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

Current and Future Applications of Arterial Spin Labeling MRI in Cerebral Arteriovenous Malformations

Arterial spin labeling (ASL) has emerged as a promising noninvasive tool for the evaluation of both pediatric and adult arteriovenous malformations (AVMs). This paper reviews the advantages and challenges associated with the use of ASL in AVM assessment. An assessment of the diagnostic workup of AVMs and their variants in both adult and pediatric populations is proposed. Evaluation after treatments, whether endovascular or microsurgical, was similarly examined. ASL, with its endogenous tracer and favorable safety profile, offers functional assessment and arterial feeder identification. ASL has demonstrated strong performance in identifying feeder arteries and detecting arteriovenous shunting, although some studies report inferior performance compared with digital subtraction angiography (DSA) in delineating venous drainage. Challenges include uncertainties in sensitivity for specific AVM features. Detecting AVMs in challenging locations, such as the apical cranial convexity, is further complicated, demanding careful consideration due to the risk of underestimating total blood flow. Navigating these challenges, ASL provides a noninvasive avenue with undeniable merits, but a balanced approach considering its limitations is crucial. Larger-scale prospective studies are needed to comprehensively evaluate the diagnostic performance of ASL in AVM assessment.

Impact of COVID-19 pandemic on treatment and outcomes of cerebral arteriovenous malformations

BACKGROUND

There has been a recent decrease in interventional management of cerebral arteriovenous malformations (AVMs). The objective of our study was to evaluate the changing patterns in management of AVMs in the first year of the COVID-19 pandemic.

METHODS

The National Inpatient Sample (NIS) database was used. From 2016 to 2020, patients with an International Classification of Diseases, 10th revision (ICD-10) diagnosis code for a cerebral AVM were included. An intervention was defined as ICD-10 code for surgical, endovascular, or stereotactic radiosurgery treatment. Odds ratios (ORs) were calculated using a logistic regression model with covariates deemed to be clinically relevant.

RESULTS

63 610 patients with AVMs were identified between 2016 and 2020, 14 340 of which were ruptured. In 2020, patients had an OR of 0.69 for intervention of an unruptured AVM (P<0.0001) compared with 2016-19. The rate of intervention for unruptured AVMs decreased to 13.5% in 2020 from 17.6% in 2016-19 (P<0.0001). The rate of AVM rupture in 2020 increased to 23.9% from 22.2% in 2016-19 (P<0.0001). In 2020, patients with ruptured AVMs had an OR for inpatient mortality of 1.72 compared with 2016-19. Linear regression analysis from 2016 to 2020 showed an inverse relationship between intervention rate and rupture rate (slope -0.499, R2=0.88, P=0.019).

CONCLUSION

In 2020, the rate of intervention for unruptured cerebral AVMs decreased compared with past years, with an associated increase in the rate of rupture. Patients with ruptured AVMs also had a higher odds of mortality.

Treatment of Brain Arteriovenous Malformations

Brain arteriovenous malformations (AVMs) are a rare entity of vascular anomalies, characteristic of anatomical shunting where arterial blood directly flows into the venous circulation. The main aim of the active treatment policy of brain AVMs is the prevention of haemorrhage. There are well-established treatment strategies that continually improve in their safety and efficacy, primarily due to the advances in imaging modalities, targeted and novel techniques, the development of alternative treatment approaches, and even better experience with the disease itself. There are interesting imaging novelties that may be prospectively applicable in the decision-making and planning of the most effective treatment approach for individual patients with intracranial AVM. Surgery is often considered the first-line treatment; however, each patient should be evaluated individually, and the risks of the active treatment policy should not overcome the benefits of the spontaneous natural history of the disease. All treatment modalities, i.e., surgery, radiosurgery, endovascular embolization, and observation, are justified but need to be meticulously selected for each individual patient in order to deliver the best treatment outcome. This chapter deals with historical and currently applied dogmas, followed by introductions of advances in each available treatment modality of AVM management.

Long-term outcomes of microsurgery and stereotactic radiosurgery as the first-line treatment for arteriovenous malformations: a propensity score-matched analysis using nationwide multicenter prospective registry data

BACKGROUND

This study aimed to compare the risk and benefit profile of microsurgery (MS) and stereotactic radiosurgery (SRS) as the first-line treatment for unruptured and ruptured arteriovenous malformations (AVMs).

MATERIALS AND METHODS

The authors included AVMs underwent MS or SRS as the first-line treatment from a nationwide prospective multicenter registry in mainland China. The authors used propensity score-matched methods to balance baseline characteristics between the MS and SRS groups. The primary outcomes were long-term hemorrhagic stroke or death, and the secondary outcomes were long-term obliteration and neurological outcomes. Subgroup analyses and sensitivity analyses with different study designs were performed to confirm the stability of our findings.

RESULTS

Of the 4286 consecutive AVMs in the registry from August 2011 to December 2021; 1604 patients were eligible. After matching, 244 unruptured and 442 ruptured AVMs remained for the final analysis. The mean follow-up duration was 7.0 years in the unruptured group and 6.1 years in the ruptured group. In the comparison of primary outcomes, SRS was associated with a higher risk of hemorrhagic stroke or death both in the unruptured and ruptured AVMs (unruptured: hazard ratio 4.06, 95% CI: 1.15-14.41; ruptured: hazard ratio 4.19, 95% CI: 1.58-11.15). In terms of the secondary outcomes, SRS was also observed to have a significant disadvantage in long-term obliteration [unruptured: odds ratio (OR) 0.01, 95% CI: 0.00-0.04; ruptured: OR 0.09, 95% CI: 0.05-0.15]. However, it should be noted that SRS may have advantages in preventing neurofunctional decline (unruptured: OR 0.56, 95% CI: 0.27-1.14; ruptured: OR 0.41, 95% CI: 0.23-0.76). The results of subgroup analyses and sensitivity analyses were consistent in trend but with slightly varied powers.

CONCLUSIONS

This clinical practice-based real-world study comprehensively compared MS and SRS for AVMs with long-term outcomes. MS is more effective in preventing future hemorrhage or death and achieving obliteration, while the risk of neurofunctional decline should not be ignored.

Impact of tailored multimodal treatment for unruptured brain arteriovenous malformation: comparison with a randomized trial of unruptured brain arteriovenous malformations

PURPOSE

The first randomized controlled study on unruptured brain arteriovenous malformations (bAVM), the ARUBA trial, demonstrate the superiority of medical management; however, it failed to completely rule out the efficacy of therapeutic interventions due to several limitations. This study aimed to examine the outcomes of multimodal interventional treatment for bAVM in terms of safety and efficacy.

METHODS

We reviewed 226 consecutive patients with unruptured bAVM admitted to our institute between 2002 and 2022. Treatment methods were divided into medical management and therapeutic intervention, including microsurgery, stereotactic surgery, and endovascular intervention. First, the choice of therapeutic modalities was assessed in the pre-ARUBA (before February 2014) and post-ARUBA (after March 2014) eras. Second, the incidence of symptomatic stroke or death and functional prognosis with a modified Rankin scale (mRS) score of ≥2 at 5 years was compared between the medical management and therapeutic intervention.

RESULTS

In the pre- and post-ARUBA groups, 73% and 84% of patients underwent therapeutic interventions, respectively (p = 0.053). The rate of symptomatic stroke or death was lower in patients who underwent interventional therapies than in those who underwent medical management (9.7% vs. 22%, p = 0.022); however, the opposite was observed in the ARUBA trial (31% vs. 10%). The annual incidence of stroke or death was also lower in the interventional therapy group (4.3%/y vs. 1.8%/year, hazard ratio = 0.45, 95% confidence interval: 0.18-1.08, p = 0.032). The rate of mRS score of ≥2 after a 5-year follow-up was 18% and 6% in the medical treatment and intervention groups (p = 0.14).

CONCLUSIONS

The therapeutic intervention rate did not decrease, even after the publication of the ARUBA trial. The rate of stroke or death was lower in the intervention group, indicating that a tailored choice of multimodality is safe and effective for managing unruptured bAVM.

Multi-Stage Treatment for Spetzler-Martin Grades III, IV, and V Arteriovenous Malformations: Preoperative Embolization and Microsurgical Resection in a Consecutive Series of 250 Patients

PURPOSE

The treatment of high-grade brain AVMs is challenging and has no guidelines available to date. This study was aimed at reporting the experience of two centers in treating these AVMs through a multi-stage approach consisting of preoperative embolization and microsurgical resection.

METHODS

A retrospective review was performed for 250 consecutive patients with a diagnosis of high-grade brain AVM (Spetzler-Martin grades III, IV, and V) treated in two centers in Germany between January 1989 and February 2023. The analyzed data included demographic, clinical, morphological, and neurological data.

RESULTS

A total of 150 cases (60%) were classified as Spetzler-Martin grade III, 82 cases (32.8%) were classified as grade IV, and 18 cases (7.2%) were classified as grade V. Eighty-seven cases (34.8%) presented with hemorrhage. The devascularization percentages achieved were <50% in 24 (9.6%), 50-80% in 55 (22%), and >80% in 171 (68.4%) cases. The average number of sessions was 5.65 ± 5.50 and 1.11 ± 0.32 endovascular and surgical procedures, respectively, and did not significantly differ by rupture status. Death or dependency (mRS score ≥ 3) after the last follow-up was observed in 18.8% of patients and was significantly associated with age > 80 years and poor baseline neurological condition. The complete resection rate was 82.3% and was significantly associated with age > 80 years, large nidus, and deep venous drainage. Permanent disabling neurological deficit after at least 3 months of follow-up was diagnosed in 13.2% of patients and was significantly associated with age > 80 years and infratentorial locations.

CONCLUSION

A multi-stage treatment for high-grade AVMs is feasible for selected cases but comes at a functional cost. The devascularization percentage was not associated with the investigated outcomes. Age > 80 years was associated with poor safety and effectiveness outcomes; consequently, this treatment should be offered only in exceptional circumstances.

Microsurgical Treatment of Arteriovenous Malformations: A Single-Center Study Experience

OBJECTIVE

The purpose of the study was to assess the functional outcomes after microsurgical resection of arteriovenous malformations (AVMs) and to compare the results between patients eligible for A Randomized Trial of Unruptured Brain Arteriovenous Malformations in this surgical series to the results reported and the ARUBA study.

