Seizures After Brain Surgery: Causes and Management

Seizures occur in roughly 3 to 15 percent of patients after craniotomy, depending on the type of surgery and the underlying condition being treated. They can happen within hours of waking from anesthesia or surface weeks to months later, and the causes range from direct irritation of brain tissue during the operation to metabolic shifts, swelling, and residual disease. Understanding what drives postoperative seizures and how they are managed matters because their presence can reshape recovery timelines, medication choices, and everyday decisions like when you can safely drive again.

How Common Are Postoperative Seizures

The numbers vary widely based on what the surgery was for. In a retrospective study of craniotomy patients across mixed diagnoses, about 4 percent experienced early seizures (within the first week) and another 5 percent developed delayed seizures.¹ For brain tumor resections specifically, one study found that about 5 percent of patients had at least one seizure in the early postoperative window, and half of those went on to seize again within a month.² A separate analysis of primary brain tumors reported a 14 percent post-craniotomy seizure rate.³

Meningioma surgery offers a useful window into how the rates split by timing. A meta-analysis covering over 4,000 meningioma patients found early postoperative seizures in about 6 percent and late postoperative seizures in about 14 percent.⁴ Among those who seized at all, roughly 57 percent did so in the first week and 43 percent had their first seizure after that seven-day mark.⁵ So while early seizures get more attention in the acute recovery setting, late-onset seizures are far from rare and actually outnumber early ones in some patient populations.

Early Versus Late Seizures and Why the Distinction Matters

Neurosurgeons typically draw the line at seven days after surgery. Early postoperative seizures are thought to result from acute, often reversible factors: direct tissue handling during the operation, transient swelling around the surgical cavity, small bleeds at the resection margin, or metabolic disturbances in the first few days. Late postoperative seizures, by contrast, tend to reflect more durable changes in the brain, including scar formation (gliosis), reorganization of neural circuits around the surgical site, or ongoing disease like residual tumor.

The practical importance of this split is that early seizures do not always mean you will develop ongoing epilepsy, while late seizures are more strongly associated with it. In the craniotomy cohort study mentioned above, all patients who had delayed postoperative seizures went on to develop epilepsy, compared with about 43 percent of those who seized early.¹ Both early and late seizures were significant risk factors for developing epilepsy, but delayed seizures carried a particularly high odds ratio. This does not mean every person with an early seizure is in the clear, but it shifts how aggressively and for how long doctors manage the situation.

What Raises the Risk

Several factors consistently show up as predictors of postoperative seizures across studies. They cluster into patient-related, tumor-related, and surgical factors.

Tumor and Lesion Characteristics

Where in the brain the tumor sits matters more than almost anything else. Tumors in or near the cortex, particularly in the frontal lobe and the central region (the strip of brain controlling movement and sensation), carry substantially higher seizure risk. One large study of 678 brain tumor patients found that tumors in the central lobe had nearly five times the seizure prevalence compared with other locations, and tumors in the precentral gyrus were associated with seizures in every single patient studied.⁶ Conversely, tumors located deeper in the brain or extending into subcortical structures were tied to lower seizure risk in the same analysis.

Tumor grade plays a role too, but in a counterintuitive direction. Low-grade gliomas (slower-growing tumors) are more likely to cause preoperative seizures than aggressive high-grade tumors, likely because they grow slowly enough for surrounding neurons to become chronically irritated rather than destroyed. For postoperative seizures, though, one study found higher-grade tumors and complete resection were risk factors for surgery-related seizures, along with older age.⁷ Having seizures before surgery also roughly doubled the odds of having them afterward.⁸

Type of Surgery

Not all brain operations carry equivalent seizure risk. Craniotomy, which involves removing a section of skull to access the brain directly, is associated with higher seizure rates than less invasive approaches. A study comparing surgical techniques for chronic subdural hematomas found a postoperative seizure rate of about 12 percent for craniotomy, versus roughly 4 percent for burr hole evacuation.⁹ Adding middle meningeal artery embolization to a craniotomy did not meaningfully lower that rate.

Awake craniotomy, used when tumors sit near areas controlling speech or movement, introduces a distinct concern: intraoperative seizures triggered by direct electrical stimulation of the brain during mapping. In one series of 109 awake surgery patients, about 8 percent experienced stimulation-related seizures during the operation itself.³ Most of those patients had preexisting seizure histories.

