.7 cm3) VS, Koos Grade IV. The patient reported complete unilateral hearing loss and hypesthesia of the maxillary branch of the trigeminal nerve (A). The patient specifically chose treatment with primary GKS. Twenty-four months after radiosurgery the tumor volume was reduced to 4.6 cm3 (B). Sensibility in the maxillary branch recovered completely, and the patient is functioning well. Axial contrast-enhanced T1-weighted MR images (C and D) obtained in an 83-year-old patient with a large cystic VS (12.9 cm3, Koos Grade IV, C). Surgical intervention was not recommended because of severe comorbidity. Therefore, primary GKS was initiated. Preoperative symptoms consisted of unilateral deafness and hypesthesia of the maxillary branch of the trigeminal nerve. After a follow-up of 24 months a significant volume reduction occurred (last volume 2.5 cm3, D). The patient is functioning well, and sensibility in the trigeminal nerve is fully recovered.

  • View in gallery

    Kaplan-Meier analysis of clinical control during follow-up after primary GKS in large VSs.

  • View in gallery

    Kaplan-Meier analysis of radiological growth control during follow-up after primary GKS in large VSs.



American Academy of Otolaryngology–Head and Neck Surgery Foundation: Committee on Hearing and Equilibrium guidelines for the evaluation of hearing preservation in acoustic neuroma (vestibular schwannoma). Otolaryngol Head Neck Surg 113:1791801995


Bennett MHaynes DS: Surgical approaches and complications in the removal of vestibular schwannomas. Otolaryngol Clin North Am 40:589609ixx2007


Briggs RJLuxford WMAtkins JS JrHitselberger WE: Translabyrinthine removal of large acoustic neuromas. Neurosurgery 34:7857911994


Charabi SKlinken LTos MThomsen J: Histopathology and growth pattern of cystic acoustic neuromas. Laryngoscope 104:134813521994


Chung WYLiu KDShiau CYWu HMWang LWGuo WY: Gamma knife surgery for vestibular schwannoma: 10-year experience of 195 cases. J Neurosurg 102:Suppl87962005


Fischer GFischer CRémond J: Hearing preservation in acoustic neurinoma surgery. J Neurosurg 76:9109171992


Flickinger JCKondziolka DNiranjan AMaitz AVoynov GLunsford LD: Acoustic neuroma radiosurgery with marginal tumor doses of 12 to 13 Gy. Int J Radiat Oncol Biol Phys 60:2252302004


Friedman WABradshaw PMyers ABova FJ: Linear accelerator radiosurgery for vestibular schwannomas. J Neurosurg 105:6576612006


Fuentes SArkha YPech-Gourg GGrisoli FDufour HRégis J: Management of large vestibular schwannomas by combined surgical resection and gamma knife radiosurgery. Prog Neurol Surg 21:79822008


Grey PLMoffat DAPalmer CRHardy DGBaguley DM: Factors which influence the facial nerve outcome in vestibular schwannoma surgery. Clin Otolaryngol Allied Sci 21:4094131996


Hasegawa TFujitani SKatsumata SKida YYoshimoto MKoike J: Stereotactic radiosurgery for vestibular schwannomas: analysis of 317 patients followed more than 5 years. Neurosurgery 57:2572652005


Hecht CSHonrubia VFWiet RJSims HS: Hearing preservation after acoustic neuroma resection with tumor size used as a clinical prognosticator. Laryngoscope 107:112211261997


House JWBrackmann DE: Facial nerve grading system. Otolaryngol Head Neck Surg 93:1461471985


Inoue HK: Low-dose radiosurgery for large vestibular schwannomas: long-term results of functional preservation. J Neurosurg 102:Suppl1111132005


Ito KShin MMatsuzaki MSugasawa KSasaki T: Risk factors for neurological complications after acoustic neurinoma radiosurgery: refinement from further experiences. Int J Radiat Oncol Biol Phys 48:75802000


Iwai YYamanaka KIshiguro T: Surgery combined with radiosurgery of large acoustic neuromas. Surg Neurol 59:2832912003


Jung SKang SSKim TSKim HJJeong SKKim SC: Current surgical results of retrosigmoid approach in extralarge vestibular schwannomas. Surg Neurol 53:3703782000


Koos WTDay JDMatula CLevy DI: Neurotopographic considerations in the microsurgical treatment of small acoustic neurinomas. J Neurosurg 88:5065121998


Lanman THBrackmann DEHitselberger WESubin B: Report of 190 consecutive cases of large acoustic tumors (vestibular schwannoma) removed via the translabyrinthine approach. J Neurosurg 90:6176231999


Lederman GLowry JWertheim SFine MLombardi EWronski M: Acoustic neuroma: potential benefits of fractionated stereotactic radiosurgery. Stereotact Funct Neurosurg 69:1751821997


Linskey MELunsford LDFlickinger JC: Neuroimaging of acoustic nerve sheath tumors after stereotaxic radiosurgery. AJNR Am J Neuroradiol 12:116511751991


Liscak RVladyka VUrgosik DSimonova GVymazal J: Repeated treatment of vestibular schwannomas after gamma knife radiosurgery. Acta Neurochir (Wien) 151:3173242009


Litvack ZNNorén GChougule PBZheng Z: Preservation of functional hearing after gamma knife surgery for vestibular schwannoma. Neurosurg Focus 14:5e32003


Lobato-Polo JKondziolka DZorro OKano HFlickinger JCLunsford LD: Gamma knife radiosurgery in younger patients with vestibular schwannomas. Neurosurgery 65:2943012009


Lunsford LDNiranjan AFlickinger JCMaitz AKondziolka D: Radiosurgery of vestibular schwannomas: summary of experience in 829 cases. J Neurosurg 102:Suppl1951992005