METHODS

We reviewed the records of 169 patients who underwent microsurgical treatment of arteriovenous malformation (AVMs) in our institution between January 2016 and December 2021. These patients' functional status was assessed using modified Rankin Scale (mRS) scores at the last follow-up and before treatment. The mRS scores at the latest follow-up were classified into good outcomes (mRS < 3) and poor outcomes (mRS ≥ 3). Clinical presentation, patients' demographics, AVM characteristics, follow-up time, and obliteration rate were analyzed. Subgroup analyses were performed on the whole cohort, comparing Spetzler-Martin Grade I and Grade II, and ARUBA-eligible AVMs.

RESULTS

The initial hemorrhagic presentation occurred in 71 (42%) out of 169 patients. The majority of the patients presented with headaches (73%). The AVMs were completely obliterated in 166 (98.2%) patients. The series included 65 Spetzler-Martin Grade I (38.5%), 46 Grade II (27.2%), 32 Grade III (18.9%), 22 Grade IV (13%), and 4 Grade V (2.4%) AVMs. There were 98 unruptured and 79 ARUBA-eligible cases. Also, optimal functional outcome was achieved in 145 (85.8%) patients. The overall mortality rate was 5.3% (9/169). The multivariate analysis illustrated that a poor outcome was significantly associated with presurgical mRS ≥3 (p < 0.013; OR, 0.206; 95% CI 0.059-0.713), increasing age (p < 0.045; odds ratio [OR], 1.022; 95% CI 1.000-0.045), and female gender (p < 0.009; OR, 2.991; 95% CI 1.309-6.832).

CONCLUSIONS

Our study suggests that better outcomes can be obtained using microsurgical resection in the majority of patients with AVMs. Independent predictors of poor outcomes after surgical resection of AVMs include increasing age at the time of surgery, poor presurgical functional status, and female gender. Supposing that patients are more suitable for microsurgery after presurgical examination, outcomes are normally better in that case than those achieved by multimodal interventions (such as conservative treatment or ARUBA treatment arm). Therefore, we recommend early surgical removal on all surgically accessible AVMs to prevent successive hemorrhages and the consequences of poor neurological outcomes.

National reduction in cerebral arteriovenous malformation treatment correlated with increased rupture incidence

BACKGROUND

Recently, there has been a shift in management of unruptured cerebral arteriovenous malformations (AVMs) following studies suggesting that medical management alone was superior to interventional therapy.

OBJECTIVE

To evaluate the influence of contemporary AVM management on AVM rupture patterns in the United States.

METHODS

154 297 AVM admissions were identified between 2003 and 2017 in the National Inpatient Sample. Annual AVM intervention and rupture rates were computed and multivariable logistic regression assessed the likelihood of AVM intervention pre- and post-2014. Segmented regression identified significant change points and fitted segmented linear models for annual intervention and rupture rates. Correlation coefficients assessed the relationship between annual AVM intervention and rupture rates.

RESULTS

For unruptured AVMs, intervention likelihood and proportion decreased after 2014 (28.1% to 22.3%, p<0.0001; adjusted OR=0.857, 95% CI 0.751 to 0.977, p=0.02). Ruptured AVM admissions increased from 14.7% to 18.6% after 2014 (p<0.0001). Between 2003 and 2017, segmented linear regression identified one significant change point in intervention rate between 2014 and 2015. Average annual percent change for rupture incidence and intervention rate increased by 0.49% (p=0.0001) and decreased by 1.17% (p=0.0001), respectively. Annual AVM intervention rates were inversely correlated with annual AVM rupture incidence (Pearson coefficient=-0.82, p=0.0002). In 2017, the annual AVM rupture rate (20.6%) surpassed the annual AVM intervention rate (19.7%).

CONCLUSIONS

After 2014, the likelihood of intervention for unruptured AVMs decreased while the incidence of ruptured AVMs increased. These findings suggest that fewer unruptured AVM treatments may lead to increases in AVM rupture incidence.

Microsurgery versus Microsurgery With Preoperative Embolization for Brain Arteriovenous Malformation Treatment: A Systematic Review and Meta-analysis

BACKGROUND

Preoperative embolization has traditionally been regarded as a safe and effective adjunct to microsurgical treatment of brain arteriovenous malformations (bAVM). However, there is currently no high-level evidence to ascertain this presumption.

OBJECTIVE

To compare the outcomes of microsurgery (MS) vs microsurgery with preoperative embolization (E + MS) in patients with bAVM through systematic review.

METHODS

We searched MEDLINE, PubMed, and Embase. The primary outcome was bAVM obliteration. Secondary outcomes were intraoperative bleeding (mL), complications, worsened modified Rankin Scale (mRS), and mortality. The pooled proportions of outcomes were calculated through the logit transformation method. The odds ratio (OR) of categorical data and mean difference of continuous data were estimated through the Mantel-Haenszel and the inverse variance methods, respectively.

RESULTS

Thirty-two studies met the eligibility criteria. One thousand eight hundred twenty-eight patients were treated by microsurgery alone, and 1088 were treated by microsurgery with preoperative embolization, respectively. The meta-analysis revealed no significant difference in AVM obliteration (94.1% vs 95.6%, OR = 1.15 [0.63-2.11], P = .65), mortality (1.7% vs 2%, OR = 0.88 [0.30-2.58], P = .82), procedural complications (18.2% vs 27.2%, OR = 0.47 [0.19-1.17], P = .10), worsened mRS (21.2% vs 18.5%, OR = 1.08 [0.33-3.54], P = .9), and intraoperative blood loss (mean difference = 182.89 [-87.76, 453.55], P = .19).

CONCLUSION

The meta-analysis showed no significant difference in AVM obliteration, mortality, complications, worse mRS, and intraoperative blood loss between MS and E + MS groups. For AVMs where MS alone has acceptable results, it is reasonable to bypass unnecessary preoperative embolization given higher postoperative complication risk.

Endovascular treatment of brain arteriovenous malformations: clinical outcomes of patients included in the registry of a pragmatic randomized trial

OBJECTIVE

The role of endovascular treatment in the management of patients with brain arteriovenous malformations (AVMs) remains uncertain. AVM embolization can be offered as stand-alone curative therapy or prior to surgery or stereotactic radiosurgery (SRS) (pre-embolization). The Treatment of Brain AVMs Study (TOBAS) is an all-inclusive pragmatic study that comprises two randomized trials and multiple registries.

METHODS

Results from the TOBAS curative and pre-embolization registries are reported. The primary outcome for this report is death or dependency (modified Rankin Scale [mRS] score > 2) at last follow-up. Secondary outcomes include angiographic results, perioperative serious adverse events (SAEs), and permanent treatment-related complications leading to an mRS score > 2.

RESULTS

From June 2014 to May 2021, 1010 patients were recruited in TOBAS. Embolization was chosen as the primary curative treatment for 116 patients and pre-embolization prior to surgery or SRS for 92 patients. Clinical and angiographic outcomes were available in 106 (91%) of 116 and 77 (84%) of 92 patients, respectively. In the curative embolization registry, 70% of AVMs were ruptured, and 62% were low-grade AVMs (Spetzler-Martin grade I or II), while the pre-embolization registry had 70% ruptured AVMs and 58% low-grade AVMs. The primary outcome of death or disability (mRS score > 2) occurred in 15 (14%, 95% CI 8%–22%) of the 106 patients in the curative embolization registry (4 [12%, 95% CI 5%–28%] of 32 unruptured AVMs and 11 [15%, 95% CI 8%–25%] of 74 ruptured AVMs) and 9 (12%, 95% CI 6%–21%) of the 77 patients in the pre-embolization registry (4 [17%, 95% CI 7%–37%] of 23 unruptured AVMs and 5 [9%, 95% CI 4%–20%] of 54 ruptured AVMs) at 2 years. Embolization alone was confirmed to occlude the AVM in 32 (30%, 95% CI 21%–40%) of the 106 curative attempts and in 9 (12%, 95% CI 6%–21%) of 77 patients in the pre-embolization registry. SAEs occurred in 28 of the 106 attempted curative patients (26%, 95% CI 18%–35%, including 21 new symptomatic hemorrhages [20%, 95% CI 13%–29%]). Five of the new hemorrhages were in previously unruptured AVMs (n = 32; 16%, 95% CI 5%–33%). Of the 77 pre-embolization patients, 18 had SAEs (23%, 95% CI 15%–34%), including 12 new symptomatic hemorrhages [16%, 95% CI 9%–26%]). Three of the hemorrhages were in previously unruptured AVMs (3/23; 13%, 95% CI 3%–34%).

CONCLUSIONS

Embolization as a curative treatment for brain AVMs was often incomplete. Hemorrhagic complications were frequent, even when the specified intent was pre-embolization before surgery or SRS. Because the role of endovascular treatment remains uncertain, it should preferably, when possible, be offered in the context of a randomized trial.

IV and V grade arteriovenous Malformations: A multicenter surgical experience. Use of multiple grading system to predict surgical risk

OBJECTIVE

The aim of our study is to report a multicenter experience in the treatment of IV and V grade arteriovenous malformations (AVMs) and to apply commonly used grading scales for surgical risk assessment for these vascular high-grade lesions.

METHODS

Between January 2015 and December 2019, a retrospective study was conducted to identify patients undergoing microsurgical intervention for cAVMs at two Italian centers specialized in the treatment of vascular pathologies. Data on patients with Spetzler-Martin IV and V and with a score equal or more than 7 according to Lawton-Young classification were collected. Ruptured AVMs at admission were subsequently classified according to the new proposed AVICH classification.

RESULTS

A total of 20 patients with high grade (IV and V) cAVMs were enrolled in the study and the average follow-up was 36.45 months. The outcome based on mRS was favorable in 65 % of cases. The pre-operative mRS was a factor influencing clinical outcome, as well as the number of bleedings preceding the treatment, age, and nidus characteristics. S-M IV, L-Y 3 and S-M supp 7 scores were associated with good outcome. Based on the AVICH classification, for ruptured cAVMs, having a score of 9 ore less was correlated to a postoperative mRS fewer or equal than 2.

CONCLUSIONS

Surgical management for high-grade AVMs should be considered in highly selected patients with repeated bleeding or disabling symptoms. Classification systems provide an aid in selecting patients for surgery, also in grade IV and V. It is essential to establish common registers for the management of these complex vascular malformations.

Endovascular treatment as the first-line approach for cure of low-grade brain arteriovenous malformation

OBJECTIVE

While microsurgery has been proposed as the first-line treatment for patients with low-grade (Spetzler-Martin grade I or II) brain arteriovenous malformations (bAVMs), recent studies have shown promising results for endovascular treatment (EVT) as a single proper choice for the management of this group of bAVMs. In this study, the authors evaluated the safety and efficacy of EVT as a first-line strategy for curing low-grade bAVMs at their center.

