SURGERY OF CEREBRAL ARTERIOVENOUS MALFORMATIONS

Neurosurgery ◽  
2007 ◽  
Vol 61 (suppl_1) ◽  
pp. SHC-375-SHC-389 ◽  
Author(s):  
Nobuo Hashimoto ◽  
Kazuhiko Nozaki ◽  
Yasushi Takagi ◽  
Ken-ichiro Kikuta ◽  
Nobuhiro Mikuni
Keyword(s):  
Arteriovenous Malformations ◽  
Early Stage ◽  
Surgical Techniques ◽  
Treatment Strategies ◽  
Neurological Deficits ◽  
Surgical Approaches ◽  
Cerebral Arteriovenous Malformations ◽  
New Horizons ◽  
Arterial Bleeding ◽  
Clip Application

Abstract Despite remarkable progress, the microsurgical extirpation of cerebral arteriovenous malformations (AVMs) even by experienced neurosurgeons is not always easy or safe. This article focuses on how to render AVM surgery safer, and offers strategies and tactics for avoiding perilous bleeding and preserving postoperative neurological function. Our treatment strategies and surgical techniques are offered from the operating surgeon's perspective. An understanding of pathophysiology of cerebral AVMs is important for their appropriate surgical treatment. Sophisticated neuroimaging techniques and scrupulous neurophysiological examinations alert to possible complications, and improved surgical approaches help to minimize the sequelae of unanticipated complications. At the early stage of cerebral AVM surgery, extensive dissection of the sulci, fissures, and subarachnoid cistern should be performed to expose feeders, nidus, and drainers. Problems with the surgery of large and/or deep-seated lesions are exacerbated when arterial bleeding from the nidus continues even after all major feeders are thought to have been occluded. We routinely place catheters for angiography at the surgery of complex AVMs to find missing feeding arteries or to identify the real-time hemodynamic status of the lesion. Temporary clip application on feeders and less coagulation of the nidus is necessary to control intranidal pressure and to avoid uncontrollable bleeding from the nidus and adjacent brain. Intraoperative navigation images superimposed on tractography images can provide us with valuable information to minimize neurological deficits. Deeper insight into AVM nature and into events that occur during AVM surgery as well as the inclusion of molecular biological approaches will open new horizons for the safe and effective treatment of AVMs.

A 3-tier classification of cerebral arteriovenous malformations

2011 ◽  
Vol 114 (3) ◽  
pp. 842-849 ◽  
Author(s):  
Robert F. Spetzler ◽  
Francisco A. Ponce
Keyword(s):  
Surgical Outcomes ◽  
Arteriovenous Malformations ◽  
Neurological Deficits ◽  
Cerebral Arteriovenous Malformations ◽  
Pooled Data ◽  
Class A ◽  
Tier System ◽  
Class B ◽  
Class C

Object The authors propose a 3-tier classification for cerebral arteriovenous malformations (AVMs). The classification is based on the original 5-tier Spetzler-Martin grading system, and reflects the treatment paradigm for these lesions. The implications of this modification in the literature are explored. Methods Class A combines Grades I and II AVMs, Class B are Grade III AVMs, and Class C combines Grades IV and V AVMs. Recommended management is surgery for Class A AVMs, multimodality treatment for Class B, and observation for Class C, with exceptions to the latter including recurrent hemorrhages and progressive neurological deficits. To evaluate whether combining grades is warranted from the perspective of surgical outcomes, the 3-tier system was applied to 1476 patients from 7 surgical series in which results were stratified according to Spetzler-Martin grades. Results Pairwise comparisons of individual Spetzler-Martin grades in the series analyzed showed the fewest significant differences (p < 0.05) in outcomes between Grades I and II AVMs and between Grades IV and V AVMs. In the pooled data analysis, significant differences in outcomes were found between all grades except IV and V (p = 0.38), and the lowest relative risks were found between Grades I and II (1.066) and between Grades IV and V (1.095). Using the pooled data, the predictive accuracies for surgical outcomes of the 5-tier and 3-tier systems were equivalent (receiver operating characteristic curve area 0.711 and 0.713, respectively). Conclusions Combining Grades I and II AVMs and combining Grades IV and V AVMs is justified in part because the differences in surgical results between these respective pairs are small. The proposed 3-tier classification of AVMs offers simplification of the Spetzler-Martin system, provides a guide to treatment, and is predictive of outcome. The revised classification not only simplifies treatment recommendations; by placing patients into 3 as opposed to 5 groups, statistical power is markedly increased for series comparisons.