Mamikoglu BWiet RJEsquivel CR: Translabyrinthine approach for the management of large and giant vestibular schwannomas. Otol Neurotol 23:2242272002


Mandl ESMeijer OWSlotman BJVandertop WPPeerdeman SM: Stereotactic radiation therapy for large vestibular schwannomas. Radiother Oncol 95:94982010


Okunaga TMatsuo THayashi NHayashi YShabani HKKaminogo M: Linear accelerator radiosurgery for vestibular schwannoma: measuring tumor volume changes on serial three-dimensional spoiled gradient-echo magnetic resonance images. J Neurosurg 103:53582005


Park CKJung HWKim JESon YJPaek SHKim DG: Therapeutic strategy for large vestibular schwannomas. J Neurooncol 77:1671712006


Pendl GGanz JCKitz KEustacchio S: Acoustic neurinomas with macrocysts treated with Gamma Knife radiosurgery. Stereotact Funct Neurosurg 66:Suppl 11031111996


Pollock BE: Vestibular schwannoma management: an evidence-based comparison of stereotactic radiosurgery and microsurgical resection. Prog Neurol Surg 21:2222272008


Pollock BELink MJ: Vestibular schwannoma radiosurgery after previous surgical resection or stereotactic radiosurgery. Prog Neurol Surg 21:1631682008


Pollock BELunsford LDFlickinger JCClyde BLKondziolka D: Vestibular schwannoma management. Part I Failed microsurgery and the role of delayed stereotactic radiosurgery. J Neurosurg 89:9449481998


Pollock BELunsford LDKondziolka DSekula RSubach BRFoote RL: Vestibular schwannoma management. Part II Failed radiosurgery and the role of delayed microsurgery. J Neurosurg 89:9499551998


Post KDEisenberg MBCatalano PJ: Hearing preservation in vestibular schwannoma surgery: what factors influence outcome?. J Neurosurg 83:1911961995


Prasad DSteiner MSteiner L: Gamma surgery for vestibular schwannoma. J Neurosurg 92:7457592000


Roche PHKhalil MThomassin JMDelsanti CRégis J: Surgical removal of vestibular schwannoma after failed gamma knife radiosurgery. Prog Neurol Surg 21:1521572008


Rowe JGRadatz MWWalton LHampshire ASeaman SKemeny AA: Gamma knife stereotactic radiosurgery for unilateral acoustic neuromas. J Neurol Neurosurg Psychiatry 74:153615422003


Samii MGerganov VSamii A: Improved preservation of hearing and facial nerve function in vestibular schwannoma surgery via the retrosigmoid approach in a series of 200 patients. J Neurosurg 105:5275352006


Samii MGerganov VMSamii A: Functional outcome after complete surgical removal of giant vestibular schwannomas. Clinical article. J Neurosurg 112:8608672010


Samii MMatthies C: Management of 1000 vestibular schwannomas (acoustic neuromas): surgical management and results with an emphasis on complications and how to avoid them. Neurosurgery 40:11231997


Slattery WH III: Microsurgery after radiosurgery or radiotherapy for vestibular schwannomas. Otolaryngol Clin North Am 42:7077152009


Thomas CDi Maio SMa RVollans EChu CClark B: Hearing preservation following fractionated stereotactic radiotherapy for vestibular schwannomas: prognostic implications of cochlear dose. J Neurosurg 107:9179262007


Timmer FCHanssens PEvan Haren AEMulder JJCremers CWBeynon AJ: Gamma knife radiosurgery for vestibular schwannomas: results of hearing preservation in relation to the cochlear radiation dose. Laryngoscope 119:107610812009


van de Langenberg Rde Bondt BJNelemans PJBaumert BGStokroos RJ: Follow-up assessment of vestibular schwannomas: volume quantification versus two-dimensional measurements. Neuroradiology 51:5175242009


van de Langenberg RHanssens PEJvan Overbeeke JJVerheul JBNelemans PJde Bondt BJ: Management of large vestibular schwannoma. Part I. Planned subtotal resection followed by Gamma Knife surgery: radiological and clinical aspects. Clinical article. J Neurosurg [epub ahead of print August 12 2011. DOI: 10.3171/2011.6.JNS101958]


Wandong SMeng LXingang LYuguang LShugan ZLei W: Cystic acoustic neuroma. J Clin Neurosci 12:2532552005


Wiet RJMamikoglu BOdom LHoistad DL: Long-term results of the first 500 cases of acoustic neuroma surgery. Otolaryngol Head Neck Surg 124:6456512001


Williams JA: Fractionated stereotactic radiotherapy for acoustic neuromas: preservation of function versus size. J Clin Neurosci 10:48522003


Yang HCKano HAwan NRLunsford LDNiranjan AFlickinger JC: Gamma Knife radiosurgery for larger-volume vestibular schwannomas. Clinical article. J Neurosurg 114:8018072011


Yang SYKim DGChung HTPark SHPaek SHJung HW: Evaluation of tumour response after gamma knife radiosurgery for residual vestibular schwannomas based on MRI morphological features. J Neurol Neurosurg Psychiatry 79:4314362008


Yu CPCheung JYLeung SHo R: Sequential volume mapping for confirmation of negative growth in vestibular schwannomas treated by gamma knife radiosurgery. J Neurosurg 93:Suppl 382892000


Zhang XFei ZChen YJFu LAZhang JNLiu WP: Facial nerve function after excision of large acoustic neuromas via the suboccipital retrosigmoid approach. J Clin Neurosci 12:4054082005




All Time Past Year Past 30 Days
Abstract Views 60 60 17
Full Text Views 163 163 18
PDF Downloads 95 95 5
EPUB Downloads 0 0 0


Google Scholar