Metabolic Triggers

Brain surgery can destabilize the body’s electrolyte balance, and low sodium (hyponatremia) is a particularly common culprit. After craniotomy, sodium levels can drop due to fluid shifts, hormonal changes involving antidiuretic hormone, or the stress response to surgery. In children undergoing brain tumor surgery, 21 percent of those who developed hyponatremia experienced seizures.¹⁰ Low sodium lowers the threshold for neurons to fire abnormally, meaning it can provoke seizures even in patients who would otherwise be at low risk.¹¹ This is one reason neurosurgical teams monitor blood chemistry closely in the days after surgery and correct electrolyte abnormalities aggressively.

Seizures After Vascular Malformation Surgery

Arteriovenous malformations (AVMs) deserve their own discussion because seizure dynamics differ from tumor cases. AVMs are tangles of abnormal blood vessels in the brain, and about 30 percent of patients with certain types have seizures before any surgical intervention.¹² The good news is that complete surgical removal tends to produce excellent seizure outcomes. In that same series of 440 patients, 96 percent achieved seizure freedom or had at most a single postoperative seizure.

The flip side is the risk of new-onset epilepsy in patients who never had seizures before surgery. A national database study of 536 patients who underwent AVM resection without a prior seizure history found that about 18 percent developed new epilepsy afterward, with a one-year cumulative incidence of roughly 14 percent.¹³ AVMs with blood supply from deep perforating arteries were linked to higher postoperative seizure risk, likely because surgery in those locations involves more manipulation of surrounding brain tissue.¹² Various surgical series report long-term seizure freedom rates ranging from roughly 62 to 96 percent, with microsurgery consistently outperforming other AVM treatments in this regard.¹⁴

The Hidden Problem of Nonconvulsive Seizures

Not every seizure involves visible shaking. Nonconvulsive seizures can present as unexplained confusion, staring, subtle twitching, or a failure to wake up as expected after surgery. They are surprisingly common in neurological intensive care settings. One study using continuous EEG monitoring in critically ill patients found that about 21 percent had nonconvulsive seizures, and the vast majority of seizures detected by the monitors were ones that clinical staff could not see at the bedside.¹⁵

This is why expert consensus recommends continuous EEG monitoring for brain-injured patients in the ICU, particularly those with unexplained altered consciousness after surgery.¹⁶ Without that monitoring, nonconvulsive seizures can go undetected for hours or even days, potentially causing additional brain injury in a patient who is already vulnerable.¹⁷ If your family member seems unusually confused or fails to “wake up right” after brain surgery, this is worth raising with the medical team even if there is no obvious convulsive activity.

Antiseizure Medications and the Prophylaxis Debate

One of the most contentious questions in neurosurgery is whether to give antiseizure medications to patients who have never had a seizure, purely to prevent postoperative ones. The answer, perhaps frustratingly, is that the evidence remains thin. A Cochrane systematic review concluded there is simply not enough high-quality evidence to determine whether prophylactic antiseizure drugs reduce or fail to reduce post-craniotomy seizures.¹⁸ Professional guidelines for brain metastases specifically recommend against routine prophylactic antiseizure drugs in patients who have not had seizures, whether or not they undergo surgery.¹⁹

Despite these guidelines, practice varies enormously. A survey of Australian and New Zealand neurosurgeons found that about 36 percent regularly prescribe prophylactic antiseizure medications after craniotomy, while 32 percent do not, and the rest decide case by case.²⁰ The split reflects genuine uncertainty: the theoretical benefit of preventing even one seizure in a freshly operated brain competes with real drug side effects and the absence of strong trial data showing that prophylaxis changes outcomes.

Choosing an Antiseizure Medication

When antiseizure medication is warranted, whether for prophylaxis or to treat a seizure that has already occurred, levetiracetam has become the dominant choice in neurosurgical settings. In one brain tumor surgery series, over 90 percent of patients with new-onset early seizures were treated with levetiracetam.² The shift toward levetiracetam and away from older drugs like phenytoin happened for practical reasons: levetiracetam does not interact with chemotherapy agents or other commonly used medications, does not require blood-level monitoring, and has a more predictable side-effect profile.

