Craniectomy: What It Is, Why It's Done, Recovery and Risks
Updated: 6 days ago
Written and medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: October 2026 · How we review
Quick Answer: What is a craniectomy?
A craniectomy is a major, usually emergency, brain surgery in which a surgeon removes a piece of the skull and leaves it out to relieve dangerous swelling, pressure or bleeding on the brain. It is often done after a traumatic brain injury or stroke. The bone is replaced later in a second surgery called a cranioplasty. [1]
What the research says
For severe brain injury with uncontrolled pressure, surgery cut the death rate — but more survivors lived with disability. In a trial of 408 people with traumatic brain injury and dangerously high brain pressure, deaths at 6 months were 26.9% after craniectomy vs. 48.9% with medical care alone. However, more surgical patients survived in a vegetative state (8.5% vs. 2.1%) or with severe disability, while rates of good recovery were similar between groups. (Hutchinson et al., N Engl J Med, 2016)
For a large, swelling stroke, early surgery more than doubled survival. A pooled analysis of three trials (93 adults aged 18–60) found that surgery within 48 hours of a major middle cerebral artery stroke raised survival from 29% to 78%, and 75% vs. 24% avoided the most severe disability or death at 1 year. (Vahedi et al., Lancet Neurol, 2007)
For acute subdural hematoma, leaving the bone out was not better than putting it back. In a trial of 450 people, disability and quality of life at 12 months were similar after craniectomy and craniotomy (deaths 32.2% vs. 30.2%). Craniectomy meant fewer repeat operations (6.9% vs. 14.6%) but more wound complications (12.2% vs. 3.9%). (Hutchinson et al., N Engl J Med, 2023)
Key takeaways
A craniectomy removes part of the skull and does not put it back during the same operation.
It treats swelling, high pressure or bleeding inside the skull, most often after a head injury or stroke.
Surgery usually takes 3 to 5 hours and is followed by a stay in intensive care.
You wear a protective helmet until a second surgery (cranioplasty) closes the opening.
The skull area heals in about 1 to 2 months, but full recovery and rehab can take months to years.
Craniectomy at a glance
Question | Short answer |
What is removed? | A section of the skull bone |
Is the bone replaced right away? | No — it is replaced later during a cranioplasty |
Main goal | Relieve swelling, pressure or bleeding on the brain |
Common causes | Traumatic brain injury, stroke, blood clot, hematoma |
Is it planned or urgent? | Usually an emergency |
Surgery length | About 3 to 5 hours (sometimes longer) |
First stop after surgery | Intensive care unit (ICU) |
Skull area healing | About 1 to 2 months |
Overall recovery | Months to years, often with rehabilitation |
What is a craniectomy?
A craniectomy is brain surgery in which a surgeon removes part of the skull to reach the brain and does not replace it during the same operation. The missing piece is put back at a later date in a follow-up surgery called a cranioplasty. [1]
Doctors often call it a decompressive craniectomy, because the goal is to "decompress" the brain — giving it room to swell without being crushed against the skull.
There is very little space between the brain and the skull. When swelling, blood or extra fluid builds up, pressure rises fast. That pressure can damage brain tissue or become life-threatening. [1]
Why is a craniectomy done?
A craniectomy is done to relieve swelling, high pressure or bleeding on the brain that could otherwise cause brain damage or death. Removing a piece of skull lets the brain expand outward instead of being squeezed. [1]
The surgery treats three main problems:
Swelling of brain tissue
High pressure inside the skull (intracranial pressure or intracranial hypertension)
Bleeding (hemorrhage) or a buildup of extra fluid
These problems are commonly caused by:
Cause | How it raises pressure on the brain |
Injured brain tissue swells and may bleed | |
A large stroke can cause major swelling; a hemorrhagic stroke adds blood inside the skull | |
A clot can block blood flow, leading to tissue damage and swelling | |
A pool of blood takes up space and presses on the brain |
What is the difference between a craniectomy and a craniotomy?
The difference between a craniectomy and a craniotomy is whether the piece of skull goes back in at the end of surgery. In a craniotomy, the bone flap is replaced during the same operation; in a craniectomy, it is left out so the brain has room to swell. [1][4]
Feature | Craniectomy | Craniotomy |
Skull piece removed? | Yes | Yes |
Bone put back at end of surgery? | No | Yes |
Main purpose | Relieve pressure from swelling or bleeding | Access the brain, then close the skull |
Helmet needed afterward? | Yes, until cranioplasty | Usually no |
Second surgery needed? | Yes — cranioplasty | Not for the bone |
How do you prepare for a craniectomy?
