Arteriovenous Malformation Surgery Research Articles

160 Gamme Knife Radio Surgery for Cerebral Arteriovenous Malformation (AVM) in Children: A Systematic Review and Meta-analysis of Clinical Outcomes

INTRODUCTION: As radiosurgical devices are becoming more commonly used and applied to treat cerebral arteriovenous malformations (cAVMs), there is a growing concern about whether the outcomes of radiosurgery might differ between children, adolescents, and adults due to the distinct characteristics of cAVMs in these age groups. METHODS: Search: A search for RCT, not RCT, prospective and retrospective cohort studies in PUBMED; SCOPUS; Central Cochrane Registry ofControlled Trials (The Cochrane Library); MEDLINE; EMBASE (Ovid); CINAHL. The search strategy include subject headings (MeSH) and text words connected with Booleans term. Population: Children (younger than 18 years old) with Cerebral Arterio-venous Malformation (AVMs). Intervention: Gamma Knife radiosurgery (GKS). Outcomes: Primary Outcome: Mortality to end of Follow-up and Surgery successfull determined by the percentage of obliterated AVMs. Secondary Outcome: New Neurological deterioration and Post-Radiosurgery intracranial hemorrhage. RESULTS: 21 studies with 2142 children who had Gamma knife surgery for cerebral arteriovenous malformations were found for this systematic review. For children with cerebral AVMs treat with GKS, the death rate was 0.725% (95% CI 0.411%-1.126%; I2 = 0%) while the success rate of gamma knife radiosurgery was 71.74% (95% CI 65.716%-77.211%; I2 = 88.13). The rate of complications, such as the rate of new neurological deficits, was 2.57% (1.43% to 3.89%; I2 = 66.78%), and the postoperative intracranial bleeding rate was 2.463% (1.348% to 3.9%; I2 = 70.14%). CONCLUSIONS: Gamma Knife radiosurgery is a safe and effective treatment option for cerebral arteriovenous malformations, with high surgical success rates, low mortality, and low complication rates. However, further high-quality case-control studies are needed to evaluate its long-term efficacy and safety.

Can exoscope improve brain AVMs surgery?

The advantages of the surgical view provided by the exoscope have been described before, although reports of its application to brain arteriovenous malformation (AVM) surgery are lacking. The ampler field of view and magnification up to ×24 allow for enhanced visualization during microsurgical procedures. Furthermore, the live visualization provided by indocyanine green video angiography (ICG-VA) helps emphasize the hemodynamics of AVMs, even allowing the detection of possible residual vein arterialization as an indirect expression of nidal remnants. With this illustrative video showing the resection of a hemorrhagic right frontoinsular Spetzler-Martin grade III AVM, the authors describe the technical implications of exoscope brain AVM surgery using the Olympus ORBEYE 4K-3D, with a final focus on ICG-VA as an asset. The video can be found here: https://stream.cadmore.media/r10.3171/2023.10.FOCVID23114.

Natural History and Histopathology of Expanding Cysts and Hematomas After Stereotactic Radiosurgery for Arteriovenous Malformations of the Brain: A Case Series

We reviewed the clinical course and histopathologic findings for cases involving the formation of expanding cysts and/or hematomas after gamma knife surgery (GKS) for arteriovenous malformations (AVMs). We report a single-center retrospective review of 18 patients who presented with cyst and/or hematoma expansion after GKS for AVMs between 1993 and 2023. Expanding cysts and hematomas were defined as well-demarcated cavities filled with fluid or well-marginated heterogenous hematomas presenting with expansion proximal to or in the location of the original AVM, respectively. Patient demographics, AVM characteristics, history of interventions and surgeries, and imaging and histopathologic features of expanding cysts and hematomas were collected for analysis. Among 1072 AVM patients treated using GKS, 18 presented with expanding cysts or hematomas during a total follow-up period of 16,757 patient-years (0.11 case/100 persons/patient-year). The time to cyst or hematoma identification was 4-13 years after initial GKS, with a mean duration of 8.6 years. Among the patients examined, 7 (38.9%) presented mainly with hematoma, 10 (55.6%) presented mainly with cysts, and 1 presented with approximately equal components of both. Among the 18 patients, 13 (72.2%) underwent craniotomy to treat cyst or hematoma expansion. All the specimens had similar histopathologic characteristics, including organizing hematoma with fresh and old hemorrhage, fibrinoid necrosis of the vessels, gliosis of normal brain tissue, infiltration of hemosiderin-laden histiocytes, and extravascular protein leakage. Our findings suggest that the formation of these 2 complications can be attributed to a common mechanism involving radiation-induced vascular damage in brain tissue adjacent to the AVM and subsequent chronic inflammation and capillary dilatation.

