Vascular malformations and epilepsy: clinical considerations and basic mechanisms

Postoperative de novo epilepsy after resection of brain arteriovenous malformations: A national database study of 536 patients

OBJECTIVE

We aimed to assess the incidence and risk factors for de novo epilepsy after arteriovenous malformation (AVM) resection and compare them with a nonresection cohort after propensity score matching, utilizing a national database.

METHODS

Utilizing the TriNetX Research Network, we queried cases from January 1, 2004 to March 1, 2022. We included patients of all ages who underwent supratentorial AVM resection, presenting without seizures on or before surgery and without being on antiseizure medications at least 1 day before surgery. The primary outcome was seizures manifesting at least 6 weeks after surgery. Patient characteristics and outcomes were compared between the cohorts with and without postoperative epilepsy. Further cohorts were created to compare cohorts with and without embolization or rupture. After propensity score matching, we compared an additional cohort of patients with an AVM diagnosis who did not undergo resection.

RESULTS

Of the 536 patients (mean age = 38.9 ± 19.6, 52% females) presenting without seizure who underwent AVM resection, 99 (18.5%) developed de novo epilepsy, with a 1-year cumulative incidence of 13.8%. Patients with epilepsy had higher rates of intracerebral hemorrhage, and intracerebral hemorrhage was less common in the embolization cohort. Patients in the ruptured cohort were older and more often males. After propensity score matching with 18 588 patients with AVM diagnosis but no resection, each group consisted of 529 patients, and de novo epilepsy at 1 year was significantly higher in the AVM resection cohort compared to the nonresection cohort (11.5% vs. 3.4%, p < .001).

SIGNIFICANCE

This analysis of 536 patients provides evidence that de novo epilepsy after brain AVM resection occurs at a 1-year cumulative incidence of 13.8%, with a total of 19.4% developing de novo epilepsy. Intracerebral hemorrhage was inconsistently associated with postoperative de novo epilepsy. De novo epilepsy was significantly less frequent after AVM diagnosis without resection.

New approaches for brain arteriovenous malformations-related epilepsy

BACKGROUND

The purpose of this review is to present the current literature and to highlight the most recent findings in brain arteriovenous malformations (bAVM)-related epilepsy research.

METHODS

We searched Medline, PubMed, Biblioinserm, Cochrane Central to study the latest research reports about the different factors that could be responsible for the genesis of bAVM-related epilepsy. We analyzed if epileptogenesis has any characteristics traits and its relation with the vascular malformation. The results of different treatments on epilepsy were considered. Typical errors that may lead towards incorrect or worse management of the seizures for these patients were also examined.

RESULTS

The development of bAVM results from multifactorial etiologies and bAVM-related epileptogenesis is likely specific for this pathology. Different types of evidence demonstrate a bidirectional relationship between bAVM and epilepsy. Currently, there is not enough published data to determine what may be the right management for these patients.

CONCLUSIONS

A better understanding of epileptogenesis in conjunction with knowledge of the complex alterations of structures and functions following bAVM-related seizures is necessary. Identification of biomarkers that can identify subgroups most likely to benefit from a specific intervention are needed to help guide clinical management. A new concept for the treatment of epilepsy related to an unruptured bAVM that cannot be treated invasively is proposed as well as new therapeutic perspectives. The next necessary step will be to propose additional algorithms to improve the development of future trials.

Unexpected median SEPs fluctuations during brain cavernous malformation resection with no post-operative deficit

Median nerve somatosensory evoked potentials (SEPs) may present changes during cavernous malformation (CM) resection unrelated to new post-operative sensory deficits. We performed intraoperative neurophysiological monitoring of median SEPs (m-SEPs) in three patients who underwent CM resection (surgery) near the sensory-motor cortex. The only preoperative clinical manifestations in all patients were seizures. All patients presented m-SEPs alterations on the side of the lesion during the procedure. Two patients presented permanent changes in the cortical potentials. In the third patient, the cortical and subcortical components suffered temporal fluctuations to return to baselines at the end of the surgery. None of these patients developed new post-operative clinical deficits. During brain cavernous malformation resection, significant fluctuations in the amplitude of different components of m-SEPs may occur. These changes may be due to excitability variations on m-SEP generators and do not translate into new post-operative neurological deficits.

Evaluating the Role of Perilesional Tissue in Pathobiology of Epileptogenesis of Vascular Malformations of the Central Nervous System

Background and Purpose

Seizures are common presentation of cerebral vascular malformation (CVM). Topography and haemodynamic alterations are proposed as mechanisms for epileptogenesis, but the role of glial/neuronal alterations in perilesional tissue has not received much attention. Identification of the exact pathophysiologic basis could have therapeutic implications. To evaluate whether angioarchitectural factors of CVM or alterations in neuroglial/stroma of the adjacent cortex contribute to seizures.

Method

The clinical, imaging and histological characteristics of arteriovenous malformation (AVM) and cerebral cavernous malformation (CCM) with and without seizures was evaluated using neuroimaging imaging and digital subtraction angiography parameters and histopathology by morphology and immunohistochemistry.

Results

Fifty-six cases of CVM were diagnosed over a 2-year study period. Of these, 32 had adequate perilesional tissue for evaluation (AVM, 24; CCM, 8). Seizures at presentation was seen in 12/24 (50%) of AVM and 5/8 (62.5%) CCM. In AVM, hemosiderin deposition and gliosis in parenchyma (p=0.01) had significant association with seizure. Siderotic vessels in the adjacent cortex was exclusively seen only in CCM with seizures (p=0.018). Angioarchitectural features of CVM on imaging and neuronal alterations in adjacent cortex on histology failed to show any statistically significant difference between the two groups (p>0.05).

Conclusions

We propose that changes in adjacent cortex appear to be epileptogenic rather than the malformation per se. Reactive gliosis and hemosiderin deposits in perilesional tissue in AVM and siderotic vessels in CCM were associated with seizure. This explains the better outcomes following extended lesionectomy that includes epileptogenic perilesional tissues.

Incidence and risk factors of epilepsy following brain arteriovenous malformation rupture in adult patients

BACKGROUND

Little is known about incidence, time of onset, clinical presentation, and risk factors of epileptic seizure following brain arteriovenous malformation (bAVM) rupture.

METHODS

We performed a monocentric retrospective cohort study from January 2003 to March 2021. The main objective of this study was to determine the incidence of seizures after spontaneous bAVM rupture in nonepileptic adult patients and describe the corresponding clinical features. The secondary objective was to identify clinical, radiological, or biological predictors for the occurrence of de novo seizures after bAVM rupture.

RESULTS

Of the 296 cases of bAVM rupture registered during the study period, 247 nonepileptic patients (male 53%, median age 40) were included in the study. Fifty-nine patients (23.9%) had at least one seizure after bAVM rupture. The use of preventive antiepileptic drugs (10.3 [1.5-74.1]; P = 0.02) and decompressive craniectomy (15.4 [2.0-125]; P < 0.009) were independently associated with the occurrence of epilepsy after the bAVM rupture. The factors independently associated with the absence of any seizure after the rupture were isolated intraventricular hemorrhage (0.3 [0.1-0.99]; P = 0.04) and infratentorial location of the bAVM (0.2 [0.1-0.5]; P = 0.09). The first seizure occurred within the first year or within 5 years in, respectively, 83.1% and 98.3% of the patients.

