Craniotomy - Neurosurgical Access to the Brain
Performing a Craniotomy
The brain is contained within the skull. The skull is like a box which houses in and protects the fragile brain. The only way to access the brain surgically, or access a lesion within the brain, is to create a window opening through the skull. The surgical term for the creation of an opening in the skull is called a “craniotomy”. Almost all operations on the brain begin with a craniotomy. A craniotomy is performed in a very standard fashion, and equally is closed in a very standard fashion. Every craniotomy has general risks associated with it but is generally well tolerated by most patients. Most craniotomies are not that painful.
A craniotomy can be performed virtually anywhere on the head depending on the location of the brain that needs to be accessed. A craniotomy can be very small, often called a burrhole, or very large involving a significant portion of the skull. The size of the craniotomy depends on the requirements of the surgery to be performed, such as the size of the tumour to be removed.
A craniotomy is most commonly performed under general anaesthesia. The patient is completely asleep for the procedure, feels no pain and has no awareness of what is going on. Under some special circumstances, it may be elected to perform a craniotomy with the patient awake. This is termed an "awake craniotomy." During an awake craniotomy, the patient is not awake for the entire procedure, they are woken up for part of the operation where neurological testing is needed to be performed. Awake craniotomy is only performed in very rare circumstances and Dr Oehme will discuss it with you if this needs to be performed. For the most part you can expect to be completely asleep for your craniotomy. |
Video - Craniotomy for Subdural HaematomaThis procedure, performed under general anaesthesia, creates an opening through the skull for removal of a blood clot on the surface of the brain. Subdural hematomas commonly result from trauma to the head, and can place harmful pressure on the brain.
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Following administration of general anaesthesia, the patient is positioned in the appropriate position on the operating table and the head is usually fixed in a rigid clamp, that prevents the head from moving. Following this, it is standard to use a cranial stereotactic navigation system, which acts as a GPS during cranial surgery. Neuronavigation allows the neurosurgeon to accurately and precisely navigate within the skull and brain during surgery, and facilitates accurate identification of lesions.
The area of the head where the craniotomy need to be performed is marked. A minimal head shave is performed to remove a small amount hair. Dr Oehme routinely performs a minimal head shave and only removes the amount of hair necessary to safely perform the procedure. The head is then cleaned with antiseptic and covered with sterile surgical drapes. All craniotomies are performed with the strictest sterile techniques to minimise the chances of infection.
The area of the head where the craniotomy need to be performed is marked. A minimal head shave is performed to remove a small amount hair. Dr Oehme routinely performs a minimal head shave and only removes the amount of hair necessary to safely perform the procedure. The head is then cleaned with antiseptic and covered with sterile surgical drapes. All craniotomies are performed with the strictest sterile techniques to minimise the chances of infection.
Video - Craniotomy for Brain Tumour
This procedure, performed under general anaesthesia, creates an opening through the skull for brain tumour removal. The surgery usually requires between two to five hours to complete. The length of surgery depends on the type and size of the tumour.
To begin a craniotomy the skull bone needs to be accessed. Local anaesthetic is infiltrated into the scalp to numb the area. An incision is made in the scalp skin with a scalpel. Clips are applied to the scalp edge to prevent bleeding from the very vascular scalp. A type of skin retractor is then placed, which exposes the underling bone. A craniotomy is then performed to elevate a piece of bone to expose the underling dura, or protective layers of the brain.
Using a high-speed drill a small pilot hole, called a burr hole, is initially made in the skull. Following this, using an undercutting drill, called a craniotome, a piece of bone is drilled out of the skull and elevated. The piece of bone drilled out is called a bone flap. This bone flap is like a window of bone, which when removed exposes a section of the protective coverings of the brain. Drilling the bone is not painful.
Removal of the bone exposes the underlying dura. The dura is the final layer that protects the brain that needs to be opened in order to access the brain. The dura can is opened to expose the underlying brain using a fine scalpel and scissors. The dura is a then retracted to expose the brain or the underlying lesion.
This is the standard way that a craniotomy is performed in all patients. The next part of the procedure depends on what condition is being treated. Once a craniotomy is performed a blood clot can be drained, a tumour removed or any other procedure on the brain performed.
Closing a Craniotomy
In order to close a craniotomy, the dura is generally closed with sutures. The bone is fixed back in place with titanium plates. Often a type of cement is then used to fill in the bony defects to give a smooth cosmetic result. This application of cement is called a cranioplasty. Any muscle that has been cuts is sutured back together. The scalp is then closed in layers over the bone with scalp clips or sutures. Dressings and head bandages are then applied and the patient is woken up.
Risks of Craniotomy
Most craniotomies can be performed without any serious complications. Like any surgical procedure there are risks associated with the anaesthetic and the procedure itself.
Risks of Anaesthesia
Risks of anaesthesia will be discussed with you by your anaesthetist prior to surgery. It is important that you inform us of your correct age and any past medical problems, as this can influence the risk of anaesthesia. Risks include:
- Heart problems, such as heart attack (AMI) or arrhythmia
- Lung problems, such as infection (pneumonia) or blood clots
- Urinary tract infection
- Deep Venous Thrombosis (DVT)
- Eye or visual problems
- Pressure wounds
- Stroke
- Small risk of significant life-threatening event
General Risks of Craniotomy
Although performing a craniotomy is generally safe, there are some risks whenever a craniotomy is performed. These include:
- Infection 1-2%
- Seizures which can require taking medication. Rarely this can lead to epilepsy requiring longterm medication.
- Bleeding. This can occur at the time of surgery and may necessitate a blood transfusion. It can also occur at some time after surgery. The bleeding may be present in the brain or adjacent to it. Sometimes another operation is required to drain the bloodclot and stop the bleeding.
- Stroke
- Brain fluid leak (CSF leak)
- Small risk of significant neurological injury causing paralysis, coma or death.
- Cosmetic defect
- Skin numbness or pain
Specific Risks of Craniotomy
The specific risks depend on the type of the procedure that is being performed. Removing a tumour has different risks to draining a blood clot. Dr Oehme will explain in detail the specific risks of the procedure you are having. Alternatively the specific risks of cranial procedures are discussed in the following information pages.
Craniotomy for Meningioma
Craniotomy for Subdural Haematoma
Craniotomy for Brain Tumour
Craniotomy for Chiari Malformation - Posterior Fossa Decompression
Craniotomy for Trigeminal Neuralgia- Microvascular Decompression (MVD)
Ventriculoperitoneal Shunt - VP Shunt