Difference between revisions of "Awake craniotomy"

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{{Infobox surgical case reference
{{Infobox surgical case reference
| anesthesia_type =  
| anesthesia_type = Scalp block
| airway =  
MAC
| lines_access =  
GA-awake-GA
| monitors =  
| airway = Noninvasive O2
| considerations_preoperative =  
LMA
| considerations_intraoperative =  
| lines_access = PIV x2
Arterial line
Central line
| monitors = Standard
5-lead ECG
Temperature
Urine output
ABP
CVP
Neuromonitoring
± Precordial doppler
| considerations_preoperative = Comprehensive patient consultation
Baseline neuro exam
| considerations_intraoperative = Scalp block required
Risk of seizure
| considerations_postoperative =  
| considerations_postoperative =  
}}
}}An '''awake craniotomy''' is a surgical procedure that is sometimes employed for patients undergoing tumor excision or clipping of arteriovenous malformation in regions of the brain that involve speech or motor function. Patients are typically sedated during line placement and cranial opening, and then awakened once the dura is opened. Due to the unconventional nature of the surgery, this technique is generally reserved for patients who have undergone careful preoperative selection, with considerations for temperament, overall health status, and adequate education. 


Awake craniotomy is a surgical technique that is sometimes employed for patients undergoing tumor excision or clipping of arteriovenous malformation in regions of the brain that involve speech or motor function. Due to the "unconventional" nature of the surgery, his technique is generally reserved for patients who have undergone careful preoperative selection, with considerations for temperament, overall health status, and adequate education.   
The procedure can be performed using either monitored anesthesia care (MAC) or using an asleep-awake-asleep (SAS) technique. A recent meta-analysis suggests that MAC was associated with lower likelihood of failure and shorter procedure time, while SAS was associated with lower incidence of intraoperative seizure.<ref>{{Cite journal|last=Natalini|first=Daniele|last2=Ganau|first2=Mario|last3=Rosenkranz|first3=Ruben|last4=Petrinic|first4=Tatjana|last5=Fitzgibbon|first5=Karina|last6=Antonelli|first6=Massimo|last7=Prisco|first7=Lara|date=2020-01-16|title=Comparison of the Asleep-Awake-Asleep Technique and Monitored Anesthesia Care During Awake Craniotomy: A Systematic Review and Meta-analysis|url=https://pubmed.ncbi.nlm.nih.gov/31972627|journal=Journal of Neurosurgical Anesthesiology|doi=10.1097/ANA.0000000000000675|issn=1537-1921|pmid=31972627}}</ref> The use of non-pharmacological anxiolytic techniques (e.g. hypnosis) to achieve success with an awake-awake-awake technique has also been reported.<ref>{{Cite journal|last=Zemmoura|first=Ilyess|last2=Fournier|first2=Eric|last3=El-Hage|first3=Wissam|last4=Jolly|first4=Virginie|last5=Destrieux|first5=Christophe|last6=Velut|first6=Stéphane|date=2016|title=Hypnosis for Awake Surgery of Low-grade Gliomas: Description of the Method and Psychological Assessment|url=https://pubmed.ncbi.nlm.nih.gov/26313220|journal=Neurosurgery|volume=78|issue=1|pages=53–61|doi=10.1227/NEU.0000000000000993|issn=1524-4040|pmid=26313220|via=}}</ref>  


== Preoperative management ==
==Preoperative management==


=== Patient evaluation<!-- Describe the unique and important aspects of preoperative evaluation. Add or remove rows from the systems table as needed. --> ===
===Patient consultation===
Detailed consultation to psychologically prepare the patient is essential to set expectations and address questions to minimize anxiety intraoperatively.<ref name=":2">{{Cite journal|last=Kulikov|first=Alexander|last2=Lubnin|first2=Andrey|date=2018|title=Anesthesia for awake craniotomy|url=https://pubmed.ncbi.nlm.nih.gov/29994938|journal=Current Opinion in Anaesthesiology|volume=31|issue=5|pages=506–510|doi=10.1097/ACO.0000000000000625|issn=1473-6500|pmid=29994938|via=}}</ref>
*Perform prior to the day of surgery
*Should include the neuropsychology team that will be performing intraoperative testing
* Discuss non-medical modalities of intraoperative anxiety management (as feasible)
**Music, hypnosis, phone calls, etc.
 