CONCLUSIONS

Epilepsy affects nearly a quarter of patients after bAVM rupture. Decompressive craniectomy represents an independent risk factor significantly associated with the occurrence of epilepsy after bAVM rupture. The introduction of preventive AEDs after rupture could be considered in these most severe patients who have a decompressive craniectomy.

De novo epilepsy after microsurgical resection of brain arteriovenous malformations

OBJECTIVE

Seizures are the second most common presenting symptom of brain arteriovenous malformations (bAVMs) after hemorrhage. Risk factors for preoperative seizures and subsequent seizure control outcomes have been well studied. There is a paucity of literature on postoperative, de novo seizures in initially seizure-naïve patients who undergo resection. Whereas this entity has been documented after craniotomy for a wide variety of neurosurgically treated pathologies including tumors, trauma, and aneurysms, de novo seizures after bAVM resection are poorly studied. Given the debilitating nature of epilepsy, the purpose of this study was to elucidate the incidence and risk factors associated with de novo epilepsy after bAVM resection.

METHODS

A retrospective review of patients who underwent resection of a bAVM over a 15-year period was performed. Patients who did not present with seizure were included, and the primary outcome was de novo epilepsy (i.e., a seizure disorder that only manifested after surgery). Demographic, clinical, and radiographic characteristics were compared between patients with and without postoperative epilepsy. Subgroup analysis was conducted on the ruptured bAVMs.

RESULTS

From a cohort of 198 patients who underwent resection of a bAVM during the study period, 111 supratentorial ruptured and unruptured bAVMs that did not present with seizure were included. Twenty-one patients (19%) developed de novo epilepsy. One-year cumulative rates of developing de novo epilepsy were 9% for the overall cohort and 8.5% for the cohort with ruptured bAVMs. There were no significant differences between the epilepsy and no-epilepsy groups overall; however, the de novo epilepsy group was younger in the cohort with ruptured bAVMs (28.7 ± 11.7 vs 35.1 ± 19.9 years; p = 0.04). The mean time between resection and first seizure was 26.0 ± 40.4 months, with the longest time being 14 years. Subgroup analysis of the ruptured and endovascular embolization cohorts did not reveal any significant differences. Of the patients who developed poorly controlled epilepsy (defined as Engel class III–IV), all had a history of hemorrhage and half had bAVMs located in the temporal lobe.

CONCLUSIONS

De novo epilepsy after bAVM resection occurs at an annual cumulative risk of 9%, with potentially long-term onset. Younger age may be a risk factor in patients who present with rupture. The development of poorly controlled epilepsy may be associated with temporal lobe location and a delay between hemorrhage and resection.

Long-Term Management of Seizures after Surgical Treatment of Supratentorial Cavernous Malformations : A Retrospective Single Centre Study

Objective

Seizure recurrence after the first-ever seizure in patients with a supratentorial cerebral cavernous malformation (CCM) is almost certain, so the diagnosis and treatment of epilepsy is justified. The optimal method of management of these patients is still a matter of debate. The aim of our study was to identify factors associated with postoperative seizure control and assess the surgical morbidity rate.

Methods

We retrospectively analysed 45 consecutive patients with a supratentorial CCM and symptomatic epilepsy in a single centre. Pre- and postoperative epidemiological data, seizure-related patient histories, neuroimaging results, surgery details and outcomes were obtained from hospital medical records. Seizure outcomes were assessed at least 12 months after surgery.

Results

Thirty-five patients (77.8%) were seizure free at the long-term follow-up (Engel class I); six (13,3%) had rare, nocturnal seizures (Engel class II); and four (8.9%) showed meaningful improvement (Engel class III). In 15 patients (33%) in the Engel I group; it was possible to discontinue antiepileptic medication. Although there was not statistical significance, our results suggest that patients can benefit from early surgery. No deaths occurred in our study, and mild postoperative neurologic deficits were observed in two patients (4%) at the long-term follow-up.

Conclusion

Surgical resection of CCMs should be considered in all patients with a supratentorial malformation and epilepsy due to the favourable surgical results in terms of the epileptic seizure control rate and low postoperative morbidity risk, despite the use of different predictors for the seizure outcome.

Seizure Outcomes After Interventional Treatment in Cerebral Arteriovenous Malformation-Associated Epilepsy: A Systematic Review and Meta-Analysis

BACKGROUND

Seizures are the second most common presenting symptom of cerebral arteriovenous malformations (AVMs). Evidence supporting different treatment modalities is continuously evolving and it remains unclear which modality offers better seizure outcomes.

OBJECTIVE

To compare various interventional treatment modalities (i.e., microsurgery, radiosurgery, endovascular embolization, or multimodality treatment), regarding outcomes in AVM-associated epilepsy.

METHODS

PubMed, Embase, and Web of Science were searched on December 31, 2020 for studies that evaluated outcomes in patients with AVM-associated epilepsy after undergoing different treatment modalities. Pooled analysis was performed using a random-effects model and stratified by different modalities.

RESULTS

Forty-nine studies including 2668 patients were included. Interventional management was associated with a 56.0% probability of seizure freedom and a 73.0% probability of seizure improvement. The probability of discontinuing antiepileptic drugs was estimated at 38.0%. The stratified analysis showed that microsurgery was associated with a higher probability of seizure freedom and seizure improvement than was radiosurgery, endovascular, or multimodality treatment. The probability of antiepileptic drug cessation was also higher after microsurgery compared with radiation therapy; however, only clinical but not statistical significance could be inferred because of the lack of comparative analyses.

CONCLUSIONS

Interventional management of AVM-related epilepsy was associated with seizure freedom and seizure improvement in 56% and 73% of cases. Microsurgery seemed to be associated with a higher incidence of seizure freedom and seizure improvement than did other modalities. Future well-designed comparative studies are needed to draw definitive conclusions regarding each modality.

Post-Traumatic Epilepsy and Comorbidities: Advanced Models, Molecular Mechanisms, Biomarkers, and Novel Therapeutic Interventions

Post-traumatic epilepsy (PTE) is one of the most devastating long-term, network consequences of traumatic brain injury (TBI). There is currently no approved treatment that can prevent onset of spontaneous seizures associated with brain injury, and many cases of PTE are refractory to antiseizure medications. Post-traumatic epileptogenesis is an enduring process by which a normal brain exhibits hypersynchronous excitability after a head injury incident. Understanding the neural networks and molecular pathologies involved in epileptogenesis are key to preventing its development or modifying disease progression. In this article, we describe a critical appraisal of the current state of PTE research with an emphasis on experimental models, molecular mechanisms of post-traumatic epileptogenesis, potential biomarkers, and the burden of PTE-associated comorbidities. The goal of epilepsy research is to identify new therapeutic strategies that can prevent PTE development or interrupt the epileptogenic process and relieve associated neuropsychiatric comorbidities. Therefore, we also describe current preclinical and clinical data on the treatment of PTE sequelae. Differences in injury patterns, latency period, and biomarkers are outlined in the context of animal model validation, pathophysiology, seizure frequency, and behavior. Improving TBI recovery and preventing seizure onset are complex and challenging tasks; however, much progress has been made within this decade demonstrating disease modifying, anti-inflammatory, and neuroprotective strategies, suggesting this goal is pragmatic. Our understanding of PTE is continuously evolving, and improved preclinical models allow for accelerated testing of critically needed novel therapeutic interventions in military and civilian persons at high risk for PTE and its devastating comorbidities.