scholarly journals Gamma Knife surgery for incidental cerebral arteriovenous malformations

2014 ◽  
Vol 121 (5) ◽  
pp. 1015-1021 ◽  
Author(s):  
Chun-Po Yen ◽  
Dale Ding ◽  
Ching-Hsiao Cheng ◽  
Robert M. Starke ◽  
Mark Shaffrey ◽  
...  
Keyword(s):  
Gamma Knife ◽  
Arteriovenous Malformations ◽  
Latency Period ◽  
Invasive Procedure ◽  
Gamma Knife Surgery ◽  
Neurological Deficits ◽  
Cerebral Arteriovenous Malformations ◽  
Long Term Follow Up

Object A relatively benign natural course of unruptured cerebral arteriovenous malformations (AVMs) has recently been recognized, and the decision to treat incidentally found AVMs has been questioned. This study aims to evaluate the long-term imaging and clinical outcomes of patients with asymptomatic, incidentally discovered AVMs treated with Gamma Knife surgery (GKS). Methods Thirty-one patients, each with an incidentally diagnosed AVM, underwent GKS between 1989 and 2009. The nidus volumes ranged from 0.3 to 11.1 cm3 (median 3.2 cm3). A margin dose between 15 and 26 Gy (median 20 Gy) was used to treat the AVMs. Four patients underwent repeat GKS for still-patent AVM residuals after the initial GKS procedure. Clinical follow-up ranged from 24 to 196 months, with a mean of 78 months (median 51 months) after the initial GKS. Results Following GKS, 19 patients (61.3%) had a total AVM obliteration on angiography. In 7 patients (22.6%), no flow voids were observed on MRI but angiographic confirmation was not available. In 5 patients (16.1%), the AVMs remained patent. A small nidus volume was significantly associated with increased AVM obliteration rate. Thirteen patients (41.9%) developed radiation-induced imaging changes: 11 were asymptomatic (35.5%), 1 had only headache (3.2%), and 1 developed seizure and neurological deficits (3.2%). Two patients each had 1 hemorrhage during the latency period (116.5 risk years), yielding an annual hemorrhage rate of 1.7% before AVM obliteration. Conclusions The decision to treat asymptomatic AVMs, and if so, which treatment approach to use, remain the subject of debate. GKS as a minimally invasive procedure appears to achieve a reasonable outcome with low procedure-related morbidity. In those patients with incidental AVMs, the benefits as well as the risks of radiosurgical intervention will only be fully defined with long-term follow-up.

scholarly journals Repeat Gamma Knife Surgery for Incompletely Obliterated Cerebral Arteriovenous Malformations

Neurosurgery ◽  
2010 ◽  
Vol 67 (1) ◽  
pp. 55-64 ◽  
Author(s):  
Chun-Po Yen ◽  
Surbhi Jain ◽  
Iftikhar-ul Haq ◽  
Jay Jagannathan ◽  
David Schlesinger ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Gamma Knife ◽  
Arteriovenous Malformations ◽  
Gamma Knife Surgery ◽  
Neurological Deficits ◽  
Resonance Imaging ◽  
Cerebral Arteriovenous Malformations ◽  
Radiation Induced ◽  
Induced Changes