The patient experience of the surgical procedure should also be discussed in detail:
*Lines and foley catheter will be placed under sedation
**May experience the feeling of a full bladder when awakened
*Patient's head will be unable to move
**Will likely feel pressure
**Pain is possible, but can be addressed
**May experience dry mouth
*Patient will be able to communicate with the OR staff at all times while awake
*Patient should be encouraged to communicate any and all concerns during the operation
**discomfort with position should be addressed early before pt becomes distressed
**presence of aura, indicating impending seizure
*Patient will be asked to perform tasks and/or answer questions to ensure neurologic intactness throughout the procedure
 
=== Patient evaluation ===
{| class="wikitable"
{| class="wikitable"
|+
|+
!System
! System
!Considerations
!Considerations
|-
|-
|Neurologic
| Neurologic
|
|  
* As with all neurosurgical techniques, a careful preoperative neurological history and exam should be conducted and documented preoperatively to obtain a baseline assessment of function preoperatively.  This exam should be particularly focused on eliciting deficits that may exist due to the nature of the lesion that is to be intervened on.
Neuro exam to establish baseline function and deficits. Consider signs and symptoms of:<ref>{{Cite journal|last=Buckner|first=JC|date=2007|title=Central nervous system tumors|url=|journal=Mayo Clin Proc|volume=82(10)|pages=1271-86|via=}}</ref>
* Patients may exhibit signs and symptoms of increased ICP, neurological deficits from impingement of motor areas, or intracranial bleeding.  
*Increased ICP
*Impingement of motor areas
*Intracranial bleeding.
|-
|-
|Cardiovascular
|Cardiovascular
|
|
* Assessed for cardiovascular comorbidities prior to the day of surgery
* Evaluate for comorbidities which may be exacerbated by intraoperative stress during the procedure (i.e. being under drapes, head clamped in Mayfield pins, surgical sounds, etc.).
* Acute intraoperative stress response associated with the procedure (i.e. being under drapes, head clamped in Mayfield pins, listening to the sound of the surgeons working, etc.) may in some instances result in cardiovascular dysfunction.
* Increased ICP may result in [[Cushing's triad]] of HTN, bradycardia, and irregular respiratory pattern.<ref name=":0">{{Cite book|last=Jaffe|first=Richard A.|title=Anesthesiologist's Manual of Surgical Procedures|publisher=Wolters Kluwer|year=2014|isbn=978-1-4511-7660-5|location=New York|pages=31-36}}</ref>
* The patient should have demonstrated no significant issues managing situations requiring exertion and psychological responses (e.g. panic episodes) that might result in tachyarrhythmias
|-
|-
|Respiratory
|Pulmonary
|
|
* Any significant respiratory comorbidity (e.g. advanced COPD requiring supplemental oxygen or history of exacerbation, asthma with history of exacerbations requiring rescue inhaler use, etc.) should elicit a preoperative assessment with an physician preoperatively prior to the day of surgery for determination of suitability for this procedure.
* Significant comorbidities (e.g. advanced COPD requiring supplemental oxygen or history of exacerbation, asthma with history of exacerbations requiring rescue inhaler use, etc.) should be assessed in advance to determine suitability for this procedure.
* Detailed airway exam to estimate risk of airway compromise during sedation.
** OSA, morbid obesity, abnormal upper airway anatomy are relative contraindications to awake technique.
|-
|-
|Gastrointestinal
|Gastrointestinal
|
|
* History of nausea and/or vomiting, especially on the day of surgery, should result in a careful reassessment in terms of proceeding to surgery immediately. 
Due to the lack of a protected airway and risk of aspiration, relative contraindications to this procedure include:
* History of significant uncontrolled gastrointestinal reflux (GERD), may be a contraindication for this procedure due to periods of the procedure that require extubation if general anesthesia for the beginning of the procedure is selected as anesthetic technique.
*History of nausea or vomiting (especially if present on the day of surgery)
|-
* History of uncontrolled [[GERD]]
|Hematologic
**If in Mayfield pins, active GERD may trigger coughing, resulting in potential for injury to head and neck
|
* Any issues with normal coagulation should be assessed to determine if significant blood loss will result, and anesthetic technique including invasive monitoring, preoperative type and screen, and adequate IV access should be obtained prior to start of the procedure.
|-
|Renal
|
* The patient should be informed that a Foley catheter will be placed at the beginning of the procedure under sedation, and that they will have the sensation of the catheter in their lower urinary tract when awakened during the procedure.
|-
|-
|Endocrine
|Endocrine
|
|
* In patients with a history of hypoglycemia and hyperglycemia in particular, intraoperative glucose monitoring should be routinely conducted to prevent complications.
In patients with a history of diabetes, intraoperative glucose should be closely monitored.
* Patients with a history of other endocrine disorders should also be counseled on possible complications associated with the particular disease process as it relates to anesthesia.
*Hypoglycemia and extreme hyperglycemia may result in altered mental status that could interfere with neurological monitoring, disinhibition, and airway compromise.
|-
|Other
|
|}
|}


