Craniotomy for intracranial vascular malformations

Craniotomy for intracranial vascular malformations

Anesthesia type	General
Airway	ETT
Lines and access	Large bore IV x2 Arterial line ± Central line (if arterial nidus)
Monitors	Standard 5-lead ECG Core temp UOP ABG ± CVP (if arterial nidus) Neuromonitoring
Primary anesthetic considerations
Preoperative	Characterize neurologic deficits
Intraoperative	Smooth induction Hemodynamic goals vary Hypotension ↑ risk of steal If arterial nidus: Hypertension ↑ risk of rupture Have adenosine available Decrease CRMO2
Postoperative	Avoid hypertension after excision (risk of hyperemia)
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Editor rating	Comprehensive
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A craniotomy for intracranial vascular malformations is a neurosurgical procedure performed to remove vascular malformations which are considered high risk for rupture or produce neurologic symptoms.

Overview

Background

• Intracranial vascular malformations are congenital defects
• Typically present in young adulthood (most commonly 15-40 years old)
• Wide anatomic variability
  • High-flow arteriovenous malformations (AVM)
  • Low-flow angiographically occult vascular malformations (AOVM)
    • Cavernous malformations
    • "Cryptic" AVMs
    • Capillary telangiectasias
    • Transitional malformations
  • Low-flow venous angiomas
• Patients may be symptomatic or asymptomatic
• AVM may have be ruptured or unruptured and can be associated with vasospasm. Can also co exist with aneurysms. Most patients will have anesthesia for preoperative embolization of the AVM.

Indications

• The Spetzler-Martin AVM grading system estimates morbidity and mortality of surgery

Preoperative management

Patient evaluation

System	Considerations
Airway
Neurologic	Neurologic symptoms and mental status, signs and symptoms of elevated ICP, seizures
Cardiovascular	Commonly associated with hypertension as well as other cardiac abnormalities including ischemia, arrhythmias, left ventricular dysfunction, and pulmonary edema.
Pulmonary
Gastrointestinal
Hematologic	Anemia
Renal
Endocrine
Other

Intraoperative management

Overall Goals

Goals are to provide a stable hemodynamic anesthetic along with reducing/normalizing the ICP and maintaining adequate CPP (at least 70 mmHg) to prevent cerebral ischemia from brain retraction, brain swelling and vasospasm. Perioperative AVM rupture from hypertension is possible, but rare. However, in case of a coexisting aneurysm, hypertension must be avoided.

Monitoring and access

Standard ASA

5-lead ECG

Core temp

UOP

Arterial line

2-3 large bore IVs

Central line if poor peripherals access

Neuromonitoring

Induction and airway management

• Stable induction of general anesthesia and intubation with fentanyl, propofol, rocuronium, and +/- vasoactive agents to avoid hypo- and hypertension. Typically MAP >65 and SBP <140, however surgical team preferences can vary.
• Moderate hyperventilation (PaCO2 30 mmHg)
• Maintain euvolemia
• Check that blood is available in the OR
• For EEG burst suppression administer additional propofol boluses (50 mg) till burst suppression is achieved. Administer additional propofol boluses as needed to maintain burst suppression (communicate with neurophysiologists).
• Typically postoperative hypertension is avoided to minimize bleeding from a coexisting aneurysm or residual AVM, as well as to avoid postoperative hyperemia. Consider prophylactic use of labetalol to attenuate emergence hypertension.

Maintenance and surgical considerations

Patients typically receive Cefazolin, 10 mg of decadron and 1 gm/kg of mannitol on skin incision (verify all with surgeon). Keppra 1g may also be utilized

Anesthesia can be maintained safely with many different medications, and can be guided primarily by other coexisting conditions.

• An isoflurane/N2O technique offers hemodynamic stability and quick wake up test if needed. This benefit is offset by increased risk of PONV and possibility for N2O closed space expansion.
• TIVA is a reasonable option however it may not allow for a rapid wake up test if needed
• Inhalational and intravenous combination may optimize rapid emergence if needed.
• One example could be propofol infusion (approximately 50mcg/kg/min), remifentanil infusion, vecuronium infusion, and sevoflurane
• Hemodynamic "uppers and downers" should be available. For example: esmolol, labatelol, nitroglycerine, nicardipine infusion. Phenylephrine, norepinephrine drip. Adenosine can also be utilized for temporary cessation of cardiac output if surgical team requests.

Potential complications

Perioperative bleeding from AVM, cerebral ischemia from brain swelling, retractor pressure, inadequate CPP (increased ICP, vasospasm), postoperative intracranial hemorrhage, postoperative brain edema.

Postoperative management

Disposition

Neuro Critical Care Unit

Procedure variants

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