Difference between revisions of "Craniotomy for extracranial-intracranial revascularization"

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| anesthesia_type = General
| anesthesia_type = General
| airway = ETT
| airway = ETT
| lines_access = PIV x 2 <br/> Art line <br/> CVC
| lines_access = PIV x2
| monitors = Standard ASA <br/>
Arterial line
5-lead EKG <br/>
| monitors = Standard ASA
Core temp <br/>
5-lead EKG
UOP <br/>
Core temp
ABG <br/>
UOP
CVP <br/>
ABG
EEG
EEG
| considerations_preoperative = Characterize neurologic deficits <br/>
| considerations_preoperative = Characterize neurologic deficits
Consider anxiolytic <br/>
Consider anxiolytic
| considerations_intraoperative = Smooth induction <br/>
| considerations_intraoperative = Smooth induction
Maintain CPP <br/>
Maintain CPP
Maximize flow to ischemic areas <br/>
Maximize flow to ischemic areas
Decrease CMRO2 <br/>
Decrease CMRO2
Decrease intracranial volume <br/>
Smooth extubation
Smooth extubation
| considerations_postoperative = Careful control of BP <br/>
| considerations_postoperative = Careful control of BP
PONV prophylaxis
PONV prophylaxis
| image_file = EC-IC_Bypass_.jpg
}}'''Craniotomy for extracranial-intracranial revascularization''' (also referred to as '''EC-IC bypass''') is an intracranial procedure which augments cerebral blood flow by relocating an extracranial vessel intracranially.
}}'''Craniotomy for extracranial-intracranial revascularization''' (also referred to as '''EC-IC bypass''') is a surgical procedure to increase cerebral blood flow. The procedure involves connecting a branch of the external carotid artery (typically the superficial temporal artery) to a branch of the internal carotid artery (typically the middle cerebral artery).  The anastomosis can be achieved via a vein graft or a direct connection.   


EC-IC bypass is generally indicated for severe stenosis or occlusion of intracranial arteries that is resulting in focal neurological symptoms.  In children, this procedure is used to treat Moya-moya disease.  
==Overview==
== Preoperative management ==
===Indications===
=== Patient evaluation ===
An EC-IC bypass is performed when there is severe stenosis or occlusion of an intracranial artery. Some common scenarios include:
 
* Moya-moya disease
* Intracranial aneurysms which cannot be directly treated and require complete occlusion of the proximal artery
 
===Surgical procedure===
The procedure is performed through a craniotomy. The extracranial source is most commonly the superficial temporal artery, but other branches of the external carotid artery are possible. The temporalis muscle or omentum can also be used when using an external carotid branch is not preferred.<ref>{{Cite book|url=https://www.worldcat.org/oclc/1117874404|title=Anesthesiologist's manual of surgical procedures|date=2020|others=Richard A. Jaffe, Clifford A. Schmiesing, Brenda Golianu|isbn=978-1-4698-2916-6|edition=6|location=Philadelphia|oclc=1117874404}}</ref>
 
The extracranial source is then routed through the craniotomy, and revascularization is achieved in one of two approaches:
 
* "Direct", where the extracranial vessel is directly anastomosed to an intracranial vessel (typically to a branch of the middle cerebral artery)
* "Indirect", where the donor source is laid on the surface of the brain but not directly anastomosed, with the expectation that over time vascular growth will occur to provide additional flow to the brain.
 
==Preoperative management==
===Patient evaluation===
{| class="wikitable"
{| class="wikitable"
|+
|+
Line 31: Line 43:
!Considerations
!Considerations
|-
|-
|Neurologic
| Neurologic
|
|
* Patients typically presenting with focal neurologic symptoms.  Pre-existing deficits should be well characterized and documented.
*Patients typically present with variable focal neurologic symptoms, which should be well characterized and documented
|-
|-
|Cardiovascular
|Cardiovascular
|
|
* Hypertension is a common adaptive response to maintain CPP.  A normal BP may be undesirable in the setting of severe cerebrovascular disease. 
*Hypertension is a common adaptive response to maintain CPP
* Patients may have generalized vascular disease, including CAD. 
**Normotension may be undesirable in the setting of severe cerebrovascular disease
**Patients are often treated with midodrine preoperatively to induce hypertension and improve CPP
|-
|-
|Hematologic
|Hematologic
|
|
* Patients often on aspirin through day of surgery
*Patients often on aspirin through day of surgery
* Anticoagulants impacting PT/PTT typically discontinued 1 week prior to surgery
*Anticoagulants impacting PT/PTT typically discontinued 1 week prior to surgery
|}
|}
=== Labs and studies ===
===Labs and studies===
 
