Burrhole Craniotomy 
Richard Davis, Gady Barutwanayo 
OPEN MANUAL OF SURGERY IN RESOURCE–LIMITED ENVIRONMENTS  
www.vumc.org/global-surgical-atlas 
This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License 
 
Introduction:  
 
 
Burrhole craniotomy is an operation that 
allows easy access to the epidural and subdural 
spaces. 
They 
can 
also 
be 
used 
to 
place 
ventriculostomy 
catheters, 
ventriculoperitoneal 
shunts, or to drain abscesses on or near the surface of 
the brain. In all cases, but especially for intracranial 
abscesses, proper positioning the burrhole is of 
critical importance.  
 
Epidural hematomas, loculated chronic 
subdural hematomas, and some subacute subdural 
hematomas will not be drained adequately through a 
burrhole and will require a craniotomy. This 
decision-making process is based on history and 
imaging findings. It is described in more detail in the 
Section Introduction chapter.  
 
The operation proceeds with the following 
general steps.  
● Review of the imaging and decision on incision 
placement 
● Scalp, galea and pericranium incision 
● Burrhole and visualization of the dura 
● Incision of the dura and drainage of the subdural 
fluid collection 
● Irrigation until return is clear 
● Placement of a drain 
● Wound closure 
 
Steps: 
1. Carefully review the imaging and correlate the 
intracranial pathology with externally palpable 
landmarks. Orient your incision using landmarks 
that are visible on both imaging and physical 
examination, such as the middle of the orbit, the 
auditory canal, the earlobe, and the palpable bony 
ridge along the origin of the temporalis muscle.  
 
 
On tomography films, distances can be measured by marking 
them with a piece of paper (Top) and then checking that 
distance against a distance marker that is usually found on the 
far right of the film (Bottom.) On this axial MRI, the maximum 
thickness of the subdural hematoma is measured at 2.5cm.  
Burrhole Craniotomy 
Richard Davis, Gady Barutwanayo 
OPEN MANUAL OF SURGERY IN RESOURCE–LIMITED ENVIRONMENTS  
www.vumc.org/global-surgical-atlas 
This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License 
 
 
On digital images, a ruler function is usually available. On this 
Coronal CT scan, the maximum thickness of the subdural 
hematoma is 8.5cm above the external auditory canal.  
 
2. General anesthesia is preferred, although in 
extreme cases it is possible to perform a burrhole 
under local anesthesia. The patient’s head is 
secured with a head ring. 
3. Position: The patient lies supine and the head is 
rotated away from the surgical side. The head 
ring prevents excessive rotation or angulation of 
the neck.  
4. The patient’s head is shaved and the location for 
a lateral craniotomy incision is marked. Burrhole 
incisions will be within this line, so that if it is 
necessary to convert to craniotomy they can be 
incorporated in the flap incision.  
 
The Blue Line indicates the scalp incision for a craniotomy. A 
burrhole placed in the area of the Red Circle should be 
horizontal. A burrhole placed in the area of the Black Circle 
should be vertical., If conversion from burrhole to craniotomy 
is necessary, the incisions could easily be integrated into the 
scalp flap. 
 
5. The areas of planned incision are injected with 
local anesthetic with epinephrine, then the 
surgical site is prepared and draped.  
6. The burrhole incision is made with a scalpel and 
extended 
with 
electrocautery. 
Slow 
even 
progress is made assuring hemostasis. Even with 
prior vasoconstrictor injection, scalp bleeding 
will occur and should be controlled. While it is 
possible to cut straight through the scalp and then 
control bleeding with the self-retaining retractor, 
this technique assures the scalp will bleed during 
closure, increasing the chances of entrapping the 
drain as described further below.  
Burrhole Craniotomy 
Richard Davis, Gady Barutwanayo 
OPEN MANUAL OF SURGERY IN RESOURCE–LIMITED ENVIRONMENTS  
www.vumc.org/global-surgical-atlas 
This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License 
 
 
Technique for incising the scalp. The surgeon holds pressure 
on one side of the incision with the non-dominant hand while 
using electrocautery to divide the subcutaneous tissue. The 
assistant holds pressure on the opposite side with the non-
dominant hand while using the Frazier suction to keep the field 
clear.  
 