Clinically Translatable Solid-State Dye for NIR-II Imaging of Medical Devices.

Medical devices are commonly implanted underneath the skin, but how to real-time noninvasively monitor their migration, integrity, and biodegradation in human body is still a formidable challenge. Here, the study demonstrates that benzyl violet 4B (BV-4B), a main component in the FDA-approved surgical suture, is found to produce fluorescence signal in the first near-infrared window (NIR-I, 700-900nm) in polar solutions, whereas BV-4B self-assembles into highly crystalline aggregates upon a formation of ultrasmall nanodots and can emit strong fluorescence in the second near-infrared window (NIR-II, 1000-1700nm) with a dramatic bathochromic shift in the absorption spectrum of ≈200nm. Intriguingly, BV-4B-involved suture knots underneath the skin can be facilely monitored during the whole degradation process in vivo, and the rupture of the customized BV-4B-coated silicone catheter is noninvasively diagnosed by NIR-II imaging. Furthermore, BV-4B suspended in embolization glue achieves hybrid fluorescence-guided surgery (hybrid FGS) for arteriovenous malformation. As a proof-of-concept study, the solid-state BV-4B is successfully used for NIR-II imaging of surgical sutures in operations of patients. Overall, as a clinically translatable solid-state dye, BV-4B can be applied for in vivo monitoring the fate of medical devices by NIR-II imaging.

Retrospective single-arm cohort study of video-assisted thoracic surgery for treatment of idiopathic peripherally located simple type pulmonary arteriovenous malformation in 23 consecutive patients

BackgroundAlthough case reports of video-assisted thoracic surgery (VATS) for pulmonary arteriovenous malformation (PAVM) have been published, studies analyzing more than 10 cases were limited. A retrospective single-arm cohort study was performed to investigate the efficacy of VATS in 23 consecutive patients with idiopathic peripherally located simple type PAVM.MethodsVATS was performed for wedge resection of 24 PAVMs in 23 patients, which included 4 males and 19 females with an age range of 25 to 80 years (mean: 59.6 ± 13.0). Two patients underwent simultaneous resection of lung carcinoma, one by wedge resection and another by lobectomy. Each medical record was analyzed according to the resected specimen, bleeding volume, postsurgical hospital stay length, duration of chest tube placement, and VATS time. The distance between pleural surface/fissure and PAVM was measured on CT, and the influence of this distance on identification of PAVM was investigated.ResultsIn all 23 patients, VATS was successfully performed, and the venous sac was included in each resected specimen. Bleeding volume was less than 10mL in all but one with 1900 mL bleeding volume due to simultaneous lobectomy for carcinoma, not wedge resection of PAVM. Postsurgical hospital stay length, duration of chest tube placement, and VATS time were 5.0 ± 1.4 days, 2.7 ± 0.7 days, and 49.3 ± 39.9 min, respectively. In 21 PAVMs with a distance of 1 mm or less, purple vessel or pleural bulge of PAVM was identified soon after insertion of a thoracoscope. In the remaining 3 PAVMs with a distance of 2.5 mm or more, additional efforts were needed for identification.ConclusionVATS was found to be a safe and effective to treatment for idiopathic peripherally located simple type PAVM. When the distance between pleural surface/fissure and PAVM was 2.5 mm or more, a plan and strategy for identification of PAVM should be prepared before VATS.