METHODS

All patients with low-grade bAVMs managed primarily by EVT between 2015 and 2021 were enrolled in this study. Patients were evaluated and treated by the same team and followed with the same protocol. The primary endpoint was the efficacy of EVT on the cure of low-grade bAVMs. The second endpoint was the safety of EVT for the treatment of low-grade bAVMs, including procedural complications and long-term clinical outcomes.

RESULTS

A total of 109 patients were enrolled and represented in the study population. The mean patient age was 31.6 ± 14.8 years. Forty-eight AVMs (44%) were Spetzler-Martin grade I and 61 (56%) were grade II. Of 99 patients who completed their EVT sessions, complete exclusion was achieved in 89 patients (89.9%). Overall, complete exclusion was achieved in 59.6% of patients after a single EVT session. At the 6-month follow-up, 106 patients (97.2%) had a favorable outcome. Four patients (4.6%) experienced transient neurological deficits, and 1 patient (0.9%) had a permanent neurological deficit.

CONCLUSIONS

EVT can be offered as the first choice of treatment for select patients with low-grade bAVMs, with a high cure rate and low morbidity.

Interventional outcomes for patients eligible for entry into the ARUBA clinical trial: a systematic review and meta-analysis

OBJECTIVE

A Randomized Trial of Unruptured Brain Arteriovenous Malformations (ARUBA) suggested that medical management afforded outcomes superior to those following intervention for unruptured arteriovenous malformations (AVMs), but its findings have been controversial. Subsequent studies of AVMs that would have met the eligibility requirements of ARUBA have supported intervention for the management of some cases. The present meta-analysis was conducted with the object of summarizing interventional outcomes for ARUBA-eligible patients reported in the literature.

METHODS

A systematic literature search (PubMed, Web of Science, Google Scholar) for AVM intervention studies that used inclusion criteria identical to those of ARUBA (age ≥ 18 years, no history of AVM hemorrhage, no prior intervention) was performed. The primary outcome was death or symptomatic stroke. Secondary outcomes included AVM obliteration, hemorrhage, death, and poor outcome (modified Rankin Scale score ≥ 2 at final follow-up). Bias assessment was performed with the Newcastle-Ottawa Scale, and the results were synthesized as pooled proportions.

RESULTS

Of the 343 articles identified through database searches, 13 studies met the inclusion criteria, yielding an overall study cohort of 1909 patients. The primary outcome occurred in 11.2% of patients (pooled = 11%, 95% CI 8%-13%). The rates of AVM obliteration, hemorrhage, poor outcome, and death were 72.7% (pooled = 78%, 95% CI 70%-85%), 8.4% (pooled = 8%, 95% CI 6%-11%), 9.9% (pooled = 10%, 95% CI 7%-13%), and 3.5% (pooled = 2%, 95% CI 1%-4%), respectively. Annualized primary outcome and hemorrhage risks were 1.85 (pooled = 2.05, 95% CI 1.31-2.94) and 1.34 (pooled = 1.41, 95% CI 0.83-2.13) per 100 patient-years, respectively.

CONCLUSIONS

Intervention for unruptured AVMs affords acceptable outcomes for appropriately selected patients. The risk of hemorrhage following intervention compared favorably to the natural history of unruptured AVMs. The included studies were retrospective and varied in treatment and AVM characteristics, thereby limiting the generalizability of their data. Future studies from prospective registries may clarify patient, nidus, and intervention selection criteria that will refine the challenging management of patients with unruptured AVMs.

Fatal ruptured occult arteriovenous malformation in a young adult: An autopsy case report

Background:

Brain arteriovenous malformations (AVMs) are congenital developmental disorders with unclear causative factors and pathogenic mechanisms. Various epigenetic factors may influence the development and rupture of AVMs. Ruptured AVMs may lead to poor outcomes. Therefore, the risk factors of AVM rupture and treatment strategies for unruptured AVMs should be explored. Herein, we report a case of a fatal ruptured AVM diagnosed by radiological and autopsy findings and review the literature regarding AVM treatment.

Case Description:

A 46-year-old man was brought to the hospital with sudden loss of consciousness while sitting on the edge of the bathtub. On examination, he was unconscious with poor breathing efforts. He was intubated and a brain CT scan was performed, which showed an intracerebral hemorrhage (ICH) adjacent to the right trigone with massive intraventricular hemorrhage (IVH) and subarachnoid hemorrhage (SAH). Contrast-enhanced CT scan showed abnormal vessels adjacent to the hematoma. He was diagnosed with ICH associated with IVH and SAH caused by a ruptured abnormal vascular lesion. He underwent external ventricular drainage to control the intracranial pressure. He remained unconscious and died 16 h after hospital admission. Autopsy was performed to identify the cause of ICH. Pathological sections showed a mass of blood vessels, measuring 20 × 10 × 10 mm in size, within the hematoma with a single drainer connecting to the transverse sinus. These blood vessels had variable size, shape, and wall thickness on microscopy. Some vessels had abnormal thickened walls with discontinuous elastic fibers. Based on the radiological and autopsy findings, an ICH secondary to SpetzlerMartin Grade I AVM was confirmed.

Conclusion:

If the cause of ICH cannot be determined during a patient’s life, autopsy may be performed to determine the pathophysiology of occult vascular lesions, including AVMs. Patients with AVMs may have moderate or no symptoms before and after rupture. Because deep AVMs fed by posterior circulation have high risk of bleeding, surgical intervention should be considered for these patients to prevent a poor outcome. Low-grade and paraventricular AVMs in a young adult may be successfully treated with multimodal surgery.

Endovascular treatment in the multimodality management of brain arteriovenous malformations: report of the Society of NeuroInterventional Surgery Standards and Guidelines Committee

BACKGROUND

The purpose of this review is to summarize the data available for the role of angiography and embolization in the comprehensive multidisciplinary management of brain arteriovenous malformations (AVMs METHODS: We performed a structured literature review for studies examining the indications, efficacy, and outcomes for patients undergoing endovascular therapy in the context of brain AVM management. We graded the quality of the evidence. Recommendations were arrived at through a consensus conference of the authors, then with additional input from the full Society of NeuroInterventional Surgery (SNIS) Standards and Guidelines Committee and the SNIS Board of Directors.

RESULTS

The multidisciplinary evaluation and treatment of brain AVMs continues to evolve. Recommendations include: (1) Digital subtraction catheter cerebral angiography (DSA)-including 2D, 3D, and reformatted cross-sectional views when appropriate-is recommended in the pre-treatment assessment of cerebral AVMs. (I, B-NR) . (2) It is recommended that endovascular embolization of cerebral arteriovenous malformations be performed in the context of a complete multidisciplinary treatment plan aiming for obliteration of the AVM and cure. (I, B-NR) . (3) Embolization of brain AVMs before surgical resection can be useful to reduce intraoperative blood loss, morbidity, and surgical complexity. (IIa, B-NR) . (4) The role of primary curative embolization of cerebral arteriovenous malformations is uncertain, particularly as compared with microsurgery and radiosurgery with or without adjunctive embolization. Further research is needed, particularly with regard to risk for AVM recurrence. (III equivocal, C-LD) . (5) Targeted embolization of high-risk features of ruptured brain AVMs may be considered to reduce the risk for recurrent hemorrhage. (IIb, C-LD) . (6) Palliative embolization may be useful to treat symptomatic AVMs in which curative therapy is otherwise not possible. (IIb, B-NR) . (7) The role of AVM embolization as an adjunct to radiosurgery is not well-established. Further research is needed. (III equivocal, C-LD) . (8) Imaging follow-up after apparent cure of brain AVMs is recommended to assess for recurrence. Although non-invasive imaging may be used for longitudinal follow-up, DSA remains the gold standard for residual or recurrent AVM detection in patients with concerning imaging and/or clinical findings. (I, C-LD) . (9) Improved national and international reporting of patients of all ages with brain AVMs, their treatments, side effects from treatment, and their long-term outcomes would enhance the ability to perform clinical trials and improve the rigor of research into this rare condition. (I, C-EO) .

CONCLUSIONS

Although the quality of evidence is lower than for more common conditions subjected to multiple randomized controlled trials, endovascular therapy has an important role in the management of brain AVMs. Prospective studies are needed to strengthen the data supporting these recommendations.

Preoperative embolisation of brain arteriovenous malformations: a systematic review and meta-analysis

Preoperative embolisation is a commonly performed adjunct to microsurgical excision of brain arteriovenous malformations (bAVMs), with aims such as lessening the technical difficulty of the microsurgical procedure, reducing operative time, decreasing blood loss, and improving patient functional outcomes. We aim to perform a systematic review of randomised trials and cohort studies evaluating preoperative embolisation of bAVMs published between 01 January 2000 and 31 March 2021 and appraise its role in clinical practice. A MEDLINE search was performed, and articles reporting on outcomes following preoperative embolisation, as an adjunct to microsurgery, were eligible for inclusion. PRISMA reporting and Cochrane Handbook guidelines were followed. The primary outcome measure was the risk of complications associated with preoperative embolisation. The study was registered with PROSPERO (CRD42021244231). Of the 1661 citations, 8 studies with 588 patients met predefined inclusion criteria. No studies specifically compared outcomes of surgical excision of bAVMs between those with and without preoperative embolisation. Spetzler Martin (SM) grading was available in 301 cases. 123 of 298 (41⋅28%) patients presented with haemorrhage. Complications related to embolisation occurred in 175/588 patients (29.4%, 95% CI 19.6–40.2). Permanent neurological deficits occurred in 36/541 (6%, 95% CI 3.9–8.5) and mortality in 6/588 (0.41%, 95% CI 0–1.4). This is the first systematic review evaluating preoperative embolisation of bAVMs. Existing studies assessing this intervention are of poor quality. Associated complication rates are significant. Based on published literature, there is currently insufficient evidence to recommend preoperative embolisation of AVMs. Further studies are required to ascertain if there are benefits of this procedure and if so, in which cases.

Efficacy and safety of embolization for arteriovenous malformations of the basal ganglia and thalamus via the transarterial approach

Background

To evaluate the effectiveness and safety profile of transarterial embolization in the treatment of brain arteriovenous malformations (bAVMs) within the basal ganglia and thalamus.