Abstract OBJECTIVE The causes of failure after an initial Gamma procedure were studied, along with imaging and clinical outcomes, in a series of 140 patients with cerebral arteriovenous malformations (AVMs) treated with repeat Gamma Knife surgery (GKS). METHODS Causes of initial treatment failure included inaccurate nidus definition in 14 patients, failure to fill part of the nidus as a result of hemodynamic factors in 16, recanalization of embolized AVM compartments in 6, and suboptimal dose (&lt; 20 Gy) in 23. Nineteen patients had repeat GKS for subtotal obliteration of AVMs. In 62 patients, the AVM failed to obliterate despite correct target definition and adequate dose. At the time of retreatment, the nidus volume ranged from 0.1 to 6.9 cm3 (mean, 1.4 cm3), and the mean prescription dose was 20.3 Gy. RESULTS Repeat GKS yielded a total angiographic obliteration in 77 patients (55%) and subtotal obliteration in 9 (6.4%). In 38 patients (27.1%), the AVMs remained patent, and in 16 patients (11.4%), no flow voids were observed on magnetic resonance imaging. Clinically, 126 patients improved or remained stable, and 14 experienced deterioration (8 resulting from a rebleed, 2 caused by persistent arteriovenous shunting, and 4 related to radiation-induced changes). CONCLUSION By using repeat GKS, we achieved a 55% angiographic cure rate. Although radiation-induced changes as visualized on magnetic resonance imaging occurred in 48 patients (39%), only 4 patients (3.6%) developed permanent neurological deficits. These findings may be useful in deciding the management of AVMs in whom total obliteration after initial GKS was not achieved.

scholarly journals Endovascular Therapy Followed by Stereotactic Radiosurgery for Cerebral Arteriovenous Malformations

2006 ◽  
Vol 12 (1_suppl) ◽  
pp. 163-166 ◽  
Author(s):  
Y. Arai ◽  
Y. Handa ◽  
H. Ishii ◽  
Y. Ueda ◽  
H. Uno ◽  
...  
Keyword(s):  
Stereotactic Radiosurgery ◽  
Arteriovenous Malformations ◽  
High Rate ◽  
Neurological Deficits ◽  
Cerebral Arteriovenous Malformations ◽  
Increased Risk ◽  
Irradiation Therapy ◽  
Complete Obliteration ◽  
Vascular Structures

Pre-radiosurgical embolization was carried out using cyanoacrylate in seven of 13 patients with cerebral arteriovenous malformations (AVMs) treated by stereotactic radiosurgery (SRS) with a linear accelerator (LINAC). The aim of embolization before SRS was the reduction of AVM volume and/or the elimination of vascular structures bearing an increased risk of haemorrhage. Staged-volume SRS was also performed in two patients because of residual irregular shaped nidus of AVMs even after the embolizations. Complete obliteration of the AVM nidus on angiogram was presented in five patients with embolizations (including one with staged-volume SRS) and in three of six patients with SRS alone, during follow-up periods after radiosurgery. No patients experienced haemorrhagic events after SRS. Although transient neurological symptoms were observed after embolizations in two patients, no permanent neurological deficits were presented in all patients with SRS. Pre-radiosurgical embolization may allow the effective influence on irradiation therapy in relatively large AVMs and promote more frequent obliteration in more small sized AVMs compared to those with SRS alone. However, further study must be needed to determine whether staged-volume SRS provides a high rate of AVM obliteration and its safeness.

Hemodynamics Associated With Intracerebral Arteriovenous Malformations: The Effects of Treatment Modalities

Neurosurgery ◽  
2017 ◽  
Vol 83 (4) ◽  
pp. 611-621 ◽  
Author(s):  
Vernard S Fennell ◽  
Nikolay L Martirosyan ◽  
Gursant S Atwal ◽  
M Yashar S Kalani ◽  
Francisco A Ponce ◽  
...  
Keyword(s):  
Arteriovenous Malformations ◽  
Treatment Options ◽  
Treatment Strategies ◽  
Endovascular Embolization ◽  
Treatment Modalities ◽  
Cerebral Arteriovenous Malformations ◽  
Venous Outflow ◽  
Comprehensive Literature Review ◽  
Flow Through ◽  
Changes Over Time

Abstract The understanding of the physiology of cerebral arteriovenous malformations (AVMs) continues to expand. Knowledge of the hemodynamics of blood flow associated with AVMs is also progressing as imaging and treatment modalities advance. The authors present a comprehensive literature review that reveals the physical hemodynamics of AVMs, and the effect that various treatment modalities have on AVM hemodynamics and the surrounding cortex and vasculature. The authors discuss feeding arteries, flow through the nidus, venous outflow, and the relative effects of radiosurgical monotherapy, endovascular embolization alone, and combined microsurgical treatments. The hemodynamics associated with intracranial AVMs is complex and likely changes over time with changes in the physical morphology and angioarchitecture of the lesions. Hemodynamic change may be even more of a factor as it pertains to the vast array of single and multimodal treatment options available. An understanding of AVM hemodynamics associated with differing treatment modalities can affect treatment strategies and should be considered for optimal clinical outcomes.