Reversible splenial lesion after surgery for distant arteriovenous malformation: a case report.

Isolated lesions of the corpus callosum are rare and may represent permanent but also transient responses to various pathology termed "reversible splenial lesion syndrome" (RESLES) when in light of relevant clinical presentation. We present the first case of the RESLES after elective surgery for distant arteriovenous malformation (AVM), followed by a slight speech disturbance and MRI verified small, oval, well-circumscribed area of apparent cytotoxic edema in the center of the corpus callosum splenium, which completely resolved within 15days. Surgery for AVM is followed by the complex adaptation to a new vascular pattern, RESLES might develop, and should be suspected.

Letter: Risk for Hemorrhage the First 2 Years After Gamma Knife Surgery for Arteriovenous Malformations: An Update.

To the Editor: We have read with great interest the article by Karlsson et al1 titled “Risk for Hemorrhage the First 2 Years After Gamma Knife Surgery for Arteriovenous Malformations: An Update.” The premise of this study was based on the findings of a 2001 study that demonstrated the risk of hemorrhage after gamma knife surgery (GKS) for arteriovenous malformations (AVMs) to be strongly correlated with large AVM size, older age, and lower therapeutic dose.2 However, contradictory data collected 17 years later revealed the risk of hemorrhage was not related to AVM size or patient age.3 To clearly define predictors of hemorrhage, the authors retrospectively reviewed the outcome of 5037 patients treated with GKS for AVM.1 The average rate of hemorrhage was determined to be 2.4%, where larger AVM size, older age, and lower therapeutic dose served as significant (P < .01) risk factors, consistent with findings from the original study.1,2 AVM location (P = .16), embolization (P = .27), and history of pre-GKS hemorrhage (P = .20) were found to be nonsignificant predictors for post-GKS hemorrhage.1 The identification of clear hemorrhage risk factors after GKS for AVM in this large, heterogeneous cohort provides clinicians with more concrete guidelines for AVM management.1 The clinical management of cerebral AVMs remains challenging due to AVM heterogeneity in size, biological composition, anatomic location, and associated symptoms.4 Thus, the treatment of AVMs to reduce hemorrhage risk must be conducted in an individualized manner specific to patient presentation and AVM profile. Although no formal guidelines exist regarding treatment of unruptured AVMs, a landmark randomized trial of unruptured brain arteriovenous malformations (trial) revealed the superiority of medical management compared with interventional therapy.5 Interventional therapy was associated with an increased risk of stroke or death as compared with medical management alone (P < .0001; hazard ratio 3.70; 95% CI 1.85–7.14).5 Five-year follow-up data confirmed these findings.6 With this understanding, along with identifying general risk factors and prevalence rates of AVM hemorrhage after GKS, it would be valuable to investigate the impact of hemorrhage on mortality and morbidity in this cohort of patients undergoing interventional therapy. Doing so, while controlling for confounding variables, such as the Spetzler-Martin grade, AVM nidus morphology or location, would be clinically significant and aid in deciding which patients would truly benefit from GKS. Hemorrhage is the leading cause of morbidity and mortality associated with AVMs.7 Consequently, common symptoms of AVM-related hemorrhage such as seizures and headaches severely impair quality of life (QOL).8,9 While it can be hypothesized that post-GKS AVM hemorrhage would have profound implications for QOL outcomes, there are no reports in the literature detailing this relationship. Future studies should investigate the impact of post-GKS hemorrhage on QOL metrics, especially as GKS continues to improve and be used for more complex disease. This study by Karlsson et al1 provides a strong foundation for the future investigation of invaluable QOL metrics to guide medical decision-making in a manner that targets patient-specific QOL discrepancies while bridging this apparent gap in the literature.