Methods

A retrospective clinical study was performed on 22 patients with bAVMs localized within the basal ganglia and thalamus who were treated with transarterial embolization (December 2012 and January 2019) in our center. The bAVMs were embolized via the transarterial approach with Onyx or Glubran according to the anatomical structure. A detachable or undetachable microcatheter was used in the procedure according to the length of the feeding artery. The data of these patients were retrospectively analyzed.

Results

Among the 22 patients, 9 bAVMs were located in the basal ganglia and 13 were located in the thalamus. Twenty patients presented with hemorrhage (90.9%), leaving 2 patients (9.1%) who had no symptoms. According to the Spetzler-Martin grading classification, 13 bAVMs (59.1%) were grade 3, 7 (31.8%) were grade 4, and 2 (9.1%) were grade 5. Procedure-related complications occurred in only 1 patient (4.5%). No deaths related to the operation occurred. All patients achieved anatomic stabilization and no bleeding was observed in the follow-up.

Conclusions

Selective embolization via the transarterial approach is safe and effective for bAVMs originating within the basal ganglia and thalamus. Our results demonstrate a low rate of complications and an elevated degree of anatomical disruption in the endovascular treatment of bAVMs stemming from the basal ganglia and thalamus.

Microsurgical Treatment of Deep and Eloquent AVMs

Over the past 30 years, the treatment of deep and eloquent arteriovenous malformations (AVMs) has moved away from microneurosurgical resection and towards medical management and the so-called minimally invasive techniques, such as endovascular embolization and radiosurgery. The Spetzler-Martin grading system (and subsequent modifications) has done much to aid in risk stratification for surgical intervention; however, the system does not predict the risk of hemorrhage nor risk from other interventions. In more recent years, the ARUBA trial has suggested that unruptured AVMs should be medically managed. In our experience, although these eloquent regions of the brain should be discussed with patients in assessing the risks and benefits of intervention, we believe each AVM should be assessed based on the characteristics of the patient and the angio-architecture of the AVM, in particular venous hypertension, which may guide us to treat even high-grade AVMs when we believe we can (and need to) to benefit the patient. Advances in imaging and intraoperative adjuncts have helped us in decision making, preoperative planning, and ensuring good outcomes for our patients. Here, we present several cases to illustrate our primary points that treating low-grade AVMs can be more difficult than treating high-grade ones, mismanagement of deep and eloquent AVMs at the behest of dogma can harm patients, and the treatment of any AVM should be tailored to the individual patient and that patient's lesion.

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.

Microsurgical Treatment of a Petrotentorial Dural Arteriovenous Fistula: The Vein, the Whole Vein, and Nothing but the Vein: 2-Dimensional Operative Video

Dural arteriovenous fistulas (dAVFs) consist of abnormal anastomoses between 1 or multiple meningeal arteries to meningeal veins, venous sinuses, or subarachnoid veins.1 dAVFs account for 10% to 15% of all intracranial arteriovenous lesions.2 dAVFs can be challenging to treat with various approaches that include microsurgical ligation, endovascular embolization (transarterial or transvenous), and stereotactic radiosurgery. All these treatments share the common goal of disconnecting the draining vein from the fistulous point. We present a case of a 43-yr-old male who presented with progressive headaches and was found to have an incidental Zipfel type 3A3 right petrotentorial dAVF on catheter angiography. The patient underwent a right retrosigmoid craniotomy and clipping of 2 separate venous outflows. The case illustrates the principle that multiple venous outflows can exist in dAVF and a thorough analysis of the venous phase of the angiogram as well as corresponding inspection of the fistula at the time of surgical exploration is a necessity to avoid partial obliteration. The patient remained neurologically intact postoperatively and had complete resolution of his fistula on postoperative angiography. We review the neuroimaging, operative video, and technical nuances and provide a short literature review on the topic.4 The patient gave informed consent for the procedure and verbal consent for this publication. The patient consented to the publication of their image.

Multimodality Management in bAVM Surgery - Recent Experience from International Cerebrovascular Fellowship

Background:

Arteriovenous malformation (bAVM) presents maldevelopment of the brain’s vessels with a direct connection between cerebral arteries and veins. By current data, patients from Spetzler Ponce A (SP) are found to benefit from the treatment. Considering the outcome, most of SP C and some of the SP B are the most debatable.

Objective:

Arteriovenous malformation presents maldevelopment of the brain’s vessels with a consequent direct connection between cerebral arteries and veins. The annual risk of hemorrhage in adults is reported for 2-3 %. They usually present with unilateral headaches seizures and intracranial hemorrhage. By current data, patients from Spetzler Ponce A (SP) are found to benefit from the treatment. Considering the outcome, most of SP C and some of the SP B are the most debatable.

Methods:

The study included a cohort of bAVM patients referred to Fujita Health University Bantane Hotokukai Hospital, Nagoya, Aichi, Japan where the main author (AA) has completed an international cerebrovascular fellowship under the mentorship of Professor Yoko Kato. Japanese Stroke Guidelines (JSG) were used for the treatment decision. Patients were graded according to the Spetzler Ponce (SP) system. Considering American Heart Association criteria (AHA), embolization was used as a part of multimodal treatment. Intraoperative microscopic video tools included Indocyanine green ICG, FLOW 800 and dual image video angiography DIVA. Clinical outcomes were measured using Modified Ranking Score (mRs).

Results:

A total of eleven patients with brain bAVM were studied with a median age of 32 years [IQR = 22-52]. There were ten patients presented with supratentorial and a single patient with infratentorial AVM. Patients were graded according to the Spetzler Ponce (SP) system. There were eight patients in SP A (72,7%), one in group B (9 %) while the rest of them were in C (18 %). Two patients had associated aneurysms that required treatment. The median size of the AVM nidus was 3,50 cm [IQR= 2-5]. Deep venous drainage was found in six patients while three were located in eloquent zones. Clinical outcomes were considered good by mRs <2 in eight patients, seven from the surgically treated group (72,7 % respectively). Surgery median length time was 427, 5 minutes; [IQR =320 - 463] with complete AVM resection in all patients and no mortality recorded in this cohort with the median follow up of 39,5 months [IQR = 19-59].

Conclusion:

Ideal management of bAVM is still controversial. Those complex vascular lesions require multimodal treatment in a majority of cases in highly specialized centers. In SP A patients, surgery provides the best results with a positive outcome and a small number of complications. With the improvement of endovascular feeder occlusion SP B patients become prone to a more positive outcome. Nowadays, intraoperative microscopic tools such as FLOW 800, ICG and DIVA are irreplaceable while improving safety to deal with bAVM. For SP C patients, a combination of endovascular and stereotactic radiosurgery was found to be a good option in the present time.

Controlled arterial hypotension during resection of cerebral arteriovenous malformations

Background

Resection of cerebral arteriovenous malformations (AVM) is technically demanding because of size, eloquent location or diffuse nidus. Controlled arterial hypotension (CAH) could facilitate haemostasis. We performed a study to characterize the duration and degree of CAH and to investigate its association with blood loss and outcome.

Methods

We retrospectively analysed intraoperative arterial blood pressure of 56 patients that underwent AVM-resection performed by the same neurosurgeon between 2003 and 2012. Degree of CAH, AVM size, grading and neurological outcome were studied. Patients were divided into two groups, depending on whether CAH was performed (hypotension group) or not (control group).

Results

The hypotension group consisted of 28 patients, which presented with riskier to treat AVMs and a higher Spetzler-Martin grading. CAH was achieved by application of urapidil, increasing anaesthetic depth or a combination thereof. Systolic and mean arterial blood pressure were lowered to 82 ± 7 and 57 ± 7 mmHg, respectively, for a median duration of 58 min [25% percentile: 26 min.; 75% percentile: 107 min]. In the hypotension group, duration of surgery (4.4 ± 1.3 h) was significantly (p <  0.001) longer, and median blood loss (500 ml) was significantly (p = 0.002) higher than in the control group (3.3 ± 0.9 h and 200 ml, respectively). No case fatalities occurred. CAH was associated with a higher amount of postoperative neurological deficits.

Conclusions

Whether CAH caused neurological deficits or prevented worse outcomes could be clarified by a prospective randomised study, which is regarded as ethically problematic in the context of bleeding. CAH should only be used after strict indication and should be applied as mild and short as possible.

Cerebral Arteriovenous Malformation Deep Draining Veins Not Observed on Preoperative Angiography Identified on Postoperative Angiography

Postoperative digital subtraction angiography (DSA) is the gold standard for establishing a cure of an arteriovenous malformation (AVM) after treatment. The incidence of residual AVM identified on postoperative DSA ranges from 1.8 to 11%. Although this is important for finalizing the treatment of AVMs, postoperative DSA rarely shows new findings that were not previously identified on preoperative imaging. We present a unique case where we identified residual AVM nidus on immediate postoperative DSA that drained into two deep veins that were not evident on preoperative DSA and increased the AVM grade from Spetzler-Martin grade II to III. To our knowledge, this finding has not been previously reported in the literature. We resected the residual AVM nidus identified on postoperative DSA, leading to an angiographic cure. The patient demonstrated a postoperative right-sided supplementary motor area syndrome that resolved over time with therapy. She made a complete functional recovery by her one-month follow-up appointment.

Spetzler-Martin Grade III Arteriovenous Malformations: A Multicenter Propensity-Adjusted Analysis of the Effects of Preoperative Embolization

BACKGROUND

Spetzler-Martin (SM) grade III arteriovenous malformations (AVMs) are at the boundary of safe operability, and preoperative embolization may reduce surgical risks.

OBJECTIVE

To evaluate the benefits of preoperative AVM embolization by comparing neurological outcomes in patients with grade III AVMs treated with or without preoperative embolization.

METHODS

All microsurgically treated grade III AVMs were identified from 2011 to 2018 at 2 medical centers. Neurological outcomes, measured as final modified Rankin Scale scores (mRS) and changes in mRS from preoperative baseline to last follow-up evaluation, were compared in patients with and without preoperative embolization.

RESULTS

Of the 102 patients with grade III AVMs who were treated microsurgically, 57 (56%) underwent preoperative embolization. Significant differences were found between the patients with and without embolization in AVM eloquence (74% vs 93%, P = .02), size ≥ 3 cm (47% vs 73%, P = .01), diffuseness (7% vs 22%, P = .04), and mean final mRS (1.1 vs 2.0, P = .005). Poor outcomes were more frequent in patients without embolization (38%) than with embolization (7%) (final mRS > 2; P < .001). Propensity-adjusted analysis revealed AVM resection without embolization was a risk factor for poor outcome (mRS score > 2; odds ratio, 4.2; 95% CI, 1.1-16; P = .03).