*EKG
*Echo (if concern for cardiovascular disease)
*Coronary angiography (depending on cardiac risk factors)
*Complete blood count
*Chemistry panel
*Coagulation panel
*Cerebral angiography performed to identify cause of neurologic symptoms
 
===Operating room setup===


* EKG
*Infusion pumps
* Echo (if concern for cardiovascular disease)
*If inducing hypothermia
* Coronary angiography (depending on cardiac risk factors)
**Surface cooling device (i.e. cold-water circulating blanket)
* Complete blood count
**Warming device
* Chemistry panel
***Patient will need aggressive rewarming post-anastomosis
* Coagulation panel
***Consider bladder irrigation, warm-water circulating blanket, forced warm air blanket
* Cerebral angiography performed to identify cause of neurologic symptoms
** Consider central heat exchanger, especially if patient has high surface-to-volume ratio


=== Operating room setup ===
===Patient preparation and premedication ===  


* Infusion pumps
*Consider aprepitant if patient has history of severe PONV
* Surface cooling device (i.e. cold-water circulating blanket)
*Avoid scopolamine for PONV, as it may confound post-op neurologic exams
* Warming device
*Anxiolysis typically reasonable
** Patient will need aggressive rewarming post-anastomosis
** Consider bladder irrigation, warm-water circulating blanket, forced warm air blanket
* Consider central heat exchanger, especially if patient has high surface-to-volume ratio


=== Patient preparation and premedication ===
===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. -->===


* Consider pre-op acetaminophen 1000mg PO
*Avoid scalp blocks, as they may interfere with donor vessel blood flow
* Consider pre-op aprepitant if patient has history of severe PONV
* Consider small dose of anxiolytic
* Detailed discussion with patient regarding anesthetic plan


=== 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 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. -->===


* Avoid scalp blocks, as they may interfere with donor vessel blood flow
*Standard ASA monitors
*5-Lead EKG
*Core temperature
*Urine output
*Arterial blood pressure
*EEG (particularly if inducing burst suppression)
*Central line typically not required


== Intraoperative management ==
===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. -->===  
=== Monitoring and access <!-- List and/or describe monitors and access typically needed for this case. Please describe rationale for any special monitors or access. --> ===


* Standard ASA monitors
*Maintain controlled hypertension throughout induction (MAPs 90-110) to maintain cerebral perfusion pressure
* 5-Lead EKG
**One effective approach is to use high-dose narcotic (fentanyl 7-10 mcg/kg) and low-dose propofol (0.5 mg/kg)
* Core temperature
***Limits postinduction hypotension
* Urine output
***Prevents hemodynamic response to laryngoscopy
* Arterial blood pressure
**Ephedrine may preserve cerebral blood flow better than phenylephrine<ref name=":0">{{Cite journal|last=Koch|first=Klaus U.|last2=Mikkelsen|first2=Irene K.|last3=Aanerud|first3=Joel|last4=Espelund|first4=Ulrick S.|last5=Tietze|first5=Anna|last6=Oettingen|first6=Gorm V.|last7=Juul|first7=Niels|last8=Nikolajsen|first8=Lone|last9=Østergaard|first9=Leif|last10=Rasmussen|first10=Mads|date=2020|title=Ephedrine versus Phenylephrine Effect on Cerebral Blood Flow and Oxygen Consumption in Anesthetized Brain Tumor Patients: A Randomized Clinical Trial|url=https://pubmed.ncbi.nlm.nih.gov/32482999|journal=Anesthesiology|volume=133|issue=2|pages=304–317|doi=10.1097/ALN.0000000000003377|issn=1528-1175|pmid=32482999}}</ref>
* Central venous pressure
* Muscle relaxant may require reversal if neuromonitoring is used
* EEG


=== 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. --> ===
===Positioning<!-- Describe any unique positioning considerations, including potential intraoperative position changes. If none, this section may be removed. -->===


* Smooth induction is essential
*Supine
* Goal is to maintain CPP
*Table turned 180
* Have vasopressors ready to maintain CPP during induction
*Mayfield skull fixation
* Use narcotic to blunt response to laryngoscopy
**Prior to pinning, a remifentanil bolus (2-4mcg/kg) is useful to minimize hemodynamic lability
* Muscle relaxant used to facilitate tracheal intubation
*Shoulder roll
*  