Non-Angry Superficial Draining Veins: A New Technique in Identifying the Extent of Nidus Excision during Cerebral Arteriovenous Malformation Surgery

As essential techniques, intraoperative indocyanine green video angiography (ICG-VA) and FLOW 800 have been widely used in microsurgery for arteriovenous malformations (AVMs). In the present report, we introduced a supplementary technical trick for judging the degree of lesion resection when there were superficial drainage veins. FLOW 800 analysis is used to verify our conjecture. A retrospective analysis of a 33 case cohort treated surgically from June 2020 to September 2022 was conducted and their lesions were removed by superficial drainage veins as a supplementary technical trick and analyzed with FLOW800. In our 33 AVMs, the feeding artery was visualized earlier than the draining vein. Intraoperatively, the T1/2 peak and slope of the draining vein were significantly higher than that of the lesion. However, the maximum fluorescence intensity (MFI) of the draining vein decreased as the procedure progressed (p < 0.001). After reducing the blood flow to the nidus by progressive dissection of the feeding artery, the arteriovenous transit time (AVTT) decreased from 0.64 ± 0.47 s, was prolonged to 2.38 ± 0.52 (p < 0.001), and the MFI and slope of the nidus decreased from the pre-resection 435.42 ± 43.90 AI and 139.77 ± 27.55 AI/s, and decreased to 386.70 ± 48.17 AI and 116.12 ± 17.46 AI/s (p < 0.001). After resection of the nidus, the T1/2 peak of the draining vein increased from 21.42 ± 4.70 s, prolonged to after dissection of the blood feeding artery, 23.07 ± 5.29 s (p = 0.424), and after resection of the lesion, 25.13 ± 5.46 s (p = 0.016), with a slope from 135.79 ± 28.17 AI/s increased to 210.86 ± 59.67 AI/s (p < 0.001). ICG-VA integrated with FLOW 800 is an available method for determining the velocity of superficial drainage veins. Whether the color of the superficial drainage veins on the cortical surface returns to normal can determine whether the lesion is completely resected and can reduce the possibility of residual postoperative lesions.

Abstract 53: Long-term Treatment Risk Of Hemorrhage In Unruptured Brain Arteriovenous Malformation Patients

Introduction: The long-term effects of interventional treatment (with surgery, stereotactic radiosurgery, or endovascular embolization) for unruptured brain arteriovenous malformations (uBAVM) are uncertain. We address this in a large multi-center international cohort study comparing risk of intracranial hemorrhage (ICH) in the treated and untreated course of uBAVM patients. Methods: We pooled individual patient data (n=3,291) from 10 cohorts and imputed missing data. Survival analysis was performed from time of uBAVM diagnosis to intracranial hemorrhage (ICH) using Cox models, stratified by cohort, censoring at death or last follow-up, and including BAVM interventional treatment as a time-varying covariate. We tested for an interaction of treatment with follow-up time, then estimated the association of interventional treatment with ICH, adjusting for propensity quintile. Individual treatment propensity scores were calculated using logistic regression with Spetzler-Martin grade, sex, diagnosis age and year, cohort, and presence of presenting symptoms (seizures, headaches, and/or deficits). Results: Median cohort age was 36 years, 48% were female, and 77% received ≥1 treatment modality for uBAVM during follow-up. 373 ICH occurred during 32,054 person-years of follow-up (median=6.6y), for an ICH rate of 1.16 per 100 P-Y. Overall, treatment was not associated with risk of ICH (HR=1.12, 95% CI=0.89-1.51, p=0.33). However, we observed a strong interaction between treatment and follow-up time (p&lt;0.001): between 0-1 year, treatment was associated with higher risk of ICH (HR=3.48, 95% CI: 2.26-5.37, p&lt;0.001); between 1-10 years, we found no association between treatment and risk of ICH (HR=1.02, 95% CI: 0.73-1.45, p=0.87); after 10 years, treatment was associated with a lower risk of ICH (HR=0.46, 95% CI: 0.30-0.70, p&lt;0.001). Survival curves for untreated and treated courses crossed around 17 years. Conclusion: After accounting for treatment propensity for uBAVM, we found an initial increased risk of ICH in the treated relative to untreated course, which continually declined over time with survival curves crossing around 17 years. These results require confirmation in a randomized controlled trial of uBAVM with long-term follow-up.

