• Awake Craniotomy
  Link:ceaccp.oxfordjournals.org/content/early/2013/06/18/bjaceaccp.mkt024.full.pdf
  
• Post-op
  - May be DSU, or 1-2 days inpatient
  - Risk of haematoma for 6 hr (may require evacuation)
• Potential issues on waking
• Pain from pins/position/catheter
• Agitation
• Nausea/vomiting
• Seizures
• Irrigate brain with ice cold water
  If not effective, benzodiazepines/anticonvulsants/GA
• Avoid increasing ICP - control CO2, haemodynamics, avoid vomiting
• Short-acting drugs eg
  - Propofol/ remifentanil TCI
  - Dexmedetomidine - anxiolysis, analgesia, sedation, ICP unaffected
• Intra-op: maximise patient comfort
• Positioning (may be long procedure) - supine/lateral/sitting
• No drapes over face (claustrophobia)
• Temperature control
• Avoid excess noise / personnel
• Catheter (but may be uncomfortable) / convene / cautious IV fluids if none
• Pre-op:
  - Anticonvulsants
  - Dexamethasone
  - Prophylactic antibiotics on induction
• Scalp block usually performed
  - Analgesia
  - Reduced haemodynamic disturbance and stress response
• Targets:
  - Branches of V1: supraorbital and supratrochlear nerves
  - Zygomaticotemporal nerve (V2)
  - Auriculotemporal nerve (V3)
  - Branches from C2-3: greater and lesser occipital, greater auricular nerves
• Usually involves sedation or GA for start and end of procedure, due to pain of:
  - Mayfield pins, skin/scalp/bone flap and dura incisions
  - Surgical closure
• Sedation:
  - Lighter anaesthesia therefore quicker emergence intra-op
  - Avoids airway manipulation
  - Reduced PONV
• GA:
  - Enables controlled ventilation and CO2
  - Secure airway (usually LMA, removed for 'awake' portion)
  - Greater depth of anaesthesia for stimulating components
• Consider BIS to titrate to lowest appropriate depth
• Requires careful patient selection
• Avoid if confusion, cannot tolerate lying/sitting still, significant chronic cough
• Advantages
  - Avoidance of functional disability
  - Increased lesion removal (secondary to mapping of critical areas)
  - Decreased postoperative neurological dysfunction
  - Decreased PONV
  - Reduced length of stay
• Indications:
  - Tumour (or AVM) excision close to critical functional area of brain
  - Epilepsy surgery
  - Deep brain stimulation surgery
• Awaken and assess patient intra-op to 'map'
  
  Broca's/Wernicke's areas for speech production/comprehension
  Motor cortex
  Sensory cortex