Geometrical Characteristics of Grade III Arteriovenous Malformations That Contribute to Better Outcomes in Endovascular Treatment

BACKGROUND

Grade III brain arteriovenous malformation (AVM) is a distinct subgroup of AVMs that encompasses multiple subtypes according to the Spetzler-Martin classification.

METHODS

This retrospective study included 61 patients with grade III AVM who underwent embolization between 2010 and 2022. The study analyzed the angioarchitecture of the AVM nidus and evaluated the outcomes of the embolization procedures.

RESULTS

There were 29 patients (47.5%) with subtype S1E1V1, 20 patients (32.8%) with subtype S2E1V0, and 12 patients (19.7%) with subtype S2E0V1. The rate of complete occlusion in all patients was 47.5% (29 patients). The rate of complete occlusion was higher in cases with a compact nidus (P < 0.001). Several parameters were associated with occlusion of the AVM nidus, including ≤3 arterial feeders (P = 0.017) and presentation with hemorrhage (P = 0.007), with the majority of patients with a compact nidus presenting with hemorrhage. Other factors associated with compact geometry were the presence of a single deep vein, ≤3 arterial feeders, ≤2 superficial draining veins, and an AVM nidus size ≤3 cm.

CONCLUSIONS

The compact nature of grade III AVM is a crucial predictor for the success of embolization. Several characteristics associated with a compact nidus, such as presentation with hemorrhage and a lower number of arterial feeders, have a significantly higher closure rate. Other factors, such as a single deep draining vein, reduced superficial venous drainage, and small size, show a strong association with complete obliteration.

Risk factors of seizure presentation in brain arteriovenous malformation patients and seizure outcomes after single-modality treatments

BACKGROUND

Epileptic seizures are common symptoms in brain arteriovenous malformation patients and seizure control was an important issue in the treatments. This retrospective study attempted to define the risk factors of seizure presentation and to evaluate the effects of treatment modalities on seizure outcomes.

METHODS

Patients receiving single treatment modality during 2013-2016 years, followed up more than 2 years were recruited. Logistic regression analysis was used to detect independent predictors. The factors associated with seizure control were analyzed in patients with pre-treatment seizures, and the factors associated with de novo seizures were analyzed in patents without pre-treatment seizures.

RESULTS

Multivariate analysis identified that the independent predictors of seizure presentation were unruptured (ruptured vs. unruptured, OR = 0.314), and in the frontal (frontal vs. parietal, OR = 3.982) or temporal lobe (temporal vs parietal, OR = 3.313). In 47 patients with seizure presentation, good seizure outcomes were achieved in 26 cases. Partial obliteration of nidus (partial vs complete, OR = 32.301) and headache presentation were independent predictors of poor outcome. In 169 patients without seizure presentation, de novo seizures occurred in 22 cases. Treatments of microsurgery or radiosurgery led to a higher incidence of de novo seizures than intravascular embolization.

CONCLUSIONS

Patients with unruptured and frontal/temporal lobe located nidus were more likely to manifest seizure presentation. Incomplete nidus obliteration was an independent risk factor of poor outcomes in patients with pre-existing seizures. However, compared to microsurgery or radiosurgery, endovascular embolization was less likely to cause de novo seizures in patients without pre-existing seizures.

Effect of Targeted Embolization on Seizure Outcomes in Patients with Brain Arteriovenous Malformations

BACKGROUND

Seizures are one of the most debilitating manifestations of brain arteriovenous malformations (AVMs). This study aimed to evaluate the effect of curative embolization on brain AVM patients presenting with seizures.

METHODS

The records of patients who underwent embolization for brain AVM from January 2012 to December 2020 were evaluated and patients presenting with seizures were interviewed. Patient responses were evaluated according to the International League Against Epilepsy (ILAE) and Engel classifications. Statistical analyses of factors associated with seizure outcomes and complications were performed using ANOVA and Fischer's exact tests.