=== Labs and studies<!-- Describe any important labs or studies. Include reasoning to justify the study and/or interpretation of results in the context of this procedure. If none, this section may be removed. --> ===
===Labs and studies<!-- Describe any important labs or studies. Include reasoning to justify the study and/or interpretation of results in the context of this procedure. If none, this section may be removed. -->===
*Complete blood count
* Metabolic panel
*Coagulation panel
*Type and screen
 
===Operating room setup<!-- Describe any unique aspects of operating room preparation. Avoid excessively granular information. Use drug classes instead of specific drugs when appropriate. If none, this section may be removed. -->===
 
*Be aware of type of table and head support to be employed to adjust anesthesia technique accordingly
 
===Patient preparation and premedication<!-- Describe any unique considerations for patient preparation and premedication. If none, this section may be removed. -->===
*For patients who are used to a morning cup of coffee, consider caffeine 200 mg PO before surgery to reduce the risk of withdrawal headache<ref>{{Cite journal|last=Potters|first=Jan-Willem|last2=Klimek|first2=Markus|date=2015|title=Awake craniotomy: improving the patient's experience|url=https://pubmed.ncbi.nlm.nih.gov/26263121/|journal=Current Opinion in Anaesthesiology|volume=28|issue=5|pages=511–516|doi=10.1097/ACO.0000000000000231|issn=1473-6500|pmid=26263121|via=}}</ref>
*[[Glycopyrrolate]] may be useful as an antisialagogue
 
=== Regional and neuraxial techniques<!-- Describe any potential regional and/or neuraxial techniques which may be used for this case. If none, this section may be removed. -->===
{{#ev:youtube|https://www.youtube.com/watch?v=5mTEa7ZdM_g|480|right|Video demonstration of a scalp block}}
[[Scalp block|Scalp blocks]] are essential to achieve adequate analgesia during the awake phase.<ref name=":0" />
*Typically placed during the pre-awake phase using [[bupivacaine]] 0.5% or [[ropivacaine]] 0.5% (with epinephrine)
**If faster onset is desired, can be pre-blocked with buffered [[lidocaine]] 2%
**Placement prior to pinning and exposure will reduce anesthetic requirements
*A single syringe with a combination of lidocaine, bupivacaine, [[sodium bicarbonate]], and [[epinephrine]] can provide fast onset, long duration, and reduced discomfort during injection<ref>{{Cite journal|last=Best|first=Corliss A|last2=Best|first2=Alyssa A|last3=Best|first3=Timothy J|last4=Hamilton|first4=Danielle A|date=2015|title=Buffered lidocaine and bupivacaine mixture – the ideal local anesthetic solution?|url=https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4459414/|journal=Plastic Surgery|volume=23|issue=2|pages=87–90|doi=10.4172/plastic-surgery.1000913|issn=2292-5503|pmc=4459414|pmid=26090348}}</ref>. For example, in a 10 mL syringe, a recommended mixture would be:
**4.5 mL of 2% lidocaine with 1:100,000 epinephrine
**4.5 mL of 0.5% bupivacaine with 1:200,000 epinephrine
**0.4 mL of 8.4% sodium bicarbonate
* Can be supplemented during the awake phase using buffered lidocaine 2%
 
