Awake craniotomy

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Revision as of 13:27, 11 July 2021 by Chris Rishel (talk | contribs) (Reorganized preoperative section, started intraoperative section)
Awake craniotomy
Anesthesia type
Airway
Lines and access
Monitors
Primary anesthetic considerations
Preoperative
Intraoperative
Postoperative
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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 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.

Preoperative management

Patient evaluation

Counsel patient in great detail about the process of an awake craniotomy to set expectations and minimize anxiety intraoperatively

  • Lines and foley catheter will be placed under sedation
    • May awaken with a feeling of a full bladder
  • Head will be unable to move, patient may feel pressure but should not feel pain
  • Patient will be asked to perform tasks and/or answer questions during procedure
System Considerations
Neurologic

Neuro exam to establish baseline function and deficits. Consider signs and symptoms of:[1]

  • 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.[2]

Respiratory

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.

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.

Regional and neuraxial techniques

Video demonstration of a scalp block
  • Scalp blocks are placed using 0.5% bupivacaine with epinephrine

Intraoperative management

Monitoring and access

  • Provide sedation and anxiolysis during line placement[2]
    • Midazolam 1-10 mg IV (titrated incremental doses)
    • Dexmedetomidine 0.2-0.7 mcg/kg/hr
  • Place lines with field blocks using buffered lidocaine for patient comfort
    • Arterial line
    • CVC vs PICC
  • Large bore IV(s)
  • Microphone for patient to communicate
  • ± Precordial doppler

Induction and airway management

Positioning

Maintenance and surgical considerations

Emergence

Postoperative management

Disposition

Pain management

Potential complications

Procedure variants

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

References

  1. Buckner, JC (2007). "Central nervous system tumors". Mayo Clin Proc. 82(10): 1271–86.
  2. 2.0 2.1 Jaffe, Richard A. (2014). Anesthesiologist's Manual of Surgical Procedures. New York: Wolters Kluwer. pp. 31–36. ISBN 978-1-4511-7660-5.