Cranioplasty

Cranioplasty is surgery to repair a missing, sunken or damaged area of the skull. It also may be done to improve the shape of the skull. The skull protects the brain and helps give the head its shape. Cranioplasty also may be called skull reconstruction.

Cranioplasty may be done after part of the skull has been removed during another surgery. It also may be done to repair a skull defect caused by an injury, an infection, a condition present at birth or removal of a tumor involving the skull.

The surgery may use the person's own skull bone, also called autologous bone. This piece of bone is called a bone flap. If the bone flap cannot be used, the surgeon may use an implant made from another material such as plastic or metal.

Cranioplasty is usually a planned surgery. It may be done after brain swelling has improved, an infection has cleared or the healthcare team decides the skull can be repaired safely.

What is the difference between a cranioplasty, craniotomy and craniectomy?

Cranioplasty, craniotomy and craniectomy are related skull surgeries. The main difference is what happens to the piece of skull bone.

• A craniotomy is surgery to open the skull. During a craniotomy, the surgeon removes a piece of skull bone, called a bone flap, to reach the brain. In many craniotomy surgeries, the bone flap is put back in place before the surgery ends.

• A craniectomy also involves removing a piece of skull bone. But with a craniectomy, the bone is not put back right away. This procedure may be done when the brain needs more room to swell after a head injury, stroke, bleeding, infection or another brain condition. Leaving the bone off for a time can help reduce pressure inside the skull.

  If the removed bone may be used later, it can be stored in a freezer or bone bank. Or it may be placed under the skin of the abdomen. This is sometimes described as storing bone "in the stomach," but the bone is placed under the skin, not inside the stomach.

• A cranioplasty is surgery to repair an opening left in the skull or missing area of the skull. Cranioplasty may be done after brain swelling has improved and the healthcare team decides it is safe to repair the skull.

  The name of a cranioplasty may describe where the repair is done. For example, it may refer to the front of the skull, called a frontal cranioplasty, or the bottom part of the skull, called a skull base cranioplasty.

In simple terms, a craniotomy opens the skull and usually closes it during the same surgery. A craniectomy removes part of the skull and leaves it off for a time. A cranioplasty repairs an opening later.

Cranioplasty is done to repair or reshape part of the skull. It may be used when an area of the skull is missing, sunken, damaged, overgrown or shaped differently than expected. This can happen after surgery, injury, infection, a condition present at birth, a bone condition such as fibrous dysplasia or removal of a tumor involving the skull.

Cranioplasty may be done to:

• Repair the skull after a craniectomy. A craniectomy removes part of the skull and leaves it off for a time, often to give the brain room to swell. After craniectomy, the area where bone is missing may look sunken or uneven, especially after swelling has improved. Cranioplasty may be done later to repair the opening and restore the shape of the head.
• Repair a defect after brain tumor surgery, infection or injury. Cranioplasty may be used when skull bone has been removed or affected because of a tumor, infection, injury or problem with a previous bone flap.
• Reshape the skull in some children. Some children have cranioplasty as part of treatment for craniosynostosis, a condition in which skull sutures close too early and affect skull growth.
• Improve the way cerebrospinal fluid moves around the brain. Cerebrospinal fluid is the clear fluid that cushions the brain and spinal cord. Repairing the skull may help support more typical fluid flow and pressure around the brain.

Cranioplasty is different from treating a depressed skull fracture. A depressed skull fracture is a break in the skull in which bone is pushed inward. That type of fracture is usually treated as part of injury care.

Cranioplasty is common, but it is still brain and skull surgery. Risks depend on the reason for surgery, the size and location of the skull defect, the material used, the condition of the skin and soft tissue, and other health conditions.

Possible risks include:

• Infection.
• Bleeding.
• Blood clots.
• Fluid collecting under the scalp or around the brain.
• Cerebrospinal fluid leak.
• Seizures.
• Hydrocephalus, which is too much cerebrospinal fluid in spaces within the brain.
• Wound healing issues.
• Bone flap resorption, which means the replaced bone breaks down or shrinks over time.
• Implant movement, loosening or exposure that may require another surgery.