Surgery in Intracerebral Arteriovenous Malformations: The Role of Preoperative Embolization.

The optimal treatment of cerebral arteriovenous malformations (AVMs) is still debated. Microsurgery and endovascular embolization can be utilized separately and in combination. However, each of these modalities harbor their own risks. In this study, we compared the outcomes of microsurgery only versus combined microsurgery+embolization approach in the treatment of AVMs. A total of 62 patients (34 men, 28 women) were recruited harboring Spetzler&Martin Grade-3 (n=44) and Grade-4 (n=18) AVMs. Among these, 37 were treated with combined microsurgery+embolization and 25 were treated with microsurgery alone. Their clinical features (ruptured/unruptured, eloquency, Modifed Rankin Scores, duration of surgery, pre- and post-op hemoglobin levels, usage of blood products) were compared. Higher number of patients with ruptured or eloquently-localized AVMs was treated with the combined approach. Duration of surgeries, pre- versus postoperative hemoglobin levels and usage of blood products did not differ between combined approach versus microsurgery alone. As eloquently located AVMs may possess higher surgical risks due to the presence of deep venous drainage or nidus size, combined treatment was more preferred. Other differences regarding selection of combined versus single approach were not associated with the lesion anatomo-physiology. Rather, we thought combined therapy was more appropriate in our initial clinical practice and planned our clinical strategy accordingly. Nonetheless, now, we found no superiority of the combined treatment in management of AVMs in parallel to recent meta-analyses. Hence, embolization before surgery is not generally advisable in the treatment of AVMs, yet some exceptions shall be considered in a patient-tailored approach.

Evaluation of the Utility of Indocyanine Green Video Angiography in Cerebral Arteriovenous Malformation Surgery

To assess the utility of intraoperative indocyanine green video angiography (ICG-VA) during microsurgical resection of arteriovenous malformations (AVMs). Data of the 24 patients, who were surgically treated for AVM using intraoperative ICG-VA, were reviewed retrospectively. Postoperative digital subtraction angiography (DSA) was performed in all patients before they regained consciousness and became fully awake, and the results were compared with those obtained with intraoperative ICG-VA. A scheduled DSA was performed in all patients in the third, sixth, and twelfth postoperative months as well. Authors retrospectively analyzed the records of intraoperative ICG-VA application of all 24 patients. Though the exposures were limited and the image qualities were poor at higher magnification on the surgical microscope within deep surgical fields, the AVM niduses, feeding arteries, draining veins, and their relations to normal vasculature were observed precisely with ICG-VA in all the procedures. Furthermore, the visualization was not qualified enough to identify these pathological vascular structures accurately before evacuating and irrigating the layer of blood clots that obscure the view in patients who presented with hemorrhage. In a patient in our series, a residual nidus in the tail of the caudate nucleus was detected with immediate postoperative DSA which was not revealed by terminal assessment with final intraoperative ICG-VA. Intraoperative ICG-VA is particularly effective in the identification of the feeder, nidus, and drainer and in the assessment of the flow dynamics of the nidus in cerebral AVM surgery. It may be a quick and safe technique for intraoperative imaging of the angioarchitecture of superficial AVMs, but it may be less helpful for deep-seated lesions. Furthermore, this method alone may not be useful in the identification of residual disease or improvement of the clinical outcomes. DSA has remained the gold standard for confirming AVM obliteration. Despite the technical limitations associated with ICG-VA, a combination of intraoperative ICG-VA and immediate postoperative DSA may advance the safety and efficacy of AVM surgery.

