Craniotomy

How do you treat extra-dural haematoma

Pathology:

· Haematoma between inner table of skull and dura due to tear in middle meningeal artery. Arterial bleeding strips dura. 80% have skull fracture – typically temporal. High attenuation in CT as acute. Lenticular (biconvex – lens-shaped).

· Extra-dural haematoma can also arise from torn venous channels in bone at point of fracture or torn dural venous sinus. Such epidural venous haematomas occur only when a depressed skull fracture has stripped dura leaving a potential space into which haematoma can develop.

Clinical:

· LOC at time of injury and lucid interval (25%).

· Transtentorial hernia – uncus of temporal lobe forced over the edge of tentorium cerebelli to compress ipsilateral III (ipsilateral dilatation) and midbrain (compressing ipsilateral pyramidal tract) to cause conterlateral hemiparesis.

· If haematoma is small and patient is asymptomatic with normal neurological exam: observation in nero-ICU

· If symptomatic extra-dural haematoma (decline in GCS by 2 or more and papillary enlargement) then urgent craniotomy.

Patient should be transferred to neurosurgery centre if less than 2 hours transit time (following intubation and administration of mannitol).

If greater than 2 hours transit time then discuss with neurosurgeon and perform locally


How do you treat a subdural haematoma

Pathology: disruption of bridging veins from cortex to dural venous sinuses, disruption of cortical arteries and extension of intra-crebral haematoma.

Acute SDH: Severe neuronal and axonal injury with SDH due to all three mechanisms above. Relief of haematoma produces relief of pressure but residual defect remains. Usually require craniectomy for treatment

Subacute: become apparent some days after injury associated with headache, lethargy, confusion, hemiparesis

Chronic: torn bridging veins after minor head injury in elderly or children. Haematoma is initially small and encased in a fibrous membrane and gradually liquefies and expands producing progressive mental status change with or without focal signs and papilloedema. Can sometimes be treated with burr hole drainage alone. Craniectomy is required if it re-accumulates.

 



How do you perform a craniotomy or craniectomy

· I ensure that the CT scan/ skull X-ray is in OT.

· I perform the procedure on the side of the CT abnormality, skull #, induration/odemea, or side of first dilated pupil after discussion with regional neurosurgical unit.

· I shave the hair on both sides in case a contre-lateral procedure is required.

· GA. Head up 20 degrees. Single dose prophylactic Abx. Maintain cervical control if C-spine not cleared prior to surgery. The eyes must be protected with tegaderm and eye shields.

· I use a neurosurgical head brace if available with sterile application of sharp perforating pins.

· If not available I will place the patient supine with a sandbag under the shoulder on the affected side and a head ring with head turned away.

· I clean the shaved head with betadine soap · I draw out three land marks on both sides of the head with indelabile ink:

· A temporal burr hole site: one finger breadths anterior and three above the tragus

· A parietal burr hole: 20 cm posterior to the nasion (intersection of frontal and nasal bone; approximatelt at superior nasal bridge), 6cm lateral to midline

· A frontal burr hole: 10cm posterior to nasion in the mid-pupillary line (3.5cm from midline).

· A draw a question-mark joining the sites of these intended burr holes.

 

Description: 4630003

 

· I then do a sterile preparation of the skin with betadine solution and drape to expose the entire head. I use skin clips to secure the drape to the head.

· I infiltrate the scalp with lignocaine with 1:200,000 adrenaline in the line of the intended incision.

· I incise the skin down to the skull at the region of the temporal burr hole using a vertical incision about 6cm long.

· I cut through the temporalis muscle with coag diathermy

· I  use diathermy and clips for haemostasis.

I use a periosteal elevator to scrape the scalp from the bone.

I insert a self-retaining retractor.

· I get my assistant to hold the head and use the Hudson brace to drill a hole.

· I use the flat-bladed perforator to slowly expose a small area of dura. I stop when the tip of the perforator wobbles.

· I switch to a conicle burr of the same size and enlarge the hole until I feel the bone is being gripped by the bone edge.

· I irrigate with saline to clear the bone dust and may apply bone wax to the bleeding bone. For dural bleeding I use coag diathermy.

I then make an assessment:

If there is an extra-dural haematoma immediately below the temporal burr hole (1cm deep with blood extruding) I convert to a craniecomty

 

Craniectomy – I use when isolated extra-dural haematoma is discovered after forming temporal burr hole

· I extend the skin incision upwards to a total of 9cm.