A head-to-head comparison of the two drugs found no meaningful difference in seizure prevention rates: one seizure occurred in each group over 90 days of follow-up. But phenytoin caused more side effects including skin rash and low platelet counts, while levetiracetam caused none of those specific problems.²¹ These differences were not statistically significant in the small study, but they align with the broader clinical experience that has driven the shift in practice. Levetiracetam’s main downside is that it can cause irritability and mood changes in some patients, something worth knowing if you or a family member notices personality shifts after starting it.

Tapering Off Medications After Surgery

If you have been seizure-free after surgery, the question of when and whether to stop antiseizure medication inevitably comes up. The evidence on timing is more reassuring than you might expect. A review of clinical experience found that seizure recurrence after planned medication withdrawal was not affected by how long patients stayed on the drugs after surgery. Delaying discontinuation beyond one to two years of complete seizure freedom did not seem to add any protective benefit.²²

In children, some centers begin tapering as early as six months after surgery, provided the child has been seizure-free and their EEG shows no epileptic discharges.²³ Adults typically follow a similar logic, though the timeline can stretch depending on the underlying condition and the surgeon’s comfort level. The taper itself is always gradual: stopping abruptly can trigger breakthrough seizures even in someone who no longer needs the medication.

When Seizures Persist Despite Treatment

For some patients, postoperative seizures are not a one-time event but the beginning of a longer battle. A study following epilepsy surgery patients with recurrent seizures over five years found that about 30 percent eventually achieved complete seizure freedom, another 18 percent had only auras without full seizures, but roughly 22 percent were unimproved at five years.²⁴ The strongest predictors of long-term outcome were where the epilepsy was coming from, what the preoperative MRI showed, and how the patient did in the first year after surgery. Those first twelve months matter: if seizures are well-controlled early, the long-term outlook is substantially better.

For patients with seizures after subdural hematoma surgery, the clinical picture is somewhat different. One study found that seizures and epileptic patterns on EEG after surgery were independently associated with worse functional status at discharge. Reassuringly, though, at follow-up one to six months later, it was the patient’s baseline functional status and consciousness level, not the seizures themselves, that predicted long-term recovery.²⁵ In other words, postoperative seizures in that context are more of a marker of severity than an independent cause of lasting disability.

Pediatric Considerations

Children face their own seizure risk profile after brain surgery. A large study of nearly 6,800 pediatric brain tumor patients found an overall postoperative seizure rate of about 2.8 percent, lower than adult rates in most studies. But age was a powerful predictor: each additional year of age reduced seizure odds by roughly 10 percent, and infants younger than about seven months were at dramatically higher risk, with over 11 times the seizure odds compared with older children.²⁶ Tumors in the upper part of the brain (supratentorial) carried about three times the seizure risk compared with those in the lower, posterior areas where many childhood brain tumors occur.

For parents, these numbers can be alarming, but context helps. The immature brain is generally more excitable than the adult brain, and very young children are more susceptible to the metabolic and electrolyte shifts that surgery provokes. Pediatric neurosurgical teams are well aware of this and typically monitor infants and toddlers more intensively in the postoperative period.

Driving Restrictions and Daily Life

One of the most immediate practical concerns after brain surgery, especially if a seizure has occurred, is when you can get behind the wheel again. Regulations vary by country and even by region, but restrictions are universal. The most common driving restriction after craniotomy reported by Australian and New Zealand neurosurgeons was six months, though opinions varied widely.²⁰ Even for deep brain stimulation, a less invasive procedure, one expert consensus proposed a minimum six-week driving restriction for private license holders, with a longer six-month restriction for commercial drivers, as the risk of adverse events including seizure drops substantially after the first postoperative month.²⁷

If you have had an actual postoperative seizure, the clock on driving restrictions typically resets. Most jurisdictions require a seizure-free interval, commonly three to twelve months depending on local laws, before driving privileges are restored. This can be one of the most frustrating aspects of recovery, particularly for people in areas without good public transportation. It is worth asking your neurosurgeon specifically about the rules that apply in your jurisdiction, because the guidelines for post-craniotomy driving were originally derived from traumatic brain injury data and may not perfectly fit your situation.

