Lateral Craniotomy 
Pitman Mbabazi and Benjamin Mutiso 
 
OPEN MANUAL OF SURGERY IN RESOURCE-LIMITED SETTINGS 
www.vumc.org/global-surgical-atlas 
This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License  
 
Introduction:  
Trauma 
is 
a 
commonly 
encountered 
pathology by a surgeon and traumatic head injury 
bears a significant burden with detrimental outcome 
if timely diagnosis and care is not executed.  
Intra cranial hematomas (acute epidural and subdural 
hematomas) are not uncommon in a set up of trauma, 
and more often than not will need emergency 
surgical evacuation.  
Epidural hematomas are commonly due to 
high impact injury to the head with an underlying 
fracture of the temporal bone and laceration of the 
middle meningeal artery, leading to hemorrhage into 
the epidural space, while subdural hematomas are 
often to shearing of the bridging vessels, or even the 
surface cortical brain vasculature, hence bleeding 
into the subdural space. The accumulating hematoma 
causes a pressure effect on the brain and 
subsequently can lead to irreversible brain injury or 
even herniation if not attended to.  
This chapter covers an approach to the surgical 
management of both intra cranial hematomas, which 
usually require an emergent evacuation through a 
craniotomy 
and 
a 
temporoparietal 
(lateral) 
craniotomy is handy for evacuation of most of these 
collections.  
Lateral craniotomy for intracranial hematoma or 
abscess proceeds in the following steps:  
● First step 
● Second step 
● Third step 
 
Steps: 
The following equipment is needed: 
Head ring (Doughnut head rest) and shoulder roll.  
Diathermy, monopolar and bipolar 
Bone wax 
Oxycellulose (Surgicel®) or absorbable gelatin 
(Gelfoam®)  (if available) 
Hudson Brace and appropriate perforators 
Functional suction machine  
For craniotomy, either of these:  
● Power Drill (Such as Midas Rex® by Medtronic) 
● Gigli saw and saw blade passer (Such as Poppen 
saw guide) 
 
1. General anesthesia is required for this operation, 
especially in moribund patients the airway must 
be controlled (see Airway Management and 
Endotracheal Intubation.)  
2. The arms are at the patient’s side. The head is 
rotated away from the side of injury and held in 
place with a head ring (see Supine Position.) The 
head of the bed is elevated to decrease venous 
pressure and blood loss.  
● If a large cerebral sinus is entered during the 
operation, place the patient horizontal again 
to decrease the chances of air aspiration into 
the vein and embolization.  
3. In cases of acute trauma, cervical spine injury 
precautions must be adhered to until a cervical 
spine injury has been ruled out. Rather than 
rotating the head, the entire patient is rotated 30 
degrees away from the site of injury, either by 
rotating the bed or by placing rolled sheets under 
the patient’s shoulders, torso, hips and legs.  
4. A urinary catheter is advised to aid peri-operative 
monitoring, if there is no sign of urethral injury 
(see Approach to Lower Genitourinary Tract 
Injuries.) 
5. The ipsilateral half of the scalp hair is clipped and 
the field washed and prepped. We use soap and 
water then later preps with chlorhexidine (avoid 
contact with the eyes) or betadine solution 
depending on availability.  
6. A “question mark” incision is marked on the 
ipsilateral 
side, 
based 
on 
the 
following 
landmarks:  
● 1cm anterior to the tragus, keenly palpate for 
the superficial temporal artery pulse, and 
mark posterior to it. Avoid injury to this 
artery because it’s a major pedicle that 
supplies the created scalp flap.   
● The mark is taken posterior and superior to 
the ear lobe (0.5cm from the pinna) and 2-
3cm posterior to the ear and curved anteriorly 
2-3cm lateral to the midline. Anterior 
extension is relative to the location of the 
target lesion and the hairline should not be 
crossed if possible.  
7. The incision site is infiltrated with local 
anesthetic agent with epinephrine (1-0.5% 
Lateral Craniotomy 
Pitman Mbabazi and Benjamin Mutiso 
 
OPEN MANUAL OF SURGERY IN RESOURCE-LIMITED SETTINGS 
www.vumc.org/global-surgical-atlas 
This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License  
 
lidocaine with epinephrine 1:100,000). This 
helps to minimize bleeding as well as enhance 
peri-operative pain management.  
 