==Intraoperative management==
 
===Monitoring and access<!-- List and/or describe monitors and access typically needed for this case. Please describe rationale for any special monitors or access. -->===
 
*Arterial line
*CVC vs PICC
*Large bore IV(s)
*Microphone for patient to communicate
*± Precordial doppler
 
===Induction and airway management<!-- Describe the important considerations and general approach to the induction of anesthesia and how the airway is typically managed for this case. -->===
The pre-awake phase of the procedure involves line placement, positioning, and cranial opening. This phase may be achieved using MAC or general anesthesia with similar outcomes, and largely depends on institution and practitioner preference.<ref name=":2" /> The decision on what technique will be informed by experience with the surgical team, a common determining factor is the duration of the pre-awake phase.
 
If using MAC:
 
*Provide sedation using:<ref name=":0" />
**Midazolam 1-10 mg IV (titrated incremental doses)
**Dexmedetomidine 0.2-0.7 mcg/kg/hr (±1 mcg/kg bolus)
**Propofol 25-50 mcg/kg/min
*Place lines with field blocks using buffered lidocaine for patient comfort
 
If using general anesthesia:<ref name=":1">{{Cite journal|last=Meng|first=Lingzhong|last2=McDonagh|first2=David L.|last3=Berger|first3=Mitchel S.|last4=Gelb|first4=Adrian W.|date=2017|title=Anesthesia for awake craniotomy: a how-to guide for the occasional practitioner|url=https://pubmed.ncbi.nlm.nih.gov/28181184/|journal=Canadian Journal of Anaesthesia = Journal Canadien D'anesthesie|volume=64|issue=5|pages=517–529|doi=10.1007/s12630-017-0840-1|issn=1496-8975|pmid=28181184|via=}}</ref>
 
*Induce with propofol
*LMA use is typical, but use ETT if indicated
*Remifentanil is the preferred narcotic due to rapid titratability
 
===Positioning<!-- Describe any unique positioning considerations, including potential intraoperative position changes. If none, this section may be removed. -->===
Positioning will vary depending on the surgical approach.<ref name=":1" /> Patients can be positioned supine, semi-laterally, or laterally.
 
The patient's head is typically secured in a pinned frame.


=== Operating room setup<!-- Describe any unique aspects of operating room preparation. Avoid excessively granular information. Use drug classes instead of specific drugs when appropriate. If none, this section may be removed. --> ===
*Pin sites should be infiltrated with local anesthetic


=== Patient preparation and premedication<!-- Describe any unique considerations for patient preparation and premedication. If none, this section may be removed. --> ===
===Maintenance and surgical considerations<!-- Describe the important considerations and general approach to the maintenance of anesthesia, including potential complications. Be sure to include any steps to the surgical procedure that have anesthetic implications. -->===


=== Regional and neuraxial techniques<!-- Describe any potential regional and/or neuraxial techniques which may be used for this case. If none, this section may be removed. --> ===
====Intraoperative seizures====