CONCLUSION

Nonembolization of SM grade III AVMs is associated with an increased risk of poor neurological outcomes after microsurgical resection. Preoperative embolization of intermediate-grade AVMs selected because of large AVM size, surgical inaccessibility of feeding arteries, and high flow should be employed more often than anticipated, even in the context of increasing microsurgical experience with AVMs.

Comparing health-related quality of life in modified Rankin Scale grades: 15D results from 323 patients with brain arteriovenous malformation and population controls

Background

We wanted to understand how patients with different modified Rankin Scale (mRS) grades differ regarding their health-related quality of life (HRQoL) and how this affects the interpretation and dichotomization of the grade.

Methods

In 2016, all adult patients in our brain arteriovenous malformation (AVM) database (n = 432) were asked to fill in mailed letters including a questionnaire about self-sufficiency and lifestyle and the 15D HRQoL questionnaire. The follow-up mRS was defined in 2016 using the electronic patient registry and the questionnaire data. The 15D profiles of each mRS grade were compared to those of the general population and to each other, using ANCOVA with age and sex standardization.

Results

Patients in mRS 0 (mean 15D score = 0.954 ± 0.060) had significantly better HRQoL than the general population (mean = 0.927 ± 0.028), p < 0.0001, whereas patients in mRS 1–4 had worse HRQoL than the general population, p < 0.0001. Patients in mRS 1 (mean = 0.844 ± 0.100) and mRS 2 (mean = 0.838 ± 0.107) had a similar HRQoL. In the recently published AVM research, the most commonly used cut points for mRS dichotomization were between mRS 1 and 2 and between mRS 2 and 3.

Conclusions

Using 15D, we were able to find significant differences in the HRQoL between mRS 0 and mRS 1 AVM patients, against the recent findings on stroke patients using EQ-5D in their analyses. Although the dichotomization cut point is commonly set between mRS 1 and 2, patients in these grades had a similar HRQoL and a decreased ability to continue their premorbid lifestyle, in contrast to patients in mRS 0.

Intermediate-grade brain arteriovenous malformations and the boundary of operability using the supplemented Spetzler-Martin grading system

OBJECTIVE

Supplemented Spetzler-Martin grading (Supp-SM), which is the combination of Spetzler-Martin and Lawton-Young grades, was validated as being more accurate than stand-alone Spetzler-Martin grading, but an operability cutoff was not established. In this study, the authors surgically treated intermediate-grade AVMs to provide prognostic factors for neurological outcomes and to define AVMs at the boundary of operability.

METHODS

Surgically treated Supp-SM intermediate-grade (5, 6, and 7) AVMs were analyzed from 2011 to 2018 at two medical centers. Worsened neurological outcomes were defined as increased modified Rankin Scale (mRS) scores on postoperative examinations. A second analysis of 2000-2011 data for Supp-SM grade 6 and 7 AVMs was performed to determine the subtypes with improved or unchanged outcomes. Patients were separated into three groups based on nidus size (S1: < 3 cm, S2: 3-6 cm, S3: > 6 cm) and age (A1: < 20 years, A2: 20-40 years, A3: > 40 years), followed by any combination of the combined supplemented grade: low risk (S1A1, S1A2, S2A1), intermediate risk (S2A2, S1A3, S3A1, or high risk (S3A3, S3A2, S2A3).

RESULTS

Two hundred forty-six patients had intermediate Supp-SM grade AVMs. Of these patients, 102 had Supp-SM grade 5 (41.5%), 99 had Supp-SM grade 6 (40.2%), and 45 had Supp-SM grade 7 (18.3%). Significant differences in the proportions of patients with worse mRS scores at follow-up were found between the groups, with 24.5% (25/102) of patients in Supp-SM grade 5, 29.3% (29/99) in Supp-SM grade 6, and 57.8% (26/45) in Supp-SM grade 7 (p < 0.001). Patients with Supp-SM grade 7 AVMs had significantly increased odds of worse postoperative mRS scores (p < 0.001; OR 3.7, 95% CI 1.9-7.3). In the expanded cohort of 349 Supp-SM grade 6 AVM patients, a significantly higher proportion of older patients with larger Supp-SM grade 6 AVMs (grade 6+, 38.6%) had neurological deterioration than the others with Supp-SM grade 6 AVMs (22.9%, p = 0.02). Conversely, in an expanded cohort of 197 Supp-SM grade 7 AVM patients, a significantly lower proportion of younger patients with smaller Supp-SM grade 7 AVMs (grade 7-, 19%) had neurological deterioration than the others with Supp-SM grade 7 AVMs (44.9%, p = 0.01).

CONCLUSIONS

Patients with Supp-SM grade 7 AVMs are at increased risk of worse postoperative neurological outcomes, making Supp-SM grade 6 an appropriate operability cutoff. However, young patients with small niduses in the low-risk Supp-SM grade 7 group (grade 7-) have favorable postoperative outcomes. Outcomes in Supp-SM grade 7 patients did not improve with surgeon experience, indicating that the operability boundary is a hard limit reflecting the complexity of high-grade AVMs.

Systematic review of brain arteriovenous malformation grading systems evaluating microsurgical treatment recommendation

When evaluating brain arteriovenous malformations (bAVMs) for microsurgical resection, the natural history of bAVM rupture must be balanced against the perioperative risks. It is therefore adamant to have a reliable surgical grading system, balancing these important factors. This study systematically reviews the literature in order to identify and assess the quality of grading systems with regard to microsurgical bAVM treatment. A systematic literature review was performed to provide an overview of all available bAVM grading systems relevant for microsurgical treatment evaluation and to assess the most comprehensive grading system specifically for each subgroup of bAVM (i.e., unruptured, ruptured, and posterior fossa). Screening of 865 papers revealed thirteen grading systems for bAVM microsurgical risk stratification. Among them, two systems were specifically developed for ruptured bAVM and one specifically for posterior fossa bAVM. With one system being fundamentally different for supratentorial bAVM, the remaining nine systems used the same parameters: “size,” “eloquence,” “venous drainage,” “arterial feeders,” “age,” “nidus compactness,” and “hemorrhagic presentation”. This study provides a comprehensive overview of all available bAVM grading systems relevant for surgical risk stratification. Furthermore, in the absence of a universal system appropriate to score all bAVMs, a workflow for selection of the best applicable scoring system in accordance with bAVM subgroups is presented.

Stereotactic Radiosurgery for Spetzler-Martin Grade I and II Arteriovenous Malformations: International Society of Stereotactic Radiosurgery (ISRS) Practice Guideline

BACKGROUND

No guidelines have been published regarding stereotactic radiosurgery (SRS) in the management of Spetzler-Martin grade I and II arteriovenous malformations (AVMs).

OBJECTIVE

To establish SRS practice guidelines for grade I-II AVMs on the basis of a systematic literature review.

METHODS

Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)-compliant search of Medline, Embase, and Scopus, 1986-2018, for publications reporting post-SRS outcomes in ≥10 grade I-II AVMs with a follow-up of ≥24 mo. Primary endpoints were obliteration and hemorrhage; secondary outcomes included Spetzler-Martin parameters, dosimetric variables, and “excellent” outcomes (defined as total obliteration without new post-SRS deficit).

RESULTS

Of 447 abstracts screened, 8 were included (n = 1, level 2 evidence; n = 7, level 4 evidence), representing 1102 AVMs, of which 836 (76%) were grade II. Obliteration was achieved in 884 (80%) at a median of 37 mo; 66 hemorrhages (6%) occurred during a median follow-up of 68 mo. Total obliteration without hemorrhage was achieved in 78%. Of 836 grade II AVMs, Spetzler-Martin parameters were reported in 680: 377 were eloquent brain and 178 had deep venous drainage, totaling 555/680 (82%) high-risk SRS-treated grade II AVMs.

CONCLUSION

The literature regarding SRS for grade I-II AVM is low quality, limiting interpretation. Cautiously, we observed that SRS appears to be a safe, effective treatment for grade I-II AVM and may be considered a front-line treatment, particularly for lesions in deep or eloquent locations. Preceding publications may be influenced by selection bias, with favorable AVMs undergoing resection, whereas those at increased risk of complications and nonobliteration are disproportionately referred for SRS.

Outcomes of stereotactic radiosurgery for hemorrhagic arteriovenous malformations with or without prior resection or embolization

OBJECTIVE

The major concern about ruptured arteriovenous malformations (rAVMs) is recurrent hemorrhage, which tends to preclude stereotactic radiosurgery (SRS) as a therapeutic modality for these brain malformations. In this study, the authors aimed to clarify the role of SRS for rAVM as a stand-alone modality and an adjunct for a remnant nidus after surgery or embolization.

METHODS

Data on 410 consecutive patients with rAVMs treated with SRS were analyzed. The patients were classified into groups, according to prior interventions: SRS-alone, surgery and SRS (Surg-SRS), and embolization and SRS (Embol-SRS) groups. The outcomes of the SRS-alone group were analyzed in comparison with those of the other two groups.

RESULTS

The obliteration rate was higher in the Surg-SRS group than in the SRS-alone group (5-year cumulative rate 97% vs 79%, p < 0.001), whereas no significant difference was observed between the Embol-SRS and SRS-alone groups. Prior resection (HR 1.78, 95% CI 1.30-2.43, p < 0.001), a maximum AVM diameter ≤ 20 mm (HR 1.81, 95% CI 1.43-2.30, p < 0.001), and a prescription dose ≥ 20 Gy (HR 2.04, 95% CI 1.28-3.27, p = 0.003) were associated with a better obliteration rate, as demonstrated by multivariate Cox proportional hazards analyses. In the SRS-alone group, the annual post-SRS hemorrhage rates were 1.5% within 5 years and 0.2% thereafter and the 10-year significant neurological event-free rate was 95%; no intergroup difference was observed in either outcome. The exclusive performance of SRS (SRS alone) was not a risk for post-SRS hemorrhage or for significant neurological events based on multivariate analyses. These results were also confirmed with propensity score-matched analyses.

CONCLUSIONS

The treatment strategy for rAVMs should be tailored with due consideration of multiple factors associated with the patients. Stand-alone SRS is effective for hemorrhagic AVMs, and the risk of post-SRS hemorrhage was low. SRS can also be favorably used for residual AVMs after initial interventions, especially after failed resection.

