Ultrasound-guided Scalp Block

for an

Awake Craniotomy

 

Carlos G. Montero, MD, Fernando Vazquez, MD, Richard Marks, MD and

Jonathan Metry, MD

 

INTRODUCTION

Awake craniotomies allow neurosurgeons to achieve

a higher rate of brain tumor resection while minimizing

significant neurological deficits. Anesthesiologists can

play a crucial role by performing scalp blocks, which

include seven bilateral nerves, implementing a sedative

plan that maintains a patent airway and a plan that

reduces interference with intraoperative neuromonitoring.

Awake craniotomies reduce the side effects of general

anesthesia, promote early postoperative neurological

evaluation, and improve resource utilization.1

In this case report, we present a patient who

underwent an awake craniotomy for a frontotemporaloccipital

brain tumor.

PATIENT PRESENTATION

Our patient is a 74-year-old female (weight 100 kg

and BMI 34) with significant past medical history of

hypertension on metoprolol, aortic prosthetic mechanical

valve on Warfarin, trigeminal neuralgia, and left temporooccipital

brain tumor associated with gait imbalance and

memory and word-finding deficits. She presented for

awake left-sided craniotomy with intraoperative brain

mapping. Airway examination demonstrated Mallampati 2,

thyromental distance >3 fingerbreadths, and full range of

motion of the neck. An asleep-awake-asleep technique

was implemented using general anesthesia with invasive

monitoring, monitored anesthesia care, and regional

anesthesia.

Standard ASA monitors were placed, and a time out

was performed. After an uneventful induction and

intubation, dexmedetomidine, propofol, and remifentanil

infusions were started.

Ultrasound guided bilateral scalp blocks and

superficial cervical plexus blocks were performed. The

patient was positioned in the supine position and a total of

25 cc of 0.5% Bupivacaine was injected under ultrasound

guidance. Bilateral supraorbital, supratrochlear,

zygomaticotemporal, and greater occipital, nerves were

individually blocked and the greater auricular and lesser

occipital nerves were blocked via the superficial cervical

plexus. A single intravenous dose of dexamethasone was

given as an adjuvant to prolong the duration and improve

the quality of analgesia provided by the ultrasound-guided

scalp blocks.2

After completion of the ultrasound-guided nerve blocks,

the patient was positioned for surgery and placed in pins

with no change in vital signs. Additionally, vital signs

remained unchanged following surgical incision with no

adjustments to the propofol, remifentanil, and

dexmedetomidine infusions.

When it was time for the awake portion of the surgery,

the patient underwent successful emergence and

extubation. Awake language mapping was performed to

maximize extent of resection and minimize functional

deficits. The patient was cooperative, calm and pain-free

throughout the awake portion of the procedure. At the

conclusion of the awake portion of the surgery, the

patient was induced and reintubated. Final motor

analysis was performed, and the patient was extubated

and transferred to the neurosurgical intensive care unit

without complications. In the immediate post-operative

period, the patient’s pain scores ranged from 0-2/10 and

required no additional analgesics.

DISCUSSION

The use of ultrasound allows for better visualization

of anatomy and neurovascular distribution, in

comparison to landmark-based scalp blocks, and may

reduce volume and concentration of local anesthetic

needed for an adequate block, thus reducing the risk of

local anesthetic systemic toxicity (LAST).3 Complications

from scalp blocks may include infection, hemodynamic

changes and arrythmias if epinephrine is used, vascular

injury and hematoma, unilateral ptosis, facial nerve

palsy, bradycardia and hypotension from the

trigeminocardiac reflex, intracerebral or subarachnoid

injection, anaphylactic response to local anesthetic, and

LAST.4

CONCLUSION

Postcraniotomy pain is most significant within the

first 48 hours post op and presents as a headache that

is generalized and pounding or pulsatile. The pain is

mostly superficial suggesting somatic rather than

visceral pain.6 This case report demonstrates that

ultrasound-guided scalp blocks provide the analgesia

required to perform an awake craniotomy. A

multidisciplinary team can interact with the awake

patient with minimal discomfort and hemodynamic

instability during pin application and scalp incision.

Regional anesthesia can play an important role to

reduce opioid requirements and allow for optimal

conditions for a neurological assessment.

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