== Intraoperative management ==
* Seizures may occur during intraoperative stimulation mapping. Rates of incidence vary widely, ranging between 3-16%.<ref name=":1" />
* Intraoperative seizures must be rapidly recognized and treated using:<ref name=":1" />
**Cold water irrigation of the surgical field
**Low doses of propofol (30-50 mg)
* Untreated intraoperative seizures may precipitate catastrophic complications
** Postictal delirium can preclude effective neuropsychological monitoring and necessitate abortion of the procedure.
** Generalized seizures may induce breath holding, and valsalva. Increased intrathoracic pressure suddenly decreases venous drainage from the brain and transcranial herniation can occur rapidly.
* There is limited evidence to support the use of levetiracetam for seizure prophylaxis.<ref>{{Cite journal|last=Pourzitaki|first=Chryssa|last2=Tsaousi|first2=Georgia|last3=Apostolidou|first3=Eirini|last4=Karakoulas|first4=Konstantinos|last5=Kouvelas|first5=Dimitrios|last6=Amaniti|first6=Ekaterini|date=2016|title=Efficacy and safety of prophylactic levetiracetam in supratentorial brain tumour surgery: a systematic review and meta-analysis|url=https://pubmed.ncbi.nlm.nih.gov/26945547/|journal=British Journal of Clinical Pharmacology|volume=82|issue=1|pages=315–325|doi=10.1111/bcp.12926|issn=1365-2125|pmc=4917799|pmid=26945547|via=}}</ref>


=== Monitoring and access<!-- List and/or describe monitors and access typically needed for this case. Please describe rationale for any special monitors or access. --> ===
==== Post-resection management ====
Patients can typically be re-sedated after resection has been completed, though some surgeons prefer to keep patients awake to continue conscious neurological monitoring.


=== Induction and airway management<!-- Describe the important considerations and general approach to the induction of anesthesia and how the airway is typically managed for this case. --> ===
===Emergence<!-- List and/or describe any important considerations related to the emergence from anesthesia for this case. --> ===


=== Positioning<!-- Describe any unique positioning considerations, including potential intraoperative position changes. If none, this section may be removed. --> ===
* If non-instrumented airway, sedation can be discontinued during closure and patient allowed to emerge after removal from pinned frame
* If LMA/ETT in place, ensure intact airway reflexes and smooth removal


=== Maintenance and surgical considerations<!-- Describe the important considerations and general approach to the maintenance of anesthesia, including potential complications. Be sure to include any steps to the surgical procedure that have anesthetic implications. --> ===
==Postoperative management==


=== Emergence<!-- List and/or describe any important considerations related to the emergence from anesthesia for this case. --> ===
===Disposition<!-- List and/or describe the postoperative disposition and any special considerations for transport of patients for this case. -->===


== Postoperative management ==
* Typically ICU for frequent neuro exams


=== Disposition<!-- List and/or describe the postoperative disposition and any special considerations for transport of patients for this case. --> ===
===Pain management<!-- Describe the expected level of postoperative pain and approaches to pain management for this case. --> ===


=== Pain management<!-- Describe the expected level of postoperative pain and approaches to pain management for this case. --> ===
* Scalp block will provide analgesia for 12-16 hours
* If supplemental analgesia is required
** Acetaminophen
** Use narcotics with caution as can interfere with neurologic examination


=== Potential complications<!-- List and/or describe any potential postoperative complications for this case. --> ===
===Potential complications<!-- List and/or describe any potential postoperative complications for this case. -->===


== Procedure variants<!-- This section should only be used for cases with multiple approaches (e.g. Laparoscopic vs. open appendectomy). Otherwise, remove this section. Use this table to very briefly compare and contrast various aspects between approaches. Add or remove rows as needed to maximize relevance. Consider using symbols rather than words when possible (e.g. +, –, additional symbols such as ↑ and ↓ are available using the "Ω" tool in the editor). --> ==
==Procedure variants<!-- This section should only be used for cases with multiple approaches (e.g. Laparoscopic vs. open appendectomy). Otherwise, remove this section. Use this table to very briefly compare and contrast various aspects between approaches. Add or remove rows as needed to maximize relevance. Consider using symbols rather than words when possible (e.g. +, –, additional symbols such as ↑ and ↓ are available using the "Ω" tool in the editor). -->==