RESULTS

The mean age of the participants was 35.2 ± 10.7 years. More than 80% of the patients received no or suboptimal dosages of antiepileptic drugs (AEDs) prior to embolization. Positive seizure dynamics were observed in 50% of the patients post-procedure. A correlation was found between length of seizures in anamnesis and outcomes of both Engel and ILAE score, where shorter length was associated with better outcomes. Post-embolization hemorrhage was associated with initial presentation with hemorrhage.

CONCLUSIONS

The embolization of brain AVMs had a positive effect on seizure presentation and a relatively low prevalence of complications. However, the results of the study are obscured by inadequate AED treatment received by the patients, which prompts prospective studies on the topic with careful patient selection.

Treatment of high-grade brain arteriovenous malformations using a hybrid operating room: A prospective single-arm study

BACKGROUND

Optimal treatment of patients with high Spetzler-Martin (S-M) grade brain arteriovenous malformations (BAVMs) remains controversial. Few studies have investigated outcomes in such patients treated in a hybrid operating room (hOR).

OBJECTIVE

To examine outcomes of one-stop hybrid BAVM treatment in patients with high-grade lesions.

METHODS

We prospectively enrolled patients with high-grade BAVMs (S-M grade ≥3) aged 18-65 years who underwent one-stop hybrid BAVM treatment at our hospital between October 2016 and March 2021. High-grade BAVM patients who underwent surgery from 2010 to 2016 served as historical controls.

RESULTS

Forty-one high-grade BAVM patients underwent one-stop hybrid treatment in a hOR. Sixty-one propensity score-matched patients comprised the historical control group. The groups did not significantly differ in patient and BAVM characteristics. Intraoperative angiography in four patients of the hOR group demonstrated residual nidus that required further immediate resection. Main procedural complications included hemorrhage, neurologic deficit, and seizure. In the historical control group, diffuse angioarchitecture and arteriovenous fistula were independent risk factors for incomplete resection.

CONCLUSIONS

One-stop hybrid BAVM treatment is safe and effective for removal of high-grade BAVMs, especially those with diffuse or complex angioarchitecture. Preoperative embolization can effectively reduce blood flow while preserving motor and language function. The combined application of functional magnetic resonance imaging, electrophysiological monitoring, and awake craniotomy can successfully avoid causing neurological injury.

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.

Ischemia-induced inflammation in arteriovenous malformations

OBJECTIVE

The pathophysiology of development, growth, and rupture of arteriovenous malformations (AVMs) is only partially understood. However, inflammation is known to play an essential role in many vascular diseases. This feasibility study was conducted to investigate the expression of enzymes (cyclooxygenase 2 [COX-2] and NLRP3 [NOD-, LRR-, and pyrin domain–containing protein 3]) in the AVM nidus that are essential in their inflammatory pathways and to explore how these influence the pathophysiology of AVMs.

METHODS

The study group comprised 21 patients with partially thrombosed AVMs. The cohort included 8 ruptured and 13 unruptured AVMs, which had all been treated microsurgically. The formaldehyde-fixed and paraffin-embedded samples were immunohistochemically stained with a monoclonal antibody against COX-2 and NLRP3 (COX-2 clone: CX-294; NLRP3: ab214185). The authors correlated MRI and clinical data with immunohistochemistry, using the Trainable Weka Segmentation algorithm for analysis.

RESULTS

The median AVM volume was 2240 mm3. The proportion of NLRP3-positive cells was significantly higher (26.23%–83.95%), compared to COX-2 positive cells (0.25%–14.94%, p < 0.0001). Ruptured AVMs had no higher expression of NLRP3 (p = 0.39) or COX-2 (p = 0.44), compared to nonruptured AVMs. Moreover, no patient characteristics could be reported that showed significant correlations to the enzyme expression.

CONCLUSIONS

NLRP3 consistently showed an approximately 10-fold higher expression level than COX-2, making the inflammatory process in AVMs appear to be mainly associated with ischemic (NLRP3)–driven rather than with mechanical (COX-2)–driven inflammatory pathways. No direct associations between NLRP3 and COX-2 expression and radiological, standard histopathological, or patient characteristics were found in this cohort.

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.

Predictors of seizure control in patients with cerebral arteriovenous malformation

PURPOSE

We aimed to define the predictors of a 2-year seizure-free outcome among patients with cerebral arteriovenous malformation (AVM).