=== Positioning <!-- Describe any unique positioning considerations, including potential intraoperative position changes. 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. -->===


* Supine
*Anesthesia is typically maintained with a combination of a general anesthetic and remifentanil
* Table typicaly turned 180
*Controlled hypertension (MAPs 90-110) to preserve cerebral perfusion pressure
* Mayfield skull fixation
**Ephedrine boluses may be preferable to improve cerebral blood flow<ref name=":0" /> and avoid reflexive bradycardia
* Shoulder roll
**Phenylephrine infusion typically used to maintain CPP during procedure
* Have all lines directed towards patient's feet, where anesthesiologist typically positioned
* Normocarbia
**Cerebral vasoconstriction from hypocarbia may lead to cerebral ischemia in these patients
*Normovolemia
*Dexamethasone useful to reduce intracranial swelling and decrease PONV
*Some centers use mild hypothermia (33-34°C) to decrease cerebral metabolic rate and increase tolerance to ischemia
*Preincision antibiotics
*If performing a direct anastomosis
**Some centers use mild hypothermia (33-34 °C) for cerebral protection
**Establish burst suppression (propofol 1mg/kg) immediately prior to cross clamping of cerebral artery
***Theoretical benefit of decreasing cerebral metabolic rate and increasing tolerance for ischemia, though evidence is limited
***A bolus dose of ephedrine and/or phenylephrine typically needed to counterbalance hypotensive effect of propofol


=== 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. --> ===
===Emergence<!-- List and/or describe any important considerations related to the emergence from anesthesia for this case. -->===


* Remifentanil (2-4mcg/kg) to minimize BP elevations during pinning
*Controlled hypertension typically maintained in postoperative period even if direct anastomosis performed
* Maintenance of anesthesia can be achieved with combination of remifentanil, propofol, and/or volatile agent
**Titrate vasoactive infusions down as anesthetic weaned
* Keep PaCO2 around 40 mmHg
**If excessive hypertension develop, beta-blockers (esmolol, labetalol) and/or vasodilators (clevidipine, SNP) may be needed to maintain control during emergence
** Hypocarbia may cause unwanted cerebral vasoconstriction in these patients
*Long-acting opioids typically not needed and may interfere with postoperative neurologic examination
* Goal net zero fluid balance / Maintain normovolemia
*Consider IV acetaminophen
* Dexamethasone may be used to decrease PONV
*Consider emergence and extubation on low-dose remifentanil (0.05 mcg/kg/min) to minimize bucking and hemodynamic lability
** Avoid scopolamine for PONV, as it may confound post-op neurologic exams
* Mild hypothermia (33-34°C) can be used to decrease CMRO2 and increase the brain's tolerance to ischemia
* Confirm pre-incision antibiotics
* Avoid long-acting opioids
* Phenylephrine infusion typically used to maintain CPP during procedure
** Phenylephrine typically preferred because it is not arrhythmogenic
* Continuous neuromuscular blockade typically not needed
* Establish burst suppression (i.e. propofol 1mg/kg) immediately prior to cross clamping of cerebral artery for anastomosis
** A bolus dose of phenylephrine and/or ephedrine typically needed to counterbalance hypotensive effect of propofol.
* Aggressive rewarming should start as soon as revascularization is complete
*


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


* As anesthetic is titrated down, patient's BP will generally increase
*ICU (typically monitored overnight in ICU)
* Beta-blockers (esmolol, labetalol) and vasodilators (clevideipine, SNP) may be needed to maintain tight BP control during emergence
*Supplemental O2
* Close regulation of blood pressure is essential
*Head of bed at 20-30°
* Reverse any residual neuromuscular blockade
*Tight BP monitoring and management post-op (typically maintain at baseline levels)
* Prophylactic antiemetics should be given before extubation
*Regular neuro checks post-op
* Consider IV acetaminophen
* If patient begins to buck or cough on ETT, extubate or suppress cough reflex (IV lidocaine)  
* Achieve appropriate core body temperature prior to extubation
*


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


* ICU (typically monitored overnight in ICU)
*Multimodal pain management
* Supplemental O2
*Consider acetaminophen
* Head of bed at 20-30°
*Avoid scalp blocks, as they can interfere with donor vessel blood flow
* Tight BP monitoring and management post-op (typically maintain at baseline levels)
* Regular neuro checks post-op