The planned incision site is infiltrated with local anesthetic with 
epinephrine. Doing this ½ hour or more before the incision 
makes hemostasis more effective than if it is done immediately 
before the incision.  
 
8. The surgical site is draped, with a midline drape 
(as a guide to the location of the sagittal sinus) 
and anterior drape at the hairline. Experienced 
neurosurgeons will not include the ear in the 
field, but the “amateur” is encouraged to include 
at least part of it to help with orientation.  
 
Planned curvilinear incision extending superiorly posterior to 
the ear lobe and then parallel but medial to the sagittal sinus. 
The superficial temporal artery, which will provide the flap’s 
blood supply, is usually palpable in the area shown by the Red 
dot. Take care to not cut or use excessive diathermy in this area.  
 
9. An incision is made along the marked area with 
a knife through the skin and dermis and then with 
mono-polar diathermy down to the bone. 
Cauterize any bleeding scalp vessels and go 
slowly by layers. Pressure on either side of the 
incision is applied by both the surgeon (using the 
non dominant hand) and assistant to minimize 
blood loss during incision. 
 
The surgeon applies pressure to one side of the incision as it 
proceeds, while the assistant applies pressure to the other side 
and suctions within the wound, to control bleeding and prevent 
excessive blood loss from the scalp.  
 
10. Carry the incision all the way down to and 
through the pericranium. 
 
Once the incision through the scalp is made, the incision is 
continued down to the pericranium.  
 
Lateral Craniotomy 
Pitman Mbabazi and Benjamin Mutiso 
 
OPEN MANUAL OF SURGERY IN RESOURCE-LIMITED SETTINGS 
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11. A periosteal elevator is used to raise the 
periosteum in bulk with the scalp layers of the 
bone from the incision. Use bone wax or the 
monopolar diathermy to control any bleeding 
from the skull itself.  
 
All of the flap, including all layers of the scalp, the periosteum, 
and eventually the temporalis muscle, are elevated together.  
 
12. The temporal muscle is raised in bulk with the 
scalp. At this point the dissection becomes more 
difficult as the tissue is more firmly adherent to 
the skull. To minimize the bleeding, a mono-
polar cautery can be used to dissect here.  
 
The tip of the diathermy shows where the temporalis muscle 
begins. It is easy to get in the wrong plane here and continue to 
elevate the scalp off the temporalis muscle. 
 
 
Elevating the temporalis muscle off of the skull is more difficult 
than elevating the periosteum alone. The diathermy is helpful 
here.  
 
13. Continue to elevate the flap all the way to the 
level of the zygomatic arch inferiorly and the 
forehead anteriorly. If your dissection extends far 
anteriorly, take care not to injure the supraorbital 
and supra trochlear nerves. As the scalp is 
elevated, often in an epidural hematoma, an 
underlying 
fracture 
line 
is 
noted- 
most 
commonly 
involving 
the 
temporal 
bone. 
However, this can vary and may extend or 
involve any bone depending on the mechanism 
of injury.  
 
The completed elevation of the scalp and temporalis muscle flap 
exposes a wide amount of the lateral skull. Elastic retraction 
hooks are being used here.  
 
Lateral Craniotomy 
Pitman Mbabazi and Benjamin Mutiso 
 
OPEN MANUAL OF SURGERY IN RESOURCE-LIMITED SETTINGS 
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14. Alternatively, if you anticipate difficulty in 
closing the dura, as with a depressed and 
comminuted skull fracture, elevate the scalp and 
temporalis muscle in two layers. This takes 
longer so it should not be done in a patient who 
is decompensating acutely. Proceed in the 
following manner:  
● Without incising the pericranium, elevate the 
scalp off the temporalis muscle to its full 
extent 
● Incise the pericranium just above the 
temporalis muscle and elevate the temporalis 
muscle to the level of the zygomatic arch as 
described above.  
● Incise and elevate the pericranium separately, 
preserving a large piece to use as a patch to 
replace damaged dura.  
 
In this photograph, the temporalis muscle (Green arrow) and 
pericranium (Blue arrows) have been elevated. If the incision 
is made just along the edge of the temporalis muscle, this leaves 
a large swathe of pericranium to be harvested intact and used 
as a patch in case of dura loss due to skull fracture.  
 