METHODS

A retrospective cohort study recruited patients diagnosed with AVM admitted in the hospital between 2002 and 2020. The demographic data, clinical presentations, seizure semiology, neuro-imaging findings, modality of treatment, and clinical outcomes were compared between the 2-year seizure-free and non-2-year seizure-free groups. A logistic regression model was applied to determine the significant predictors of a 2-year seizure-free outcome.

RESULTS

Of 372 radiologically confirmed patients with cerebral AVM, 105 (28.23%) experienced seizure and a 2-year seizure-free outcome was achieved in 76.19%. Most seizures presented as the initial symptom. Generalized onset seizure was the most common seizure semiology. A nidus diameter < 3 cm (adjusted odds ratio [aOR] 3.102; 95% CI 1.129-9.683; p = 0.046) was the independent predictor of a 2-year seizure-free period, whereas underlying epilepsy (aOR 0.141; 95% CI 0.010-0.688; p = 0.015) was an independent predictor against a 2-year seizure-free outcome.

CONCLUSION

A nidus diameter < 3 cm was the independent predictor of a 2-year seizure-free outcome, whereas underlying epilepsy was the factor against a 2-year seizure-free outcome.

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.

Three-Dimensional Printing Assisted Preoperative Surgical Planning for Cerebral Arteriovenous Malformation

Objective

The aim of this study to investigate the benefits of patient-based 3-dimensional (3D) cerebral arteriovenous malformation (AVM) models for preoperative surgical planning and education.

Methods

Fifteen patients were operated on for AVMs between 2015 and 2019 with patient-based 3D models. Ten patients’ preoperative cranial angiogram screenings were evaluated preoperatively or perioperatively via patient-based 3D models. Two patients needed emergent surgical intervention; their models were solely designed based on their AVMs and used during the operation. However, the other patients who underwent elective surgery had the modeling starting from the skull base. These models were used both preoperatively and perioperatively. The benefits of patients arising from treatment with these models were evaluated via patient files and radiological data.

Results

Fifteen patients (10 males and five females) between 16 and 66 years underwent surgery. The mean age of the patients was 40.0±14.72. The most frequent symptom patients observed were headaches. Four patients had intracranial bleeding; the symptom of admission was a loss of consciousness. Two patients (13.3%) belonged to Spetzler-Martin (SM) grade I, four (26.7%) belonged to SM grade II, eight (53.3%) belonged to SM grade III, and one (6.7%) belonged to SM grade IV. The mean operation duration was 3.44±0.47 hours. Three patients (20%) developed transient neurologic deficits postoperatively, whereas three other patients died (20%).

Conclusion

Several technological innovations have emerged in recent years to reduce undesired outcomes and support the surgical team. For example, 3D models have been employed in various surgical procedures in the last decade. The routine usage of patient-based 3D models will not only support better surgical planning and practice, but it will also be useful in educating assistants and explaining the situation to the patient as well.

Histopathology of brain AVMs part I: microhemorrhages and changes in the nidal vessels

Background

Arteriovenous malformations of the brain (bAVM) may rupture from aneurysms or ectasias of the feeding, draining, or nidal vessels. Moreover, they may rupture from the immature, fragile nidal vessels that are characteristic to bAVMs. How the histopathological changes of the nidal vessels associate with clinical presentation and hemorrhage of the lesion is not well known.

Materials and methods

We investigated tissue samples from surgically treated bAVMs (n = 85) using standard histological and immunohistochemical stainings. Histological features were compared with the clinical presentation of the patient.

Results

Microhemorrhages from nidal vessels were found both in bAVMs with a history of clinically evident rupture and in bAVMs considered unruptured. These microhemorrhages were associated with presence of immature, pathological nidal vessels (p = 0.010) and perivascular inflammation of these vessels (p = 0.001), especially with adhesion of neutrophils (p < 0.001). In multivariate analysis, perivascular inflammation (OR = 19, 95% CI 1.6 to 230), neutrophil infiltration of the vessel wall (OR = 13, 95% CI 1.9 to 94), and rupture status (OR = 0.13, 95% CI 0.017 to 0.92) were significantly associated with microhemorrhages.