=== Pain management <!-- Describe the expected level of postoperative pain and approaches to pain management for this case. --> ===
===Potential complications<!-- List and/or describe any potential postoperative complications for this case. -->===


* Multimodal pain management
*Seizures
* Consider post-op acetaminophen
*Stroke
* Avoid scalp blocks, as they can interfere with donor vessel blood flow
*Hemorrhage at anastomosis
*Brain swelling can be caused by hyperemia in revascularized areas


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


* Seizures
{| class="wikitable wikitable-horizontal-scroll"
* Stroke
|+
* Hemorrhage at anastomosis
!
* Brain swelling can be caused by hyperemia in revascularized areas
!"Direct" revascularization
!"Indirect" revascularization
|-
|Unique considerations
|Involves temporary clipping of intracranial vessel to perform anastomosis
Cerebral protection strategies may include burst suppression and mild hypothermia
|
|-
|Surgical time
|↑
|↓
|-
|Potential complications
|Cerebral infarction
|
|}


== References ==
==References==
<references />
<references />


Latest revision as of 11:40, 5 April 2022

Craniotomy for extracranial-intracranial revascularization
Anesthesia type

General

Airway

ETT

Lines and access

PIV x2 Arterial line

Monitors

Standard ASA 5-lead EKG Core temp UOP ABG EEG

Primary anesthetic considerations
Preoperative

Characterize neurologic deficits Consider anxiolytic

Intraoperative

Smooth induction Maintain CPP Maximize flow to ischemic areas Decrease CMRO2 Smooth extubation

Postoperative

Careful control of BP PONV prophylaxis

Article quality
Editor rating
Comprehensive
User likes
2

Craniotomy for extracranial-intracranial revascularization (also referred to as EC-IC bypass) is an intracranial procedure which augments cerebral blood flow by relocating an extracranial vessel intracranially.

Overview

Indications

An EC-IC bypass is performed when there is severe stenosis or occlusion of an intracranial artery. Some common scenarios include:

  • Moya-moya disease
  • Intracranial aneurysms which cannot be directly treated and require complete occlusion of the proximal artery

Surgical procedure

The procedure is performed through a craniotomy. The extracranial source is most commonly the superficial temporal artery, but other branches of the external carotid artery are possible. The temporalis muscle or omentum can also be used when using an external carotid branch is not preferred.[1]

The extracranial source is then routed through the craniotomy, and revascularization is achieved in one of two approaches:

  • "Direct", where the extracranial vessel is directly anastomosed to an intracranial vessel (typically to a branch of the middle cerebral artery)
  • "Indirect", where the donor source is laid on the surface of the brain but not directly anastomosed, with the expectation that over time vascular growth will occur to provide additional flow to the brain.

Preoperative management

Patient evaluation

System Considerations
Neurologic
  • Patients typically present with variable focal neurologic symptoms, which should be well characterized and documented
Cardiovascular
  • Hypertension is a common adaptive response to maintain CPP
    • Normotension may be undesirable in the setting of severe cerebrovascular disease
    • Patients are often treated with midodrine preoperatively to induce hypertension and improve CPP
Hematologic
  • Patients often on aspirin through day of surgery
  • Anticoagulants impacting PT/PTT typically discontinued 1 week prior to surgery

Labs and studies

  • EKG
  • Echo (if concern for cardiovascular disease)
  • Coronary angiography (depending on cardiac risk factors)
  • Complete blood count
  • Chemistry panel
  • Coagulation panel
  • Cerebral angiography performed to identify cause of neurologic symptoms

Operating room setup

  • Infusion pumps
  • If inducing hypothermia
    • Surface cooling device (i.e. cold-water circulating blanket)
    • Warming device
      • Patient will need aggressive rewarming post-anastomosis
      • Consider bladder irrigation, warm-water circulating blanket, forced warm air blanket
    • Consider central heat exchanger, especially if patient has high surface-to-volume ratio

Patient preparation and premedication

  • Consider aprepitant if patient has history of severe PONV
  • Avoid scopolamine for PONV, as it may confound post-op neurologic exams
  • Anxiolysis typically reasonable

Regional and neuraxial techniques

  • Avoid scalp blocks, as they may interfere with donor vessel blood flow

Intraoperative management

Monitoring and access

  • Standard ASA monitors
  • 5-Lead EKG
  • Core temperature
  • Urine output
  • Arterial blood pressure
  • EEG (particularly if inducing burst suppression)
  • Central line typically not required

