Gamma Knife surgery for large vestibular schwannomas: a single-center retrospective case-matched comparison assessing the effect of lesion size

Clinical article

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Gamma Knife surgery (GKS) is a safe and effective treatment for patients with small to moderately sized vestibular schwannomas (VSs). Reports of stereotactic radiosurgery for large VSs have demonstrated worse tumor control and preservation of neurological function. The authors endeavored to assess the effect of size of VSs treated using GKS.


This study was a retrospective comparison of 24 patients with large VSs (> 3 cm in maximum diameter) treated with GKS compared with 49 small VSs (≤ 3 cm) matched for age, sex, radiosurgical margin and maximal doses, length of follow-up, and indication.


Actuarial tumor progression-free survival (PFS) for the large VS cohort was 95.2% and 81.8% at 3 and 5 years, respectively, compared with 97% and 90% for small VSs (p = 0.009). Overall clinical outcome was better in small VSs compared with large VSs (p < 0.001). Patients with small VSs presenting with House-Brackmann Grade I (good facial function) had better neurological outcomes compared with patients with large VSs (p = 0.003). Treatment failure occurred in 6 patients with large VSs; 3 each were treated with resection or repeat GKS. Treatment failure did not occur in the small VS group. Two patients in the large VS group required ventriculoperitoneal shunt placement. Univariate analysis did not identify any predictors of treatment failure among the large VS cohort.


Patients with large VSs treated using GKS had shorter PFS and worse clinical outcomes compared with age-, sex-, and indication-matched patients with small VSs. Nevertheless, GKS has efficacy for some patients with large VSs and represents a reasonable treatment option for selected patients.

Abbreviations used in this paper:GKS = Gamma Knife surgery; PFS = progression-free survival; SRS = stereotactic radiosurgery; VP = ventriculoperitoneal; VS = vestibular schwannoma.

Article Information

Address correspondence to: Jason P. Sheehan, M.D., Ph.D., Department of Neurological Surgery, University of Virginia, Charlottesville, Virginia 22908. email:

Please include this information when citing this paper: published online May 24, 2013; DOI: 10.3171/2013.4.JNS122195.

© AANS, except where prohibited by US copyright law.



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    Actuarial PFS dichotomized into large (> 3 cm) and small (≤ 3 cm) VSs treated using GKS.

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    Clinical outcome of the large VS cohort stratified by symptoms and signs at presentation. Upper: Clinical outcome of cases presenting with trigeminal neuropathy. Lower: Clinical outcome of cases stratified by the presenting facial nerve function.

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    An illustrative case of a typical patient treated using GKS for a large VS. This was a 74-year-old woman who presented with hydrocephalus. She underwent VP shunt placement prior to GKS. She did not have useful hearing in her left ear. She had House-Brackmann Grade V facial function on the left at presentation. The patient remained clinically stable throughout her 4-year follow-up. Preoperative axial (A–C), coronal (D), and sagittal (E) MRI is displayed in the first row (A–E) with comparative 4-year follow-up MRI displayed in the second row (F–J). A: A T1-weighted image through the level of the lateral ventricles demonstrating ventriculomegaly. B: A constructive interference in steady-state sequence depicting a left cerebellopontine angle lesion effacing the brainstem and causing mass effect on the fourth ventricle. C–E: These T1-weighted images obtained after contrast administration depict heterogeneous contrast enhancement. F: A T2-weighted image through the level of the lateral ventricles demonstrating diminished size of the lateral ventricles and no evidence of transependymal flow. G: Constructive interference in steady-state sequence demonstrating stable tumor size, brainstem effacement, and fourth ventricle mass effect. H–J: These T1-weighted images obtained after contrast administration demonstrate slightly decreased tumor size with cyst formation.


  • 1

    Bloch DCOghalai JSJackler RKOsofsky MPitts LH: The fate of the tumor remnant after less-than-complete acoustic neuroma resection. Otolaryngol Head Neck Surg 130:1041122004

  • 2

    Chung WYPan DHLee CCWu HMLiu KDYen YS: Large vestibular schwannomas treated by Gamma Knife surgery: long-term outcomes. Clinical article. J Neurosurg 113:Suppl1121212010

  • 3

    Flickinger JCKondziolka DNiranjan ALunsford LD: Results of acoustic neuroma radiosurgery: an analysis of 5 years' experience using current methods. J Neurosurg 94:162001