Conclusions

Clinically silent microhemorrhages from nidal vessels seem to be very common in bAVMs, and associate with perivascular inflammation and neutrophil infiltration. Further studies on the role of perivascular inflammation in the clinical course of bAVMs are indicated.

Electronic supplementary material

The online version of this article (10.1007/s00701-020-04391-w) contains supplementary material, which is available to authorized users.

Intracranial Gorgon: Surgical Case Report of a Large Calcified Brain Arteriovenous Malformation

Patient: Male, 55-year-old

Final Diagnosis: Right frontal arteriovenous malformation, partially calcified • multiple generalised epileptic seizures • chronic headache

Symptoms: Epilectic seizure • headache

Medication: —

Clinical Procedure: Neurosurgical resection of the right frontal AVM

Specialty: Neurosurgery

Long-term health-related quality of life in 262 patients with brain arteriovenous malformation

OBJECTIVE

To discover the health-related quality of life (HRQOL) of patients with treated arteriovenous malformation (AVM), we used the self-applicable HRQOL instrument, the 15D, and analyzed the scores in both in the whole study population and specified cohorts.

METHODS

The 15D questionnaires were mailed to adult patients with AVM alive in 2016 (n = 432) in our database. Patients with completely eradicated AVM (n = 262) were included in a subsequent analysis. The results were compared with those of the general population standardized for age and sex. Subgroup analyses were conducted for epilepsy, number of bleeding episodes, location of the lesion, modified Rankin Scale score, and Spetzler-Ponce classification (SPC) using independent-samples t test or analysis of covariance. Tobit regression was used to explain the variance in the 15D score.

RESULTS

Patients had impaired HRQOL compared to the reference population (p < 0.0001). Deep location, multiple bleeding episodes, and refractory epilepsy were associated with impaired HRQOL. Patients in SPC A and B had similar posttreatment 15D scores, whereas those in class C had an impaired HRQOL. Significant explanatory variables in the regression model were age, sex, number of bleeding episodes, refractory epilepsy, and SPC.

CONCLUSIONS

With careful patient selection, patients in SPC B can reach as favorable HRQOL as those in SPC A provided the operation is successful. Multiple bleeding episodes should be prevented with effective treatment aiming at complete AVM obliteration. The postoperative treatment of patients with AVM should focus on preventing depressive symptoms, anxiety, and epileptic seizures. We encourage other research groups to use HRQOL instruments to fully understand the consequences of neurologic and neurosurgical diseases on patients' HRQOL.

Volume-Staged CyberKnife Stereotactic Radiosurgery for Treatment of Drug-Resistant Epilepsy for a Spetzler-Martin Grade V Arteriovenous Malformation: A Case Report and Review of the Literature

BACKGROUND

Evidence to support the use of stereotactic radiosurgery (SRS) in the treatment of epilepsy secondary to cerebral arteriovenous malformations (AVMs) is emerging. However, these studies have not clearly demonstrated the use of SRS in the treatment of drug-resistant epilepsy (DRE) in high Spetzler-Martin grade (IV-V) AVMs.

CASE DESCRIPTION

We present a 48-year-old woman with DRE secondary to a Spetzler-Martin grade V cerebral AVM. She was treated with volume-staged SRS (VS-SRS) and achieved near-complete resolution of her seizures with incomplete obliteration of the AVM. Six years after treatment, she has experienced no serious complications.

CONCLUSIONS

VS-SRS successfully controlled seizures (Engel Outcome Measure of 1A) in a patient with intractable, DRE secondary to a high-grade cerebral AVM.

Predictors of Epilepsy Presentation in Unruptured Brain Arteriovenous Malformations: A Quantitative Evaluation of Location and Radiomics Features on T2-Weighted Imaging

OBJECTIVE

To explore predictors of epilepsy presentation in unruptured brain arteriovenous malformations (bAVMs) with quantitative evaluation of location and radiomics features on T2-weighted imaging.