Complete seizure-free rates following interventional treatment of intracranial arteriovenous malformations: a systematic review and meta-analysis

Seizures are common presenting symptoms of intracranial arteriovenous malformations (AVMs). This systematic review and meta-analysis aims to assess the current evidence regarding complete seizure freedom rates following surgical resection, stereotactic radiosurgery (SRS), and/or endovascular embolization of intracranial AVMs. A systematic review of PubMed, Ovid MEDLINE, and Ovid EMBASE was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Included manuscripts were methodically scrutinized for quality, spontaneous AVM-associated or hemorrhage-associated seizures, complete seizure-free rates following each interventional treatment, follow-up duration; determination methods of seizure outcomes, and average time-to-onset of recurrent seizures after each treatment. Manuscripts that described patients with nondisabling seizures or reduced seizure frequency in their seizure-free calculations were excluded. Seizure freedom rates following surgical resection, SRS, and endovascular embolization were compared via random-effect analysis. Thirty-four studies with a total of 1765 intracranial AVM patients presenting with spontaneous AVM-associated seizures and 408 patients presenting with hemorrhage-associated seizures were qualitatively analyzed. For patients presenting with AVM-associated seizures, the complete seizure-free rates were 73.0% (321/440 patients; 95% CI 68.8-77.1%) following surgical resection, 60.5% (376/622 patients; 95% CI 56.6-64.3%) following SRS, and 44.6% (29/65 patients; 95% CI 32.5-56.7%) following endovascular embolization alone. For patients presenting with either AVM-associated or hemorrhage-associated seizures, the complete seizure-free rates were 73.0% (584/800 patients; 95% CI 69.9-76.1%) following surgical resection, 46.4% (572/1233 patients; 95% CI 43.6-49.2%) following SRS, and 44.6% (29/65 patients; 95% CI 32.5-56.7%) following embolization. For patients presenting with either AVM-associated or hemorrhage-associated seizures, the overall improvements in seizure outcomes regardless of complete seizure freedom were 82.6% (661/800 patients; 95% CI 80.0-85.3%), 70.6% (870/1233 patients; 95% CI 68.0-73.1%), and 70.8% (46/65 patients; 95% CI 59.7-81.1%) following surgical resection, SRS, and embolization, respectively. No study reported information about the time-to-onset for recurrent seizures in any patient following treatment, as seizure outcomes were only described at the last follow-up visit. The available data suggests that surgical resection results in the highest rate of complete seizure freedom. The rate of seizure improvement following surgery increased further to 82.3% when including patients who had improved seizure frequency without achieving true seizure freedom. Complete seizure-free rates following SRS or embolization were more ambiguous and lower when compared to surgical resection. There is a need for high quality studies evaluating AVM treatment modalities and clearly defined seizure outcomes, as the current literature consists mostly of heterogenous patient populations.

Displacement of Gray Matter and Incidence of Seizures in Patients with Cerebral Cavernous Malformations

Seizures are the most common presentation in patients with cerebral cavernous malformations (CCMs). Based on the hypothesis that the volume or proportion of gray matter (GM) displaced by CCMs is associated with the risk of seizure, we developed an algorithm by which to quantify the volume and proportion of displaced GM and the risk of seizure. Image analysis was conducted on 111 patients with solitary CCMs (divided into seizure and nonseizure groups) from our gamma knife radiosurgery (GKRS) database from February 2005 and March 2020. The CCM algorithm proved effective in quantifying the GM and CCM using T1WI MRI images. In the seizure group, 11 of the 12 patients exhibited seizures at the initial presentation, and all CCMs in the seizure group were supratentorial. The location of the limbic lobe within the CCM was significantly associated with the risk of seizure (OR = 19.6, p = 0.02). The risk of seizure increased when the proportion of GM displaced by the CCM exceeded 31%. It was also strongly correlated with the volume of displaced GM. The volume and proportion of displaced GM were both positively correlated with the risk of seizure presentation/development and thus could be used to guide seizure prophylaxis in CCM patients.

Epilepsy Syndromes: Current Classifications and Future Directions

This review describes the clinical presentations and treatment options for commonly recognized epilepsy syndromes in the pediatric age group, based on the 2017 International League Against Epilepsy classification. Structural epilepsies that are amenable to surgical intervention are discussed. Lastly, emerging technologies are reviewed that are expanding our knowledge of underlying epilepsy pathologies and will guide future syndromic classification systems including genetic testing and tissue repositories.

Benefits from Exclusion Treatment of Unruptured Brain Arteriovenous Malformations on Epilepsy in Adults

PURPOSE

In approximately 30% of the patients, brain arteriovenous malformations (bAVMs) are revealed by seizures, which may alter the patients' quality of life. Our objective was to evaluate the benefits of exclusion treatment (radiosurgery, embolization and/or surgery) on posttherapeutic epilepsy in bAVM patients without intracranial hemorrhage prior to treatment.

METHODS

Our retrospective observational single-center study included all consecutive adult patients with an unruptured bAVM and epilepsy, treated at our institution from 1995 to 2019 and who were followed for at least 1 year. Data on angioarchitectural characteristics of bAVMs, on epilepsy and posttreatment modified Rankin Scale (mRS) were collected. The primary endpoint was a seizure-free status (defined as Engel class IA) after exclusion treatment versus conservative management.

RESULTS

In this study one hundred and one consecutive adult patients with bAVMs, epilepsy and without bAVM rupture before any treatment were included; 21 (21%) in the conservative management group vs. 80 (79%) in the exclusion treatment group. After exclusion treatment, 55% of the patients from the group were Engel IA after treatment vs. 10% of the conservative management group (odds ratio [OR] 11.37, 95% confidence interval [CI] 2.48-107.24, p < 0.001).

CONCLUSION

Our results suggest that exclusion treatment in unruptured bAVMs with epilepsy is associated with a higher seizure-free rate in comparison with conservative management. Data from randomized controlled studies are necessary to confirm these findings.

Seizure Rates After Stereotactic Radiosurgery for Cerebral AVMs: A Single Center Study

OBJECTIVES

Seizure control after stereotactic radiosurgery (SRS) for arteriovenous malformations (AVMs) is an area of growing interest, with previous studies reporting up to 70% seizure freedom after treatment. The goals of this study were to identify specific patient and AVM characteristics associated with seizure presentation and seizure outcomes after SRS treatment.

METHODS

A retrospective review of consecutive patients undergoing SRS for brain AVMs between 2009 and 2019 at our institution was conducted. Chi-squared and logistic regression analyses were utilized to identify patient and AVM factors associated with preoperative seizure presentation and development of new onset seizures after SRS.

RESULTS

Two hundred ten consecutive patients presenting with AVMs treated with SRS were reviewed. Factors associated with seizure presentation included larger AVM size (P = 0.02), superficial venous drainage (P < 0.05), and parietal location (P = 0.04). Of 188 patients with follow-up (90%), 30 patients presented with seizures and 14 (47%) were seizure-free post-SRS. Of 158 patients presenting without seizure, 29 (18%) developed de novo seizures during follow-up. De novo post-SRS seizures were associated with prior craniotomy for resection of AVM (P = 0.04), post-treatment hemorrhage (P = 0.02), parietal location (P = 0.05), adverse effect requiring steroids (P < 0.01), and adverse effect requiring surgery (P < 0.01).

CONCLUSIONS

Seizures are a common presentation of brain AVMs and can be treated effectively with SRS. However, seizures can also be a complication of SRS and are associated with post-treatment hemorrhage, edema, and need for future open surgery.