Most people cannot prepare for a craniectomy because it is usually done as emergency surgery. Even so, the care team still needs a few key checks before operating. [1]
Before surgery, the team typically performs:
A physical exam
Blood tests
Imaging tests, such as an X-ray, MRI, CT scan, PET scan or angiography
If the surgery is not an emergency, the surgeon may also:
Ask you to stop certain medicines, especially blood thinners
Recommend antibiotics or antiseizure medications (anticonvulsants)
Ask you not to eat before surgery
What happens during a craniectomy?
During a craniectomy, the surgeon opens the scalp, removes a section of skull, treats the cause of the pressure, and closes the skin without putting the bone back. An anesthesiologist first gives anesthesia so you do not feel pain. [1]
Depending on the type of craniectomy, you may be fully asleep — or awake, so the surgeon can check your thinking and responses during the operation. [1]
Step by step, the surgeon will:
Shave and clean the area of the head near the incision site.
Make an incision in the skin and move muscle and tissue aside.
Drill small holes in the skull, then cut between them to lift out a piece of bone.
Treat the cause of the swelling, pressure or bleeding.
Cover the opening in the skull with a mesh material.
Close the incision with staples or stitches after moving the skin and muscle back into place.
How long does a craniectomy take?
A craniectomy usually takes between 3 and 5 hours. Some operations take longer, depending on why the surgery is needed. [1]
What is a suboccipital craniectomy?
A suboccipital craniectomy is a type of craniectomy that removes bone from the base of the skull, at the back of the head near the neck. [1]
What happens after a craniectomy?
After a craniectomy, you are moved to an intensive care unit (ICU), where the team closely monitors your vital signs and watches for any new bleeding or swelling in the brain. [1]
Because part of the skull is missing, you need to wear a helmet to protect the brain from injury. [1]
What happens to the removed bone?
The surgeon may save the original piece of skull to put back later during a cranioplasty.
Or the surgeon may later use a metal plate or synthetic material instead. [1]
During the hospital stay:
Rest as much as possible.
Keep your head upright rather than lying flat.
Expect follow-up appointments after discharge to make sure you are healing as expected. [1]
How long is recovery after a craniectomy?
Recovery after a craniectomy depends on why the surgery was done and how extensive it was. On average, the skull area heals in about 1 to 2 months, but overall recovery can take years. [1]
A few things affect the timeline:
The second surgery. The cranioplasty to replace the skull piece adds more recovery time.
Rehabilitation. Extended rehab is common, and some people need lifelong care.
The original cause. People who needed surgery after a stroke may be less likely to fully recover. [1]
When can you return to normal activities after a craniectomy?
You can return to normal activities after a craniectomy only when your surgeon says it is safe — and for some activities, that may not happen. Until then, avoid: [1]
Avoid until cleared | Why it matters |
Walking without help | Balance and coordination may be affected, raising fall risk |
Heavy lifting | Strain can be unsafe while healing |
Driving | Reaction time, vision or thinking may be affected |
Manual labor | Physical strain and risk of head injury |
Exercise | Wait for your surgeon's approval |
What are the benefits of a craniectomy?
The main benefit of a craniectomy is treating the cause of dangerous pressure on the brain, which can reduce brain damage and life-threatening complications. [1]
How successful is a craniectomy?
The success of a craniectomy depends on many factors, including your general health and the reason for surgery. Results improve with long-term neurological care and rehabilitation. [1]
Many people recover from a craniectomy, but side effects are possible. Some people may not fully recover — especially when the surgery was needed because of a stroke. [1]
What are the risks of a craniectomy?
The risks of a craniectomy include bleeding, infection, seizures, ongoing high pressure in the skull and brain damage, and some of these complications can be fatal. [1]
Possible complications include:
Because falls are more likely after surgery, it is important to rest until you can walk and move safely on your own. Your surgeon will tell you when you can start moving again. [1]
When should you call a doctor after a craniectomy?
You should call your doctor after a craniectomy if you develop a fever, severe pain or swelling, severe headaches, or changes in thinking, mood or behavior. Some symptoms need emergency care right away. [1]
Contact your healthcare provider if you have:
A fever
Severe pain and swelling
Changes in thinking (cognitive function), mood or behavior
Severe headaches
Call emergency services immediately if you have:
A seizure
Difficulty breathing
Signs of a stroke
Conclusion
A craniectomy is a major, life-saving surgery that relieves dangerous pressure on the brain from swelling or bleeding — most often after a traumatic brain injury or stroke. Removing part of the skull gives the brain room to swell, and the bone is replaced later during a cranioplasty.
