title: Microsurgical management of 53 jugular foramen schwannomas: lessons learned incorporated into a modified grading system.
abstract: OBJECTIVE
  Due to the proximity and involvement of critical neurovascular structures, the resection of jugular foramen schwannomas can pose a formidable challenge. The authors review their experience in the microsurgical management of jugular foramen schwannomas and propose a modified grading scale to guide surgical management.
  
  
  METHODS
  All jugular foramen schwannoma cases treated by the senior author (T.F.) between 1980 and 2004 were retrospectively reviewed. The average age at presentation, surgical approach, tumor characteristics, cranial nerve (CN) deficits, and tumor recurrence rates were assessed. The authors present the following modified grading scale: Type A, intradural tumors; Type B, dumbbell-shaped tumors; and Type C, triple dumbbell tumors with a high cervical extension.
  
  
  RESULTS
  The authors treated jugular foramen tumors in 129 patients during the study period. Of these, 53 patients (41%) had jugular foramen schwannomas. The mean patient age was 52 years (range 14-74 years); there were 12 male and 41 female patients. The mean follow-up period was 8.4 years. Patients presented most commonly with deficits of the vagus nerve, followed by vestibular/cochlear nerve and glossopharyngeal nerve deficits. Gross-total resection of the tumor was achieved in 48 patients (90.5%). New postoperative paresis in a previously normal CN was not seen; however, worsening of preoperative CN deficits was frequently noted. The highest incidence occurred with the glossopharyngeal and vagus nerves (30%), with 26% of the deficits being permanent. There were no deaths related to surgery in this series. Three patients (5.7%) experienced tumor recurrence.
  
  
  CONCLUSIONS
  The microsurgical resection of jugular foramen schwannomas carries a risk of worsening preoperative CN deficits; however, these are often transient. Based on their experience, the authors have formulated a grading scale that predicts the optimal surgical approach to these lesions. Considerable technical training and microneuroanatomical knowledge of the region is required. The modified grading scale presented facilitates preoperative planning.
authors.affiliation: Yale University School of Medicine, Department of Neurosurgery, New Haven, Connecticut, USA.
authors.forename: Ketan R
authors.initials: KR
authors.lastname: Bulsara
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Sameshima
authors.forename: Allan H
authors.initials: AH
authors.lastname: Friedman
authors.forename: Takanori
authors.initials: T
authors.lastname: Fukushima
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001932:Brain Neoplasms / Q000145:classification* / Q000473:pathology / Q000601:surgery*; D002490:Central Nervous System / Q000293:injuries; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008866:Microsurgery / Q000009:adverse effects / Q000379:methods*; D008875:Middle Aged; D009442:Neurilemmoma / Q000145:classification* / Q000473:pathology / Q000601:surgery*; D019635:Neurosurgical Procedures / Q000009:adverse effects / Q000379:methods*; D012189:Retrospective Studies; D019291:Skull Base / Q000601:surgery; D055815:Young Adult