Selection of Patients for Treatment of Brain Arteriovenous Malformations by the Transvenous Approach: Relationship with Venous Anatomy and Risk of Hemorrhagic Complications

BACKGROUND AND PURPOSE

Intracranial hemorrhage represents a severe complication of brain arteriovenous malformation treatment. The aim of this cohort was to report the rate of hemorrhagic complications after transvenous endovascular embolization and analyze the potential angioarchitectural risk factors as well as clinical outcomes.

MATERIALS AND METHODS

During an 11-year period, 57 patients underwent transvenous endovascular embolization. All cases of hemorrhagic complications were identified. We analyzed the following variables: sex, age, hemorrhagic presentation, Spetzler-Martin grade, size of the AVM before the transvenous treatment, number of venous collectors, pattern of drainage, presence of dilated veins, and technical aspects. Univariate and multivariate multiple regression analyses were performed to evaluate the potential risk factors for procedure-related hemorrhagic complications.

RESULTS

Hemorrhagic complications (either intraprocedural or periprocedural) unrelated to a perforation due to micronavigation occurred in 8 (14.0%) procedures. Significant (mRS > 2) and persistent neurologic deficits were present in 2 (3.5%) patients at 6-month control. Larger nidi, especially >3 cm (P = .03), and a larger number of venous collectors have shown a statistically significant correlation with hemorrhagic complications. Only the number of venous collectors was identified as an independent predictor of hemorrhagic complications in the multivariate analysis (OR, 8.7; 95% confidence interval, 2.2-58.2) (P = .006).

CONCLUSIONS

Larger nidus sizes and an increased number of venous collectors may increase the risk of hemorrhagic complications when implementing transvenous endovascular treatment of AVMs. The technique is effective and promising, especially with small nidi and single venous collectors.

Brain arteriovenous malformations: A review of natural history, pathobiology, and interventions

Brain arteriovenous malformations (AVMs) are anomalous direct shunts between cerebral arteries and veins that convalesce into a vascular nidus. The treatment strategies for AVMs are challenging and variable. Intracranial hemorrhage and seizures comprise the most common presentations of AVMs. However, incidental AVMs are being diagnosed with increasing frequency due to widespread use of noninvasive neuroimaging. The balance between the estimated cumulative lifetime hemorrhage risk vs the risk of intervention is often the major determinant for treatment. Current management options include surgical resection, embolization, stereotactic radiosurgery (SRS), and observation. Complete nidal obliteration is the goal of AVM intervention. The risks and benefits of interventions vary and can be used in a combinatorial fashion. Resection of the AVM nidus affords high rates of immediate obliteration, but it is invasive and carries a moderate risk of neurologic morbidity. AVM embolization is minimally invasive, but cure can only be achieved in a minority of lesions. SRS is also minimally invasive and has little immediate morbidity, but AVM obliteration occurs in a delayed fashion, so the patient remains at risk of hemorrhage during the latency period. Whether obliteration can be achieved in unruptured AVMs with a lower risk of stroke or death compared with the natural history of AVMs remains controversial. Over the past 5 years, multicenter prospective and retrospective studies describing AVM natural history and treatment outcomes have been published. This review provides a contemporary and comprehensive discussion of the natural history, pathobiology, and interventions for brain AVMs.

Microsurgical approach for symptomatic brain AVMs - single center experience

Objectives: Brain arteriovenous malformations (AVMs) represent high-flow vascular lesions made up of a complex network of feeding arteries and draining veins interposed by a nidus and without a capillary bed. The management of the AVMs represents a challenge, and the optimal treatment should be considered based on the particularities of each AVM. This paper aims to provide outcome data for the cohort of patients with AVMs that underwent surgical treatment. Methods: A retrospective review of patients who presented with AVMs between 2001 and 2019 was conducted. Patients were included if they underwent surgery, preoperative and postoperative angiographic studies were available. Results: 91 patients were included. The SM grade was 1 in 16 cases (17,6%), 2 in 27 patients (29.7%), 3 in 29 patients (31,9%), 4 in 12 cases (13.2%) and grade 5 in 7 cases (7.7%). In 58 (63.7%) cases the AVMs were ruptured. Complete microsurgical resection was achieved in 82 cases (90.1%). Unruptured AVM (87.9% vs. 63.8% for ruptured AVMs; p = 0.015), low-grade AVM (86% vs. 60.4% for grade III-V AVMs; p = 0.006) and cortical location (79.5% vs. 30.8% for deep AVM; p < 0.0001) were the factors associated with a good outcome on mRS scale. Conclusions: Microsurgical resection is the curative treatment for AVMs and offers a good functional outcome if selection criteria are met.

More II It than Meets the Eye: Outcomes After Single-Fraction Stereotactic Radiosurgery in a Case Series of Low-Grade Arteriovenous Malformations

BACKGROUND

Surgical resection is typically cited as the optimal treatment of patients with Spetzler-Martin Grade I-II arteriovenous malformation (AVM).

OBJECTIVE

To report our experience with single-fraction stereotactic radiosurgery (SRS) for Spetzler-Martin Grade I-II AVM.

METHODS

A prospectively maintained registry was reviewed for patients with nonsyndromic Spetzler-Martin Grade I-II AVM having SRS from 1990 to 2011. Patients with <24 mo of follow-up or prior radiotherapy/SRS were excluded, resulting in a study population of 173 patients. Actuarial analysis was performed using the Kaplan-Meier method, and Cox proportional hazards modeling was performed with excellent outcomes (obliteration without new deficits) as the dependent variable.

RESULTS

Median post-SRS follow-up was 68 mo (range, 24-275). AVM obliteration was achieved in 132 (76%) after initial SRS. Eleven additional patients achieved obliteration after repeat SRS for an overall obliteration rate of 83%. The rate of obliteration was 60% at 4 yr and 78% at 8 yr. Post-SRS hemorrhage occurred in 7 patients (4%), resulting in 3 minor deficits (2%) and 1 death (<1%). Radiation-induced complications occurred in 5 patients (3%), resulting in minor deficits only. One hundred and thirty-seven patients (79%) had excellent outcomes at last follow-up.

CONCLUSION

SRS is a safe and effective treatment for patients with Spetzler-Martin Grade I-II AVM. Selection bias is likely a contributing factor to explain the superior outcomes generally noted in reported series of microsurgery for patients with low grade AVM.

Results of Surgery for Low-Grade Brain Arteriovenous Malformation Resection by Early Career Neurosurgeons: An Observational Study

BACKGROUND

For sustainability of arteriovenous malformation (AVM) surgery, results from early career cerebrovascular neurosurgeons (ECCNs) must be acceptably safe.

OBJECTIVE

To determine whether ECCNs performance of Spetzler-Ponce Class A AVM (SPC A) resection can be acceptably safe.

METHODS

ECCNs completing a cerebrovascular fellowship (2004-2015) with the last author were included. Inclusion of the ECCN cases occurred if they: had a prospective database of all AVM cases since commencing independent practice; were the primary surgeon on SPC A; and had made the significant management decisions. All SPC A surgical cases from the beginning of the ECCN's independent surgical practice to a maximum of 8 yr were included. An adverse outcome was considered a complication of surgery leading to a new permanent neurological deficit with a last modified Rankin Scale score >1. A cumulative summation (Cusum) plot examined the performance of each surgery. The highest acceptable level of adverse outcomes for the Cusum was 3.3%, derived from the upper 95% confidence interval of the last author's reported series.

RESULTS

Six ECCNs contributed 110 cases for analysis. The median number of SPC A cases operated by each ECCN was 16.5 (range 4-40). Preoperative embolization was performed in 5 (4.5%). The incidence of adverse outcomes was 1.8% (95% confidence interval: <0.01%-6.8%). At no point during the accumulated series did the combined cohort become unacceptable by the Cusum plot.

CONCLUSION

ECCNs with appropriate training appointed to large-volume cerebrovascular centers can achieve results for surgery for SPC A that are not appreciably worse than those published from high-volume neurosurgeons.

Multimodal cerebral arteriovenous malformation treatment: a 12-year experience and comparison of key outcomes to ARUBA

OBJECTIVE

Curative treatment of unruptured brain arteriovenous malformations (AVMs) remains controversial after the only randomized controlled trial, A Randomized Trial of Unruptured Brain Arteriovenous Malformations (ARUBA), was halted prematurely because interim analysis revealed superiority of the medical management group. In contrast, meta-analyses of retrospective cohorts suggest that intervention is much safer than was found in ARUBA.

METHODS

The authors retrospectively analyzed 318 consecutive adult patients with brain AVMs treated at their institution with embolization, surgery, and/or proton beam radiosurgery. Analysis was performed in 142 ARUBA-eligible patients (baseline modified Rankin Scale [mRS] score 0-1, no history of hemorrhage), and results were compared to primary and secondary outcomes from ARUBA, as well as to natural history cohorts.

RESULTS

The annualized stroke rate (hemorrhagic or ischemic) in this cohort was 1.8%, 4.9% in the first 12 months and 0.8% after the first 12 months, which was lower than in natural history studies and the ARUBA medical management arm (p = 0.001). The primary ARUBA endpoint of symptomatic stroke was reached in 13 patients (9.2%), which compares favorably to the ARUBA intervention arm (39.6%, p = 0.0001) and is similar to the ARUBA medical management arm (9.2%, p = 1.0). The secondary ARUBA endpoint (mRS score ≥ 2 at 5 years of follow-up) was reached in 14.3% of patients, compared to 40.5% in the ARUBA intervention arm (p = 0.002) and 16.7% in the ARUBA medical management arm (p = 0.6).

CONCLUSIONS

This multimodal approach to the selection and treatment of patients with brain AVMs yields good clinical outcomes with key safety endpoints (stroke, death, and mRS score 0-1) better than the ARUBA intervention arm and similar to the ARUBA medical arm at 5 years of follow-up. Results compare favorably to natural history cohorts at longer follow-up times. This suggests that tertiary care centers with integrated programs, expertise in patient selection, and individualized treatment approaches may allow for better clinical outcomes than reported in ARUBA. It supports current registry studies and merits consideration of future randomized controlled trials in patients with brain AVMs.

Utilidad de las Escalas de Gradación en el Tratamiento Quirúrgico de Malformaciones Arteriovenosas Cerebrales

Introducción:

Las malformaciones arteriovenosas (MAVs) cerebrales comprenden una compleja pato-logía responsable de hasta el 38% de las hemorragias en pacientes de entre 15-45 años, acarreando cada episodio de sangrado un 25-50% de morbilidad y un 10-20% de mortalidad. La decisión terapéu-tica en un paciente con una MAV debe tener en cuenta la comparación entre los riesgos propios de la intervención y los de la historia natural de esta enfermedad.