Epilepsy-Related Outcomes in Children With Neonatal Cerebellar Injury

OBJECTIVE

Acute brain injury is a frequent perinatal neurologic complication that can involve the cerebellum. Although short-term outcomes of infants with neonatal cerebellar injury are well described, neurologic sequelae in older children are underreported. Here, we describe epilepsy-related outcomes in young children who suffered from neonatal cerebellar injuries.

METHODS

In-house automated software identified patients with neonatal brain injuries who were evaluated at our institution both as neonates (≤28 days) and as children (≥1 year). Neonatal hospital course, neuroimaging, and outcomes related to epilepsy were reviewed from the medical record. Patients were stratified into 2 groups based on neonatal brain injuries: those with cerebellar injury and those without cerebellar involvement.

RESULTS

Of the 282 neonates followed through childhood over the decade-long study period, 33 (12%) experienced neonatal brain injury. All 33 cases involved supratentorial injury, and 5 (15%) also included cerebellar injury. The development of epilepsy was significantly less likely in the group with cerebellar involvement (40%) compared to that with cerebellar sparing (82%; P = 0.043). In some cases, children with cerebellum-sparing injuries required admission for seizure control and developed drug-resistant epilepsy as well as status epilepticus. These outcomes occurred less frequently in the group with cerebellar involvement.

CONCLUSIONS

Epilepsy-related sequelae may occur less frequently when the cerebellum is involved in neonatal brain injury. Larger prospective studies are needed to clarify how cerebellocortical networks impact functional brain connectivity and epilepsy longitudinally.

Case Report: Late-Onset Temporal Lobe Epilepsy Following Subarachnoid Hemorrhage: An Interplay Between Pre-existing Cortical Development Abnormality and Tissue Damage

Epileptogenicity following brain insult depends on various factors including severity of the resulting lesion and extent of brain damage. We report a 54-year-old female patient who developed medically refractory epilepsy resulting from the interplay of pre-existing and post-insult pathologies. She presented with subarachnoid hemorrhage (SAH) due to a ruptured aneurysm and underwent clipping surgery. Seizures started 3 months post-operatively. MRI revealed cerebral ischemia and hemosiderin deposits in the left temporal lobes, and left hippocampal atrophy was suspected. As anti-seizure medications and vagus nerve stimulation failed to control her seizures, she underwent left temporal lobe resection and placement of a ventriculoperitoneal shunt for the post-operative complication of hydrocephalus. She remains seizure-free to date. Neuropathology revealed a previously undiagnosed focal cortical dysplasia (FCD) type 1a. Brain insult likely had a second hit effect in the late onset of epilepsy in this patient with pre-existing mild MCD, in whom secondary epilepsy can be attributed to the interplay of multiple underlying pathologies.

Seizure Outcome in Adult Patients with Supratentorial Cavernomas

Background  Cavernomas are usually found in the supratentorial area, and epileptic seizures are one of the presenting symptoms.

Objective  This study aims to provide the seizure outcome in adult patients who underwent surgical excision of single supratentorial cavernomas.

Materials and Methods  A total of 23 patients with single supratentorial cavernomas were operated between May 2011 and January 2019. Pre- and postoperative seizure semiology, clinical, and radiological findings were collected from medical records. At the last follow-up, each patient was seen during regular visits and clinical variables were noted.

Results  The mean age was 37.08 ± 10.5 years, and 11 (57.8%) and 12 (52.2%) were females and males, respectively. Headache (43.5%) and seizure (43.5%) were the most common presenting symptoms. Cavernomas were located on the right side in 13 and on the left side in 10 patients. The most common locations were the frontal (43.5%) and temporal (43.5%) lobes. The mean follow-up in this series was 41.4 ± 30.8 months. Our results showed that surgery was effective in seizure outcome, as almost 70% of patients who had seizure before surgery was seizure free after surgery, and the difference between those who had seizure pre- and postoperative periods was statistically significant ( p = 0.0001).

Conclusion  Surgery is safe and effective for supratentorial cavernomas. The excision of cavernoma together with the surrounding hemosiderin should be performed to obtain a satisfactory seizure outcome.

Predictors of Epileptic Seizures and Ability to Work in Supratentorial Cavernous Angioma Located Within Eloquent Brain Areas

BACKGROUND

The postoperative outcomes and the predictors of seizure control are poorly studied for supratentorial cavernous angiomas (CA) within or close to the eloquent brain area.

OBJECTIVE

To assess the predictors of preoperative seizure control, postoperative seizure control, and postoperative ability to work, and the safety of the surgery.

METHODS

Multicenter international retrospective cohort analysis of adult patients benefitting from a functional-based surgical resection with intraoperative functional brain mapping for a supratentorial CA within or close to eloquent brain areas.

RESULTS

A total of 109 patients (66.1% women; mean age 38.4 ± 12.5 yr), were studied. Age >38 yr (odds ratio [OR], 7.33; 95% confidence interval [CI], 1.53-35.19; P = .013) and time to surgery > 12 mo (OR, 18.21; 95% CI, 1.11-296.55; P = .042) are independent predictors of uncontrolled seizures at the time of surgery. Focal deficit (OR, 10.25; 95% CI, 3.16-33.28; P < .001) is an independent predictor of inability to work at the time of surgery. History of epileptic seizures at the time of surgery (OR, 7.61; 95% CI, 1.67-85.42; P = .003) and partial resection of the CA and/or of the hemosiderin rim (OR, 12.02; 95% CI, 3.01-48.13; P < .001) are independent predictors of uncontrolled seizures postoperatively. Inability to work at the time of surgery (OR, 19.54; 95% CI, 1.90-425.48; P = .050), Karnofsky Performance Status ≤ 70 (OR, 51.20; 95% CI, 1.20-2175.37; P = .039), uncontrolled seizures postoperatively (OR, 105.33; 95% CI, 4.32-2566.27; P = .004), and worsening of cognitive functions postoperatively (OR, 13.71; 95% CI, 1.06-176.66; P = .045) are independent predictors of inability to work postoperatively.

CONCLUSION

The functional-based resection using intraoperative functional brain mapping allows safe resection of CA and the peripheral hemosiderin rim located within or close to eloquent brain areas.

Effects of Hemosiderosis on Epilepsy Following Subarachnoid Hemorrhage

Epilepsy after aneurysmal subarachnoid hemorrhage (post-SAH epilepsy) is a critical complication that influences clinical and social prognoses. However, the underlying mechanisms remain unclear. We investigated the relationship between hemosiderosis and the incidence of post-SAH epilepsy. About 50 patients with aneurysmal SAH who were admitted to Sapporo Medical University and Oji General Hospital between April 2010 and June 2016 were enrolled in this retrospective study. Hemosiderosis detected by T2^*-weighted magnetic resonance imaging(MRI) and the incidence of post-SAH epilepsy were retrospectively analyzed. Post-SAH epilepsy was defined as an unprovoked seizures occurring more than 1 week after the onset of SAH. Six patients (12%) developed post-SAH epilepsy. In all patients, hemosiderosis in the cortex or cerebral parenchyma was detected by T2^*-weighted MRI. Statistical analyses revealed that hemosiderosis and the co-existence of intracerebral hemorrhage (ICH) related with post-SAH epilepsy (Fisher’s exact test, univariate exact logistic regression analysis: P < 0.05). Post-SAH epilepsy was predicted by hemosiderosis and the co-existence of ICH. The present results suggest that hemosiderin is the principal cause of post-SAH epilepsy and may be a predictor of this critical complication.