Efficacy of Utilizing Both 3-Dimensional Multimodal Fusion Image and Intra-Arterial Indocyanine Green Videoangiography in Cerebral Arteriovenous Malformation Surgery

An understanding of the complex morphology of an arteriovenous malformation (AVM) is important for successful resection. We have previously reported the utility of intra-arterial indocyanine green (ICG) videoangiography for this purpose, but that method cannot detect the angioarchitecture covered by brain tissue. 3-dimensional (3D) multimodal fusion imaging is reportedly useful for this same purpose, but cannot always visualize the exact angioarchitecture due to poor source images and processing techniques. This study examined the results of utilizing both techniques in patients with AVMs. Both techniques were applied in 12 patients with AVMs. Both images were compared with surgical views and evaluated by surgeons. Although evaluations for identifying superficial feeders by ICG videoangiography were high in all cases, the more complicated the AVM, the lower the evaluation by 3D multimodal fusion imaging. Conversely, evaluation of the estimated range of the nidus was high in all cases by 3D multimodal fusion imaging, but low in all but one case by ICG videoangiography. Nidus flow reduction was recognized by Flow 800 analysis obtained after ICG videoangiography. These results showed that utilizing both techniques together was more useful than each modality alone in AVM surgery. This was particularly effective in identifying superficial feeders and estimating the range of the nidus. This technique is expected to offer an optimal tool for AVM surgery.

Commentary: Risk for Hemorrhage the First 2 Years After Gamma Knife Surgery for Arteriovenous Malformations: An Update.

Commentary: Risk for Hemorrhage the First 2 Years After Gamma Knife Surgery for Arteriovenous Malformations: An Update.

Risk for Hemorrhage the First 2 Years After Gamma Knife Surgery for Arteriovenous Malformations: An Update.

Knowledge about the natural course of brain arteriovenous malformations (AVMs) have increased during the past 20 years, as has the number of AVMs treated, especially larger ones. It is thus timely to again analyze the risk for hemorrhage after Gamma Knife Surgery (GKS). To confirm or contradict conclusions drawn 20 years ago regarding factors that affect the risk for post-GKS hemorrhage. The outcome after GKS was studied in 5037 AVM patients followed for up to 2 years. The relation between post-treatment hemorrhage rate and a number of patient, AVM, and treatment parameters was analyzed. The results were also compared with the results from our earlier study. The annual post-treatment hemorrhage rate was 2.4% the first 2 years after GKS. Large size, low treatment dose, and old age were independent risk factors for AVM hemorrhage. After having compensated for the factors above, peripheral AVM location and female sex, at least during their child bearing ages, were factors associated with a lower post-GKS hemorrhage rate. Large AVMs (>5 cm 3 ) treated with low doses (≤16 Gy) had higher and small AVMs treated with high doses a lower risk for hemorrhage as compared with untreated AVMs. This was detectable within the first 6 months after GKS. No difference in hemorrhage rate could be detected for the other AVMs. Based on our findings, it is advisable to prescribe >16 Gy to larger AVMs, assuming that the risk for radiation-induced complications can be kept at an acceptable level.

Principles and strategies for step-by-step AVM excision.

Arteriovenous malformations (AVMs) are some of the most challenging surgical entities. Like any challenging surgical procedure, AVM surgery is a series of basic but fundamental steps, each with its own nuances. Despite a myriad of published material regarding AVMs, there are few succinct illustrated summaries of these steps with an accompanying elucidation of the most common pitfalls. This paper provides a step-by-step description and illustration of the basic surgical principles of AVM microsurgical resection, focusing on the main key points and addressing the critical issues that surround this surgery. Deep anatomical knowledge and presurgical planning of these basic steps, combined with good contingency management skills, are paramount for an effective and safe AVM surgery.