Induction and airway management

  • Maintain controlled hypertension throughout induction (MAPs 90-110) to maintain cerebral perfusion pressure
    • One effective approach is to use high-dose narcotic (fentanyl 7-10 mcg/kg) and low-dose propofol (0.5 mg/kg)
      • Limits postinduction hypotension
      • Prevents hemodynamic response to laryngoscopy
    • Ephedrine may preserve cerebral blood flow better than phenylephrine[2]
  • Muscle relaxant may require reversal if neuromonitoring is used

Positioning

  • Supine
  • Table turned 180
  • Mayfield skull fixation
    • Prior to pinning, a remifentanil bolus (2-4mcg/kg) is useful to minimize hemodynamic lability
  • Shoulder roll

Maintenance and surgical considerations

  • Anesthesia is typically maintained with a combination of a general anesthetic and remifentanil
  • Controlled hypertension (MAPs 90-110) to preserve cerebral perfusion pressure
    • Ephedrine boluses may be preferable to improve cerebral blood flow[2] and avoid reflexive bradycardia
    • Phenylephrine infusion typically used to maintain CPP during procedure
  • Normocarbia
    • Cerebral vasoconstriction from hypocarbia may lead to cerebral ischemia in these patients
  • Normovolemia
  • Dexamethasone useful to reduce intracranial swelling and decrease PONV
  • Some centers use mild hypothermia (33-34°C) to decrease cerebral metabolic rate and increase tolerance to ischemia
  • Preincision antibiotics
  • If performing a direct anastomosis
    • Some centers use mild hypothermia (33-34 °C) for cerebral protection
    • Establish burst suppression (propofol 1mg/kg) immediately prior to cross clamping of cerebral artery
      • Theoretical benefit of decreasing cerebral metabolic rate and increasing tolerance for ischemia, though evidence is limited
      • A bolus dose of ephedrine and/or phenylephrine typically needed to counterbalance hypotensive effect of propofol

Emergence

  • Controlled hypertension typically maintained in postoperative period even if direct anastomosis performed
    • Titrate vasoactive infusions down as anesthetic weaned
    • If excessive hypertension develop, beta-blockers (esmolol, labetalol) and/or vasodilators (clevidipine, SNP) may be needed to maintain control during emergence
  • Long-acting opioids typically not needed and may interfere with postoperative neurologic examination
  • Consider IV acetaminophen
  • Consider emergence and extubation on low-dose remifentanil (0.05 mcg/kg/min) to minimize bucking and hemodynamic lability

Postoperative management

Disposition

  • ICU (typically monitored overnight in ICU)
  • Supplemental O2
  • Head of bed at 20-30°
  • Tight BP monitoring and management post-op (typically maintain at baseline levels)
  • Regular neuro checks post-op

Pain management

  • Multimodal pain management
  • Consider acetaminophen
  • Avoid scalp blocks, as they can interfere with donor vessel blood flow

Potential complications

  • Seizures
  • Stroke
  • Hemorrhage at anastomosis
  • Brain swelling can be caused by hyperemia in revascularized areas

Procedure variants

"Direct" revascularization "Indirect" revascularization
Unique considerations Involves temporary clipping of intracranial vessel to perform anastomosis

Cerebral protection strategies may include burst suppression and mild hypothermia

Surgical time ↑ ↓
Potential complications Cerebral infarction

References

  1. ↑ Anesthesiologist's manual of surgical procedures. Richard A. Jaffe, Clifford A. Schmiesing, Brenda Golianu (6 ed.). Philadelphia. 2020. ISBN 978-1-4698-2916-6. OCLC 1117874404.CS1 maint: others (link)
  2. ↑ 2.0 2.1 Koch, Klaus U.; Mikkelsen, Irene K.; Aanerud, Joel; Espelund, Ulrick S.; Tietze, Anna; Oettingen, Gorm V.; Juul, Niels; Nikolajsen, Lone; Østergaard, Leif; Rasmussen, Mads (2020). "Ephedrine versus Phenylephrine Effect on Cerebral Blood Flow and Oxygen Consumption in Anesthetized Brain Tumor Patients: A Randomized Clinical Trial". Anesthesiology. 133 (2): 304–317. doi:10.1097/ALN.0000000000003377. ISSN 1528-1175. PMID 32482999.

Top contributors: Chris Rishel and Barrett Larson

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