The Awake Craniotomy April 2013 Mark Angle, M.D. Kuwait City Mark Angle, April 13th 20131

The Awake Craniotomy It’s how we started : Unknown~2200 BCETrepanation Unknown1640Epilepsy Surgery Hughling Jackson 1864Epilepsy Surgery Penfield1920Epilepsy Surgery Archer1988Epilepsy + Tumour Surgery Mark Angle, April 13th 20132

Awake Craniotomy Classical Indications 1.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 20133

Awake Craniotomy Why bother ? 1.Neuroimaging (FMRI, Activation PET, ESAM) renders 60-70% accuracy 2.Neuroplasticity and transferrence alter classical functional anatomy 3.Neuronavigation loses accuracy post durotomy and during resection Mark Angle, April 13th 20134

Awake Craniotomy Why bother ? 4.Generally good physiological control (BP, pCO 2, SaO 2 ) 5.Acceptable failure rates 5-8 % 6.Acceptable deficit 15 % Mark Angle, April 13th 20135

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 Mark Angle, April 13th 20136

Awake Craniotomy 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” Mark Angle, April 13th 20137

Awake Craniotomy Goals 1.Conditions for surgical success 2.Patient compliance 3.Patient safety 4.Patient comfort (forgiveness) Mark Angle, April 13th 20138

Awake Craniotomy Understanding the goals 1.Surface mapping for corticectomy  Limited wakefulness 2.Brain mapping for tumours in eloquent regions  Moderate wakefulness 3.Function-limited tumour resection  Prolonged wakefulness Mark Angle, April 13th 20139

Awake Craniotomy Understanding the goals 4.Functions to be tested determine permissible degrees of sedation  SSEP  Motor  Speech  Cognition Mark Angle, April 13th

Awake Craniotomy Patient selection 1.Exclude uncooperative patients 2.Exclude significant deficits : motor, cognitive and memory 3.Exclude panic and claustrophobia 4.Exclude children ≤ 8 years Mark Angle, April 13th

Awake Craniotomy Patient assessment  Comprehension / Cooperation  Airway  Mobility / Positioning  Pain tolerance  Surgical risks :  Hemorrhage  Seizures  Co-morbidities Mark Angle, April 13th

Awake Craniotomy Pre-surgical  Explanation / Complicity /Consent  Clonidine 0.1 – 0.3 mg P.O.  Nabilone 0.5 – 1.0 mg P.O Mark Angle, April 13th

Awake Craniotomy Induction  Zofran 8 mg  Propofol / Remifentanyl “cocktail”  Provocation / Sensitivity testing  Obstruction  Apnea Mark Angle, April 13th

Awake Craniotomy Monitoring  Arterial line contralateral  Foley catheter  Nasal Et CO 2  SaO 2  2 IV peripheral : bilateral Mark Angle, April 13th

Awake Craniotomy Local Anaesthesia 1.Mayfield pin sites 2.Scalp block :  Auriculo-temporal  Zygmatico-temporal  Supra-Orbital  Greater-Occipital  Lesser-Occipital 3.Incisional block Mark Angle, April 13th

Awake Craniotomy Positioning : (Post-Mayfield)  Awake if possible  No weight-bearing by Mayfield  Hands lightly restrained  Free movement of legs  Sight-lines clear  Airway accessible  Fresh-air blower Mark Angle, April 13th

Awake Craniotomy Maintenance : TIVA  Droperidol / Fentanyl  Propofol/ Remifentanyl  Dexmedetomidine Mark Angle, April 13th

Awake Craniotomy Maintenance :  Remifentanyl/Propofol infusion, titrated to stimulation  Repeat Clonidine / Nabilone at hour 6  Sips of H 2 O as requested  Distraction/Communication Mark Angle, April 13th

Awake Craniotomy Events  Obstruction  Hyperventilation / Apnea  Vomiting  Seizures  Loss of compliance : pain, panic  Deficits Emergence  Closure under deep sedation  Infusion (at lower dose) continued into PACU Mark Angle, April 13th

Awake Craniotomy Conclusions:  High success and satisfaction rates  Clear facilitation of aggressive tumour resection paradigm  Demanding on both patient and anaesthetist Mark Angle, April 13th