title: The anterior interhemispheric approach: a safe and effective approach to anterior skull base lesions.
abstract: BACKGROUND
  Many approaches to the anterior skull base have been reported. Frequently used are the pterional, the unilateral or bilateral frontobasal, the supraorbital and the frontolateral approach. Recently, endoscopic transnasal approaches have become more popular. The benefits of each approach has to be weighted against its complications and limitations. The aim of this study was to investigate if the anterior interhemispheric approach (AIA) could be a safe and effective alternative approach to tumorous and non-tumorous lesions of the anterior skull base.
  
  
  METHODS
  We screened the operative records of all patients with an anterior skull base lesion undergoing transcranial surgery. We have used the AIA in 61 patients. These were exclusively patients with either olfactory groove meningioma (OGM) (n = 43), ethmoidal dural arteriovenous fistula (dAVF) ( n = 6) or frontobasal fractures of the anterior midline with cerebrospinal fluid (CSF) leakage ( n = 12). Patient records were evaluated concerning accessibility of the lesion, realization of surgical aims (complete tumor removal, dAVF obliteration, closure of the dural tear), and approach related complications.
  
  
  RESULTS
  The use of the AIA exclusively in OGMs, ethmoidal dAVFs and midline frontobasal fractures indicated that we considered lateralized frontobasal lesions not suitable to be treated successfully. If restricted to these three pathologies, the AIA is highly effective and safe. The surgical aim (complete tumor removal, complete dAVF occlusion, no rhinorrhea) was achieved in all patients. The complication rate was 11.5 % (wound infection (n = 2; 3.2 %), contusion of the genu of the corpus callosum, subdural hygroma, epileptic seizure, anosmia and asymptomatic bleed into the tumor cavity (n = 1 each). Only the contusion of the corpus callosum was directly related to the approach (1.6 %). Olfaction, if present before surgery, was preserved in all patients, except one (1.6 %).
  
  
  CONCLUSIONS
  The AIA is an effective and a safe approach to tumorous, vascular and traumatic pathologies of the midline anterior skull base. This approach should be part of the armamentarium of skull base surgeons.
authors.affiliation: Department of Neurosurgery, Georg-August-University Göttingen, Robert-Koch-Strasse 40, 37075, Göttingen, Germany, doromielke@hotmail.com.
authors.forename: Dorothee
authors.initials: D
authors.lastname: Mielke
authors.forename: Lothar
authors.initials: L
authors.lastname: Mayfrank
authors.forename: Marios Nikos
authors.initials: MN
authors.lastname: Psychogios
authors.forename: Veit
authors.initials: V
authors.lastname: Rohde
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D020785:Central Nervous System Vascular Malformations / Q000473:pathology / Q000601:surgery*; D054022:Cerebrum / Q000473:pathology / Q000601:surgery*; D004724:Endoscopy / Q000379:methods; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008577:Meningeal Neoplasms / Q000473:pathology / Q000601:surgery*; D008579:Meningioma / Q000473:pathology / Q000601:surgery*; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000379:methods*; D012189:Retrospective Studies; D019291:Skull Base / Q000473:pathology / Q000601:surgery*; D020205:Skull Fracture, Basilar / Q000473:pathology / Q000601:surgery*; D016896:Treatment Outcome