METHODS

This retrospective study identified 117 patients with unruptured bAVMs. Cases were randomly split into training dataset (n = 90) and test dataset (n = 27). On the training dataset, we applied atlas-based analysis to identify epilepsy-susceptible brain regions of bAVMs, and then applied the radiomics technique to explore shape, intensity, and textural features that were correlated with epilepsy presentation. Informative radiomics predictors were selected by least absolute shrinkage and selection operator with 3-fold cross-validation. A linear classification score was then constructed, and we tested if we could precisely identify epilepsy-susceptible bAVMs with the location and radiomics predictors.

RESULTS

Two brain regions and 4 radiomics features were screened out as predictors for epilepsy. The percent of damage of the right precentral gyrus and the right superior longitudinal fasciculus was associated with epilepsy presentation. The 4 radiomics features were Original_firstorder_Median, Wavelet-LHL_firstorder_InterquartileRange, Wavelet-HHL_firstorder_InterquartileRange, and Wavelet-HHH_glrlm_RunVariance. Epileptogenic bAVMs had larger variance of run lengths, larger median value, and interquartile range of voxel intensities. On the training dataset, these 6 predictors were able to classify epilepsy-susceptible bAVMs with accuracy at 0.822, and the area under the curve was 0.866 (95% confidence interval, 0.791-0.940). On the test dataset, sensitivity, specificity, and accuracy of classification reached 0.786, 0.769, and 0.778, respectively.

CONCLUSIONS

Epilepsy-susceptible bAVMs had distinct locations and radiomics features on T2-weighted imaging.

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.

Critical review of brain AVM surgery, surgical results and natural history in 2017

BACKGROUND

An understanding of the present standing of surgery, surgical results and the role in altering the future morbidity and mortality of untreated brain arteriovenous malformations (bAVMs) is appropriate considering the myriad alternative management pathways (including radiosurgery, embolization or some combination of treatments), varying risks and selection biases that have contributed to confusion regarding management. The purpose of this review is to clarify the link between the incidence of adverse outcomes that are reported from a management pathway of either surgery or no intervention with the projected risks of surgery or no intervention.

METHODS

A critical review of the literature was performed on the outcomes of surgery and non-intervention for bAVM. An analysis of the biases and how these may have influenced the outcomes was included to attempt to identify reasonable estimates of risks.

RESULTS

In the absence of treatment, the cumulative risk of future hemorrhage is approximately 16% and 29% at 10 and 20 years after diagnosis of bAVM without hemorrhage and 35% and 45% at 10 and 20 years when presenting with hemorrhage (annualized, this risk would be approximately 1.8% for unruptured bAVMs and 4.7% for 8 years for bAVMs presenting with hemorrhage followed by the unruptured bAVM rate). The cumulative outcome of these hemorrhages depends upon whether the patient remains untreated and is allowed to have a further hemorrhage or is treated at this time. Overall, approximately 42% will develop a new permanent neurological deficit or death from a hemorrhagic event. The presence of an associated proximal intracranial aneurysm (APIA) and restriction of venous outflow may increase the risk for subsequent hemorrhage. Other risks for increased risk of hemorrhage (age, pregnancy, female) were examined, and their purported association with hemorrhage is difficult to support. Both the Spetzler-Martin grading system (and its compaction into the Spetzler-Ponce tiers) and Lawton-Young supplementary grading system are excellent in predicting the risk of surgery. The 8-year risk of unfavorable outcome from surgery (complication leading to a permanent new neurological deficit with a modified Rankin Scale score of greater than one, residual bAVM or recurrence) is dependent on bAVM size, the presence of deep venous drainage (DVD) and location in critical brain (eloquent location). For patients with bAVMs who have neither a DVD nor eloquent location, the 8-year risk for an unfavorable outcome increases with size (increasing from 1 cm to 6 cm) from 1% to 9%. For patients with bAVM who have either a DVD or eloquent location (but not both), the 8-year risk for an unfavorable outcome increases with the size (increasing from 1 cm to 6 cm) from 4% to 35%. For patients with bAVM who have both a DVD and eloquent location, the 8-year risk for unfavorable outcome increases with size (increasing from 1 cm to 3 cm) from 12% to 38%.