7. Once the pericranium is reached, a self-retaining 
retractor is placed.  
8. The pericranium is incised and elevated laterally. 
The self-retaining retractor is repositioned to 
hold the elevated pericranium as well.  
 
With a self-retaining retractor such as the Weitlaner, the 
incised scalp is retracted over the periosteum. The periosteum 
is then incised and elevated laterally with a periosteal elevator. 
The retractor is then repositioned to hold the periosteum as 
well.  
 
9. The burr and Hudson Brace is used to perforate 
the skull. Irrigate during this process to avoid 
overheating the bone and killing osteoblasts. 
Progress is slow and steady, with frequent 
checks. At all costs, the burr must not be allowed 
to “break through” the skull.  
 
The table is set to a height such that the surgeon can 
comfortably lean on the Hudson Brace while rotating the 
handle. The assistant steadies the head so that there is no 
excessive movement or tension on the neck.  
10. Once the inner table is breached, the operator of 
the Hudson Brace will feel that progress becomes 
less “smooth.” This is because the blade of the 
burr is now engaging the edge of the inner table 
of the skull rather than cutting evenly through 
bone. An experienced operator will feel this 
change and stop when this happens.  
Burrhole Craniotomy 
Richard Davis, Gady Barutwanayo 
OPEN MANUAL OF SURGERY IN RESOURCE–LIMITED ENVIRONMENTS  
www.vumc.org/global-surgical-atlas 
This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License 
 
 
A variety of perforators are available for the Hudson Brace. All 
have a center that penetrates deeper than the sides. Progress is 
slow with frequent stops to check that the inner table has not 
been breached with the tip of the perforator. When the inner 
table of the skull (represented by a Red Line) is breached, the 
sharp edge of the perforator is now engaging the edge of the 
bone. The surgeon feels that resistance to turning the Hudson 
Brace suddenly becomes less “smooth.” Stop at this point to 
avoid the possibility of the burr plunging through the bone into 
the brain parenchyma. 
 
11. At this point there is a wide circular defect in the 
skull with a smaller defect at its base that 
communicates with the inside of the skull. The 
Kerrison rongeur is passed through this defect 
and used to widen it to about 12-14mm.  
 
Once the tip of the perforator has breached the inner table of 
the skull, the most superficial part of the burrhole will be as 
wide as the widest part of the perforator, with a small defect at 
the base. The Kerrison rongeur (Inset) is a side-biting rongeur 
that can be used to widen the base of the burrhole until it is of 
a uniform width throughout.  
 
12. The dura is inspected carefully; occasionally a 
blood vessel will be running through it directly 
below the burrhole. If the cut edges of the bone 
are bleeding and obscuring your view, apply 
bone wax to the bleeding site.  
13. With the assistant ready with the Frasier suction, 
make a cruciate incision in the dura, avoiding any 
nearby blood vessels. The dura is thick. Proceed 
in layers, making all of the incision through the 
outer layer before cutting through to the inner 
layer. A rush of dark red or brown fluid is seen.  
 
Burrhole with cruciate incision in the dura.  
 
14. Suction the fluid until the flow decreases. If the 
flow does not decrease or changes from dark to 
bright, consider whether the dura incision 
lacerated a vessel. Bipolar cautery can usually 
stop bleeding from dural vessels. If not, enlarge 
the burrhole with a rongeur until it can 
accommodate a suture and ligate the vessel.  
15. Insert a soft pediatric feeding tube and irrigate 
with warm saline until return is clear.  
Burrhole Craniotomy 
Richard Davis, Gady Barutwanayo 
OPEN MANUAL OF SURGERY IN RESOURCE–LIMITED ENVIRONMENTS  
www.vumc.org/global-surgical-atlas 
This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License 
 
 
The subdural space is gently irrigated with warm saline 
through a soft pediatric feeding tube.  
 