{| class="wikitable"
{| class="wikitable"
|+
|+
!
!
!Variant 1
! Variant 1
!Variant 2
!Variant 2
|-
|-
Line 121: Line 217:
|}
|}


== References ==
==References==
<references />
<references />
[[Category:Surgical procedures]]
[[Category:Surgical procedures]]
[[Category:Neurosurgery]]

Latest revision as of 15:53, 11 July 2024

Awake craniotomy
Anesthesia type

Scalp block MAC GA-awake-GA

Airway

Noninvasive O2 LMA

Lines and access

PIV x2 Arterial line Central line

Monitors

Standard 5-lead ECG Temperature Urine output ABP CVP Neuromonitoring ± Precordial doppler

Primary anesthetic considerations
Preoperative

Comprehensive patient consultation Baseline neuro exam

Intraoperative

Scalp block required Risk of seizure

Postoperative
Article quality
Editor rating
Certified
User likes
0

An awake craniotomy is a surgical procedure that is sometimes employed for patients undergoing tumor excision or clipping of arteriovenous malformation in regions of the brain that involve speech or motor function. Patients are typically sedated during line placement and cranial opening, and then awakened once the dura is opened. Due to the unconventional nature of the surgery, this technique is generally reserved for patients who have undergone careful preoperative selection, with considerations for temperament, overall health status, and adequate education.

The procedure can be performed using either monitored anesthesia care (MAC) or using an asleep-awake-asleep (SAS) technique. A recent meta-analysis suggests that MAC was associated with lower likelihood of failure and shorter procedure time, while SAS was associated with lower incidence of intraoperative seizure.[1] The use of non-pharmacological anxiolytic techniques (e.g. hypnosis) to achieve success with an awake-awake-awake technique has also been reported.[2]

Preoperative management

Patient consultation

Detailed consultation to psychologically prepare the patient is essential to set expectations and address questions to minimize anxiety intraoperatively.[3]

  • Perform prior to the day of surgery
  • Should include the neuropsychology team that will be performing intraoperative testing
  • Discuss non-medical modalities of intraoperative anxiety management (as feasible)
    • Music, hypnosis, phone calls, etc.

The patient experience of the surgical procedure should also be discussed in detail:

  • Lines and foley catheter will be placed under sedation
    • May experience the feeling of a full bladder when awakened
  • Patient's head will be unable to move
    • Will likely feel pressure
    • Pain is possible, but can be addressed
    • May experience dry mouth
  • Patient will be able to communicate with the OR staff at all times while awake
  • Patient should be encouraged to communicate any and all concerns during the operation
    • discomfort with position should be addressed early before pt becomes distressed
    • presence of aura, indicating impending seizure
  • Patient will be asked to perform tasks and/or answer questions to ensure neurologic intactness throughout the procedure

Patient evaluation

System Considerations
Neurologic

Neuro exam to establish baseline function and deficits. Consider signs and symptoms of:[4]

  • Increased ICP
  • Impingement of motor areas
  • Intracranial bleeding.
Cardiovascular
  • Evaluate for comorbidities which may be exacerbated by intraoperative stress during the procedure (i.e. being under drapes, head clamped in Mayfield pins, surgical sounds, etc.).
  • Increased ICP may result in Cushing's triad of HTN, bradycardia, and irregular respiratory pattern.[5]
Pulmonary
  • Significant comorbidities (e.g. advanced COPD requiring supplemental oxygen or history of exacerbation, asthma with history of exacerbations requiring rescue inhaler use, etc.) should be assessed in advance to determine suitability for this procedure.
  • Detailed airway exam to estimate risk of airway compromise during sedation.
    • OSA, morbid obesity, abnormal upper airway anatomy are relative contraindications to awake technique.
Gastrointestinal

Due to the lack of a protected airway and risk of aspiration, relative contraindications to this procedure include:

  • History of nausea or vomiting (especially if present on the day of surgery)
  • History of uncontrolled GERD
    • If in Mayfield pins, active GERD may trigger coughing, resulting in potential for injury to head and neck
Endocrine

In patients with a history of diabetes, intraoperative glucose should be closely monitored.