Seizure predictors and outcome after Onyx embolization in patients with brain arteriovenous malformations

BACKGROUND

Brain arteriovenous malformation (bAVM)-related epilepsy can significantly affect patient quality of life. We aimed to identify the factors associated with seizures occurrence and evaluate the long-term outcome following Onyx embolization in bAVM patients.

METHODS

Between July 2014 and July 2016, 239 consecutive patients underwent treatment for bAVMs in our institute and were respectively analyzed. Demographics, seizure status and bAVM morphologic characteristics were recorded. Modified Engel classification was used to evaluate the long-term seizure outcomes.

RESULTS

Of 239 bAVM patients, 68 (28.5%) initially presented with seizures. Seizure occurrence was associated with cerebral hemorrhage history, frontal-temporal location and arterial borderzone location. Of the 37 patients who presented with initial seizures and were treated with Onyx embolization, 23 (62.2%) were treated with antiepileptic drugs (AEDs) before Onyx embolization. At the last follow-up visit, 19 (51.4%) of the 37 patients reached modified Engel class I outcome. Of the 23 patients who had ever been treated with AEDs, 12 (52.2%) were still taking AEDs at the last follow-up visit. Single-factor analysis showed that arterial borderzone location was significantly correlated with higher modified Engel class outcome ( p = 0.046).

CONCLUSION

Patients with bAVM hemorrhage history, frontal-temporal location and arterial borderzone location were associated with seizure occurrence. Seizure-free status was not obtained in AVM patients with arterial borderzone after embolization, though it may have benefits in other ways. The seizure-free mechanism of bAVM with Onyx embolization is worth further study.

Cavernous malformations of central nervous system in pediatric patients: our single-centered experience in 50 patients and review of literature

PURPOSE

Cavernous malformations (CMs) are rare developmental cerebrovascular malformations of the central nervous system with a childhood prevalence of 0.3 to 0.53%. Our purpose was to assess the clinical features and microsurgical outcome in pediatric central nervous system (CNS) CMs.

MATERIAL AND METHODS

We retrospectively enrolled all the CM patients admitted to our institute from 1 January 2001 to 31 December 2014. Data was analyzed for their clinical features and surgical outcome.

RESULTS

A total of 50 patients with CMs (30 supratentorial, 14 infratentorial, and 6 spinal) with a mean age of 14 years (3-18 years, SD ±4.64) were enrolled into the study. Most of these patients (78%) were male. Size varied from 1.2 to 6 cm. Three patients had multiple CMs. Symptoms of CMs were site specific. Seizure was the most common symptom (63.3%) of CMs at supratentorial location followed by headache (46%) and neurodeficiency (26%), while all brainstem and spinal CMs presented with neurodeficiencies. History of clinically significant acute hemorrhage was present in 19.2% of supratentorial (ST) superficial CMs, 50% of ST deep CMs, 25% of cerebellar CMs, 44.4% of brainstem CMs, and 50% of spinal CMs. Forty-five CMs in 44 patients were surgically excised. Their follow-up ranged from 6 to 162 months (mean 47.2 months, SD ±53). All supratentorial CM patients showed improvement in their symptoms. Patients with preoperative seizure showed good seizure control with Engel scale I in 16 (94.1%) and Engel scale II in 1 (5.9%). In infratentorial (IT) and spinal CM patients, 92.3 and 66.7% had improvement in their neurodeficiencies, respectively. There was no mortality in our series.

CONCLUSION

Microsurgical excision of CNS CM results in excellent neurological outcome in pediatric patients. Early intervention is necessary in spinal CMs for better outcome.

The Risk of Seizure Following Surgery for Brain Arteriovenous Malformation: A Prospective Cohort Study

BACKGROUND

The evidence for the risk of seizures following surgery for brain arteriovenous malformations (bAVM) is limited.

OBJECTIVE

To determine the risk of seizures after discharge from surgery for supratentorial bAVM.

METHODS

A prospectively collected cohort database of 559 supratentorial bAVM patients (excluding patients where surgery was not performed with the primary intention of treating the bAVM) was analyzed. Cox proportional hazards regression models (Cox regression) were generated assessing risk factors, a Receiver Operator Characteristic curve was generated to identify a cut-point for size and Kaplan–Meier life table curves created to identify the cumulative freedom from postoperative seizure.

RESULTS

Preoperative histories of more than 2 seizures and increasing maximum diameter (size, cm) of bAVM were found to be significantly (P &lt; .01) associated with the development of postoperative seizures and remained significant in the Cox regression (size as continuous variable: P = .01; hazard ratio: 1.2; 95% confidence interval: 1.0-1.3; more than 2 seizures: P = .02; hazard ratio: 2.1; 95% confidence interval: 1.1-3.8). The cumulative risk of first seizure after discharge from hospital following resection surgery for all patients with bAVM was 5.8% and 18% at 12 mo and 7 yr, respectively. The 7-yr risk of developing postoperative seizures ranged from 11% for patients with bAVM ≤4 cm and with 0 to 2 preoperative seizures, to 59% for patients with bAVM &gt;4 cm and with &gt;2 preoperative.

CONCLUSION

The risk of seizures after discharge from hospital following surgery for bAVM increases with the maximum diameter of the bAVM and a patient history of more than 2 preoperative seizures.

Seizure outcomes after stereotactic radiosurgery for the treatment of cerebral arteriovenous malformations

OBJECTIVE

Patients with cerebral arteriovenous malformations (AVMs) commonly present with seizure. Seizure outcomes in patients treated with stereotactic radiosurgery (SRS) are poorly defined. A case series of patients with cerebral AVMs treated with SRS is presented to evaluate long-term seizure outcome.

METHODS

A retrospective review of the medical record was performed, identifying 204 consecutive patients with AVMs treated with SRS between January 1991 and June 2012. Clinical and radiographic data were evaluated. Seizure outcome was measured using the Engel Epilepsy Surgery Outcome Scale. Mean duration of follow-up was 37.1 months (SD 38.3 months) with a minimum follow-up period of 1 month.

RESULTS

Of the 204 patients with cerebral AVMs treated with SRS, 78 patients (38.2%) presented with seizures and 49 of those patients were treated with antiepileptic drugs (AEDs). Following SRS, 63 (80.8%) of the 78 patients who had had seizures prior to SRS were seizure-free at a mean follow-up time of 37.2 months (SD 41.3 months). Of the 49 patients who had been treated with AEDs, 17 were still taking AEDs at last follow-up. Of the 126 patients who did not present with seizures prior to treatment with SRS, only 5 patients (4.0%) had seizures in the post-SRS period. There was no significant correlation between post-SRS seizure status and patient demographic features, comorbidities, AVM characteristics, history of operative intervention, pre- or posttreatment hemorrhage, or radiographic degree of AVM resolution.

CONCLUSIONS

Stereotactic radiosurgery for treatment of cerebral AVMs is effective at providing long-term control of seizures. A substantial number of patients who were treated with SRS were not only seizure free at their last follow-up, but had been successfully weaned from antiepileptic medications.

Venous angioma may be associated with epilepsy in children

Purpose

Venous angioma (VA) is the most common congenital abnormality of the intracranial vasculature. This study aimed to investigate the relationship between VA and epilepsy and to identify the characteristics of children with VA and epilepsy.

Methods

The records of all patients aged less than 18 years who underwent brain magnetic resonance imaging (MRI) at Pusan National University Hospital were retrospectively reviewed. Patients with isolated VA and patients with normal MRI were compared in terms of the prevalence of epilepsy.