Quality of Life After Seizures and Surgery

Beyond the medical management, postoperative seizures carry a psychological and social weight that can be hard to quantify. A study of patients after temporal lobe resection found that health-related quality of life improved or held steady in those who became seizure-free, even when they experienced some degree of memory decline. But when persistent seizures combined with memory decline, quality of life dropped.²⁸ The finding is a useful reminder that seizure control is not just a medical checkbox. Freedom from seizures seems to buffer against other cognitive losses, while ongoing seizures amplify the impact of every other deficit.

For patients coping with postoperative seizures, this means that aggressive pursuit of seizure control is not merely about preventing the seizures themselves. It has downstream effects on mood, independence, and the ability to tolerate and adapt to whatever other neurological changes the surgery may have caused. If you are in that situation and feel that your seizure management is not being prioritized, pushing for a referral to an epileptologist, a neurologist who specializes in seizures, is a reasonable step.

1
PubMed Central. The Occurrence and Relationship of Postoperative Seizure and de novo Epilepsy after Craniotomy Surgery: A Retrospective Single-Center Cohort Study
2
PubMed Central. Early postoperative seizures (EPS) in patients undergoing brain tumour surgery
3
PubMed. Risk factors for intraoperative stimulation-related seizures during awake surgery: an analysis of 109 consecutive patients
4
PubMed. Predictors of early and late postoperative seizures in meningioma patients: a systematic review and meta-analysis
5
PubMed Central. Early and Late Postoperative Seizures in Meningioma Patients and Prediction by a Recent Scoring System
6
PubMed Central. Anatomical features of primary brain tumors affect seizure risk and semiology
7
PubMed. Predictors of preoperative and early postoperative seizures in patients with intra-axial primary and metastatic brain tumors: A retrospective observational single center study
8
PubMed Central. Incidence, risk factors and outcomes of seizures occurring after craniotomy for primary brain tumor resection
9
PubMed. Understanding Risk Factors for Postoperative Seizure Following Surgical Treatment and Middle Meningeal Artery Embolization of Chronic Subdural Hematomas
10
Journal of Neurosurgery: Pediatrics. The incidence of postoperative hyponatremia and associated neurological sequelae in children with intracranial neoplasms
11
European Journal of Cardiovascular Medicine. Effect and Management of Hyponatremia in Post-Operative Craniotomy Cases
12
PubMed Central. Seizure Predictors and Control After Microsurgical Resection of Supratentorial Arteriovenous Malformations in 440 Patients
13
PubMed. Postoperative de novo epilepsy after resection of brain arteriovenous malformations: A national database study of 536 patients
14
Exploratory Neuroscience. Current advances in epilepsy among patients with arteriovenous malformations
15
PubMed. Baseline EEG pattern on continuous ICU EEG monitoring and incidence of seizures
16
PubMed. Recommendations on the use of EEG monitoring in critically ill patients: consensus statement from the neurointensive care section of the ESICM
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PubMed. Continuous electroencephalogram monitoring in critically ill patients
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Neurosurgery. Guidelines for the Treatment of Adults with Metastatic Brain Tumors: The Role of Prophylactic Anticonvulsants in the Treatment of Adults with Metastatic Brain Tumors
20
PubMed. The use of prophylactic antiepileptic medication and driving restrictions for craniotomies among Australian and New Zealand neurosurgeons
21
PubMed Central. Comparison of Efficacy and Safety of Levetiracetam Versus Phenytoin for Post-craniotomy Seizure Prophylaxis
22
PubMed. Seizure recurrence after planned discontinuation of antiepileptic drugs in seizure-free patients after epilepsy surgery: a review of current clinical experience
23
PubMed. Early antiseizure medication withdrawal and risk of seizure recurrence in children after epilepsy surgery: A retrospective study
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Epilepsia. Long-term approach to patients with postsurgical seizures
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Journal of Neurosurgery. Seizures after evacuation of subdural hematomas: incidence, risk factors, and functional impact
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PubMed Central. Factors affecting postoperative seizure risk and perioperative outcomes in pediatric brain tumor resections
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PubMed Central. Driving restrictions following deep brain stimulation surgery
28
PubMed. Worsening of quality of life after epilepsy surgery: effect of seizures and memory decline