title: [Cystic vestibular schwannomas].
abstract: BACKGROUND
  Patients with cystic vestibular schwannomas (VS) are a radiologically well-defined subgroup of patients who classically have poor outcome after microsurgical resection. Since Pendl's report of a high rate of failures, they are also considered as poor candidates for radiosurgery.
  
  
  METHODS
  Among the 1000 consecutive patients who underwent Gamma Knife surgery in Marseilles, France between July 1992 and January 2002, we have collected and studied 54 patients with cystic VS at the time of treatment.
  
  
  RESULTS
  The median follow-up of this group was 26 Months (mean: 33, range: 6-90). Failure (6.4%) led to microsurgical removal in 2 patients and a radiosurgery in 1 patient with a delay of 2 Years for 2 of them and 3 Years for the third. No facial palsy has been reported. Two patients developed transient hypesthesia. Among the 32 patients with functional hearing at the time of treatment, 53% preserved their hearing function at 3 Years.
  
  
  CONCLUSIONS
  We found an increased risk of failure in this group compared to patients with no cyst at time of radiosurgery (93.6% instead of 98%). But this is also a group were we observe most dramatic shrinkage. Prudent radiosurgical treatment of cystic vestibular schwannomas remains mandatory: strict follow-up is specially important.
authors.affiliation: Service de Neurochirurgie Fonctionnelle, Groupe d'Oto-Neurochirurgie, Hôpital de La Timone, Marseille.
authors.forename: C
authors.initials: C
authors.lastname: Delsanti
authors.forename: J
authors.initials: J
authors.lastname: Régis
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003560:Cysts / Q000453:epidemiology / Q000473:pathology* / Q000601:surgery; D004428:Ear Neoplasms / Q000150:complications / Q000473:pathology* / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D006311:Hearing Disorders / Q000175:diagnosis / Q000453:epidemiology; D006801:Humans; D006987:Hypesthesia / Q000209:etiology; D008297:Male; D008875:Middle Aged; D009464:Neuroma, Acoustic / Q000150:complications / Q000473:pathology* / Q000601:surgery; D011183:Postoperative Complications; D016634:Radiosurgery / Q000295:instrumentation; D012720:Severity of Illness Index