Results

In total, 2,385 pediatric patients who underwent brain MRI were enrolled. Isolated VA was identified in 26 patients (VA group). Among the patients with normal MRI findings, 225 age- and sex-matched patients to the VA-group were assigned to the control group. Nine patients in the VA group (9 of 26, 34.6%) and 27 patients in the control group (26 of 225, 11.5%; P<0.001) had epilepsy. In the VA group, 20 patients (76.9%) had the VA in the cerebral hemispheres, and 6 patients (23.1%) had the VA in the brainstem and cerebellum. The latter showed a higher prevalence of epilepsy (5 of 6, 83.3%) than the former (4 of 20, 20.0%; P=0.004). Among the nine patients who had epilepsy with VA, patients whose VA involved the brainstem and cerebellum showed a significantly higher frequency of abnormal Electroencephalographic findings than patients whose VA involved the cerebral hemispheres (P=0.016).

Conclusion

VA, especially in the brainstem and cerebellum, might be associated with epilepsy.

Radiosurgery for temporal lobe arteriovenous malformations: effect of temporal location on seizure outcomes

OBJECT

The temporal lobe is particularly susceptible to epileptogenesis. However, the routine use of anticonvulsant therapy is not implemented in temporal lobe AVM patients without seizures at presentation. The goals of this case-control study were to determine the radiosurgical outcomes for temporal lobe AVMs and to define the effect of temporal lobe location on postradiosurgery AVM seizure outcomes.

METHODS

From a database of approximately 1400 patients, the authors generated a case cohort from patients with temporal lobe AVMs with at least 2 years follow-up or obliteration. A control cohort with similar baseline AVM characteristics was generated, blinded to outcome, from patients with non-temporal, cortical AVMs. They evaluated the rates and predictors of seizure freedom or decreased seizure frequency in patients with seizures or de novo seizures in those without seizures.

RESULTS

A total of 175 temporal lobe AVMs were identified based on the inclusion criteria. Seizure was the presenting symptom in 38% of patients. The median AVM volume was 3.3 cm3, and the Spetzler-Martin grade was III or higher in 39% of cases. The median radiosurgical prescription dose was 22 Gy. At a median clinical follow-up of 73 months, the rates of seizure control and de novo seizures were 62% and 2%, respectively. Prior embolization (p = 0.023) and lower radiosurgical dose (p = 0.027) were significant predictors of seizure control. Neither temporal lobe location (p = 0.187) nor obliteration (p = 0.522) affected seizure outcomes. The cumulative obliteration rate was 63%, which was significantly higher in patients without seizures at presentation (p = 0.046). The rates of symptomatic and permanent radiation-induced changes were 3% and 1%, respectively. The annual risk of postradiosurgery hemorrhage was 1.3%.

CONCLUSIONS

Radiosurgery is an effective treatment for temporal lobe AVMs. Furthermore, radiosurgery is protective against seizure progression in patients with temporal lobe AVM–associated seizures. Temporal lobe location does not affect radiosurgery-induced seizure control. The low risk of new-onset seizures in patients with temporal or extratemporal AVMs does not seem to warrant prophylactic use of anticonvulsants.

The Role of Hemosiderin Excision in Seizure Outcome in Cerebral Cavernous Malformation Surgery: A Systematic Review and Meta-Analysis

Background and Purpose

Whether the excision of hemosiderin surrounding cerebral cavernous malformations (CCMs) is necessary to achieve a seizure-free result has been the subject of debate. Here, we report a systematic review of related literature up to Jan 1, 2015 including 594 patients to assess the effect of hemosiderin excision on seizure outcome in patients with CCMs by meta-analysis.

Methods

Ten studies comparing extended hemosiderin excision with only lesion resection were identified by searching the English-language literature. Meta-analyses, subgroup analyses and sensitivity analysis were conducted to determine the association between hemosiderin excision and seizure outcome after surgery.

Results

Seizure outcome was significantly improved in the patients who underwent an extended excision of the surrounding hemosiderin (OR, 0.62; 95% CI: 0.42–0.91; P = 0.01). In subgroup analysis, studies from Asia (OR, 0.42; 95% CI: 0.25–0.71; P = 0.001), male-majority (female ratio < 50%) studies (OR, 0.56; 95% CI: 0.33–0.96; P = 0.04), low occurrence rate of multiple CCMs (OR, 0.37; 95% CI: 0.20–0.71; P = 0.003), cohort studies (OR, 0.44; 95% CI: 0.28–0.68; P = 0.78), longer duration of seizure symptoms (> 1 year) before surgery (OR, 0.43; 95% CI: 0.22–0.84; P = 0.01), lesion diameter > 2 cm (OR, 0.41; 95% CI: 0.19–0.87; P = 0.02) and short-term (< 3 years) follow-up (OR, 0.48; 95% CI: 0.29–0.80; P = 0.005) tended to correlate with a significantly favorable outcome.

Conclusion

Patients who underwent extended surrounding hemosiderin excision could exhibit significantly improved seizure outcomes compared to patients without hemosiderin excision. However, further well-designed prospective multiple-center RCT studies are still needed.

Seizure Outcomes in Patients With Surgically Treated Cerebral Arteriovenous Malformations

BACKGROUND:

Epilepsy is the second most common symptom in cerebral arteriovenous malformation (AVM) patients. The consecutive reduction of life quality is a clinically underrated problem because treatment usually focuses on the prevention of intracerebral hemorrhage.

OBJECTIVE:

To evaluate postoperative seizure outcome with the aim of more accurate counseling for postoperative seizure outcome.

METHODS:

From 1985 to 2012, 293 patients with an AVM were surgically treated by J.S. One hundred twenty-six patients with preoperative seizures or epilepsy could be identified; 103 of 126 had a follow-up of at least 12 months and were included in the analysis. The different epilepsy subtypes were categorized (sporadic seizures, chronic epilepsy, drug-resistant epilepsy [DRE]). Preoperative workup and surgical technique were evaluated. Seizure outcome was analyzed by using International League Against Epilepsy classification.

RESULTS:

Sporadic seizures were identified in 41% of patients (chronic epilepsy and DRE were identified in 36% and 23%, respectively). Detailed preoperative epileptological workup was done in 13%. Seizure freedom was achieved in 77% (79% at 5 years, 84% at 10 years). Outcome was significantly poorer in DRE cases. More extensive resection was performed in 11 cases with longstanding symptoms (&gt;24 months) and resulted in better seizure outcome as well as the short duration of preoperative seizure history.

CONCLUSION:

Patients presenting with AVM-associated epilepsy have a favorable seizure outcome after surgical treatment. Long-standing epilepsy and the progress into DRE markedly deteriorate the chances to obtain seizure freedom and should be considered an early factor in establishing the indication for AVM removal.

Seizure outcomes following radiosurgery for cerebral arteriovenous malformations

Object

Seizures are a common presentation of cerebral arteriovenous malformations (AVMs). The authors evaluated the efficacy of stereotactic radiosurgery (SRS) for the management of seizures associated with AVMs and identified factors influencing seizure outcomes following SRS for AVMs.

Methods

A systematic literature review was performed using PubMed. Studies selected for review were published in English, included at least 5 patients with both cerebral AVMs and presenting seizures treated with SRS, and provided post-SRS outcome data regarding obliteration of AVMs and/or seizures. Demographic, radiosurgical, radiological, and seizure outcome data were extracted and analyzed. All seizure outcomes were categorized as follows: 1) seizure free, 2) seizure improvement, 3) seizure unchanged, and 4) seizure worsened. Systematic statistical analysis was conducted to assess the effect of post-SRS AVM obliteration on seizure outcome.

