Operative Planning

• Review preoperative imaging studies (magnetic resonance imaging [MRI], functional MRI, MR spectroscopy, computed tomography [CT])
  
• Intracarotid sodium amobarbital testing (Wada test) may be indicated to determine the hemisphere of language dominance
  
• Anticonvulsants should be administered, with therapeutic levels achieved

Special Equipment

• Language mapping and/or motor equipment, if indicated
  
• Cavitron ultrasonic aspirator (CUSA)
  
• Ultrasound machine
  
• MRI navigation and/or intraoperative MRI

Anesthetic Issues

• 1.0 g/kg body weight intravenous (IV) mannitol (given as a 20% solution, Osmitrol [Baxter])
  
• Dexamethasone 10 mg IV
  
• If patient is not on anticonvulsants preoperatively, 15 mg/kg body weight of phenytoin should be administered IV at a rate not exceeding 50 mg/min
  
• Hyperventilation with resultant arterial pCO₂ 27 to 32 mm Hg
  
• Minimize volatile inhalant anesthetics, which can cause brain swelling

Positioning

• Mayfield head holder, malar eminence high point (as for pterional craniotomies)
  
• Reverse Trendelenburg position with neck as neutral as possible to optimize venous jugular return
  
• Glioma patients are often hypercoagulable; therefore, deep venous thrombosis prophylaxis with thromboembolism deterrent hose and pneumatic compression stockings are used

• As per standard temporal craniotomies
  
• Gliomas can induce adhesions between the dura and the pial surface, so care should be taken during the durotomy

Cortical Stimulation Mapping

• Language mapping may be indicated for dominant temporal glioma resections
  
• Gliomas that extend into the temporal stem require subcortical motor mapping to avoid injury to the descending motor fibers

Identification of Tumor Borders

• Intraoperative ultrasound and MRI navigation are used prior to beginning resection; if the tumor is isoechoic with the brain, then ultrasound will not be helpful and the machine can be taken away

Tumor Resection