title: Gamma Knife Radiosurgery for Residual and Recurrent Vestibular Schwannomas After Previous Surgery: Clinical Results in a Series of 90 Patients and Review of the Literature.
abstract: OBJECTIVE
  Complete removal of vestibular schwannomas (VS) is not always achievable without any risk of disabling postoperative complications, especially in terms of facial nerve function. Moreover, even after gross total removal, a relevant rate of recurrence has been reported. The aim of this study is to validate Gamma Knife radiosurgery (GKRS) as an effective strategy to treat tumor regrowth after previous surgery.
  
  
  METHODS
  Ninety patients treated with GKRS for VS after previous microsurgery were included in the present study. GKRS was performed at a median of 31 months (range, 4-174 months) postoperatively. Mean tumor volume was 3.35 cm3(median, 2.5 cm3; range, 0.027-13 cm3) and median marginal dose was 13 Gy.
  
  
  RESULTS
  At a mean follow-up of 77.2 months, tumor control was achieved in 90% of patients: 2 patients underwent repeated GKRS, and 7 patients underwent further microsurgery. Tumor shrinkage at last follow-up was recorded in 80.3% of cases. The complication rate was low and many consisted of a transient worsening of preexisting symptoms. The overall incidence of persisting facial nerve deficit and trigeminal nerve impairment was, in both cases, 3.3%. Two of 5 patients (40%) preserved functional hearing at last follow-up. One patient (1.1%) underwent ventriculoperitoneal shunting 12 months after GKRS.
  
  
  CONCLUSIONS
  GKRS is a safe and effective treatment for growing residual and recurrent VSs, with tumor control obtained in 90% of cases and a low morbidity rate. Moreover, the possibility of treating patients with major medical comorbidities constitutes a significant advantage over repeated surgery.
authors: Department of Neurosurgery, I.R.C.C.S. Ospedale San Raffaele, Milan, Italy.
authors: Michele
authors: M
authors: Bailo
authors: Department of Neurosurgery, I.R.C.C.S. Ospedale San Raffaele, Milan, Italy. Electronic address: boari.nicola@hsr.it.
authors: Nicola
authors: N
authors: Boari
authors: Department of Neurosurgery, I.R.C.C.S. Ospedale San Raffaele, Milan, Italy.
authors: Filippo
authors: F
authors: Gagliardi
authors: Department of Neurosurgery, I.R.C.C.S. Ospedale San Raffaele, Milan, Italy.
authors: Alberto
authors: A
authors: Franzin
authors: Department of Neurosurgery, I.R.C.C.S. Ospedale San Raffaele, Milan, Italy.
authors: Martina
authors: M
authors: Piloni
authors: Department of Neurosurgery, I.R.C.C.S. Ospedale San Raffaele, Milan, Italy.
authors: Alfio
authors: A
authors: Spina
authors: Service of Neuro-anesthesia, I.R.C.C.S. Ospedale San Raffaele, Milan, Italy.
authors: Marco
authors: M
authors: Gemma
authors: Service of Medical Physics, I.R.C.C.S. Ospedale San Raffaele, Milan, Italy.
authors: Antonella Del
authors: AD
authors: Vecchio
authors: Service of Radiation Oncology, I.R.C.C.S. Ospedale San Raffaele, Milan, Italy.
authors: Angelo
authors: A
authors: Bolognesi
authors: Department of Neurosurgery, I.R.C.C.S. Ospedale San Raffaele, Milan, Italy; Vita-Salute San Raffaele University, Milan, Italy.
authors: Pietro
authors: P
authors: Mortini
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D016206:Databases, Bibliographic / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D016015:Logistic Models; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000601:surgery*; D009464:Neuroma, Acoustic / Q000000981:diagnostic imaging / Q000601:surgery*; D016634:Radiosurgery / Q000379:methods*; D012086:Reoperation; D012189:Retrospective Studies; D016896:Treatment Outcome; D055815:Young Adult
keywords: Acoustic neuroma; Gamma Knife; Previous surgery; Radiosurgery; Recurrent; Regrowth; Residual; Review; Vestibular schwannoma