15. With the bone exposed, sites of burr holes are 
marked out and using a Hudson brace the burr 
holes are made. Available are the self-locking 
and 
non-locking 
perforators. 
The 
former 
automatically stop drilling and do not advance 
beyond the inner table of the skull while the latter 
do not, hence can plunge into the brain.  
● We prefer to make 3 to 4 burr holes at the 
pterion, posterior frontal bone, inferior and 
superior temporal bone. However these are 
guided by the location of the hematoma. 
Subdural 
hematomas 
and 
empyemas 
generally require larger sized craniotomies 
(at least 8 by 10cm). 
● While drilling the burr holes, saline irrigation 
is done onto the site to reduce the amount of 
heat generated and subsequent necrosis.  
● A smooth dissector (number 9) is used to 
dissect the dura off the inner table, 
circumferentially in all the burr holes.  
 
A non-locking perforator for the Hudson Brace. The surgeon 
should proceed carefully and stop when the tip reaches the 
inner table (shown by the Red line) before the entire perforator 
passes through the skull.  
 
 
Proper technique for making a burr hole, shown from a simple 
burrhole operation. The principles are the same for burrhole 
made during craniotomy. At the base of the cranial incision, 
only the tip of the bone has been breached. The surgeon stops 
before the entire perforator goes through the bone.  
 
Lateral Craniotomy 
Pitman Mbabazi and Benjamin Mutiso 
 
OPEN MANUAL OF SURGERY IN RESOURCE-LIMITED SETTINGS 
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This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License  
 
 
The side-biting (Kerrison) rongeur is used to widen the burr 
hole to its full size, as shown here in a simple burrhole 
craniostomy operation. 
 
16. The bone flap can be raised at this point: Using a 
power drill (Medtronic Midas Rex®) or a Gigli 
saw. 
● The power drill cutter is introduced in one of 
the burr holes and used to connect to the 
subsequent holes. If you have incised the 
dura already, ensure that the “foot” of the saw 
does not go through the dura, only cut the 
bone at this time.  
● Connect the inferior burr holes last due to the 
increased risk of injury to the middle 
meningeal artery. Also, a dural tear is more 
likely at this location.  
● Cold saline irrigation is used during this 
process to reduce the heat generated while 
cutting the bone.  
 
The power drill is equipped with a rotating blade and a foot. 
This is engaged and used to cut the bone proceeding from one 
burr hole to another. It is important to continuously irrigate 
while using the electrical drill, because excessive heat can 
damage bone and impair healing.  
 
17. Alternatively, with a gigli saw: a saw introducer 
(Poppen saw guide) is used to pass the saw across 
two burr holes. Alternatively the saw blade can 
be bent so it curves upwards and then passed by 
itself from one burr hole to the other.  
● The incision between the holes is cut in a 
slanting manner to ease re-placement of the 
bone flap.  
● The same is done to connect all the holes and 
subsequently fully elevated the flap.  
 
Gigli Saw: Cutting wire can be detached from the handles and 
passed between two burrholes. Alternatively, Kocher clamps 
can be used to grasp each end of the saw blade. Source: Olek 
Lateral Craniotomy 
Pitman Mbabazi and Benjamin Mutiso 
 
OPEN MANUAL OF SURGERY IN RESOURCE-LIMITED SETTINGS 
www.vumc.org/global-surgical-atlas 
This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License  
 
Remesz (wiki-pl: Orem, commons: Orem) - Own work, CC BY-
SA 3.0,  
https://commons.wikimedia.org/w/index.php?curid=16104615  
 
 
Using a fine periosteal elevator (Penfield,) separate the dura 
from the bone adjacent to each burr hole before attempting to 
pass the wire saw blade.  
 
 
A gentle upward bend is made in the wire blade and then it can 
be passed from one burr hole to the other and retrieved with a 
hemostat.  
 
 
When using the wire saw, spread your arms out as wide as you 
can to avoid breaking the saw blade. Pull the wire towards 
yourself while cutting so that an angled cut in the bone is made.  
 
18. Use a periosteal elevator to raise the bone flap off 
the dura. This layer is adherent to the bone; the 
outer layer of the dura is the inner skull’s 
pericranium. Go slowly and separate the dura 
from the bone.  
 