· I insert a second self-retaining retractor and coagulate any temporal artery branches with diathermy.

· I use a periosteal elevator to expose a wide area of the squamous temporal bone

· I use bone nibblers to remove an oval area of bone of about 5cm diameter

· I secure haemostasis from the middle meningeal artery – using bipolar coag or under-running the dural vessel with 3/0PDS.

· If bleeding is coming from the foramen spinosum I use coag diathermy in the foramen and plug it with bone wax.

Open the dura?

· I then examine the dura. If the dura is tense or blue discolouration is present I open the dura.

I evacuate the clot by irrigation with warm saline and place a sheet or surgicel on the area. If bleeding persists I suture the dural edges to the temporalis muscle with interrupted 3/0 Vicryl at 2cm intervals

Closure of craniectomy

If the dura was opened I close it with interrupted 2/0 Vicryl sutures

I f the dura will not close I cover it with surgicel

If the dura was not opened I insert a 10F haemovac drain into the extra-dural space.

I close temporalis with interrupted 3/0 Vicryl

I close the galea with interrupted 2/0 vicryl and 2/0 Nylon to skin.

 

When would you use a craniotomy

· Most traumatic intra-cranial haematomas require craniotomy the exception being the small extra-dural that can be dealt with using a limited sub-temporal craniectomy.

· I complete the question-mark shaped incision joining the temporal to the parietal and frontal burr hole sites

· I incise almost down to the bone  grasping the Galea as I cut with straight artery forceps.

· I reflect the scalp flap in the plane between the Galea and the temporalis/pericranium.

· I secure the bundles of artery forceps to the drapes with towel clips

· I fashion an osteoplastic flap by dividing the temporalis as a horse-shoe using cutting diathermy to the bone.

· I leave a 5cm band of muscle intact inferiorly as the hinge of the flap

· I use a periosteal elevator to expose the bone widely in the margins of the flap leaving the pericranium and muscle attached centrally

· I place two burr hole either side of the base of the flap (about 5cm apart)

· I then place an additional 4 burr holes about 6cm apart along the periphery of the flap

· I separate the bone from the dura between the burr holes using Adson’s periosteal elevator with great care not to tear the dura.

· I connect the burr holes using a Gigli saw beveling the bone so that it will form a self to slot back when replaced.

· I use the bone nibbler at the base of the flap to encroach on the remaining island of temporalis muscle.

· I hinge the bone flap backwards on the stalk of temoralis muscle to expose widely the dura.

· I suture the dura to the pericranium around the bone defect edges to prevent bleeding into the extra-dural space around the flap. I use bone wax on bleeding cortex of skull.

· Extra-dural haematoma: A thin sliver of blood (1-2mm) is not significant and a further search should be continued for source of bleeding if this alone is found.

· If a significant haematoma is found, I wash the clot with warmed saline and gently suck it away.

· I secure haemostasis from the middle meningeal artery – using bipolar coag or under-running the dural vessel with 3/0PDS.

· If bleeding is coming from the foramen spinosum I use coag diathermy in the foramen and plug it with bone wax.

Subdural haematoma: If there is no appreciable extra-dural haemtoma or the dura is bulging and tense with a blue discolouration then the dura should be opened.

   I lift the dura with a sharp hook and incise it with a scalpel, protecting the brain below

   I form a dural falp with its base towards the base of the skull flap.

   I cut the dura with scissors in small sections gently lifting it to avoid tearing bridging veins.

   I coagulate the edge of the dura with bipolar diathermy

   I evacuate the clot with warm water and suction with the sucker tip kept on the bone edge.

   Esure haemostasis from brain surface with Weck clips and low current bipolar .

   Place Surgicel onto the brain surface and allow the pressure of a wet Raytech to press it to  the brain surface. Remove the raytech and leave the surgicel.

   I close the dura with interrpted 3/0 Vicryl sutures after perfect haemostasis.

   If the dural edges will not come together I cover with surgicel

Closure of craniotomy

   If the brain is bulging I will not return the bone flap, but store it at -20 degrees in a solution of sterile saline. In a double sterile plastic bag clearly marked with the patient’s details.

   If the dura is not bulging I secure perfect haemostasis and replace the bone flap holding it in place with 4-6 plate and screw pieces or if this is not available then I suture the pericranium around the flap to the temporalis muscle on the falp using interrupted 2/0 Vicryl.

   I insert a 10F redivac subgaleal drain and close the scalp in two layers.