Objetivo:

Evaluar la utilidad de predecir riesgo quirúrgico de diferentes escalas de gradación de MAV cerebrales según nuestra experiencia en una serie de casos.

Material y Métodos:

Se realizó un análisis bibliográfico de escalas de gradación de riesgo quirúrgico de MAV cerebrales utilizando como motor de búsqueda Pubmed incluyendo como palabras clave “malformación arteriovenosa cerebral”y “scala de gradación” (brain arteriovenous and malfor- mation grading scale). Se analizaron de forma retrospectiva aquellos pacientes intervenidos quirúrgi-camente por MAV en este hospital público, se las clasificó acorde a las escalas analizadas y se compa-raron los resultados obtenidos con los previstos en ellas.

Resultados:

Se analizaron 90 pacientes intervenidos quirúrgicamente por MAV, sin tratamiento coad-yuvante. De forma retrospectiva se los agrupó acorde a las escalas de Spetzler Martin (SM), Spetzler-Ponce (SP) y suplementaria de Lawton. Las MAV grado 3 se subclasificaron según las escalas de Lawton y de de Oliveira. Considerando buenos resultados aquellos con Rankin modificado (mRs) igual o menor a 2. Con un rango de seguimiento de 12 a 48 meses, encontramos buenos resultados en el 100% de MAV SM grado 1, 91.7% de las grado 2, 80% en grado 3 y 42.9% en grado 4. Utilizando la escala SP, 93.7% de buenos resultados en tipo A, 80% en tipo B y 42.9% en tipo C. Subclasifican-do las MAV SM 3 acorde a las escalas de de Oliveira y Lawton, 84% de buenos resultados en el tipo 3A, 71.3% en las 3B, 92% en MAV tipo 3-, 72.1% en el tipo 3+, 60% en tipo 3. Utilizando la escala suplementaria de Lawton combinada con SM, buen resultado en 100% grados II y III, 85,7% grado IV, 87,6 grado V, 80% grado VI, 75% grado VII y 66,6% grado VIII.

Conclusión:

Reafirmamos en esta serie, la utilidad de estimar riesgo quirúrgico con las escalas SM, SP, y la subclasificación de las MAV grado 3 propuesta por Lawton. Y principalmente el utilizar la escala suplementaria de Lawton-Young al considerar el tratamiento quirúrgico de los pacientes con MAV que sangraron.

Updates in arteriovenous malformation management: the post-ARUBA era

Brain arteriovenous malformations (AVMs) are complex and heterogeneous lesions that can rupture, causing significant morbidity and mortality. While ruptured lesions are usually treated, the management of unruptured AVMs remains unclear. A Randomized trial of Unruptured Brain Arteriovenous Malformations (ARUBA) was the first trial conducted to compare the effects of medical and interventional therapy. Although it concluded that medical therapy was superior in preventing stroke and death over a follow-up period of 33 months, the findings were met with intense criticism regarding several aspects of study design, progression, and analysis/conclusion. Namely, the increased use of stand-alone embolisation relative to microsurgery in a cohort with predominantly low-grade lesions combined with a short follow-up period amplified treatment risk. Subsequently, several observational studies were conducted on ARUBA-eligible patients to investigate the safety and efficacy of microsurgery, radiosurgery, and endovascular embolisation over longer follow-up periods. These reports showed that favourable safety profiles and cure rates can be achieved with appropriate patient selection and judicious use of different treatment modalities in multidisciplinary centres. Since large prospective randomised trials on AVMs may not be feasible, it is important to make use of practice-based data beyond the flawed ARUBA study to optimise patients' lifetime outcomes.

Curative treatment for low-grade arteriovenous malformations

Background

Spetzler-Martin (SM) grade I-II (low-grade) arteriovenous malformations (AVMs) are often considered safe for microsurgery or radiosurgery. The adjunctive use of preoperative embolization to reduce surgical risk in these AVMs remains controversial.

Objective

To assess the safety of combined treatment of grade I-II AVMs with preoperative embolization followed by surgical resection or radiosurgery, and determine the long-term functional outcomes.

Methods

With institutional review board approval, a retrospective analysis was carried out on patients with ruptured and unruptured SM I-II AVMs between 2002 and 2017. Details of the endovascular procedures, including number of arteries supplying the AVM, number of branches embolized, embolic agent(s) used, and complications were studied. Baseline clinical and imaging characteristics were compared. Functional status using the modified Rankin Scale (mRS) before and after endovascular and microsurgical treatments was compared.

Results

258 SM I-II AVMs (36% SM I, 64% SM II) were identified in patients with a mean age of 38 ± 17 years. 48% presented with hemorrhage, 21% with seizure, 16% with headache, 10% with no symptoms, and 5% with clinical deficits. 90 patients (68%) in the unruptured group and 74 patients (59%) in the ruptured group underwent presurgical embolization (p = 0.0013). The mean number of arteries supplying the AVM was 1.44 and 1.41 in the unruptured and ruptured groups, respectively (p = 0.75). The mean number of arteries embolized was 2.51 in the unruptured group and 1.82 in the ruptured group (p = 0.003). n-Butyl cyanoacrylate and Onyx were the two most commonly used embolic agents. Four complications were seen in four patients (4/164 patients embolized): two peri-/postprocedural hemorrhage, one dissection, and one infarct. All patients undergoing surgery had a complete cure on postoperative angiography. Patients were followed up for a mean of 55 months. Good long-term outcomes (mRS score ≤ 2) were seen in 92.5% of patients with unruptured AVMs and 88.0% of those with ruptured AVMs. Permanent neurological morbidity occurred in 1.2%.

Conclusions

Curative treatment of SM I-II AVMs can be performed using endovascular embolization with microsurgical resection or radiosurgery in selected cases, with very low morbidity and high cure rates. Compared with other published series, these outcomes suggest that preoperative embolization is a safe and effective adjunct to definitive surgical treatment. Long-term follow-up showed that patients with low-grade AVMs undergoing surgical resection or radiosurgery have good functional outcomes.

Interval angioarchitectural evolution of brain arteriovenous malformations following rupture

OBJECTIVE

The goal of this study was to describe changes in the angioarchitecture of brain arteriovenous malformations (bAVMs) between acute and delayed cerebral digital subtraction angiography (DSA) obtained after hemorrhage, and to examine bAVM characteristics predicting change.

METHODS

This is a retrospective study of a prospective institutional bAVM database. The authors included all patients with ruptured bAVMs who had DSA in both acute and delayed phases, with no interval treatment of their bAVM, between January 2000 and April 2017. The authors evaluated the existence or absence of angioarchitectural changes. Demographic data, radiological characteristics of hemorrhages, and angioarchitectural features of the bAVMs of the two patients' groups were analyzed. Univariate and multivariate logistic analyses were performed to identify predictors of angioarchitectural change.

RESULTS

A total of 42 patients were included in the series. Seventeen (40.5%) patients had angioarchitectural changes including bAVM only visible on the delayed DSA study (n = 8), spontaneous thrombosis of the AVM (n = 3), or alteration of the size or the opacification of the nidus (n = 6). The factors associated with angioarchitectural changes were a small nidus (3.8 ± 7.9 ml vs 6.1 ± 9.5 ml, p = 0.046), a superficial location (94.1% vs 5.9%, p = 0.016), and a single superficial draining vein (58.8% vs 24.0%, p = 0.029).

CONCLUSIONS

Angioarchitectural changes can be seen in 40% of ruptured bAVMs between the acute- and delayed-phase DSA. A small nidus, a superficial location, and a single superficial draining vein were statistically associated with the occurrence of angioarchitectural changes. These changes included either enlargement or spontaneous occlusion of the bAVM, as well as subsequent diagnosis of a bAVM following an initial negative DSA study.

The future of open vascular neurosurgery: perspectives on cavernous malformations, AVMs, and bypasses for complex aneurysms

Despite the erosion of microsurgical case volume because of advances in endovascular and radiosurgical therapies, indications remain for open resection of pathology and highly technical vascular repairs. Treatment risk, efficacy, and durability make open microsurgery a preferred option for cerebral cavernous malformations, arteriovenous malformations (AVMs), and many aneurysms. In this paper, a 21-year experience with 7348 cases was reviewed to identify trends in microsurgical management. Brainstem cavernous malformations (227 cases), once considered inoperable and managed conservatively, are now resected in increasing numbers through elegant skull base approaches and newly defined safe entry zones, demonstrating that microsurgical techniques can be applied in ways that generate entirely new areas of practice. Despite excellent results with microsurgery for low-grade AVMs, brain AVM management (836 cases) is being challenged by endovascular embolization and radiosurgery, as well as by randomized trials that show superior results with medical management. Reviews of ARUBA-eligible AVM patients treated at high-volume centers have demonstrated that open microsurgery with AVM resection is still better than many new techniques and less invasive approaches that are occlusive or obliterative. Although the volume of open aneurysm surgery is declining (4479 cases), complex aneurysms still require open microsurgery, often with bypass techniques. Intracranial arterial reconstructions with reimplantations, reanastomoses, in situ bypasses, and intracranial interpositional bypasses (third-generation bypasses) augment conventional extracranial-intracranial techniques (first- and second-generation bypasses) and generate innovative bypasses in deep locations, such as for anterior inferior cerebellar artery aneurysms. When conventional combinations of anastomoses and suturing techniques are reshuffled, a fourth generation of bypasses results, with eight new types of bypasses. Type 4A bypasses use in situ suturing techniques within the conventional anastomosis, whereas type 4B bypasses maintain the basic construct of reimplantations or reanastomoses but use an unconventional anastomosis. Bypass surgery (605 cases) demonstrates that open microsurgery will continue to evolve. The best neurosurgeons will be needed to tackle the complex lesions that cannot be managed with other modalities. Becoming an open vascular neurosurgeon will be intensely competitive. The microvascular practice of the future will require subspecialization, collaborative team effort, an academic medical center, regional prominence, and a large catchment population, as well as a health system that funnels patients from hospital networks outside the region. Dexterity and meticulous application of microsurgical technique will remain the fundamental skills of the open vascular neurosurgeon.

