Download - The Awake Craniotomy April 2013 Mark Angle, M.D. Kuwait City Mark Angle, April 13th 20131
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The Awake Craniotomy
It’s how we started :
Unknown ~2200 BCE Trepanation
Unknown 1640 Epilepsy Surgery
Hughling Jackson
1864 Epilepsy Surgery
Penfield 1920 Epilepsy Surgery
Archer 1988 Epilepsy + Tumour Surgery
Mark Angle, April 13th 2013
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Awake Craniotomy
Classical Indications1. Brain-mapping
Cortical Stimulation Cortical Recording
2. Patient-directed tumour resection in eloquent regions
Positive Mapping – 5% deficits Negative Mapping – 2% deficits
Mark Angle, April 13th 2013
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Awake Craniotomy
Why bother ?1. Neuroimaging (FMRI, Activation PET, ESAM)
renders 60-70% accuracy2. Neuroplasticity and transferrence alter
classical functional anatomy3. Neuronavigation loses accuracy post
durotomy and during resection
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Awake Craniotomy
Why bother ?4. Generally good physiological control
(BP, pCO2, SaO2)
5. Acceptable failure rates 5-8 %
6. Acceptable deficit rates @ 15 %
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Awake Craniotomy
Why bother ?7. Function-limited tumour resection
Higher rate of total resection Maximum cytoreduction 20-30% deficits acutely diminishing to 5-8% at 3
months
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Why anaesthetists hate them :1. Failures :
Loss of communication 5% Seizures 2% Loss of airway 2% Loss of compliance 2%
2. Long periods of jeopardy Unsecured airway Risk of :
◦ Vomiting◦ Obstruction◦ Hemorrhage◦ Hyperventilation◦ Deficits
3. “A different type of practice”
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Awake Craniotomy
Goals1. Conditions for surgical success2. Patient compliance3. Patient safety4. Patient comfort (forgiveness)
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Awake Craniotomy
Understanding the goals1. Surface mapping for corticectomy
Limited wakefulness
2. Brain mapping for tumours in eloquent regions
Moderate wakefulness
3. Function-limited tumour resection Prolonged wakefulness
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Awake Craniotomy
Understanding the goals4. Functions to be tested determine permissible
degrees of sedation SSEP Motor Speech Cognition
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Awake Craniotomy
Patient selection1. Exclude uncooperative patients2. Exclude significant deficits : motor, cognitive
and memory3. Exclude panic and claustrophobia4. Exclude children ≤ 8 years
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Awake Craniotomy
Patient assessment Comprehension / Cooperation Airway Mobility / Positioning Pain tolerance Surgical risks :
Hemorrhage Seizures Co-morbidities
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Awake Craniotomy
Pre-surgical Explanation / Complicity /Consent Clonidine 0.1 – 0.3 mg P.O. Nabilone 0.5 – 1.0 mg P.O
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Awake Craniotomy
Induction Zofran 8 mg Propofol / Remifentanyl “cocktail” Provocation / Sensitivity testing
Obstruction Apnea
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Awake Craniotomy
MonitoringArterial line contralateralFoley catheterNasal Et CO2
SaO2
2 IV peripheral : bilateral
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Awake Craniotomy
Local Anaesthesia1. Mayfield pin sites2. Scalp block :
Auriculo-temporal Zygmatico-temporal Supra-Orbital Greater-Occipital Lesser-Occipital
3. Incisional block
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Awake Craniotomy
Positioning : (Post-Mayfield)Awake if possibleNo weight-bearing by MayfieldHands lightly restrainedFree movement of legsSight-lines clearAirway accessibleFresh-air blower
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Maintenance : TIVADroperidol / FentanylPropofol/ RemifentanylDexmedetomidine
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Awake Craniotomy
Maintenance : Remifentanyl/Propofol infusion, titrated to
stimulationRepeat Clonidine / Nabilone at hour 6Sips of H2O as requestedDistraction/Communication
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Awake Craniotomy
EventsObstructionHyperventilation / ApneaVomitingSeizuresLoss of compliance : pain, panicDeficits
EmergenceClosure under deep sedationInfusion (at lower dose) continued into PACU
Mark Angle, April 13th 2013