  • Hypoglycemia and extreme hyperglycemia may result in altered mental status that could interfere with neurological monitoring, disinhibition, and airway compromise.

Labs and studies

  • Complete blood count
  • Metabolic panel
  • Coagulation panel
  • Type and screen

Operating room setup

  • Be aware of type of table and head support to be employed to adjust anesthesia technique accordingly

Patient preparation and premedication

  • For patients who are used to a morning cup of coffee, consider caffeine 200 mg PO before surgery to reduce the risk of withdrawal headache[6]
  • Glycopyrrolate may be useful as an antisialagogue

Regional and neuraxial techniques

Video demonstration of a scalp block

Scalp blocks are essential to achieve adequate analgesia during the awake phase.[5]

  • Typically placed during the pre-awake phase using bupivacaine 0.5% or ropivacaine 0.5% (with epinephrine)
    • If faster onset is desired, can be pre-blocked with buffered lidocaine 2%
    • Placement prior to pinning and exposure will reduce anesthetic requirements
  • A single syringe with a combination of lidocaine, bupivacaine, sodium bicarbonate, and epinephrine can provide fast onset, long duration, and reduced discomfort during injection[7]. For example, in a 10 mL syringe, a recommended mixture would be:
    • 4.5 mL of 2% lidocaine with 1:100,000 epinephrine
    • 4.5 mL of 0.5% bupivacaine with 1:200,000 epinephrine
    • 0.4 mL of 8.4% sodium bicarbonate
  • Can be supplemented during the awake phase using buffered lidocaine 2%

Intraoperative management

Monitoring and access

  • Arterial line
  • CVC vs PICC
  • Large bore IV(s)
  • Microphone for patient to communicate
  • ± Precordial doppler

Induction and airway management

The pre-awake phase of the procedure involves line placement, positioning, and cranial opening. This phase may be achieved using MAC or general anesthesia with similar outcomes, and largely depends on institution and practitioner preference.[3] The decision on what technique will be informed by experience with the surgical team, a common determining factor is the duration of the pre-awake phase.

If using MAC:

  • Provide sedation using:[5]
    • Midazolam 1-10 mg IV (titrated incremental doses)
    • Dexmedetomidine 0.2-0.7 mcg/kg/hr (±1 mcg/kg bolus)
    • Propofol 25-50 mcg/kg/min
  • Place lines with field blocks using buffered lidocaine for patient comfort

If using general anesthesia:[8]

  • Induce with propofol
  • LMA use is typical, but use ETT if indicated
  • Remifentanil is the preferred narcotic due to rapid titratability

Positioning

Positioning will vary depending on the surgical approach.[8] Patients can be positioned supine, semi-laterally, or laterally.

The patient's head is typically secured in a pinned frame.

  • Pin sites should be infiltrated with local anesthetic

Maintenance and surgical considerations

Intraoperative seizures

  • Seizures may occur during intraoperative stimulation mapping. Rates of incidence vary widely, ranging between 3-16%.[8]
  • Intraoperative seizures must be rapidly recognized and treated using:[8]
    • Cold water irrigation of the surgical field
    • Low doses of propofol (30-50 mg)
  • Untreated intraoperative seizures may precipitate catastrophic complications
    • Postictal delirium can preclude effective neuropsychological monitoring and necessitate abortion of the procedure.
    • Generalized seizures may induce breath holding, and valsalva. Increased intrathoracic pressure suddenly decreases venous drainage from the brain and transcranial herniation can occur rapidly.
  • There is limited evidence to support the use of levetiracetam for seizure prophylaxis.[9]

Post-resection management

Patients can typically be re-sedated after resection has been completed, though some surgeons prefer to keep patients awake to continue conscious neurological monitoring.