Surgical management of complex brain arteriovenous malformations with hybrid operating technique: study protocol of a prospective registry and a pragmatic clinical trial

BACKGROUND

Complex brain arteriovenous malformations (bAVMs) in ≥3 Spetzler-Martin grades have long been challenges among cerebrovascular diseases. None of the traditional methods, such as microsurgical operation, endovascular intervention, or stereotactic radiotherapy, can completely eliminate complex bAVMs without a risk of neural function deterioration. The multistaged hybrid operation solved part of the challenge but remained risky in the installment procedures and intervals. The one-staged hybrid operation was applied in the surgical treatment of cerebrovascular diseases and proved to be a potentially safe and effective method for curing complex bAVMs. However, lacking the support of high-level evidence, its advantages remain unclear. This study was proposed to validate the benefits and risks of one-staged hybrid operation in the treatment of complex bAVMs, as well as its indications, key technologies, and workflows.

METHODS

The study is being conducted from Jan 2016 to Dec 2020 with 20 cooperation centers. It consists of 2 sets. The registry set is designed as a prospective real-world registry. The trial set is designed as a prospective pragmatic clinical trial, specifically for the patients with perforating arterial feeders. The two sets share a common grouping: the traditional operation group and the one-staged hybrid operation group. The assignment is based on the clinical condition in the registry set and is randomized in the trial set. End points will be evaluated at scheduled time points. The safety and efficiency of one-staged hybrid operation in treating complex bAVMs will be validated.

DISCUSSION

The study is designed for a real-world exploration of benefits and risks of one-staged hybrid operation in the treatment of complex bAVMs. The two-set design reduces the compromise of clinical practice due to the study and improves the statistical power and research quality with a practical sample size. In the study, advantages of the one-staged hybrid operation will be evaluated and compared to those of traditional operation. A spanning development of neurosurgical operation might be facilitated by the study, which means a higher cure rate and lower disability rate in patients with complex bAVMs.

TRIAL REGISTRATION

The study was retrospectively registered in ClinicalTrials.gov ( NCT03774017 ) on 11th Dec, 2018.

[Immediate outcomes of microsurgical treatment of cerebral arteriovenous malformations in non-hemorrhagic patients]

Arteriovenous malformations (AVMs) are some of the most frequent congenital abnormalities of the cerebral vascular system and usually occur at a young age. Given the fact that AVMs can manifest, in addition to hemorrhages, as symptomatic epilepsy (17-40%) that occurs more often at a young age and may lead to significant disability, investigation of this pathology remains topical. Particular attention has recently been paid to the management of AVM patients without clinical signs of hemorrhage at the time of pathology diagnosis.

OBJECTIVE

The objective of this study was to optimize the management of patients with unruptured AVMs based on analysis of the immediate outcomes of microsurgical treatment.

MATERIAL AND METHODS

We retrospectively analyzed the immediate outcomes of microsurgical treatment of AVM patients hospitalized to the Burdenko Neurosurgical Institute in the period from 2009 to 2017. The patients included in the study met the following criteria: age over 18 years; microsurgical resection of AVM. The main exclusion criterion was a hemorrhage history confirmed by clinical data or verified by a neuroimaging study (MRI/CT). The study included 160 patients (58.1% males and 41.9% females) aged 18 to 67 years (mean, 33.5 years). According to the clinical course, patients with epileptic syndrome prevailed: 99 (61.9%) cases. Headaches occurred in 49 (30.6%) patients; 8 (5%) patients had asymptomatic AVMs; 4 (2.5%) patients had ischemic stroke. The surgical risk was assessed by using the Spetzler-Martin (S-M) scale: Grade I - 18 (11.3%) patients, Grade II - 71 (44.4%) patients, Grade III - 60 (37.5%) patients, and Grade IV - 11 (6.8%) patients. Direct surgery in patients with AVMs classified as S-M V was not planned.

RESULTS

Postoperative analysis revealed that 33 patients included in the study group in accordance with the above criteria had silent AVM hemorrhage that was confirmed only based on the intraoperative picture. The best surgical treatment outcomes were observed in patients with S-M I and II AVMs. The outcome scored 4 and 5 on the Glasgow Outcome Scale (GOS) was in 100% of cases in the S-M I group, 98.6% in the S-M II group, 86.7% in the S-M III group, and 81.8% in the S-M IV group. The relatively good outcomes of S-M IV AVM resection are explained by careful selection of patients for surgery. In general, good postoperative outcomes (GOS score of 4 and 5) were in 93.2% of patients. The main newly developed postoperative symptoms were visual impairments - visual field defects (64.7% of all complications). Postoperative mortality was 1.3%.

CONCLUSION

Surgical treatment is indicated for patients with unruptured AVMs and S-M I or II surgical risk, regardless of clinical manifestations. In other cases, the treatment approach depends on a number of risk factors.

Delayed hemorrhagic complication after complete embolization of a brain arteriovenous malformation

Endovascular embolization is an essential therapeutic approach in the multidisciplinary management of cerebral arteriovenous malformations (AVM). However, it rarely occludes the AVM in its entirety. It is often combined with surgery or stereotactic radiosurgery. The aim of embolization is to reduce the size of the nidus and the intra-nidal flow in order to facilitate the microsurgical or the radiosurgical procedure. We report the case of a 61-year-old patient with a right frontal hemorrhagic AVM treated with complete embolization in a single session. Initially, a surgical procedure for excision of the AVM was scheduled 24hours post-embolization. This surgery was canceled due to a good angiographic result of the embolization. Eight days post-embolization, there was a massive re-bleed of the AVM which justified emergency surgical management. This case illustrates a delayed post-embolization hemorrhagic complication of an occluded AVM and prompts a review of the therapeutic strategy of the cerebral AVM to select the most effective and least morbid procedure or combination of procedures.

Comparison of the Long-term Efficacy and Safety of Gamma Knife Radiosurgery for Arteriovenous Malformations in Pediatric and Adult Patients

It is debated whether the efficacy and long-term safety of gamma knife radiosurgery (GKRS) for arteriovenous malformations (AVMs) differs between adult and pediatric patients. We aimed to clarify the long-term outcomes of GKRS in pediatric patients and how they compare to those in adult patients. We collected data for 736 consecutive patients with AVMs treated with GKRS between 1990 and 2014 and divided the patients into pediatric (age < 20 years, n = 144) and adult (age ≥ 20 years, n = 592) cohorts. The mean follow-up period in the pediatric cohort was 130 months. Compared to the adult patients, the pediatric patients were significantly more likely to have a history of hemorrhage (P < 0.001). The actuarial rates of post-GKRS nidus obliteration in the pediatric cohort were 36%, 60%, and 87% at 2, 3, and 6 years, respectively. Nidus obliteration occurred earlier in the pediatric cohort than in the adult cohort (P = 0.015). The actuarial rates of post-GKRS hemorrhage in the pediatric cohort were 0.7%, 2.5%, and 2.5% at 1, 5, and 10 years, respectively. Post-GKRS hemorrhage was marginally less common in the pediatric cohort than in the adult cohort (P = 0.056). Cyst formation/encapsulated hematoma were detected in seven pediatric patients (4.9%) at a median post-GKRS timepoint of 111 months, which was not significantly different from the rate in the adult cohort. Compared to adult patients, pediatric patients experience earlier therapeutic effects from GKRS for AVMs, and this improves long-term outcomes.

The impact of nTMS mapping on treatment of brain AVMs

BACKGROUND

The treatment of brain arteriovenous malformations (BAVMs) is still contrarily discussed. Despite the debatable results of the ARUBA trial, most BAVMs still require treatment depending on the Spetzler-Martin (SM) grading. Since size is measurable and venous drainage is visible, the determination of eloquence is comparably crucial but not fully objective. The present bicentric cohort study aims to examine the influence of preoperative navigated transcranial magnetic stimulation (nTMS) motor and language mapping data on decision-making for or against surgical treatment of BAVMs.

METHODS

The influence of data from nTMS on decision-making for or against treatment of BAVMs was examined by confirming/falsifying presumed motor or language eloquence.

RESULTS

The results of nTMS mappings changed the SM grading in nine cases. In six cases, the SM grading changed to a lower grade (= falsified eloquence); in three cases, the SM grading changed to a higher grade due to nTMS mappings (= unexpected eloquence). Out of all 34 cases, indication for surgery was supported by nTMS mappings in 15 cases (7 motors, 8 languages). In six cases, the decision against surgery was made based on nTMS mappings (three motors, three languages).

CONCLUSION

In 21 of 34 cases (62%), nTMS was a supportive argument. We could show that nTMS motor and language data can be used for a more objective decision-making regarding the treatment of BAVMs and for a more detailed SM grading regarding the rating of eloquence.

Quality of life and disability 12 months after surgery vs. conservative management for unruptured brain arteriovenous malformations: Scottish population-based and Australian hospital-based studies

BACKGROUND

Few data are available on disability and quality of life (QOL) after surgery versus conservative management for unruptured brain arteriovenous malformations (uAVMs).

OBJECTIVE

The aim of this study was to test the hypothesis that QOL and disability are worse after surgery ± preoperative embolisation for uAVM compared with conservative management.

METHODS

We included consecutive patients diagnosed with uAVM from a prospective population-based study in Scotland (1999-2003; 2006-2010) and a prospective hospital-based series in Australia (2011-2015). We assessed outcomes on the modified Rankin Scale (mRS) and the Short Form (SF)-36 at ~ 12 months after surgery or conservative treatment and compared these groups using continuous ordinal regression in the two cohorts separately.

RESULTS

Surgery was performed for 29% of all uAVM cases diagnosed in Scotland and 84% of all uAVM referred in Australia. There was no statistically significant difference between surgery and conservative management at 12 months among 79 patients in Scotland (mean SF-36 Physical Component Score (PCS) 39 [SD 14] vs. 39 [SD 13]; mean SF-36 Mental Component Score (MCS) 38 [SD 14] vs. 39 [SD 14]; mRS > 1, 24 vs. 9%), nor among 37 patients in Australia (PCS 51 [SD 10] vs. 49 [SD 6]; MCS 48 [SD 12] vs. 49 [SD 10]; mRS > 1, 19 vs. 30%). In the Australian series, there was no statistically significant change in the MCS and PCS between baseline before surgery or conservative management and 12 months.

CONCLUSIONS

We did not find a statistically significant difference between surgery ± preoperative embolisation and conservative management in disability or QOL at 12 months.

[Microsurgical treatment of non-bleeding cerebral arteriovenous malformations]

Treatment of non-bleeding cerebral arteriovenous malformations (AVMs) causes a lot of controversy among neurosurgeons around the world. The most discussed issue is choosing the method and indications for a certain treatment option. Despite the accumulated data, including the results of randomized studies, there is no consensus on this issue among experts. The purpose of this review is to analyze current concepts of the management and reasonability of microsurgical treatment of non-bleeding cerebral AVMs based on the latest published studies.