VESTIBULAR SCHWANNOMA: SURGERY OR GAMMA KNIFE RADIOSURGERY? A PROSPECTIVE, NONRANDOMIZED STUDY

OBJECTIVETo conduct a prospective, open, nonrandomized study of treatment-associated morbidity in patients undergoing microsurgery or gamma knife radiosurgery (GKRS) for vestibular schwannomas. METHODSNinety-one patients with vestibular schwannomas with a maximum tumor diameter of 25 mm in the cerebellopontine angle were treated according to a prospective protocol either by GKRS (63 patients) or open microsurgery (28 patients) using the suboccipital approach. Primary end points included hearing function, according to the Gardner-Robertson scale, and facial nerve function, according to the House-Brackmann scale at 2 years. Clinical data included a balance platform test, score for tinnitus and vertigo using a visual analog scale, and working ability. Patients responded to the quality-of-life questionnaires Short-Form 36 and Glasgow Benefit Inventory. RESULTSThree elderly GKRS patients withdrew; all remaining patients were followed for 2 years. Both primary end points were highly significant in favor of GKRS (P < 0.001). Evidence of reduced facial nerve function (House-Brackmann grade 2 or poorer) at 2 years was found in 13 of 28 open microsurgery patients and 1 of 60 GKRS patients. Thirteen of 28 patients who underwent surgery had serviceable hearing (Gardner-Robertson grade A or B) preoperatively, but none had serviceable hearing postoperatively. Twenty-five of 60 GKRS patients had serviceable hearing before treatment, and 17 (68%) of them had serviceable hearing 2 years after treatment. The tinnitus and vertigo visual analog scale score, as well as balance platform tests, did not change significantly after treatment, and working status did not differ between the groups at 2 years. Quality of life was significantly better in the GKRS group at 2 years, based on the Glasgow Benefit Inventory questionnaire. One GKRS patient required operative treatment within the 2-year study period. CONCLUSIONThis is the second prospective study to demonstrate better facial nerve and hearing outcomes from GKRS than from open surgery for small- and medium-sized vestibular schwannomas.

[1]  S. Lownie,et al.  Assessing impairment and disability of facial paralysis in patients with vestibular schwannoma. , 2007, Archives of otolaryngology--head & neck surgery.

[2]  P. Møller,et al.  Treatment of vestibular schwannomas. Why, when and how? , 2007, Acta Neurochirurgica.

[3]  A. Yamaura,et al.  Conservative management, gamma-knife radiosurgery, and microsurgery for acoustic neurinomas: A systematic review of outcome and risk of three therapeutic options , 2003, Neurological research.

[4]  M Samii,et al.  Management of 1000 vestibular schwannomas (acoustic neuromas): hearing function in 1000 tumor resections. , 1997, Neurosurgery.

[5]  D. Kondziolka,et al.  Long-term outcomes after radiosurgery for acoustic neuromas. , 1998, The New England journal of medicine.

[6]  H. Inoue.  Low-dose radiosurgery for large vestibular schwannomas: long-term results of functional preservation. , 2005, Journal of neurosurgery.

[7]  G. Horstmann,et al.  Increased preservation of functional hearing after gamma knife surgery for vestibular schwannoma. , 2005, Journal of neurosurgery.

[8]  Jackson Le,et al.  Acoustic neuroma surgery: use of cochlear nerve action potential monitoring for hearing preservation. , 2000, The American journal of otology.

[9]  D. Baguley,et al.  Facial nerve recovery after acoustic neuroma removal , 1989, Journal of Laryngology and Otology.

[10]  M. Samii,et al.  Management of 1000 Vestibular Schwannomas (Acoustic Neuromas): The Facial Nerve-Preservation and Restitution of Function. , 1997, Neurosurgery.

[11]  D. Kondziolka,et al.  Outcome Analysis of Acoustic Neuroma Management: A Comparison of Microsurgery and Stereotactic Radiosurgery: 215 , 1995, Neurosurgery.

[12]  Effets posturaux du traitement par Gamma Knife des neurinomes de l'acoustique (schwannomes vestibulaires) , 2004 .

[13]  C. Strauss,et al.  The prognostic value of intraoperative BAEP patterns in acoustic neurinoma surgery , 1999, Clinical Neurophysiology.

[14]  G. Noren.  Long-Term Complications following Gamma Knife Radiosurgery of Vestibular Schwannomas , 1998, Stereotactic and Functional Neurosurgery.

[15]  L. Sacchetto,et al.  Intraoperative monitoring for hearing preservation and restoration in acoustic neuroma surgery. , 2000, Skull base surgery.

[16]  J. Régis,et al.  Injury of the lacrimal component of the nervus intermedius function after radiosurgery versus microsurgery. , 2004, Neuro-Chirurgie.

[17]  Ajay Niranjan,et al.  Radiosurgery of vestibular schwannomas: summary of experience in 829 cases. , 2005, Journal of neurosurgery.

[18]  J. Guérin,et al.  Vestibular Schwannoma Surgery Outcomes: Our Multidisciplinary Experience in 400 Cases Over 17 Years , 2004, The Laryngoscope.

[19]  M. Bush,et al.  Long‐Term Hearing Results in Gamma Knife Radiosurgery for Acoustic Neuromas , 2008, The Laryngoscope.

[20]  J. Roberson,et al.  Acoustic neuroma surgery: use of cochlear nerve action potential monitoring for hearing preservation. , 2000, The American journal of otology.

