You are here

Craniotomy – Basic Facts


Craniotomy is a commonly performed procedure where a portion of skull is opened to access the brain for treatment of many different conditions, and the skull flap is returned and secured at the end of the procedure. The term is derived from ‘cranium’ (Latin for skull) and ‘tomy’ (Greek for cutting), which literally refers to opening of the skull. In some circumstances, the piece of bone opening is removed and not immediately replaced, which is termed ‘craniectomy’.


There are multiple reasons why a craniotomy is needed:

  • Trauma – To remove bleeding inside the skull / brain (e.g. Extradural haematoma, acute and chronic subdural haematoma, or intracerebral haematoma).
  • Tumour – To remove, or biopsy or debulk any brain tumours inside the skull.
  • Neurovascular conditions – For aneurysm clipping, or removal of brain arteriovenous malformations or disconnection of dural arteriovenous fistulas, performing a brain blood vessel bypass.
  • Trigeminal Neuralgia – For decompression of blood vessels compressing on nerves.

Preoperative Instructions

Before all neurosurgical procedures, including craniotomy, you should…

  • Not eat or drink anything after midnight the night before the procedure (medication can be taken with very small sips of water).
  • Stop taking any aspirin, warfarin or other blood-thinning medications, as well as non-steroidal anti-inflammatory medication (NSAIDs) at least one week ahead of the procedure.
  • Notify our office if you develop any symptoms of infection, e.g. a cold or flu, before surgery, or if you are receiving treatment for an infection.
  • If you are taking seizure medications, continue to take these up to the date of the operation.
  • Your doctor will advise you whether you need to take additional new medications, such as dexamethasone, prior to surgery.


This procedure is performed usually under general anaesthesia, although sometimes awake craniotomies are performed with sedation and local anaesthesia alone.

Often a navigation system (called ‘stereotaxy’) is used, similar to a GPS system, which is matched to scans performed on the patient before the operation. This allows accurate mapping of the vital structures encountered during the craniotomy operation as well as planning to minimise the size of the incisions, but still obtain optimal operating views.

The head of the patient is securely placed in a head holder, which contains metal pins. Sometimes, these pins can cause shallow dimples in the skin, which will heal over several days after the operation. An incision is made through the scalp layers to expose the skull.

In order to make an opening through the skull, small holes are made with a medical power drill (‘burrholes’), which allow a side-cutting medical saw (‘craniotome’) to cut out an appropriately-sized bone opening. Once this piece of bone is removed, it is kept safe until it is placed back on the skull at the end of the case.

After removing the bone piece (‘bone flap’), the outer covering of the brain (‘dura mater’) is revealed. This is incised to expose the brain underneath. Depending on the reason for the craniotomy operation, the entry path through the brain tissue is kept to a minimum to reduce the likelihood of causing strokes from the operation.

When the main objective of the operation is achieved, the dura is closed with sutures, and sometimes, additional material (‘duraplasty’) is used to ensure that cerebrospinal fluid (CSF) does not leak through the dura opening. At this stage, the bone flap is replaced and secured with bone plates and screws, or sometimes rivets. In some instances, bone cement is placed to fill any major gaps in the skull after a craniotomy (‘cranioplasty’). Once this is done, the skin and soft tissue layers are closed with sutures, and surgical staples.

Postoperative Instructions

Patients generally spend 3 – 7 days in hospital after the procedure. For up to 12 weeks after the procedure, it is normal for patients to have headaches and neck pain, as well as numbness and a degree of fatigue. It is also not uncommon to have problems concentrating and to have some emotional changes, such as increased irritability, anxiety or even depression.

We will give you more detailed instructions about postoperative care, however, in general terms, if any of the following symptoms occur after returning home, you should contact us immediately…

  • Headache not improved with pain medication.
  • Temperature over 38 °C.
  • Signs of wound infection e.g. swelling, redness, tenderness, pain, wound breaking open or discharge / seepage of fluid or pus.
  • Seizure.
  • Weakness / numbness.
  • Drowsiness.
  • Balance issues.
  • Nausea / vomiting.


Risks associated with the procedure are those of surgery generally (risks associated with anaesthesia, chest infection, wound infection, blood clots in the legs, such as “DVT’s”). Specifically, there is a risk of stroke from damage relating to the region of brain operated upon, bleeding into the brain and leakage of cerebrospinal fluid (CSF) through the wound. Additional procedures may need to be performed, including insertion of lumbar drain or revision surgery.

After a craniotomy, patients are at increased risk of having seizures. It is a regulation from Austroads that patients cannot drive after a craniotomy until advised otherwise by their neurosurgeon (usually for at least 6 weeks – 6 months).