  • 4

    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

  • 5

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

  • 6

    Henzel MHamm KSitter HGross MWSurber GKleinert G: Comparison of stereotactic radiosurgery and fractionated stereotactic radiotherapy of acoustic neurinomas according to 3-D tumor volume shrinkage and quality of life. Strahlenther Onkol 185:5675732009

  • 7

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

  • 8

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

  • 9

    Karpinos MTeh BSZeck OCarpenter LSPhan CMai WY: Treatment of acoustic neuroma: stereotactic radiosurgery vs. microsurgery. Int J Radiat Oncol Biol Phys 54:141014212002

  • 10

    Kondziolka DLunsford LDFlickinger JC: Acoustic tumors: operation versus radiation—making sense of opposing viewpoints. Part II. Acoustic neuromas: sorting out management options. Clin Neurosurg 50:3133282003

  • 11

    Kondziolka DLunsford LDMcLaughlin MRFlickinger JC: Long-term outcomes after radiosurgery for acoustic neuromas. N Engl J Med 339:142614331998

  • 12

    Lee SHWillcox TOBuchheit WA: Current results of the surgical management of acoustic neuroma. Skull Base 12:1891952002

  • 13

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

  • 14

    Milligan BDPollock BEFoote RLLink MJ: Long-term tumor control and cranial nerve outcomes following gamma knife surgery for larger-volume vestibular schwannomas. Clinical article. J Neurosurg 116:5986042012

  • 15

    Myrseth EMøller PPedersen PHLund-Johansen M: Vestibular schwannoma: surgery or gamma knife radiosurgery? A prospective, nonrandomized study. Neurosurgery 64:6546632009

  • 16

    Myrseth EMøller PPedersen PHVassbotn FSWentzel-Larsen TLund-Johansen M: Vestibular schwannomas: clinical results and quality of life after microsurgery or gamma knife radiosurgery. Neurosurgery 56:9279352005

  • 17

    Nicoucar KMomjian SVader JPDe Tribolet N: Surgery for large vestibular schwannomas: how patients and surgeons perceive quality of life. J Neurosurg 105:2052122006

  • 18

    Pollock BEDriscoll CLFoote RLLink MJGorman DABauch CD: Patient outcomes after vestibular schwannoma management: a prospective comparison of microsurgical resection and stereotactic radiosurgery. Neurosurgery 59:77852006

  • 19

    Pollock BELunsford LDKondziolka DFlickinger JCBissonette DJKelsey SF: Outcome analysis of acoustic neuroma management: a comparison of microsurgery and stereotactic radiosurgery. Neurosurgery 36:2152291995

  • 20

    Ramina RCoelho Neto MBordignon KCMattei TClemente RPires Aguiar PH: Treatment of large and giant residual and recurrent vestibular schwannomas. Skull Base 17:1091172007

  • 21

    Régis JPellet WDelsanti CDufour HRoche PHThomassin JM: Functional outcome after gamma knife surgery or microsurgery for vestibular schwannomas. J Neurosurg 97:109111002002

  • 22

    Roos DEPotter AEBrophy BP: Stereotactic radiosurgery for acoustic neuromas: what happens long term?. Int J Radiat Oncol Biol Phys 82:135213552012

  • 23

    Snell JWSheehan JStroila MSteiner L: Assessment of imaging studies used with radiosurgery: a volumetric algorithm and an estimation of its error. Technical note. J Neurosurg 104:1571622006

  • 24

    Stangerup SECaye-Thomasen PTos MThomsen J: The natural history of vestibular schwannoma. Otol Neurotol 27:5475522006

  • 25

    Steiner LSheehan JLindquist CStroila MSteiner MGamma surgery in cerebral vascular lesions, malformations, tumors, and functional disorders. Schmidek HHRoberts DW: Schmidek & Sweet Operative Neurosurgical Techniques: Indications Methods and Results ed 5PhiladelphiaWB Saunders2006. 1:530576

  • 26

    van de Langenberg RHanssens PEVerheul JBvan Overbeeke JJNelemans PJDohmen AJ: Management of large vestibular schwannoma. Part II. Primary Gamma Knife surgery: radiological and clinical aspects. Clinical article. J Neurosurg 115:8858932011

  • 27

    Wallner KESheline GEPitts LHWara WMDavis RLBoldrey EB: Efficacy of irradiation for incompletely excised acoustic neurilemomas. J Neurosurg 67:8588631987

  • 28

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




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