[21]  L. Pitts,et al.  The Fate of the Tumor Remnant after Less-than-Complete Acoustic Neuroma Resection , 2004, Otolaryngology--head and neck surgery : official journal of American Academy of Otolaryngology-Head and Neck Surgery.

[22]  T. Wentzel‐Larsen,et al.  Untreated vestibular schwannomas: vertigo is a powerful predictor for health-related quality of life. , 2006, Neurosurgery.

[23]  J. Tonn,et al.  Outpatient gamma knife surgery for vestibular schwannoma: definition of the therapeutic profile based on a 10-year experience. , 2005, Journal of neurosurgery.

[24]  T. Nikolopoulos,et al.  Impairments, disabilities, and handicaps after acoustic neuroma surgery. , 2000, Clinical otolaryngology and allied sciences.

[25]  V. Colletti,et al.  ECochG, CNAP and ABR monitoring during vestibular Schwannoma surgery. , 1998, Audiology : official organ of the International Society of Audiology.

[26]  Y. Iwai,et al.  Surgery combined with radiosurgery of large acoustic neuromas. , 2003, Surgical neurology.

[27]  R. Cueva,et al.  A Comparison of Direct Eighth Nerve Monitoring and Auditory Brainstem Response in Hearing Preservation Surgery for Vestibular Schwannoma , 2004, Otology & neurotology : official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology.

[28]  J. Yoshida,et al.  Long-term outcomes in patients with vestibular schwannomas treated using gamma knife surgery: 10-year follow up. , 2005, Journal of neurosurgery.

[29]  M. Samii,et al.  Management of 1000 vestibular schwannomas (acoustic neuromas): surgical management and results with an emphasis on complications and how to avoid them. , 1997, Neurosurgery.

[30]  J. Gavilán,et al.  Impact of Facial Dysfunction on Quality of Life after Vestibular Schwannoma Surgery , 2006, The Annals of otology, rhinology, and laryngology.

[31]  A. Kaye,et al.  Current management of acoustic neuromas: review of surgical approaches and outcomes , 2000, Journal of Clinical Neuroscience.

[32]  O. Schröttner,et al.  Cranial nerve preservation after radiosurgery of vestibular schwannomas. , 2002, Acta neurochirurgica. Supplement.

[33]  Chul-Kee Park,et al.  Hearing preservation after gamma knife stereotactic radiosurgery of vestibular schwannoma , 2005, Cancer.

[34]  A. De Stefano,et al.  Intraoperative Cochlear Nerve Monitoring in Vestibular Schwannoma Surgery – Does It Really Affect Hearing Outcome? , 2007, Audiology and Neurotology.

[35]  J. Debus,et al.  Long-term outcome of stereotactic radiosurgery (SRS) in patients with acoustic neuromas. , 2006, International journal of radiation oncology, biology, physics.

[36]  D. Brackmann,et al.  Report of 190 consecutive cases of large acoustic tumors (vestibular schwannoma) removed via the translabyrinthine approach. , 1999, Journal of neurosurgery.

[37]  J. Polligkeit,et al.  Quality of life after unilateral acoustic neuroma surgery via middle cranial fossa approach , 2005, Acta oto-laryngologica.

[38]  R. Ojemann,et al.  Surgical Treatment of Acoustic Neuroma (Vestibular Schwannoma) in the United States , 1996, The Laryngoscope.

[39]  J. Tonn,et al.  Results of outpatient gamma knife radiosurgery for primary therapy of acoustic neuromas. , 2004, Acta neurochirurgica. Supplement.

[40]  K. Post,et al.  Self-assessed quality of life after acoustic neuroma surgery. , 2003, Journal of neurosurgery.

[41]  S. Schmerber,et al.  Intraoperative auditory monitoring in vestibular schwannoma surgery: new trends , 2004, Acta oto-laryngologica.

[42]  Tore Wentzel-Larsen,et al.  Vestibular schwannomas: Clinical results and quality of life after microsurgery or gamma knife radiosurgery. Neurosurgery 2005;56:927-935 , 2005, Neurosurgery.

[43]  L. Yardley,et al.  Patient-assessed outcomes after excision of acoustic neuroma: postoperative symptoms and quality of life. , 2001, Journal of neurosurgery.

[44]  A. V. D. van der Mey,et al.  Translabyrinthine surgery for disabling vertigo in vestibular schwannoma patients , 2007, Clinical otolaryngology : official journal of ENT-UK ; official journal of Netherlands Society for Oto-Rhino-Laryngology & Cervico-Facial Surgery.

[45]  J. Régis,et al.  Functional outcome after gamma knife surgery or microsurgery for vestibular schwannomas. , 2002, Journal of neurosurgery.

[46]  D. Baguley,et al.  Nervus intermedius function after vestibular schwannoma removal: Clinical features and pathophysiological mechanisms , 1995, The Laryngoscope.

[47]  D. Kondziolka,et al.  Results of acoustic neuroma radiosurgery: an analysis of 5 years' experience using current methods. , 2001, Journal of neurosurgery.

[48]  E. B. Butler,et al.  Treatment of acoustic neuroma: stereotactic radiosurgery vs. microsurgery. , 2001, International journal of radiation oncology, biology, physics.

[49]  J. Mandrekar,et al.  Patient outcomes after vestibular schwannoma management: a prospective comparison of microsurgical resection and stereotactic radiosurgery. , 2006, Neurosurgery.

[50]  J. Helms,et al.  Acoustic neuroma surgery as an interdisciplinary approach: a neurosurgical series of 508 patients , 2000, Journal of neurology, neurosurgery, and psychiatry.