Gamma Knife surgery for basal ganglia and thalamic arteriovenous malformations

2012 ◽  
Vol 116 (4) ◽  
pp. 899-908 ◽  
Author(s):  
Ching-Hsiao Cheng ◽  
R. Webster Crowley ◽  
Chun-Po Yen ◽  
David Schlesinger ◽  
Mark E. Shaffrey ◽  
...  
Keyword(s):  
Basal Ganglia ◽  
Mr Imaging ◽  
Gamma Knife ◽  
Treatment Option ◽  
Arteriovenous Malformations ◽  
Gamma Knife Surgery ◽  
Neurological Deficits ◽  
Cerebral Arteriovenous Malformations ◽  
History Of ◽  
The Mean

Object Gamma Knife surgery (GKS) has emerged as the treatment of choice for small- to medium-sized cerebral arteriovenous malformations (AVMs) in deep locations. The present study aims to investigate the outcomes of GKS for AVMs in the basal ganglia and thalamus. Methods Between 1989 and 2007, 85 patients with AVMs in the basal ganglia and 97 in the thalamus underwent GKS and were followed up for more than 2 years. The nidus volumes ranged from 0.1 to 29.4 cm3 (mean 3.4 cm3). The mean margin dose at the initial GKS was 21.3 Gy (range 10–28 Gy). Thirty-six patients underwent repeat GKS for residual AVMs at a median 4 years after initial GKS. The mean margin dose at repeat GKS was 21.1 Gy (range 7.5–27 Gy). Results Following a single GKS, total obliteration of the nidus was confirmed on angiograms in 91 patients (50%). In 12 patients (6.6%) a subtotal obliteration was achieved. No flow voids were observed on MR imaging in 14 patients (7.7%). Following single or repeat GKS, total obliteration was angiographically confirmed in 106 patients (58.2%) and subtotal obliteration in 8 patients (4.4%). No flow voids on MR imaging were observed in 18 patients (9.9%). The overall obliteration rates following one or multiple GKSs based on MR imaging or angiography was 68%. A small nidus volume, high margin dose, low number of isocenters, and no history of embolization were significantly associated with an increased rate of obliteration. Twenty-one patients experienced 25 episodes of hemorrhage in 850 risk-years following GKS, yielding an annual hemorrhage rate of 2.9%. Four patients died in this series: 2 due to complications of hemorrhage and 2 due to unrelated diseases. Permanent neurological deficits caused by radiation were noted in 9 patients (4.9%). Conclusions Gamma Knife surgery offers a reasonable chance of obliterating basal ganglia and thalamic AVMs and does so with a low risk of complications. It is an optimal treatment option in patients for whom the anticipated risk of microsurgery is too high.

Treatment of Cerebral Arteriovenous Malformations with a Combination of Preoperative Embolization and Surgery

Neurosurgery ◽  
1991 ◽  
Vol 29 (3) ◽  
pp. 358-368 ◽  
Author(s):  
Alberto Pasqualin ◽  
Renato Scienza ◽  
Fabrizia Cioffi ◽  
Giovanni Barone ◽  
Aldo Benati ◽  
...  
Keyword(s):  
Clinical Outcome ◽  
Arteriovenous Malformations ◽  
Combined Treatment ◽  
Neurological Deficits ◽  
Preoperative Embolization ◽  
Surgical Removal ◽  
Cerebral Arteriovenous Malformations ◽  
Selective Embolization ◽  
Intraoperative Bleeding ◽  
Microsurgical Approach