16. Insert a drain through a separate incision and pass 
it through the dura. A small Foley catheter or red 
Robinson drain with extra side holes cut in it is 
acceptable. Make sure to not narrow the catheter 
too much while cutting the side holes, so it is less 
likely to fracture while being removed. Irrigate 
and aspirate gently on this drain to make sure that 
it is patent, as it can kink during insertion. The 
drain is placed to gravity.  
 
A drain is fashioned by cutting off the tip of a Foley catheter 
(including the balloon) and adding side holes.  
17. Close the skin and galea. Using a single layer of 
running monofilament Nylon suture is more 
hemostatic. Using two layers, closing the Galea 
with interrupted absorbable suture and the skin 
subcuticular, has a superior cosmetic appearance. 
Take care not to entrap the drain in any of the 
suture.  
 
The scalp can be closed in one or two layers. Care is taken to 
close the Galea and to avoid incorporating the drain in the 
closure. Direct visualization of each pass of the needle is 
mandatory.  
 
18. The drain can be removed in 1-3 days after 
surgery.  
 
Pitfalls 
● The brain can be injured through careless use of 
the perforator. Impatience and excessive pressure 
while using the perforator is inappropriate. Stop 
frequently to check the progress. Switch to a 
rongeur to widen the hole as soon as the tip of the 
burr has passed through the inner table of the 
skull.  
● A loculated or clotted subdural hematoma, or an 
epidural hematoma, will not evacuate through a 
burrhole alone. The preoperative imaging, as 
well as increasing experience, will help avoid 
“surprises” where the hematoma does not fully 
Burrhole Craniotomy 
Richard Davis, Gady Barutwanayo 
OPEN MANUAL OF SURGERY IN RESOURCE–LIMITED ENVIRONMENTS  
www.vumc.org/global-surgical-atlas 
This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License 
 
evacuate as expected. Do every burrhole with the 
head fully prepared and draped so that you could 
convert to craniotomy if necessary.  
● Recurrence of a hematoma may require a second 
burrhole operation to evacuate it again. While 
this is a known complication, the surgeon must 
be certain that the patient has a true recurrence, 
and not just failure to evacuate the first 
hematoma because it was clotted or loculated. 
Removal of less fluid than expected at initial 
operation should prompt the surgeon to convert 
to craniotomy to fully inspect the subdural space.  
● A drain should always be left in the subdural 
space after burrhole evacuation. This makes a 
recurrence less likely, though still possible. If the 
hematoma is truly recurrent (rather than 
inadequately treated, as described above) a repeat 
operation 
through 
the 
same 
burrhole 
is 
acceptable.  
● Recurrence of a subdural or epidural abscess 
after burrhole evacuation is possible and should 
be watched for. A craniotomy will be required if 
this occurs; a repeat burrhole is not adequate.  
● Patients whose subdural hematoma has been 
present for a long time, especially if there was 
significant midline shift, brain compression, or 
advanced age, may not recover neurologic 
function 
despite 
a 
successful 
operation. 
Ipsilateral pupillary dilation in a longstanding 
subdural hematoma is a particularly ominous 
sign.  
● Careless skin closure can entrap the drain tube 
easily, since it runs directly underneath the 
incision. Make sure that each pass with the 
needle is visualized. Avoid “blind” suturing 
through both edges of the wound at the same 
time. If entrapment of the drain occurs, the 
sutures can be removed and replaced under local 
anesthesia with meticulous sterile technique.  
● Avoid placing the drain to strong suction, as this 
can damage the brain underneath. Gravity 
drainage is quite sufficient in this situation.  
 
 
 
 
 
 
Richard Davis MD FACS FCS(ECSA) 
AIC Kijabe Hospital 
Kenya 
 
Gady Barutwanayo, MBBS 
AIC Kijabe Hospital 
Kenya 
 
February 2022 