Results

Nineteen case series with a total of 3971 AVM patients were included for analysis. Of these, 28% of patients presented with seizures, and data for 997 patients with available seizure outcome data who met the inclusion criteria were evaluated. Of these, 437 (43.8%) patients achieved seizure-free status after SRS, and 530 (68.7%) of 771 patients with available data achieved seizure control (seizure freedom or seizure improvement) following SRS. Factors associated with improved seizure outcomes following SRS for AVMs were analyzed in 9 studies. Seizure-free status was achieved in 82% and 41.0% of patients with complete and incomplete AVM obliteration, respectively. Complete AVM obliteration offered superior seizure-free rates compared with incomplete AVM obliteration (OR 6.13; 95% CI 2.16–17.44; p = 0.0007).

Conclusions

Stereotactic radiosurgery offers favorable seizure outcomes for AVM patients presenting with seizures. Improved seizure control is significantly more likely with complete AVM obliteration.

Temporal lobe arteriovenous malformations: surgical outcomes with a focus on visual field defects and epilepsy

BACKGROUND

Temporal lobe arteriovenous malformations (AVMs) represent a subgroup of intracranial AVMs with particular characteristics and management issues.

OBJECTIVE

To characterize the surgical outcomes of temporal lobe AVMs with emphasis on visual field deficits (VFDs) and seizures.

METHODS

Between 1992 and 2008, 29 patients were operated on for temporal lobe AVMs. Patient data were retrospectively collected and analyzed.

RESULTS

Twelve of 29 patients (41.4%) presented with seizures and 4 (13.7%) presented with VFDs. Postoperatively, 6 patients (24%) showed new VFDs and 2 improved, with a rate of preservation of full visual fields of 84%. Larger AVMs (> 3 cm) were significantly associated with postoperative VFD (P = .008). Epilepsy outcomes assessed by the Engel scale were as follows: 9 patients (75%) were in class I (seizure free), 1 patient (8.3%) was in class III, and 2 patients (16.6%) were in class IV (no change or worsening). Postoperative modified Rankin Scale outcomes were excellent (grade 0-1) in 18 patients, good (grade 2) in 7, and poor (grade 3-4) in 4. Older age at diagnosis correlated with a worse functional outcome (Spearman ρ = 0.369; P = .049). AVMs were totally removed in 27 of 29 patients (93.1%). Complete surgical excision was confirmed with angiography. Two patients needed reoperation for AVM remnant. Three patients had persistent hemiparesis (10.3% permanent morbidity). There was no mortality.

CONCLUSION

Seizure control is usually underappreciated in the surgical management of AVMs. However, in temporal lobe AVMs, good outcomes with low morbidity and good visual field preservation can be accomplished.

Surgical management and long-term outcome of pediatric patients with different subtypes of epilepsy associated with cerebral cavernous malformations

OBJECT

Sufficient data on surgical treatment and seizure outcome of pediatric patients with different types of epilepsy, especially drug-resistant epilepsy and associated cerebral cavernous malformations, are scarce. The aim of this study was to carefully evaluate seizure outcome using the International League Against Epilepsy (ILAE) classification with regard to the presurgical symptom duration.

METHODS

Fifty-one pediatric patients younger than 19 years with cerebral cavernous malformations of all CNS localizations have been surgically treated at the authors' institution. Twenty-two patients with seizures or epilepsy who harbored cortically located supratentorial cerebral cavernous malformations underwent surgical treatment and were retrospectively analyzed.

RESULTS

More extensive resections were used in 82% of all patients with epilepsy symptoms for longer than 2 years. Eighty-two percent of patients with symptom duration shorter than 2 years underwent circumscribed lesionectomy including the surrounding hemosiderotic rim. The overall rate of mild permanent, unanticipated postoperative deficits was 4.5%; the rate of anticipated neurological deficits was 9%. The mean follow-up was longer than 117 months in all groups. Seizure outcome was excellent in the group with symptom duration shorter than 2 years (100% ILAE Class 1). Seizure outcome was significantly worse in the group with longer symptom duration (p = 0.02). Seven patients were seizure free after surgery. Seizure outcome was stable over the years.

CONCLUSIONS

Since seizure outcome is worse with longer seizure duration, early surgery and, if needed, interdisciplinary intervention, is recommended. Even in cases of multiple cerebral cavernous malformations and epilepsy, surgery should be considered.

Brain arteriovenous malformations and seizures: an Italian study

OBJECTIVE

To evaluate seizures as first clinical manifestation of brain arteriovenous malformations (AVMs), in relation to angioarchitectural features of these vascular anomalies.

METHODS

We performed a prospective observational study, collecting records of patients with AVMs consecutively admitted to the Neurological and Neurosurgery Units of Perugia University and to the Neurosurgery Unit of Terni Hospital, during a 10-year period (1 January 2002 to 1 June 2012). Two groups of patients, with or without seizures as AVM first presentation, were analysed to identify differences in demographic and angiographic features. A multivariate logistic regression model was also developed.

RESULTS

We examined 101 patients with AVMs, 55 male and 46 female. Seizures were the initial clinical manifestation in 31 (30.7%) patients. We found a significant difference (p<0.05) between two groups of patients, with or without seizures as AVM first presentation concerning location, side, topography and venous drainage. A multivariate logistic regression model showed that clinical presentation with seizures was correlated with a location in the temporal and frontal lobes, and with a superficial topography. The strongest association (OR 3.48; 95% CI 1.77 to 6.85) was observed between seizures and AVM location in the temporal lobe.

CONCLUSIONS

Vascular remodelling and haemodynamic changes of AVMs might create conditions for epileptogenesis. However, here we show that malformations with specific angiographic characteristics are more likely to be associated with seizures as first clinical presentation. Location is the most important feature related to epilepsy and in particular the temporal lobe might play a crucial role in the occurrence of seizure.

Rates and predictors of seizure freedom in resective epilepsy surgery: an update

Epilepsy is a debilitating neurological disorder affecting approximately 1 % of the world's population. Drug-resistant focal epilepsies are potentially surgically remediable. Although epilepsy surgery is dramatically underutilized among medically refractory patients, there is an expanding collection of evidence supporting its efficacy which may soon compel a paradigm shift. Of note is that a recent randomized controlled trial demonstrated that early resection leads to considerably better seizure outcomes than continued medical therapy in patients with pharmacoresistant temporal lobe epilepsy. In the present review, we provide a timely update of seizure freedom rates and predictors in resective epilepsy surgery, organized by the distinct pathological entities most commonly observed. Class I evidence, meta-analyses, and individual observational case series are considered, including the experiences of both our institution and others. Overall, resective epilepsy surgery leads to seizure freedom in approximately two thirds of patients with intractable temporal lobe epilepsy and about one half of individuals with focal neocortical epilepsy, although only the former observation is supported by class I evidence. Two common modifiable predictors of postoperative seizure freedom are early operative intervention and, in the case of a discrete lesion, gross total resection. Evidence-based practice guidelines recommend that epilepsy patients who continue to have seizures after trialing two or more medication regimens should be referred to a comprehensive epilepsy center for multidisciplinary evaluation, including surgical consideration.

Seizure outcome after surgical resection of supratentorial cavernous malformations plus hemosiderin rim in patients with short duration of epilepsy

OBJECTIVE

The objective of this study was to retrospectively review the postoperative seizure outcome in patients with short duration of epilepsy associated with cavernous malformations and analyze the effect of surgical methods on seizure outcome in such population.

