Awake Craniotomy

Murali Magesh, Nivetha Ganasundara sureshkumar*

Consultant, Department of Anaesthesiology, Kauvery Hospital, Chennai

DNB Resident, Department of Anaesthesiology, Kauvery Hospital, Chennai

*Correspondence: [email protected]

Background

Awake craniotomy is used for mapping and resection of lesions in important brain areas while preserving neurological functions. Goal is to have an awake, cooperative patient for motor function assessment during tumor resection.

Case Presentation

A 50-year-old female, known patient of Diabetes Mellitus, hypertension, asthma and carcinoma breast, who had undergone S/P BCS and oncoplastic reduction. Now came with complaints of headache and vomiting.

MRI showed a tumor in the left frontal 2 x 2 cm in the left frontal lobe, close to the eloquent area.

We performed an awake craniotomy to monitor motor functions.

Anaesthesia technique

Preanaesthetic evaluation done ASA III, ET > 4 METS, MPG I, normal LV, Hb 10.

Informed consent obtained for awake craniotomy.

Two large IV bore needles were secured.

Right radial artery cannulated and routine monitors attached.

Patient sedated with injection midazolam 1mg, dexmedetomidine 50 mcgs.

Paracetamol 1 g IV given after sedation.

Left side scalp block was given using a landmark technique with 2% Lox with adrenaline 10 ml, 0.25% bupivacaine 20 ml and 4 mg dexamethasone.

Local infiltration given at site of Mayfield pins.

Before incising dura, gauze soaked with LA placed on the top of dura for 3 min to decrease the pain.

During tumor resection the patient was in constant communication with anaesthesiologist and motor movement was assessed.

Once the lesion was removed and motor function was monitored, closure of the skull began.

Intraop was uneventful. Boluses of sedation given to make patient stay comfortable.

Duration of surgery 6 hours.

After surgery, the patient was shifted to the ICU and continuous assessment of motor function was done.

Patient was discharged on the third post op day.

Discussion

So, what is awake craniotomy?

Awake craniotomy is a surgical procedure where the patient is deliberately kept awake during surgery, usually for mapping and resection of tumour.

A variety of anaesthetic techniques have been developed for awake craniotomy.

In the present study we used a technique awake throughout.

In this technique the aim is to vary the levels of sedation according to the stage of surgery while maintaining spontaneous ventilation without any airway device. Sedation is deepened during application of Mayfield pins, skin incision, removal bone flap and dura mater, and then decreased or stopped for neurocognitive testing; it can be restarted during closure. If the sedation is not titrated correctly, there can be airway obstruction leading to hypoxia and hypercarbia.

We also gave scalp block to this patient; this blocks the following nerves: supra orbital, supra trochlear, zygomatico temporal, auriculo temporal, greater and lesser occipital nerves.

The drugs commonly used are propofol, dexmedetomidine, remifentanyl (currently not available in India).

Awake-Craniotomy-1
Awake-Craniotomy-2

Indications

  1. The most common surgical indication for awake craniotomy is resection of the tumor in the vitally important area of the brain like the motor cortex located in the prefrontal gyrus (Brodmann area 4), the sensory cortex located in the postcentral gyrus (Brodmann areas 3,1,2), and language cortex (Broca’s and Wernicke’s area).
  2. Awake craniotomy is used to facilitate electrocorticography for localization of the focus of seizure.
  3. Awake craniotomy is also used for deep brain stimulation surgery, classically for Parkinson disease, and other central movement disorders, Alzheimer disease, and psychiatric disease.
  4. Used for stereotactic brain biopsy and ventriculostomy.
  5. Awake craniotomy is also used in interventional pain procedures such as pallidotomy and thalamotomy.

When to convert into general anaesthesia?

The conversion is dome when there are airway obstructions, hypoxia, local anaesthesia toxicity, pain, poor cooperation/ agitation, seizure. It is very difficult to convert into general anaesthesia in between the surgery since the patient- head is attached to the mayfield pins and flexed and we cannot extend the head to see the vocal cords and intubate without removing the mayfield pins.

Conclusion

Management of awake craniotomy is challenging. The success of this procedure depends on multi‑disciplinary team involving neurosurgeons, anesthesiologists and competent operating room personnel apart from a co‑operative patient.

References

  1. Sarang A, et al. Anaesthesia for awake craniotomy: evolution of a technique that facilitates awake neurological testing. Br J Anaesthesia 2003;90(2):161-5.
  2. Hyun Kim S. Anesthetic considerations for awake craniotomy. Anesth Pain Med. 2020;15(3):269-274.
  3. Lobo FA, et al. Anaesthesia for awake craniotomy. Br J Anaesth. 2016;116(6):740-4.
  4. Bonhomme V, et al. Awake craniotomy. Eur J Anaesthesiol. 2009;26(11):906-12.
  5. Piccioni F, et al. Management of anesthesia in awake craniotomy. Anestesiol. 2008;74(7-8):393-408.

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