There will be resistance to elevating the bone flap because the 
dura is adherent to the inner table of the skull. Elevate the bone 
slowly and then use the elevator to dissect the dura off of the 
inner table of the bone.  
 
19. In an epidural hematoma, upon raising the bone 
flap, the hematoma should be in the surgical 
field. This is gently evacuated under direct 
vision. The bleeding lacerated vessel is identified 
and hemostasis is achieved with bipolar 
diathermy. The field is irrigated and hemostasis 
confirmed. Leaving a thin layer of coagulated 
blood adherent to the dura will lead to less blood 
Lateral Craniotomy 
Pitman Mbabazi and Benjamin Mutiso 
 
OPEN MANUAL OF SURGERY IN RESOURCE-LIMITED SETTINGS 
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loss, rather than trying to meticulously clear all 
clot off the dura.  
 
Upon removing the bone flap, the epidural clot is visible. This 
is gently removed with suction and a fine periosteal elevator.  
 
Remove most, but not all, of the blood that is adherent to the 
dura. Attempting to completely clear the dura of all blood clots 
actually leads to more bleeding from this surface.  
 
20. In a subdural hematoma or abscess, the 
pathology is underneath the dura, hence requires 
durotomy. Make a durotomy using a #15 blade or 
sharp curved (Metzenbaum or Tenotomy) 
scissors about 1 cm from the bone cut edge, this 
will make closure of the dura easier.  
 
Incising the dura circumferentially while preserving its blood 
supply, the middle meningeal artery (Black arrow.) If you are 
unable to start your incision with scissors, it is acceptable to 
carefully use a #15 blade.  
 
21. The dura flap is extended inferiorly on both sides, 
leaving a wide base at the caudal end of the 
incision (adjacent to the zygomatic arch.)  
 
The dura is usually not adherent to the surface of the brain, but 
if there is a loculated subdural hematoma the dura will be 
adherent to its capsule and must be gently elevated off.  
 
22. With suction and gentle irrigation or a blunt 
dissector, the hematoma is evacuated.  
Lateral Craniotomy 
Pitman Mbabazi and Benjamin Mutiso 
 
OPEN MANUAL OF SURGERY IN RESOURCE-LIMITED SETTINGS 
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This acute subdural hematoma is not loculated and can be 
carefully evacuated from the surface of the brain using suction 
and a fine elevator.  
 
23. In case any bleeding vessels are identified, 
hemostasis is achieved with bipolar diathermy. 
Sometimes a bridging vein will retract into the 
cortex and bleed uncontrollably. This situation 
should be approached with caution, as there is a 
risk of suctioning the brain or injuring the cortical 
vessels 
if 
these 
bleeders 
are 
pursued 
aggressively. If you cannot definitely locate the 
vein and treat it with bipolar diathermy, it is 
better to place a piece of surgicel or gelfoam and 
apply gentle pressure.  
24. A loculated subdural hematoma will have a 
membrane that must be entered sharply and 
debrided before it can be completely evacuated. 
Incise it carefully with a scalpel and scissors.  
 
The membrane of a loculated hematoma must be incised before 
its contents can be cleared. Be extremely careful and 
meticulous here as you cut right next to the brain cortex. 
 
25. For hematomas extending towards the midline, 
beware of the sagittal sinus. It can easily be 
lacerated through careless dissection. Often it is 
safer to leave residual hematoma than cause a 
sinus bleed! 
26. Topical hemostatic agents like oxycellulose 
(Surgicel®) or absorbable gelatin (Gelfoam®) 
can be used at this point. Assure hemostasis, 
being especially careful on the surface of the 
brain as described above.  
27. If the brain is swelling and preventing dura 
closure, this can be treated by administering 
mannitol, hyperventilating, or elevating the head 
of the bed further. The effect of these 
interventions are immediately visible, as the 
brain can be seen to recede again.  
28. If the dura has been opened, as for subdural 
hematoma or empyema evacuation, the dura is 
re-aligned and closed from one end of the flap 
using a running suture. We prefer polyglycolic 
acid (Vicryl®) 3/0 on a tapered needle. Try to 
take symmetrical bites to avoid uneven edges at 
the edge of the closure. Avoid excess tension, 
which causes one side of the closure to “buckle” 
leading to difficulty approximating the other 
side.  
● If the dura was damaged by a bone fragment, 
suture into place the pericranial patch that 
you harvested previously. 
● If you are unable to close the dura because of 
brain swelling, lay pieces of Surgicel over the 
open areas. Refer to instructions below for 
dealing with the bone flap in this situation.  
Lateral Craniotomy 
Pitman Mbabazi and Benjamin Mutiso 
 
OPEN MANUAL OF SURGERY IN RESOURCE-LIMITED SETTINGS 
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This photograph of the bipolar diathermy being used to obtain 
hemostasis on the surface of the dura also shows the proper 
spacing and distance of the sutures used to close the dura 
(Black arrow.)  
 