Abstract Forty-nine patients with cerebral arteriovenous malformations (AVMs) were treated with preoperative embolization followed by resection using a microsurgical approach. In 27 patients, the AVM was located in an eloquent area; in 32 patients, the volume of the AVM was over 20 cm3. Preoperatively, flow-directed embolization was performed in 10 patients (28 procedures), selective embolization with threads was performed in 35 patients (46 procedures), and a combination of flow-directed and selective embolization was performed in 4 patients (12 procedures). The percentage of reduction of the AVM volume averaged 36% after embolization. Five minor complications (transient neurological deficits, in 2 cases associated with ischemic areas on the CT scan) were observed after embolization. The interval between the last embolization and surgery was as follows: within 10 days in 7 patients; between 11 and 20 days in 3 patients; between 21 and 30 days in 10 patients; between 31 and 60 days in 11 patients; and 2 months later in 18 patients. The efficacy of this combined treatment (embolization plus surgery) was evaluated by the incidence of hyperemic complications and the clinical outcome. Hyperemic complications occurred more frequently in patients with an AVM volume greater than 20 cm3. When compared with flow-directed embolization, selective embolization was linked with decreased bleeding during surgery; postoperatively, the incidence of cerebral edema was also lower. Clinical outcome was better after selective embolization, with no occurrence of major deficits and no mortality. When the percentage of reduction of the AVM volume after embolization was 40% or more, the incidence of intraoperative hyperemic complications was lower; moreover, new permanent deficits were never observed in patients with this volume reduction. A retrospective clinical comparison of two groups of patients with similar AVM volumes (&gt;20 cm3)—those given combined treatment (n = 32) versus those treated by direct surgery alone (n = 27)—showed that intraoperative bleeding appeared to decrease in patients treated by embolization; the incidence of postoperative hyperemic complications was not different in the two groups. New major deficits and deaths were less frequent in patients treated by embolization (P= 0.05 for the incidence of major deficits); postoperative epilepsy was also less common in these patients. In conclusion, combined treatment with selective preoperative embolization and direct surgery may help the neurosurgeon in the treatment of large, high-flow AVMs, reducing the risks connected with their surgical removal. (Neurosurgery 29:358-368, 1991)

Risk factors for subsequent hemorrhage in patients with cerebral arteriovenous malformations

2007 ◽  
Vol 107 (5) ◽  
pp. 965-972 ◽  
Author(s):  
Shigeki Yamada ◽  
Yasushi Takagi ◽  
Kazuhiko Nozaki ◽  
Ken-ichiro Kikuta ◽  
Nobuo Hashimoto
Keyword(s):  
Risk Factors ◽  
Arteriovenous Malformations ◽  
Venous Drainage ◽  
University Hospital ◽  
Neurological Deficits ◽  
First Year ◽  
Cerebral Arteriovenous Malformations ◽  
Drainage Pattern ◽  
Bleeding Rate ◽  
Increased Risk

Object The aim of this study was to identify the natural history of untreated cerebral arteriovenous malformations (AVMs) and the risk factors for subsequent hemorrhage after an initial AVM diagnosis. Methods The authors studied 305 consecutive patients with AVMs at the Kyoto University Hospital between 1983 and 2005. These patients were followed up until the first subsequent hemorrhage, the start of any treatment, or the end of 2005. Possible risk factors that were investigated included age at initial diagnosis, sex, type of initial presentation, size and location of the AVM nidus, and the venous drainage pattern. Subsequent hemorrhage occurred in 26 patients from the hemorrhagic group during 380 patient–years, and in 16 patients from the nonhemorrhagic group during 512 patient–years. Results The annual bleeding rate in the hemorrhagic group was 6.84% after the initial hemorrhage; however, that rate decreased in the first 5 years (15.42% in the first year, 5.32% in the subsequent 4 years, and 1.72% in more than 5 years). In the nonhemorrhagic group (annual bleeding rate of 3.12%), the patients initially presenting with headaches (annual bleeding rate of 6.48%) or asymptomatic presentations (annual bleeding rate of 6.44%) had a higher risk for subsequent hemorrhage. Conversely, those patients presenting with seizures (annual bleeding rate of 2.20%) or neurological deficits (annual bleeding rate of 1.73%) had a lower risk. A significantly increased risk (p < 0.05) of rebleeding was found among children (hazard ratio [HR] = 2.69), females (HR = 2.93), or patients with deep-seated AVMs (HR = 3.07). Conclusions Children, females, and patients with deep-seated AVMs had a threefold increased risk of rebleeding after an initial cerebral AVM. This increased risk was highest in the first year after the initial hemorrhage, and thereafter gradually decreased.

