title: Postoperative Gamma Knife surgery for benign meningiomas of the cranial base.
abstract: OBJECTIVE
  The standard treatment for meningiomas is complete resection, but the proximity of skull base meningiomas to important neurovascular structures makes complete excision of the lesion difficult or impossible. The authors analyzed the mid- and long-term results obtained in patients treated with postresection Gamma Knife surgery (GKS) for residual or recurrent benign meningiomas of the cranial base.
  
  
  METHODS
  Thirty-six patients with residual or recurrent benign meningiomas of the skull base following one or more surgical procedures underwent GKS. There were 31 women and five men, ranging in age from 22 to 73 years. The median tumor volume was 4.1 ml (range 0.8-20 ml) and the median radiation dose to the tumor margin was 16 Gy (range 15-16 Gy).
  
  
  RESULTS
  Patients were followed for a median of 81 months (range 30-141 months) after GKS. At the end of the follow-up period, overall neurological improvement was observed in 16 patients (44.4%), whereas the condition in 20 patients (55.6%) was unchanged. One patient suffered transient cerebral edema 6 months after GKS. Based on imaging documentation, a partial response was seen in five patients (13.9%), the disease remained stable in 30 patients (83.3%), and in one patient (2.8%) there was an increase in tumor size. The actuarial progression-free survival rate was 100% at 5 years and 94.7% at 10 years.
  
  
  CONCLUSIONS
  Gamma Knife surgery was shown to be an excellent adjunct to resection because of its durable rate of tumor control and low toxicity. It should be initially considered along with surgery for the treatment of complex skull base meningiomas.
authors.affiliation: Department of Neurosurgery, Keck School of Medicine, University of Southern California, Los Angeles, California, USA. ldavidso@usc.edu
authors.forename: Laurence
authors.initials: L
authors.lastname: Davidson
authors.forename: Dawn
authors.initials: D
authors.lastname: Fishback
authors.forename: Jonathan J
authors.initials: JJ
authors.lastname: Russin
authors.forename: Martin H
authors.initials: MH
authors.lastname: Weiss
authors.forename: Cheng
authors.initials: C
authors.lastname: Yu
authors.forename: Paul G
authors.initials: PG
authors.lastname: Pagnini
authors.forename: Vladimir
authors.initials: V
authors.lastname: Zelman
authors.forename: Michael L J
authors.initials: ML
authors.lastname: Apuzzo
authors.forename: Steven L
authors.initials: SL
authors.lastname: Giannotta
mesh_terms: D000328:Adult; D000368:Aged; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008577:Meningeal Neoplasms / Q000473:pathology / Q000601:surgery*; D008579:Meningioma / Q000473:pathology / Q000601:surgery*; D008875:Middle Aged; D016634:Radiosurgery; D012189:Retrospective Studies; D019292:Skull Base Neoplasms / Q000473:pathology / Q000601:surgery*; D016896:Treatment Outcome