Evaluating Early Cavernous Malformation Surgery and Epilepsy Prognosis

Cavernous malformations (CM) can be highly epileptogenic. While half of these patients can control their seizures with long-term medical treatment, the other half will develop drug-resistant epilepsy (DRE).

DRE patients are typically offered surgery if seizures persist for longer than two years, and around 75% tend to have overall good outcomes of staying seizure-free after the procedure. However, there is currently no research on epilepsy prognosis in patients who are offered the surgery at their initial admission to a neurosurgical clinic.

In their 2021 study published in Epilepsy & Behavior, Kapadia et al. sought to address this issue by comparing seizure outcome in cavernous malformation patients who had undergone late vs. early epilepsy surgery.

Epilepsy Prognosis and Timing of Epilepsy Surgery

Kapadia et al. noticed that at their institution, many cavernous malformation patients who present with seizures chose to undergo epilepsy surgery right after their first or second seizure. This decision was found to be associated with a long-term seizure-free rate of 95% and most of these patients were able to discontinue antiepileptic drugs (AEDs).

In their present study, they analyzed data from 35 cavernous malformation patients with preoperative seizures who had been examined at their single-institution neurosurgical clinic over a 10-year period. Nineteen of these patients had two or fewer preoperative seizures and 16 had greater than two preoperative seizures. Among the greater than two seizures group, six patients had DRE for over two years.

Looking at the outcomes among these groups, the study authors found that 95% of patients in the two or fewer seizures group and 63% of the greater than two seizures group were seizure free during the first-year after epilepsy surgery.

Within the two or fewer seizures group, 79% were able to wean off AEDs after cavernous malformation surgery, and 25% of the greater than two seizures group were able to as well. Of the six patients with DRE for over two years, three became seizure-free after surgery.

Additionally, long-term data (average of 5.6 years) showed that all 18 patients in the two or fewer seizures group that were seizure-free after surgery remained seizure-free. In the greater than two seizure group, only two patients had delayed postoperative seizures after one year, and 50% of the remaining patients remained seizure-free long term.

However, they note that some limitations of their study include that patients’ presurgical workup was very inconsistent, and many did not get a routine EEG. The two seizure groups also differed in several other characteristics such as time to surgery and medication responsiveness, which can have an impact on epilepsy prognosis as well.

Overall, while the results of their study suggest that cavernous malformation patients who undergo early surgery may have improved epilepsy prognosis, they cannot offer an optimal time point for intervention. Further research is needed to evaluate early surgery vs. medical management for these patients in order to determine the optimal timeframe.

Other Factors Linked to Success of Cavernous Malformation Surgery

In their 2021 retrospective study, Rumalla et al. sought to describe nationally representative outcomes following cavernous malformation surgery. Their study, to their knowledge, is the first of its kind to do so. Using data from the Nationwide Readmission Database and a retrospective patient cohort from the Baylor College of Medicine, they examined medical records of 1,235 patients who underwent cavernous malformation surgery between January 2016 and December 2019.

Most of the patients examined presented with a supratentorial CM (1,073), compared to infratentorial (162). Epilepsy was found to be the most common coexisting diagnosis within supratentorial patients and was significantly more common in these patients than in infratentorial patients (47.5% vs. 5%).

Looking at the discharge outcomes in the supratentorial patients, there were found to be less than 11 deaths, and 82% of patients received a routine discharge to home. Epileptic supratentorial patients were found to have lower rates of adverse disposition.

Within the infratentorial group, the most common coexisting diagnoses were symptomatic mass effect or brainstem compression (39%). With regards to discharge outcomes, 33.6% had an “other than routine” (OTR) disposition, including discharge to a nursing facility, intermediate care, or home health care. Infratentorial patients had higher rates of adverse disposition than supratentorial patients, at 34.3% vs. 17.4% respectively. The overall rate of adverse disposition was 19.7%.

Rumalla et al. note that nationwide causes of readmission for cavernous malformation patients post-surgery have not previously been reported; their study found that the most common cause was seizure/epilepsy (3.1%). Overall, the 30-day readmission rate was 7.5%.

Likewise, their study was the first to examine the relationship between hospital case volume and surgical outcomes in this patient population. Rumalla et al. found that patients underwent at high-volume centers, defined as having a minimum of six CM cases per year, were four times less likely to have adverse discharge disposition after undergoing supratentorial CM surgery. They note, however, that only 24% of the patients in the study underwent cavernous malformation surgery at a high-volume center.

Overall, they believe that their findings suggest that cavernous malformation surgery should be localized to “centers of excellence” to help improve patient outcomes.