Evolution of the Management of Tentorial Dural Arteriovenous Malformations

Neurosurgery ◽  
2003 ◽  
Vol 52 (4) ◽  
pp. 750-762 ◽  
Author(s):  
Patrick R. Tomak ◽  
Harry J. Cloft ◽  
Akihiko Kaga ◽  
C. Michael Cawley ◽  
Jacques Dion ◽  
...  
Keyword(s):  
Arteriovenous Malformations ◽  
Therapeutic Strategy ◽  
Transarterial Embolization ◽  
Treatment Strategies ◽  
Venous Drainage ◽  
Neurological Deficits ◽  
Transvenous Embolization ◽  
Single Institution ◽  
Clinical Presentations

Abstract OBJECTIVE Tentorial dural arteriovenous malformations (DAVMs) are uncommon lesions associated with an aggressive natural history. Controversy exists regarding their optimal treatment. We present a single-institution series of tentorial DAVMs treated during a 12-year period, address the current controversies, and present the rationale for our current therapeutic strategy. METHODS Twenty-two patients with tentorial DAVMs were treated between 1988 and 2000. Treatment consisted of transarterial or transvenous embolization, surgical resection, disconnection of venous drainage, or a combination of these therapies. The clinical presentations, radiological features, treatment strategies, and results were studied. RESULTS Eighteen patients (82%) presented with intracranial hemorrhage or progressive neurological deficits. Retrograde leptomeningeal venous drainage was documented in 22 cases (100%), classifying the lesions as Borden Type III. Angiographic follow-up monitoring was performed for 0 to 120 months and clinical follow-up monitoring for 1 to 120 months. Posttreatment angiography demonstrated obliteration in 22 cases (100%). Two patients experienced neurological decline after endovascular treatment and died. All of the 20 surviving patients exhibited clinical improvement; there were no episodes of rehemorrhage or new neurological deficits. Outcomes were excellent in 17 cases (77%), good in 2 cases (9%), and fair in 1 case (5%), and there were 2 deaths (9%). CONCLUSION Tentorial DAVMs are aggressive lesions that require prompt total angiographic obliteration. Disconnection of the venous drainage from the fistula may be accomplished with transarterial embolization to the venous side, transvenous embolization, or surgical disconnection of the fistula. We think that extensive nidal resections carry more risk and are unnecessary. We do not think there is a role for stereotactic radiosurgery in the treatment of these lesions.

Acute Effect of the Nd:YAG Laser on the Cerebral Arteriovenous Malformation: A Histological Study

Neurosurgery ◽  
1989 ◽  
Vol 24 (3) ◽  
pp. 328-333 ◽  
Author(s):  
Mario Zuccarello ◽  
Thaddeus I. Mandybur ◽  
John M. Tew ◽  
William D. Tobler
Keyword(s):  
Nd:Yag Laser ◽  
Arteriovenous Malformations ◽  
Histological Study ◽  
Acute Effect ◽  
Cerebral Arteriovenous Malformation ◽  
Neurological Deficits ◽  
Cerebral Arteriovenous Malformations ◽  
Laser Technique ◽  
Histological Evidence ◽  
The Brain

Abstract The acute effect of Nd:YAG laser beam on cerebral arteriovenous malformations (AVMs) was examined. Histological examination of the specimens after treatment with the Nd:YAG laser revealed that the most prominent effect of the laser was shrinkage of the collagen of the vessels of the AVM, which led to laser-induced narrowing of blood vessels. The brain tissue confined to the resected AVM did not contain any histological evidence of acute damage. The resection of 10 cases of AVMs was safely accomplished with no morbidity or increased neurological deficits attributable to the laser technique.

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