CONCLUSION

Patients with a Spetzler-Ponce A bAVM expecting a good quality of life for the next 8 years are likely to do better with surgery in expert centers than remaining untreated. Ongoing research is urgently required on the outcome of management pathways for bAVM.

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.

Seizures associated with cerebral arteriovenous malformations

Various types of seizures and epilepsy are associated with 20-45% of cerebral arteriovenous malformations (AVMs). The necessity to differentiate between occasional seizures, epilepsy with repetitive seizures, and the much rarer drug-resistant epilepsy (DRE) is underlined. It is clear that where there is frequent seizures or DRE, vascular surgeons should take epilepsy surgery aspects into account. The epidemiology of AVM-associated seizures, assumed pathophysiologic mechanisms, most frequent seizures types, and medical treatment are described. Depending on the severity of the epilepsy, the diagnostic workup, including electroencephalogram (EEG), video-EEG, and, rarely, invasive evaluation, is explained. An invasive presurgical workup is only necessary in rare cases of DRE. The indication to extend the resection to more than just removal of the AVM is defined and the various specific resection techniques for this rare form are outlined. In the vast majority of AVM cases removal of the AVM with some adjoining gliotic or hemosiderotic rim of cortex will be sufficient, however. In the majority of cases with preoperative epilepsy, patients will be seizure-free after surgery. Patients who never had a seizure before AVM removal may develop de novo epilepsy postoperatively (5-15%). Rates of seizure freedom after different treatments (microsurgery, radiosurgery, endovascular) vary.

Microsurgical Outcome of Unruptured Brain Arteriovenous Malformations: A Single-Center Experience

OBJECTIVE

We describe our single-center experience treating unruptured brain arteriovenous malformations (uBAVMs) with microsurgical treatment.

METHODS

During a 7-year period, 282 patients with uBAVMs were surgically treated at our institution. Patient clinical features, postsurgical complications, arteriovenous malformation obliteration rate, seizure control, and functional outcome were collected and analyzed. Seizure control was evaluated with the Engel classification system. Patient functional outcome was assessed with modified Rankin Scale score.

RESULTS

Complete obliteration was achieved in 98.2% of cases. Surgical mortality rate was zero, and overall mortality rate was 1.1%. Good functional outcome (modified Rankin Scale score 0-1) was achieved in 86.9% of all patients, including 92.5% of patients with Spetzler-Martin (S-M) grade I and II uBAVMs, 80.6% of patients with S-M grade III uBAVMs, and 62.5% of patients with S-M grade IV and V uBAVMs. Poor outcome was significantly associated with arteriovenous malformation size ≥6 cm, deep venous drainage, eloquent location, and poor seizure control (all P < 0.05). For 177 patients with presurgical seizures, good seizure outcome (Engel class I) was achieved in 124 (70.1%) patients after microsurgical treatment. A short history of seizure occurrence, fewer presurgical seizures, and generalized tonic-clonic seizure type may be predictors of good seizure outcome (all P < 0.05).

CONCLUSIONS

Good functional outcome can be achieved by microsurgical resection in S-M grade I and II and selected grade III uBAVMs. Surgical resection for high-grade (grade IV and V) uBAVMs is challenging. A high seizure-free rate can be achieved in patients with initial seizure presentation.

Seizure control following treatment of brain arteriovenous malformations in pediatric patients

PURPOSE

Seizure outcome after treatment for pediatric patients with arteriovenous malformations (AVMs) has been rarely described in the literature. The aim of this study was to determine the risk factors for seizure presentation in pediatric AVM patients and the predictors for seizure control following treatment.

METHODS

We searched our characteristics of seizures associated with brain arteriovenous malformations prospectively maintained AVM database at Beijing Tiantan Hospital and identified 198 pediatric patients with brain AVMs between the year 2009 and 2014. Seizure presentation, patient characteristics, AVM features, treatment modalities, and postoperative outcomes, especially post-treatment seizure control were collected. Univariate and multivariate logistic regression analyses were applied to determine the risk factors for seizure presentation as well as the predictors for seizure control.