Emergence

  • If non-instrumented airway, sedation can be discontinued during closure and patient allowed to emerge after removal from pinned frame
  • If LMA/ETT in place, ensure intact airway reflexes and smooth removal

Postoperative management

Disposition

  • Typically ICU for frequent neuro exams

Pain management

  • Scalp block will provide analgesia for 12-16 hours
  • If supplemental analgesia is required
    • Acetaminophen
    • Use narcotics with caution as can interfere with neurologic examination

Potential complications

Procedure variants

Variant 1 Variant 2
Unique considerations
Position
Surgical time
EBL
Postoperative disposition
Pain management
Potential complications

References

  1. ↑ Natalini, Daniele; Ganau, Mario; Rosenkranz, Ruben; Petrinic, Tatjana; Fitzgibbon, Karina; Antonelli, Massimo; Prisco, Lara (2020-01-16). "Comparison of the Asleep-Awake-Asleep Technique and Monitored Anesthesia Care During Awake Craniotomy: A Systematic Review and Meta-analysis". Journal of Neurosurgical Anesthesiology. doi:10.1097/ANA.0000000000000675. ISSN 1537-1921. PMID 31972627.
  2. ↑ Zemmoura, Ilyess; Fournier, Eric; El-Hage, Wissam; Jolly, Virginie; Destrieux, Christophe; Velut, Stéphane (2016). "Hypnosis for Awake Surgery of Low-grade Gliomas: Description of the Method and Psychological Assessment". Neurosurgery. 78 (1): 53–61. doi:10.1227/NEU.0000000000000993. ISSN 1524-4040. PMID 26313220.
  3. ↑ 3.0 3.1 Kulikov, Alexander; Lubnin, Andrey (2018). "Anesthesia for awake craniotomy". Current Opinion in Anaesthesiology. 31 (5): 506–510. doi:10.1097/ACO.0000000000000625. ISSN 1473-6500. PMID 29994938.
  4. ↑ Buckner, JC (2007). "Central nervous system tumors". Mayo Clin Proc. 82(10): 1271–86.
  5. ↑ 5.0 5.1 5.2 Jaffe, Richard A. (2014). Anesthesiologist's Manual of Surgical Procedures. New York: Wolters Kluwer. pp. 31–36. ISBN 978-1-4511-7660-5.
  6. ↑ Potters, Jan-Willem; Klimek, Markus (2015). "Awake craniotomy: improving the patient's experience". Current Opinion in Anaesthesiology. 28 (5): 511–516. doi:10.1097/ACO.0000000000000231. ISSN 1473-6500. PMID 26263121.
  7. ↑ Best, Corliss A; Best, Alyssa A; Best, Timothy J; Hamilton, Danielle A (2015). "Buffered lidocaine and bupivacaine mixture – the ideal local anesthetic solution?". Plastic Surgery. 23 (2): 87–90. doi:10.4172/plastic-surgery.1000913. ISSN 2292-5503. PMC 4459414. PMID 26090348.
  8. ↑ 8.0 8.1 8.2 8.3 Meng, Lingzhong; McDonagh, David L.; Berger, Mitchel S.; Gelb, Adrian W. (2017). "Anesthesia for awake craniotomy: a how-to guide for the occasional practitioner". Canadian Journal of Anaesthesia = Journal Canadien D'anesthesie. 64 (5): 517–529. doi:10.1007/s12630-017-0840-1. ISSN 1496-8975. PMID 28181184.
  9. ↑ Pourzitaki, Chryssa; Tsaousi, Georgia; Apostolidou, Eirini; Karakoulas, Konstantinos; Kouvelas, Dimitrios; Amaniti, Ekaterini (2016). "Efficacy and safety of prophylactic levetiracetam in supratentorial brain tumour surgery: a systematic review and meta-analysis". British Journal of Clinical Pharmacology. 82 (1): 315–325. doi:10.1111/bcp.12926. ISSN 1365-2125. PMC 4917799. PMID 26945547.

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