Awake Craniotomy
Patient phenotype
Tumor (often glioma) or epileptic focus near eloquent cortex (motor, sensory, language). Patient must be able to cooperate during awake mapping — no severe anxiety, deafness, severe aphasia, or pediatric (rare). Pre-op neuropsych evaluation + extensive counseling.
Procedure
Asleep-awake-asleep (AAA) or monitored anesthesia care (MAC) technique. Asleep for craniotomy + closure, awake for cortical mapping + tumor resection in eloquent cortex. Mayfield pin head fixation. Often 4-6 hours total.
Anesthetic plan
Asleep-awake-asleep with LMA or supraglottic airway (placed/removed per phase) OR MAC with dexmedetomidine + remifentanil (no airway). Scalp block (extensive — see concerns). Goal: comfortable sedated for opening, fully cooperative for mapping, deeper for closure.
Setup
- ·A-line pre-induction (ulnar or radial — accessible during awake phase)
- ·PIVs accessible
- ·Foley (long case)
- ·Forced air warmer
- ·BIS or processed EEG
- ·Scalp block kit (ropivacaine 0.5% + lidocaine + epi)
- ·LMA/supraglottic + intubation cart available
- ·Patient positioning aids (warm, comfortable, accessible during mapping)
Biggest concerns by phase
Patient selection + counseling
Detailed preop visit: explain awake portion, rehearse mapping tasks (naming, motor commands), reassure about pain control. Anxious or claustrophobic patients are POOR candidates. Preop benzodiazepine generally avoided (interferes with cooperation).
Scalp block — extensive + multilevel
6 nerves bilaterally: supraorbital + supratrochlear (V1), zygomaticotemporal + auriculotemporal (V3), greater + lesser occipital. Ropivacaine 0.5% 20-40 mL with epi (not exceeding toxic dose). Test before pin placement.
Asleep phase — propofol + remifentanil + LMA OR dex + remi MAC
AAA: propofol 50-100 mcg/kg/min + remi 0.05-0.1 mcg/kg/min + LMA. MAC: dex bolus 0.5-1 mcg/kg over 10 min + 0.4-0.7 mcg/kg/h infusion + remi 0.02-0.05 mcg/kg/min. Goal: spontaneous ventilation, easy arousal.
Awake phase — eliminate sedation, manage cooperation
Stop propofol/dec dex 10-15 min before mapping. Remi may continue at low dose. Remove LMA gently. Position adjusted for comfort. Reassure throughout. Common issues: nausea, anxiety, seizure during stimulation, agitation.
Intraoperative seizure — common during stimulation
Direct cortical stimulation can trigger focal or generalized seizure. Treatment: cold saline irrigation directly on cortex (first-line — surgeon does this), small midazolam bolus, propofol if generalized. Continue mapping after resolution.
Airway loss in MAC technique
Patient deep + obtunded → obstruction → CO₂ retention. Always be ready to convert to GA: backup intubation plan, positioning to allow access, available drugs + tube. Lateral or supine positions easier than prone.
Closure phase — back asleep or maintain MAC
After mapping + resection: re-deepen with propofol (or just dex/remi). Skin closure variable: many awake throughout if patient comfortable. Postop: monitored bed, frequent neuro checks for hematoma/edema.
Mock-defense scenarios
Practice answering these out loud. The probes show what an examiner is listening for.
47-year-old R-handed F with low-grade glioma in left frontal lobe near Broca's area. Planned awake craniotomy with language mapping. She's reasonably calm but worried about pain. Plan?
What an examiner probes for
- ▹Patient selection + preop psychological prep
- ▹Detailed scalp block plan
- ▹AAA vs MAC choice + drug combinations
- ▹Awake-phase management: cooperation, nausea prevention, seizure backup
- ▹Conversion to GA backup plan
Sources
- Miller's Ch 69
- Cottrell + Patel Neuroanesthesia 6e Ch 16
- Bonhomme + Hans 2014 review
Anatomy reference
Sourced reference images. 4 matches for "brain cortex cerebrum frontal".
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