RESULTS

Before initiation of any treatments, 63 (31.8 %) of the overall 198 patients presented with seizure. According to multivariate analyses, larger AVM size, frontal AVM location, and history of prior hemorrhage were significantly associated with seizure presentation (all p < 0.05). For patients with pre-treatment seizure presentation, good seizure outcome was achieved in 73.8 %. AVM obliteration, short-period history of seizure, and short duration for seizure onset were independent predictors of good seizure outcome in the multivariate analysis. For the 135 patients without seizures at presentation, the overall rate of de novo seizures was 4.4 %.

CONCLUSION

In pediatric patients with brain AVMs, prior hemorrhage, larger AVM size, and frontal lobe location may predict subsequent seizures. Highest seizure control can be achieved by complete obliteration of the AVMs with microsurgical resection.

Microsurgery for cerebral arteriovenous malformations: subgroup outcomes in a consecutive series of 288 cases

OBJECTIVE The objective of this study was to review the outcomes after microsurgical resection of cerebral arteriovenous malformations (AVMs) from a consecutive single-surgeon series. Clinical and imaging data were analyzed to address the following questions concerning AVM treatment in the post-ARUBA (A Randomized Trial of Unruptured Brain Arteriovenous Malformations) era. 1) Are the patients who present with unruptured or ruptured AVMs doing better at long-term follow-up? 2) Is the differentiation between Ponce Class A (Spetzler-Martin Grade I and II) patients versus Ponce Class B and C patients (Spetzler-Martin Grade III and IV) meaningful and applicable to surgical practice? 3) How did the ARUBA-eligible patients of this surgical series compare with the results reported in ARUBA? METHODS Two hundred eighty-eight patients with cerebral AVMs underwent microsurgical resection between 1983 and 2012 performed by the same surgeon (J.S.). This is a prospective case collection study that represents a consecutive series. The results are based on prospectively collected, early-outcome data that were supplemented by retrospectively collected, follow-up data for 94% of those cases. The analyzed data included the initial presentation, Spetzler-Martin grade, obliteration rates, surgical and neurological complications, and frequency of pretreatment with embolization or radiosurgery. The total cohort was compared using "small-AVM," Spetzler-Martin Grade I and II, and ARUBA-eligible AVM subgroups. RESULTS The initial presentation was hemorrhage in 50.0% and seizures in 43.1% of patients. The series included 53 Spetzler-Martin Grade I (18.4%), 114 Spetzler-Martin Grade II (39.6%), 90 Spetzler-Martin Grade III (31.3%), 28 Spetzler-Martin Grade IV (9.7%), and 3 Spetzler-Martin Grade V (1.0%) AVMs. There were 144 unruptured and 104 ARUBA-eligible cases. Preembolization was used in 39 cases (13.5%). The occlusion rates for the total series and small AVM subgroup were 99% and 98.7%, respectively. The mean follow-up duration was 64 months. Early neurological deterioration was seen in 39.2% of patients, of which 12.2% had permanent and 5.6% had permanent significant deficits, and the mortality rate was 1.7% (n = 5). Outcome was better for patients with AVMs smaller than 3 cm (permanent deficit in 7.8% and permanent significant deficit in 3.2% of patients) and Ponce Class A status (permanent deficit in 7.8% and significant deficit in 3.2% of patients). Unruptured AVMs showed slightly higher new deficit rates (but 0 instances of mortality) among all cases, and in the small AVM and Ponce Class A subgroups. Unruptured Spetzler-Martin Grade I and II lesions had the best outcome (1.8% permanent significant deficit), and ARUBA-eligible Spetzler-Martin Grade I and II lesions had a slightly higher rate of permanent significant deficits (3.2%). CONCLUSIONS Microsurgery has a very high cure rate. Focusing microsurgical AVM resection on unruptured lesions smaller than 3 cm or on Spetzler-Martin Grade I and II lesions is a good strategy for minimizing long-term morbidity. Well-selected microsurgical cases lead to better outcomes than with multimodal interventions, as in the ARUBA treatment arm, or conservative treatment alone. Long-term prospective data collection is valuable.