Craniotomy

A craniotomy is a neurosurgical operation in which a section of the skull is temporarily removed so that surgeons can access the brain.

Once the bone flap (the removed piece of skull) is lifted away, the surgeon works on the brain tissue, blood vessels, or surrounding membranes to treat the specific problem. When the work is finished, the bone flap is secured back in place using small titanium plates or sutures, and the scalp is closed over it. The skull heals around the plates over the following weeks and months.

A craniotomy is used when a condition inside the skull requires direct surgical treatment. Doctors recommend it when less invasive options are not sufficient to safely treat the problem.

• Brain tumors — both tumors that start in the brain and tumors that have spread from elsewhere in the body
• Brain aneurysm (a bulge in a blood vessel that may rupture) — to clip the vessel and prevent bleeding
• Arteriovenous malformation or AVM (an abnormal tangle of blood vessels in the brain) — to remove or disconnect it
• Intracerebral hemorrhage (bleeding inside the brain) — to remove the blood clot and relieve pressure
• Traumatic brain injury — to remove bone fragments, foreign objects, or blood clots caused by a head injury
• Brain abscess (a pocket of infection inside the brain) — to drain pus and relieve pressure
• Epilepsy (recurrent seizures) that does not respond to medication — to remove the area of brain triggering the seizures
• Hydrocephalus (a build-up of fluid around the brain) in some cases, when other procedures are not appropriate
• Certain infections or inflammatory conditions affecting the brain's covering membranes

A craniotomy is not always the right choice. Doctors will usually look for alternative approaches in the following situations.

• The patient's overall health is too poor to safely tolerate general anaesthesia (the state of being fully unconscious during surgery)
• The area of the brain affected is too deep or too close to vital structures, making open surgery riskier than other techniques
• Radiosurgery (a non-cutting radiation treatment) or catheter-based techniques can achieve the same result with less risk
• The condition is expected to respond well to medication or other non-surgical treatment

A craniotomy is a major operation on a delicate organ, and like any brain surgery it carries meaningful risks that your surgical team will discuss with you in detail beforehand.

• Swelling of the brain (cerebral oedema) in the days after surgery, which can cause headache, confusion, or worsening of symptoms
• Bleeding (haemorrhage) inside the skull during or after the operation
• Infection of the wound, the bone flap, or the membranes surrounding the brain (meningitis)
• Seizures (fits), which may be new or temporarily worsen existing epilepsy
• Neurological deficits — new weakness, numbness, speech difficulty, or vision changes, depending on which part of the brain was operated on
• Blood clots forming in the legs (deep vein thrombosis) or travelling to the lungs (pulmonary embolism)
• Stroke (interruption of blood supply to part of the brain) during or shortly after surgery
• Cerebrospinal fluid leak (CSF leak) — a leakage of the fluid that cushions the brain, sometimes through the wound or the nose
• Reactions to general anaesthesia, including breathing difficulties, nausea, or, very rarely, allergic reactions
• Bone flap complications — the replaced piece of skull may fail to heal, become infected, or, rarely, require permanent removal

Careful preparation before a craniotomy helps reduce risk during the operation. The team will guide you through each step, but the following gives a general picture of what to expect.

Before the day of surgery, patients are usually asked to stop blood thinners (medicines that prevent clotting) and certain anti-inflammatory painkillers for a period that the surgeon specifies. Smoking impairs healing and blood flow to the brain, so most teams ask patients to stop as far in advance as possible. Alcohol thins the blood and interacts with anaesthesia, so it is usually avoided in the days before surgery. On the night before and the morning of surgery, patients are typically asked to fast — eating and drinking nothing — for several hours, to make anaesthesia safer.

A number of tests are usually done in the days before the operation to help plan the surgery and check that the patient is fit to undergo it.

• MRI or CT scan of the brain — to give the surgeon a detailed map of the area to be operated on
• Cerebral angiography (an X-ray of the brain's blood vessels using a dye injected into an artery) — if blood vessels are involved
• Blood tests — to check clotting, kidney function, blood count, and blood group
• Electrocardiogram or EKG — to assess heart health before general anaesthesia
• Chest X-ray — in some patients, to check lung health
• Neuropsychological assessment (tests of memory, language, and other brain functions) — before surgery on areas near speech or movement, to create a baseline for comparison after surgery

On the day of surgery, the steps typically follow this order, though the exact sequence varies between hospitals and individual cases.

• 1. The patient is admitted and identity and consent documents are confirmed.
• 2. A nurse shaves or trims hair in the area where the incision will be made.
• 3. An intravenous (IV) line is placed in the arm to deliver fluids and medicines.
• 4. In some cases, a stereotactic frame or navigation markers are attached to the head — these act like a GPS system to guide the surgeon to the exact spot in the brain.
• 5. The patient is taken to the operating theatre and general anaesthesia is given. In rare cases, an 'awake craniotomy' is performed: the patient is kept awake during part of the procedure so surgeons can map brain functions such as speech — the brain itself feels no pain.
• 6. The surgical team positions the head in a frame that holds it completely still.
• 7. The scalp is cleaned and a surgical incision is made, usually following the natural hairline where possible.
• 8. The scalp is folded back to expose the skull.
• 9. Small holes (called burr holes) are drilled into the skull, and a special saw is used to cut between them, freeing the bone flap.
• 10. The bone flap is carefully lifted away and kept sterile for later replacement.
• 11. The dura mater (the tough membrane covering the brain) is opened to expose the brain.
• 12. The surgeon carries out the planned procedure — removing a tumour, clipping an aneurysm, draining a clot, or another intervention.
• 13. The dura mater is closed with fine stitches.
• 14. The bone flap is replaced and secured with small titanium plates and screws.
• 15. The scalp is closed with stitches or staples.
• 16. The patient is moved to the recovery room and then, in most cases, to an intensive care unit (ICU) for close monitoring.

Recovery after a craniotomy is a gradual process that varies widely depending on which part of the brain was operated on, the reason for surgery, and the patient's overall health. Most patients spend the first day or more in the ICU, where the nursing team monitors brain function, blood pressure, and oxygen levels very closely. The total hospital stay is usually several days, but this can be longer if complications arise or if intensive rehabilitation is needed.

• ICU monitoring: nurses check pupil responses, limb strength, speech, and consciousness level frequently in the first hours and days after surgery.
• Pain and swelling: headache and scalp tenderness are common in the early days; the team will manage this with appropriate pain relief.
• Wound care: the surgical wound must be kept clean and dry; staples or stitches are usually removed after about a week to ten days, though the exact timing depends on healing.
• Activity restrictions: patients are generally advised to avoid heavy lifting, strenuous exercise, and bending sharply at the waist for several weeks while the skull heals.
• Driving: driving is not permitted until the medical team confirms it is safe — this is often a matter of months rather than weeks, particularly if seizures occurred.
• Return to work and daily life: this depends heavily on the type of work and what was treated; some patients return to light activity within weeks, while others require months of rehabilitation.
• Rehabilitation: depending on any new neurological deficits (such as weakness or speech changes), physiotherapy (physical therapy), speech therapy, or occupational therapy may be arranged.
• Medications: the team will specify which medicines — such as anti-seizure drugs, steroids to reduce swelling, or antibiotics — to continue after discharge, and for how long.
• Follow-up imaging: MRI or CT scans are usually scheduled at regular intervals after surgery to check healing and monitor the treated condition.
• Warning signs to act on promptly: sudden severe headache, fever, redness or discharge from the wound, new weakness or confusion, or a seizure should prompt immediate medical attention.