Now imagine — a 35-year-old male patient has been referred from an outside hospital to your tertiary care centre, diagnosed with Acute SDH secondary to RTA with a Midline shift >15 mm. The patient is intubated in view of a fall in GCS score. You, being the anaesthesiologist, have just completed the pre-operative evaluation.
This is the picture — gathered quickly, under pressure, the way emergency PAC always is. The patient was wheeled into the OT. Baseline vitals noted. Lines secured. Ventilator connected. The surgeon was scrubbing in.
And before handing the patient over — my senior turned to me.
What I am about to share is my experience of performing a scalp block for the very first time — not just the steps, but what it feels like to do it for the very first time.
Come, let's visualise this together.
Before we do anything — we ask five questions.
For anything we hear, discuss, or do, we need to ask ourselves:
The Scalp Block
What it is · When we give it
A scalp block is a regional block procedure given most specifically in awake craniotomies — to provide analgesia to the patient and to avoid the need for sedation or GA. The patient must stay awake, cooperative, and responsive to commands from the neurosurgeon throughout the procedure.
This is a technique where precision is everything. We cannot afford the patient moving or responding to painful stimuli. The margin for error is zero.
Now — why do we give it under GA?
Getting to basics — in GA we give three categories of medications:
For abdominal and lower limb procedures — we have epidurals to provide peripheral analgesia. But we cannot place an epidural for a craniotomy. And henceforth — here comes the importance of the scalp block.
In a patient undergoing awake craniotomy, the goals of anaesthetic technique are:
- 1Minimise patient discomfort associated with painful portions of the procedure.
- 2Ensure patient responsiveness and compliance during cortical stimulation assessment.
- 3Select an anaesthetic technique that produces minimal inhibition of spontaneous seizure activity.
Many techniques exist — minimal sedation, asleep-awake-asleep and more. But none of them alone provide adequate scalp analgesia. Every technique must be supplemented with a scalp nerve block.
The Nerves
Six nerves · Each with its own landmark · Miss one and the block is incomplete
- Supraorbital and Supratrochlear nerves
- Zygomaticotemporal nerve
- Auriculotemporal nerve
- Greater occipital and Lesser occipital nerve
The Landmarks
| Nerve | Landmark |
|---|---|
| Supraorbital & Supratrochlear | Palpate the supraorbital notch at the medial aspect of the orbital ridge |
| Zygomaticotemporal | About 1–2 cm lateral to the lateral canthus of the eye |
| Auriculotemporal | A centimetre or two in front of the tragus of the ear |
| Greater & Lesser Occipital | Medial 1/3rd of the imaginary line joining the mastoid process to the external occipital protuberance — feel for the occipital artery pulsations and infiltrate just lateral and medial to the artery |
The Drug
What we give · How we mix it
The Combination
Rapid onset
Long duration
Localises the block
Mixed in 1:1 dilution. Preferred in combinations already containing adrenaline — if not, add adrenaline at 1:200,000 dilution.
💬 Open for discussion: What is the maximum safe dose of LA? What is LAST and how do we manage it? Write to me in the comments or ping me on mail. Let us discuss this together.
The Advantage
Why the block matters · Why fentanyl alone is not enough
Fentanyl is given in GA to modulate conscious pain and to attenuate the transmission of nociceptive signals at the level of the spinal cord and brainstem. Which means — fentanyl does not adequately block nociception at the peripheral level. And that is exactly why we need a scalp block.
With fentanyl, the pain response is still there. The peripheral nerve signal is still firing. So to blunt this response — we give a scalp block. This blocks the nerves at the site. And therefore — no transmission.
A well-administered block makes the haemodynamics of the patient stable — and we as anaesthesiologists can be confident that the pain response is truly attenuated, not merely suppressed.
With a midline shift already exceeding 15mm and intracranial compliance completely exhausted — this haemodynamic stability is not a luxury. It is the difference between a successful decompression and a catastrophic intraoperative herniation.
And now — let me tell you what it felt like when I finally picked up that syringe.
Surreal is the only word that comes close.
The patient was sedated in front of me. The syringe was in my hands. My senior was beside me, guiding me through each landmark, each injection point, each aspiration. The anticipation in the moments before — the weight of knowing this was mine to do — felt heavier than the procedure itself.
Because the procedure, when you actually do it, is remarkably precise and elegant. Simpler than you imagined. More deliberate than you feared. And when the needle found each nerve point accurately — when the landmarks you had read about in textbooks became real, palpable, confirmable under your fingertip — it felt like nothing less than magic.
But even in that moment — especially in that moment — the clinical mind never rests.
And when it was done — when every nerve point had been infiltrated, the syringe was empty, and the block was in — I looked at the monitor.
And it held.
The surgery that could have been a haemodynamic nightmare in a patient with a midline shift exceeding 15mm — was controlled, deliberate and calm.
That was the scalp block working.
Not in a textbook. Not in a case report. Right there — in front of me — in a real patient whose brain had no room for a single moment of instability.
And I understood, in that moment, everything we had discussed about nociception and fentanyl and peripheral signals and fires that must never be allowed to start — not as theory, but as truth.
Why is haemodynamic stability so critical in a patient undergoing craniotomy?
Think about this before you scroll to the next section.
Tell me in the comments. Let us discuss this together.
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