After a severe brain injury, stroke, or bleed, surgeons sometimes remove a section of skull so the brain has room to swell safely. This page walks through why that happens, what it's like to live with a skull defect in the meantime, and the later surgery, cranioplasty, that reconstructs it.
Two different operations, done at two different times, for two different reasons.
The skull is a rigid, closed box. Under normal conditions that's a good thing: it protects the brain. But when the brain swells, or when blood collects inside the skull after an injury, stroke, or hemorrhage, that same rigid box becomes a problem: there is nowhere for the extra volume to go, so pressure inside the skull (intracranial pressure) climbs. If it climbs high enough for long enough, the brain's own blood supply can be choked off, causing further, often irreversible, damage.
A craniectomy removes a section of skull bone and, unlike a routine craniotomy, does not put it back right away. That missing piece gives the swollen or bleeding brain somewhere to expand that isn't inward against itself. It is a temporary, deliberately incomplete operation: the goal in the moment is survival and protecting brain tissue, not a finished result.
Cranioplasty is the second operation that completes the story: once the swelling has resolved and the patient has recovered, surgeons reconstruct the missing section of skull, using either the patient's own stored bone flap or a custom synthetic implant. Brown's Neuroplastic Center brings neurosurgeons and plastic and reconstructive surgeons together specifically for this decision, since the best material and timing choice is rarely obvious and often benefits from more than one specialist's perspective.
Select a cause to see how it can lead to dangerously high pressure inside the skull.
Select a step to learn what happens and why.
When part of the skull has been removed to relieve pressure on the brain, that part of the brain is protected only by skin. In some cases, over time, ordinary atmospheric pressure can push the flap inward, causing symptoms. Learn here about specific symptoms that may arise in certain cases.
In rare, severe cases, the pressure gradient across the defect becomes strong enough that the brain itself shifts inward through the opening, called paradoxical herniation. This can cause rapid neurological decline and is treated as an emergency. It's part of why the team watches for syndrome of the trephined closely rather than waiting for it to become severe.
There is no single "best" material for every patient. Select an option to see how it compares.
Timing is individualized, but tends to fall into three general windows.
May allow earlier relief from syndrome of the trephined symptoms and a quicker return to normal activity, but carries a somewhat higher risk of fluid buildup (hydrocephalus) if the brain hasn't fully settled.
Swelling has usually resolved and the scalp has fully healed, without waiting so long that the soft tissue has tightened firmly over the open defect.
Infection, wound healing problems, or other medical issues can delay surgery. Timing is always adjusted around what's safest for that patient, not a fixed calendar date.
Several factors shape when cranioplasty happens and which material is used. Select one to learn more.
A sunken temple is not the same problem as a skull defect, and fixing the bone alone does not fix it.
The temporalis muscle is a fan-shaped chewing muscle that sits just under the skin at the temple, directly over the bone that many cranial approaches need to reach. During surgery, it is often detached, retracted, or thinned to expose the skull, and it does not always heal back to its original bulk or position. The result, in a large share of patients after this kind of approach, is a visible flattening or dent at the temple, called temporal hollowing, that persists even after cranioplasty has fully reconstructed the bone underneath it.
Because this is a muscle and soft-tissue problem rather than a bone problem, Brown's Neuroplastic Center approaches it as a true team decision between neurosurgery and plastic and reconstructive surgery, matching several dedicated techniques to how mild or pronounced the hollowing is.
The patient's own fat is harvested from elsewhere in the body and injected to fill mild-to-moderate hollowing. It's a relatively minor procedure, though results can soften somewhat over time and occasionally need a touch-up.
The temporalis muscle is surgically returned to its natural position, often combined with cranioplasty in the same operation. This addresses the underlying cause rather than just adding volume on top of it.
A shaped implant, sometimes built directly into the cranioplasty implant itself, restores lost temple volume. This is often the most reliable option for more pronounced or long-standing hollowing.
Both operations are generally well tolerated, but all neurosurgical procedures carry risks.
Craniectomy and cranioplasty care at Brown Neurosurgery draws on both neurotrauma neurosurgery and the Neuroplastic Center's plastic and reconstructive surgery expertise.