Stereotactic Radio Surgery, Embolization and Conservative Management for Cerebral Arteriovenous Malformation: A New Zealand Experience of Long-Term Outcomes

Cerebral arteriovenous malformations (AVMs) can be treated by microsurgery, stereotactic radiosurgery (SRS) as a stand-alone procedure, or combining embolization and conservative management. This single-center, retrospective review explored the outcomes of patients treated with SRS alone, embolization before SRS (ESRS), or conservative management for cerebral AVMs. Demographic details, Spetzler-Martin grade, SRS dose, obliteration, time to obliteration, imaging modality, rebleed, disease-specific mortality, and post-SRS complications were collected. Chi-square tests of independence and 1-way analysis of variance/Kruskal-Wallis tests were performed. Two-hundred and thirty-nine patients were treated with SRS alone, 37 were treated with ESRS, and 83 were conservatively managed. Obliteration rates were 78% (SRS alone) and 70% (ESRS). Rebleed rates were comparable among SRS alone (4%), ESRS (0%), and conservative management (8%). Disease-specific mortality rates were significantly lower for SRS alone (1%) and ESRS (0%) compared with conservative management (6%, X2 [2, n= 358]= 7.50, P= 0.024). Post-SRS complications occurred with SRS alone only and included radiation necrosis (n=5), cavernous malformations (n= 2), and stroke (n= 1). Obliteration, rebleed, and disease-specific mortality rates were comparable among pediatric (<18 years), nonelderly (18-59 years), and elderly (≥60 years) age groups. Findings suggest that SRS and ESRS are safe and effective treatments for cerebral AVM (when quantified by obliteration, rebleed, and disease-specific mortality rates). With multinational, prospective, randomized controlled trials with long follow-up periods, the effectiveness and safety of SRS and ESRS compared with conservative management for AVM will be further clarified.

Awake Surgery for Arteriovenous Malformations in Eloquent Areas Does Not Increase Intraoperative Risks and Allows for Shorter-Term Recovery and Improved Status

Arteriovenous malformations (AVMs) located in eloquent areas are associated with a significant risk of neurologic deterioration. Awake surgery applied to intracranial AVMs could better identify eloquent areas, but its feasibility and application are controversial and limited to small case series. We retrospectively reviewed a group of 59 brain AVMs located in eloquent areas surgically treated with asleep craniotomy and compared it with a combined group of patients treated with awake craniotomy. Patients were stratified into 2 groups: patients who underwent asleep surgery and patients who underwent awake surgery. With this study, we aimed to perform a complete analysis of surgical risks and outcomes for this subgroup of patients in order to provide a basis for a future prospective study. We compared the asleep group of 25 patients and the awake group of 34 patients. No statistically significant differences were identified regarding the risk of postoperative complications, surgical radicality, presence of residual, and need for adjuvant treatment (P= 1.00). The improvement in Karnofsky Performance Status (KPS) was more rapid and effective during follow-up in patients treated with awake surgery compared with asleep surgery (KPS at day 30 >70%-80% versus 87.2%, P= 0.01 and at 1year KPS >70%-80% vs. 96.9%, P= 0.02). In contrast to what is commonly believed, applying awake surgery to this lesion does not involve increased intraoperative risks. Still, it seems to determine a significant improvement in the outcome of patients from postoperative day 30 onwards.

Pseudo-residual nidus after arteriovenous malformation surgery: illustrative case

BACKGROUNDIntraoperative indocyanine green video angiography (ICG-VA) is useful for determining the extent of lesion removal during cerebral arteriovenous malformation (AVM) surgery. The authors described a case of surgical removal of an AVM presenting with early venous filling mimicking a residual nidus on intraoperative ICG-VA.OBSERVATIONSA 7-year-old girl experienced a sudden disturbance of consciousness. Computed tomography revealed right frontal intracerebral hemorrhage. Digital subtraction angiography showed a Spetzler-Martin grade 1 AVM in the right frontal lobe. The patient received surgical removal of the AVM after endovascular embolization. After removal of the nidus, the first intraoperative ICG-VA revealed early venous filling of the cortex around the excision cavity. Additional resection of the cortex around this area was performed. Histopathological examination of the lesion revealed a dilated normal vascular structure without an AVM.LESSONSEarly venous filling in the surrounding brain tissue after AVM removal does not necessarily indicate a residual nidus. The need for additional resection of the lesion depends on the eloquence of the area.