29. In case of bleeding from the space between the 
bone and the dura at the edge of the craniotomy: 
This can be difficult to treat, especially if 
associated with a nondisplaced fracture. One 
option is to stuff a piece of oxycellulose into the 
space and then to use a suture to pull the dura 
upwards, applying pressure on the space.  
 
For troublesome bleeding from between the dura and the skull, 
if no obvious source is found on exploration, stuff a small piece 
of oxycellulose into the space and tack the dura to the 
pericranium, pulling it upwards and applying pressure to the 
space.  
 
30. Replacement of the bone flap: The bone flap is 
aligned and anchored with absorbable suture 
Appropriate bone placement can be guided by 
aligning the burr holes that were initially made in 
the skull. Plates and screws can be used if they 
are available: ones made for this purpose cover 
the burr hole entirely and allow screws to be 
placed at the periphery of the plate to anchor the 
bone flap.  
● If the brain swelling is under control but 
might continue to require intermittent 
osmolar or hyperventilation therapy, reattach 
the bone flap with a “hinge craniotomy.” 
Anchor it to the skull on the cranial side only 
using suture tied through two small holes 
drilled in the cranial aspect of the bone. 
● If the brain swelling is uncontrolled and it is 
impossible to replace the bone flap, prepare 
and drape the abdomen, make an incision and 
place the bone within the subcutaneous fat. 
The patient must wear a helmet of some kind 
to protect the brain while the bone is not in 
place. The bone can be replaced once the 
swelling has gone down, but if the dura was 
also damaged the brain is vulnerable to injury 
during elevation of the scalp flap. Refer this 
patient to a neurosurgeon if you can.  
 
Suture anchored to the pericranium on either side of the flap is 
is tied down to hold the bone in place: repeat this maneuver 3 
or 4 times to secure it well.  
 
Pitfalls 
● Injury to the brain while drilling the burr-holes. 
This can occur while using the non locking 
Hudson brace perforators, once the cortical bone 
Lateral Craniotomy 
Pitman Mbabazi and Benjamin Mutiso 
 
OPEN MANUAL OF SURGERY IN RESOURCE-LIMITED SETTINGS 
www.vumc.org/global-surgical-atlas 
This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License  
 
has been penetrated, often the bleeding from the 
bone is noted to increase. At this point the 
surgeon should look out for change in 
consistency to the “feel” of the brace as it is 
turned. This is an indicator to stop and check 
whether the inner table has been breached. One 
can probe with a hemostat or side-biting rongeur 
as a guide and begin to incise the bone at this 
point.  
● Injury to the dura and the middle meningeal 
artery. Sometimes this happens because the 
artery passes through the part of the bone that is 
cut. Blood coming from a canal in the bone can 
be controlled with bone wax.  
● The dura is often more adherent to the 
zygomaticotemporal bone and is prone to injury 
while cutting the bone flap with a power drill. 
● Brain herniation after evacuation of the 
hematoma: It is not uncommon for the brain to 
expand significantly and herniate through the 
durotomy after the hematoma has been 
evacuated. This can pose a dilemma. A bolus of 
mannitol can be given to help relax the brain, 
however this should only be used in an 
adequately resuscitated patient. Harvesting a peri 
cranial flap (as described above) can help with 
the closure of the dura. It is acceptable to create 
an abdominal subdermal pouch for storage of the 
bone flap. If the facility has a freezer for tissue 
storage, this can also be used to keep the flap and 
cranioplasty done at a later time.  
 
Pitman Mbabazi, MBChB 
AIC Kijabe Hospital 
Kenya 
 
Benjamin Mutiso, MBChB, MMed (Neurosurgery) 
AIC Kijabe Hospital 
Kenya 