The incision can heal within weeks and the skull area within a month or two, but most people need months to years of rehabilitation and lifelong follow-up care. Many people make a full recovery, while others live with lasting effects. Research shows the surgery can sharply improve survival in certain situations, but it does not guarantee a return to full function — which is why honest conversations with the care team matter.
Supporting someone through a craniectomy? Save or share this guide so you can bring it to your next appointment, and talk with the neurosurgery team about the reason for surgery, the cranioplasty plan and what rehabilitation will look like. For more on the conditions that lead to this surgery, read our guides to traumatic brain injury, MCA stroke and epidural hematoma.
FAQ
Is a craniectomy a major surgery?
Yes. A craniectomy is major brain surgery that removes part of the skull, usually takes 3 to 5 hours, and is followed by a stay in intensive care. [1]
Why is the skull piece not put back right away?
The skull piece is left out so the swollen brain has room to expand without being squeezed. It is replaced later in a separate surgery called a cranioplasty. [1]
Why do you need to wear a helmet after a craniectomy?
You need a helmet after a craniectomy because part of the skull is missing, leaving the brain unprotected. The helmet guards against injury until the opening is closed. [1]
What happens to the bone that was removed?
The surgeon may save the removed bone to put back during a cranioplasty, or later use a metal plate or synthetic material instead. [1]
How long does it take for the skull to heal after a craniectomy?
The skull area usually heals in about 1 to 2 months, but overall recovery can take years, especially with a second surgery and rehabilitation. [1]
Do people survive a craniectomy?
Yes, many people survive a craniectomy and make a full recovery, while others survive with side effects. Survival depends on the reason for surgery and general health. [1]
Can you be awake during a craniectomy?
Yes, for some types of craniectomy you may be awake so the surgeon can check your thinking during the operation; for others, you are fully asleep. [1]
Can I drive after a craniectomy?
You should not drive after a craniectomy until your surgeon says it is safe. Heavy lifting, manual labor, exercise and walking without help should also wait. [1]
What is the difference between a craniectomy and a cranioplasty?
A craniectomy removes part of the skull to relieve pressure on the brain, while a cranioplasty is the later surgery that replaces or repairs that missing piece. [1]
How long will I stay in the hospital after a craniectomy?
After surgery, you are cared for in the intensive care unit (ICU) and then on a regular hospital floor. The total stay depends on why the surgery was done and how you recover, and your care team will guide you.
Related Reading
Craniotomy: What It Is, Why It's Done, Types, Steps and Recovery explains brain surgery where the skull piece is put back right away.
Cranioplasty: What It Is, How It's Done, Recovery Time and Risks describes the later surgery that repairs the skull after a craniectomy.
Traumatic Brain Injury: Symptoms, Emergency Signs, Diagnosis and Recovery covers head injury symptoms, emergency signs and how doctors diagnose them.
Hemorrhagic Stroke: Emergency Recognition and Critical Care explains bleeding strokes, warning signs and emergency hospital care.
References
Cleveland Clinic. Craniectomy: What It Is, Procedure, Recovery & Risks. Cleveland Clinic. Last updated April 13, 2023. https://my.clevelandclinic.org/health/treatments/24901-craniectomy
Hutchinson PJ, Kolias AG, Timofeev IS, et al. Trial of decompressive craniectomy for traumatic intracranial hypertension. N Engl J Med. 2016;375(12):1119-1130. PMID 27602507. https://doi.org/10.1056/NEJMoa1605215
Vahedi K, Hofmeijer J, Juettler E, et al. Early decompressive surgery in malignant infarction of the middle cerebral artery: a pooled analysis of three randomised controlled trials. Lancet Neurol. 2007;6(3):215-222. PMID 17303527. https://doi.org/10.1016/S1474-4422(07)70036-4
Hutchinson PJ, Adams H, Mohan M, et al. Decompressive craniectomy versus craniotomy for acute subdural hematoma. N Engl J Med. 2023;388(24):2219-2229. PMID 37092792. https://doi.org/10.1056/NEJMoa2214172
National Institute of Neurological Disorders and Stroke. Traumatic Brain Injury (TBI). NINDS Health Information. Last reviewed March 13, 2026. https://www.ninds.nih.gov/health-information/disorders/traumatic-brain-injury-tbi
Disclaimer
This article is for educational purposes only and is not a substitute for professional medical advice, diagnosis or treatment. Always follow the instructions of your neurosurgery and care team. If you or someone you care for has a seizure, trouble breathing or signs of a stroke, call your local emergency number right away.
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