Before cranioplasty, your healthcare team reviews your health, any prior surgery and your imaging. You may need a CT scan. Sometimes 3D imaging is used to plan the repair or create a custom implant.

Your healthcare team may check to see that:

• Brain swelling has improved.
• There is no active infection.
• The incision from earlier surgery has healed.
• Your blood pressure, breathing and overall health are stable enough for surgery.
• The saved bone flap or custom implant is ready.
• Your medicines have been reviewed, including blood thinners.

Cranioplasty may be delayed if there is infection, ongoing swelling, unstable health or other concerns that make surgery less safe. Waiting can be an active part of care. It gives the healthcare team time to make sure the repair is done when the risks are lower.

Ask your healthcare team:

• What material will be used for the repair?
• Will my own bone be used, or will I need an implant?
• Is the implant custom-made?
• What are the main risks in my situation?
• How long might I be in the hospital?
• What symptoms should I watch for after I go home?
• What follow-up imaging or visits will I need?

Before the procedure

Cranioplasty is done in a hospital. You typically receive general anesthesia, which means you are asleep and do not feel pain during surgery.

The healthcare team may give antibiotics before cranioplasty to lower the risk of infection. The healthcare team may trim or shave hair near the surgery area. The team also cleans the skin with an antiseptic solution and positions you so the surgeon can reach the skull defect.

During the procedure

The surgeon usually uses the previous incision when possible. The scalp and soft tissues are carefully moved aside to reach the skull defect. Scar tissue may make this part of the procedure delicate.

The surgeon then fits the bone flap or implant into the skull defect. The repair is secured to the surrounding skull, often with small plates, screws or other fixation devices.

The repair may use the person's own stored bone flap. If that bone can't be used, the surgeon may use an implant. Implant materials may include titanium, polymethylmethacrylate (PMMA), hydroxyapatite or polyetheretherketone (PEEK). These materials can be shaped or custom-made to fit the skull defect. PEEK is a strong medical plastic that does not usually interfere with imaging the way some metals can. Custom implants often are made using CT images and computer planning.

Sometimes the healthcare team needs to manage fluid around the brain during surgery. In some cases, a person may need a shunt. A shunt is a tube that helps move extra cerebrospinal fluid away from the brain to another part of the body.

After the procedure

After surgery, you are moved to a recovery area. Some people spend time in an intensive care unit so the care team can watch neurological status closely. Others may go to a non-intensive hospital unit after imaging and recovery from anesthesia.

You may have:

• A head dressing.
• A drain under the scalp to remove extra fluid.
• Pain medicine.
• Antibiotics.
• A CT scan after surgery.
• Neurological checks to monitor how your brain and nervous system are working.

How long you stay in the hospital depends on the reason for surgery, the type of repair and how recovery goes. Your healthcare team will give you instructions about incision care, activity, medicines and follow-up visits.

Contact your healthcare team right away if you have:

• Fever.
• New or worsening headache.
• Swelling, drainage, opening or a change in skin color at the incision. This change may be a shade of red, purple or brown depending on your skin color.
• New weakness, numbness, confusion, seizure or trouble speaking.
• Clear fluid leaking from the incision.
• Greater swelling of the scalp or face.

Cranioplasty can restore skull protection and improve the shape of the head. It also may help improve cerebrospinal fluid movement and pressure around the brain. Some studies have reported neurological improvement after cranioplasty, but outcomes vary. Recovery depends on the original brain condition, the reason for craniectomy, the timing of repair and overall health.

A cranioplasty is not usually the main factor that determines life expectancy. Life expectancy depends more on the underlying condition, such as tumor type, stroke, injury, bleeding, infection or other health concerns. Your healthcare team can explain what cranioplasty is expected to do in your situation and what it cannot change.

If your own bone is used, it may heal well. But in some cases, the bone flap can resorb. This means it breaks down or shrinks over time.  If this happens, and protection or appearance is affected, another surgery or a synthetic implant may be needed.

No single cranioplasty material is best for every person. PEEK, titanium, PMMA, hydroxyapatite and a person's own bone each have possible pros and cons. The right choice varies by person.