03 / Neurosurgery · open
Burr-hole drainage of chronic subdural
Two small holes in the skull to let out the old blood that has been slowly squeezing an older brain; among neurosurgery's simplest operations and most grateful recoveries.
Indication: Symptomatic chronic subdural haematoma, typically weeks after minor trauma in an older or anticoagulated patient.
Read the imaging first
Practice before you scrub
Name the compartment
Knocked out briefly at football, talking normally in the ED, now drowsy two hours later. CT head. (Fictional educational case.)
- Lens means extradural, and extradural means arterial: a middle meningeal bleed under a pterional impact, on a clock measured in hours.
- Shift and effacement grade the urgency better than the collection's size alone: mass effect is the pressure story made visible.
On the tray for this operation
Test yourself on the tray
Scalpel
Sharp division of tissue, most visibly the skin incision.
Electrosurgical pencil
Cutting and coagulating with high-frequency current.
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Mosquito clamp
Clamping small bleeders and fine structures.
Metzenbaum scissors
Fine dissection of delicate tissue and planes.
Yankauer suction
Clearing blood and fluid from the field.
Needle driver
Holding the curved needle while suturing.
Stage
1 / 4
Planning from the scan
Burr-hole sites are marked over the thickest collection, usually two spaced along it, away from dural venous sinuses.
Watch for: Wrong-site surgery: laterality checking is a named step of the time-out
Why are we operating?
Burr-hole drainage evacuates a chronic subdural haematoma through openings the width of a coin: the collection is liquid, so it drains rather than needing excision, and a confused, declining patient can be returned to themselves by one of neurosurgery's simplest and most grateful operations. The physics is Monro-Kellie in reverse: remove the extra volume and the compensating brain re-expands.
Pulls toward surgery
Gives the team pause
Shared foundations
What the surgeon is thinking
Planning from the scan
How does the CT decide where the holes go?
The holes are placed over the collection's thickest points, typically parietal and frontal, so irrigation can flow between them and the cavity drains by gravity and rinse rather than by scraping: the scan is the map, and the marking happens with it on the screen.
The burr holes
What is actually felt and heard while drilling a skull?
The perforator's clutch is designed to disengage as the inner table yields, but the operator still drills by feedback: resistance, pitch and the give of each table. The dura beneath is the last wall, respected with the drill and opened deliberately, not by momentum.
Opening the dura and washing out
Why does old subdural blood look like motor oil, and why does that matter?
Weeks of breakdown liquefy the clot into dark, thin fluid: that is what makes burr-hole drainage possible at all. The dura is opened, the fluid delivered under its own pressure, and warm irrigation run between holes until it clears: the moment fresh, clotted blood appears instead, the operation's premise is being renegotiated.
Subdural drain and closure
Why leave a drain in the subdural space?
The evidence is unusually clean: a soft subdural drain for a day or two roughly halves recurrence. The brain re-expands slowly, and the drain evacuates what refills the gap in the meantime; nursing the patient flat serves the same re-expansion.
Decision points
The CT shows a mixed collection: chronic fluid with a fresh acute layer. Still burr holes?
Burr holes and irrigation
Works when the acute component is minor: the liquid majority drains and the rinse does the rest.
Craniotomy
A substantially clotted collection will not pass a burr hole: the acute-on-chronic subdural with mass effect earns a flap.
The operation is chosen by the blood's age and consistency, read on CT density: liquid drains, clot needs a door. Calling this wrong means an inadequate first operation and a return trip.
The apixaban this patient takes for AF: when does it restart?
Restart after an interval, individualised
The stroke risk that earned the anticoagulant has not gone: most patients restart within weeks, with the timing negotiated against recurrence risk and repeat imaging.
Never restart
Occasionally right in the recurrent collection or the frail faller: a documented decision with cardiology, not a default born of fear.
The anticoagulation question has two halves, reversal now and resumption later, and the second is the one routinely fumbled: it needs an owner, a date and a reason written in the notes, whichever way it goes.
Leaving the OR
The handoff
- Procedure
- Bilateral parietal burr holes, irrigation of chronic subdural, subdural drain left
- Fluid
- Dark, liquefied; irrigated until clear; brain beginning to re-expand
- Anticoagulation
- Apixaban held and reversed pre-op; resumption decision pending at review
- Watch for
- Neuro obs hourly, drain volume and character, flat positioning per instruction
A fictional educational patient, handed over the way real ones are.
The postoperative course
- POD 0-1Often a startling improvement: the confused admission becomes a conversation. Flat nursing and the drain give the brain time to reclaim its space.
- POD 1-2Drain out per protocol; mobilisation begins; a routine scan in many units to document the result.
- WeeksRecurrence is the named risk (a tenth or so even with drains): returning symptoms mean a scan, and the family leaves knowing which symptoms.
- Follow-upThe falls-and-anticoagulation clinic work that prevents the next one: this operation's epidemiology is frailty, and the aftercare should treat it.
Watch it done
Chronic subdural hematoma management
Who gets burr holes, who gets watched, and what recurrence means.
Source: Johns Hopkins Medicine · Watch on YouTube