METHODS

36 patients with short duration of epilepsy (shorter than 12 months) associated with cavernous malformations in temporal or frontal lobe underwent microsurgical resection. The patients were retrospectively divided into two groups: Group A (21 patients) with complete removal of hemosiderin rim and Group B (15 patients) with partial removal of hemosiderin rim. Clinical follow-up was achieved with telephone correspondence or outpatient assessment. The seizure outcome was based on Engel's classification.

RESULTS

After a mean follow-up period of 18 months, 77.8% of the patients (28/36) were classified into Engel class I, including 19 patients (90.5%) in the complete removal of hemosiderin rim group (Group A) and 9 patients (60%) in the partial removal of hemosiderin rim group (Group B). Seizure outcome was significantly better in Group A. There was no mortality and all the postoperative neurological deficits were recovered at the time of follow-up.

CONCLUSION

The analysis of the seizure outcome demonstrate patients with short duration of epilepsy associated with cavernous malformations could benefit greatly from complete resection of hemosiderin rim and cavernous malformations.

Surgical Resection Can Be Successful in a Large Fraction of Patients With Drug-Resistant Epilepsy Associated With Multiple Cerebral Cavernous Malformations

BACKGROUND:

Multiple cerebral cavernous malformations (mCCMs) are known as potentially epileptogenic lesions. Treatment might be multimodal. Management of patients with mCCMs and epilepsy is challenging.

OBJECTIVE:

To evaluate (1) algorhythmic therapeutic sequences in patients with epilepsy associated to mCCMs, (2) whether there are predictive parameters to anticipate the development of drug-resistant epilepsy, and (3) seizure after epilepsy surgery compared to conservatively-treated drug-resistant patients.

METHODS:

All inpatients and outpatients with epilepsy associated to mCCMs from 1990 to 2010 and follow-up &gt;12 months available were retrospectively analyzed.

RESULTS:

Twenty-three patients matched inclusion criteria. Epilepsy became drug-resistant in 18/23 (78%) patients. No predictors were found for development of drug-resistant epilepsy. Median follow-up for both groups was 7.8 years. Nine patients did not qualify for surgical therapy and were treated conservatively. One patient of this cohort (11%) was seizure-free (International League Against Epilepsy [ILAE] class 1). Surgical treatment was performed in 9 patients; 7/9 (78%) of these patients were seizure-free (ILAE class 1) after epilepsy surgery for at least 12 months compared with 1/9 patients in the non-operated group. In 7/9 cases (78%) the largest CCM was resected. In 8/9 (89%) not all CCMs were resected.

CONCLUSION:

After initial diagnosis of epilepsy associated to mCCMs, a primary conservative approach is reasonable. Surgical treatment can be successful in a large fraction of cases with drug-resistant epilepsy where an epileptogenic lesion is identified. Cases where surgery is not undertaken are likely to remain intractable.

Impact on Seizure Control of Surgical Resection or Radiosurgery for Cerebral Arteriovenous Malformations

BACKGROUND:

Seizures are a common presenting symptom of arteriovenous malformations (AVMs). However, the impact of treatment modality on seizure control remains unclear.

OBJECTIVE:

To compare seizure control after surgical resection or radiosurgery for AVMs.

METHODS:

We analyzed retrospectively collected information for 378 patients with cerebral AVMs treated at our institution from 1990 to 2010. The application of strict inclusion criteria resulted in a study population of 164 patients.

RESULTS:

In our cohort, 31 patients (20.7%) had Spetzler-Martin grade I AVMs, 51 (34.0%) grade II, 47 (31.3%) grade III, 20 (13.3%) grade IV, and 1 (0.7%) grade V. Of the 49 patients (30%) presenting with seizures, 60.4% experienced seizure persistence after treatment. For these patients, radiosurgery was associated with seizure recurrence (odds ratio: 4.32, 95% confidence interval: 1.24-15.02, P = .021). AVM obliteration was predictive of seizure freedom at last follow-up (P = .002). In contrast, for patients presenting without seizures, 18.4% experienced de novo seizures after treatment, for which surgical resection was identified as an independent risk factor (hazard ratio: 8.65, 95% confidence interval: 3.05-24.5, P &lt; .001).

CONCLUSION:

Although our data suggest that achieving seizure freedom should not be the primary goal of AVM treatment, surgical resection may result in improved seizure control compared with radiosurgery for patients who present with seizures. Conversely, in patients without presenting seizures, surgical resection increases the risk of new-onset seizures compared with radiosurgery, but primarily within the early posttreatment period. Surgical resection and radiosurgery result in divergent seizure control rates depending on seizure presentation.

Technical, Anatomical, and Functional Study after Removal of a Symptomatic Cavernous Angioma Located in Deep Wernicke's Territories with Cortico-Subcortical Awake Mapping

Introduction. The subcortical region underneath Wernicke's area (WA) is a critical crossing of the eloquent language pathways involved in all semantic, phonological, syntactic, and working memory elaboration. We report the resection of a CA located underneath the dominant WA discussing the functional and anatomical evidence provided by fMRI, dissections with Klingler's technique, and intraoperative mapping during awake surgery. Case Report. A 64-year-old right-handed female affected by daily complex focal seizures underwent f-MRI, showing language activations in the middle and inferior temporal gyri and an unusual free entry zone in the “classical” WA. The cortical intraoperative mapping partially confirmed the f-MRI results, and we approached the lesion directly through WA. Subcortical DES allowed the identification of the eloquent language pathways and the radical resection of the perilesional gliotic rim. The patient did not report deficits and she is seizures and drug free after 1-year surgery. Discussion. Cortical DES demonstrated the variability of the eloquent areas within the cortex of the dominant temporal lobe. The subcortical DES confirmed the crucial role in language elaboration and the anatomical course of the bundles underneath WA. Conclusions. Awake surgery with DES represents a reliable and dynamic technique also for safer and functional-customized resection of CAs.

The value of T(2) (*)-weighted gradient echo imaging for detection of familial cerebral cavernous malformation: A study of two families

The aim of this study was to investigate the value of T₂^*-weighted gradient echo imaging (GRE T₂^*-WI) for the detection of familial cerebral cavernous malformation (FCCM). Twenty-six members of 2 families with FCCM were examined using computed tomography (CT), conventional magnetic resonance imaging (MRI) and GRE T₂^*-WI sequences. We identified 12 cases of FCCM using GRE T₂^*-WI sequences. These 12 patients had multiple lesions (mean 23). The lesions were most commonly located in the ganglia. Other areas included the cortex-subcortex, thalamus, cerebellum and brainstem. These lesions appeared as a reticulated core of mixed signal intensity with a surrounding rim of decreased signal intensity representing hemosiderin from previous hemorrhages. The mean numbers of lesions and cases of FCCM identified by various conventional MRI sequences were 5–17 and 3–9, respectively. Conventional MRI examination involved T₁-weighted imaging (T₁WI), T₂-weighted imaging (T₂WI), T₂-fluid-attenuated inversion recovery (T₂Flair), diffusion-weighted imaging (DWI) and spin-echo imaging (SE) sequences, in that order. The numbers of lesions identified by MRI were fewer than those identified by GRE T₂^*-WI. CT only identified 3 cases with large lesions combined with hemorrhage and calcification. These findings suggest that GRE T₂^*-WI is the first choice when diagnosing FCCM compared with CT and conventional MRI.