Intraoperative Monitoring Cerebral Blood Flow During the Treatment of Brain Arteriovenous Malformations in Hybrid Operating Room by Laser Speckle Contrast Imaging.

BackgroundHemodynamic changes caused by hybrid surgery for brain arteriovenous malformations (bAVM) are usually related to long-term lesions from “blood stealing”. There are currently no viable low-cost, noninvasive procedures for assessing cerebral perfusion in the operating room. This study aims to investigate the use of intraoperative laser speckle contrast image (LSCI) software in AVM surgery.MethodsIn Zhongnan Hospital of Wuhan University, 14 patients who underwent surgery with LSCI were collected. To analyze the hemodynamic features of AVM and the influence on the peripheral cortex of AVM embolization and resection, we assessed the transit time between feeding arteries and drainage veins by intraoperative digital subtraction angiography (DSA). Meanwhile, LSCI was performed at pre-embolization, post-embolization, and after complete resection of bAVM.ResultsIn this study, the transit time of bAVM before and after embolization was compared, the transit time before embolization was significantly shorter than that after embolization (p < 0.05). We also got good visualization of relative CBF, in addition, to flow imaging in the cortical vasculature round bAVM with LSCI. The flux of post-surgery was significantly higher than pre-embolization (p < 0.01).ConclusionHemodynamic variable assessment plays an important role in the resection of AVM in the hybrid operative room and LSCI can be used to visualize and evaluate cortical cerebral blood flow to detect pathological hyperperfusion in real-time with a good spatial-temporal resolution in a sensitive and continuous, non-invasive mode.

Impact of Pre-operative Embolization With Onyx for Brain Arteriovenous Malformation Surgery.

ObjectiveTo clarify the safety and efficacy of pre-operative embolization using Onyx liquid embolic agent (Onyx; ev3) compared with N-butyl cyanoacrylate (NBCA; Cordis Neurovascular, Inc.) or coils in cerebral arteriovenous malformation (AVM) surgery.MethodsThis was a retrospective review of a prospectively collected clinical database of brain AVMs treated at our institute from January 2005 to March 2021. A total of 38 consecutive patients who underwent AVM resection after pre-operative embolization were included. Based on pre-operative embolization materials, the patients were divided into the pre-Onyx group (n = 16), in which NBCA or coils were used for embolization, and the Onyx group (n = 22). Patient characteristics and treatment results were compared between the two groups.ResultsPatient characteristics were comparable between the two groups in terms of age, sex, and rupture status. While the Spetzler–Martin grade was also similar between the two groups, the location of the AVM nidus in the eloquent area was slightly higher in patients in the Onyx group (72.7%) than in patients in the pre-Onyx group (43.8%) (P = 0.09). The embolization rate was higher in the pre-Onyx group (mean: 63.0%; range: 12.7–100%) than in the Onyx group (mean: 50.0%; range: 15.8–100%), but the difference was not statistically significant (P = 0.06). The time needed for surgical removal was shorter in the Onyx group (mean: 354.8 min; range: 144–884 min) than in the pre-Onyx group (mean: 457.9 min; range: 240–1,294 min); however, this difference was not statistically significant (P = 0.13). The amount of intraoperative bleeding was significantly lower in the Onyx group (mean: 129.8 ml; range: 20–540 mL) than in the pre-Onyx group (mean: 448.8 mL; range: 120–1,550 ml) (P = 0.0008). The surgical complication rates were comparable between the two groups (pre-Onyx group, 18.8%; Onyx group, 4.5%; P = 0.29).ConclusionsPre-operative embolization with Onyx can significantly reduce the amount of intraoperative bleeding in AVM resection and may contribute to safe AVM surgery.