Radiosurgical treatment for rolandic arteriovenous malformations

2006 ◽  
Vol 105 (5) ◽  
pp. 689-697 ◽  
Author(s):  
Yuri M. Andrade-Souza ◽  
Meera Ramani ◽  
Daryl Scora ◽  
May N. Tsao ◽  
Karel terBrugge ◽  
...  
Keyword(s):  
Arteriovenous Malformations ◽  
Latency Period ◽  
Obliteration Rate ◽  
University Of Toronto ◽  
First Choice ◽  
Study Population ◽  
Radiation Induced ◽  
Risk Of Hemorrhage ◽  
The University

Object The authors reviewed the radiosurgical outcomes in patients with arteriovenous malformations (AVMs) located in the rolandic area, including the primary motor and sensory gyri. Methods The study population consisted of 38 patients with rolandic-area AVMs who underwent linear accelerator radiosurgery at the University of Toronto between 1989 and 2000. Obliteration rate, risk of hemorrhage during the latency period, radiation-induced complications, seizure control, and functional status were evaluated. Patients were also divided into two subgroups according to AVM volume (< 3 cm3 and ≥ 3 cm3). Patients were followed up for a median of 42.4 months (range 30–103 months), and the median age of the patients was 40 years (range 12–67 years). The median AVM volume was 8.1 cm3 (range 0.32–21, mean 8.32 cm3), and the median dose at the tumor margin was 15 Gy (range 15–22, mean 16.8 Gy). The risk of hemorrhage after radiosurgery was 5.3% for the 1st year, 2.6% for the 2nd, and 0% for the 3rd. Two patients (5.3%) sustained adverse effects related to radiation for more than 6 months. Complete nidus obliteration after a single radiosurgical treatment was achieved in 23 patients (60.5%). The obliteration rate for AVMs smaller than 3 cm3 was 83.3% (10 of 12) and that for AVMs larger than or equal to 3 cm3 was 50% (13 of 26). Among the patients who had seizures as the initial presentation, 51.8% were free of seizures after radiosurgery and the seizure pattern improved in 40.7% during the 3rd and last year of follow up. Overall, excellent results (obliteration and no new or worsening neurological deficit) can be achieved in approximately 60% of patients. This percentage varies according to the AVM size and can reach 83% in patients with AVMs smaller than 3 cm3. Conclusions Radiosurgery is a safe and effective treatment for people with rolandic AVMs. The low rate of morbidity associated with radiosurgery, compared with other treatments, indicates that this method may be the first choice for patients with AVMs located in this area.

Radiosurgery for ruptured intracranial arteriovenous malformations

2014 ◽  
Vol 121 (2) ◽  
pp. 470-481 ◽  
Author(s):  
Dale Ding ◽  
Chun-Po Yen ◽  
Robert M. Starke ◽  
Zhiyuan Xu ◽  
Jason P. Sheehan
Keyword(s):  
Multivariate Analysis ◽  
Arteriovenous Malformations ◽  
Latency Period ◽  
Intracranial Arteriovenous Malformations ◽  
Available N ◽  
Obliteration Rate ◽  
Radiation Induced ◽  
Prescription Dose ◽  
Induced Changes

Object Ruptured intracranial arteriovenous malformations (AVMs) are at a significantly greater risk for future hemorrhage than unruptured lesions, thereby necessitating treatment in the majority of cases. In a retrospective, single-center study, the authors describe the outcomes after radiosurgery in a large cohort of patients with ruptured AVMs. Methods From an institutional review board–approved, prospectively collected AVM radiosurgery database, the authors identified all patients with a history of AVM rupture. They analyzed obliteration rates in all patients in whom radiological follow-up data were available (n = 639). However, to account for the latency period associated with radiosurgery, only those patients with more than 2 years of radiological follow-up and those with earlier AMV obliteration were included in the analysis of prognostic factors related to obliteration and complications. This resulted in a cohort of 565 patients with ruptured AVMs for whom data were analyzed; these patients had a median radiological follow-up of 57 months and a median age of 29 years. Twenty-one percent of the patients underwent preradiosurgery embolization. The median volume and prescription dose were 2.1 cm3 and 22 Gy, respectively. The Spetzler-Martin grade was III or higher in 56% of patients, the median radiosurgery-based AVM score was 1.08, and the Virginia Radiosurgery AVM Scale (RAS) score was 3 to 4 points in 44%. Survival and regression analyses were performed to determine obliteration rates over time and predictors of obliteration and complications. Results In the overall population of 639 patients with ruptured AVMs, the obliteration rate was 11.1% based on MRI only (71 of 639 patients), 56.0% based on angiography (358 of 639), and 67.1% based on combined modalities (429 of 639 patients). In the cohort of patients with 2 years of follow-up or an earlier AVM obliteration, the cumulative obliteration rate was 76% and the actuarial obliteration rates were 41% and 64% at 3 and 5 years, respectively. Multivariate analysis identified the absence of preradiosurgery embolization (p < 0.001), increased prescription dose (p = 0.001), the presence of a single draining vein (p = 0.046), no postradiosurgery-related hemorrhage (p = 0.007), and lower Virginia RAS score (p = 0.020) as independent predictors of obliteration. The annual risk of a hemorrhage occurring during the latency period was 2.0% and the rate of hemorrhage-related morbidity and mortality was 1.6%. Multivariate analysis showed that decreased prescription dose (p < 0.001) and multiple draining veins (p = 0.003) were independent predictors of postradiosurgery hemorrhage. The rates of symptomatic and permanent radiation-induced changes were 8% and 2.7%, respectively. In the multivariate analysis, a single draining vein (p < 0.001) and higher Virginia RAS score (p = 0.005) were independent predictors of radiation-induced changes following radiosurgery. Conclusions Radiosurgery effectively treats ruptured AVMs with an acceptably low risk-to-benefit ratio. For patients with ruptured AVMs, favorable outcomes are more likely when preradiosurgical embolization is avoided and a higher prescription dose can be delivered.

Advances in the radiosurgical treatment of large inoperable arteriovenous malformations

2007 ◽  
Vol 23 (6) ◽  
pp. E6 ◽  
Author(s):  
Jesse Jones ◽  
Sunyoung Jang ◽  
Christopher C. Getch ◽  
Alan G. Kepka ◽  
Maryanne H. Marymont
Keyword(s):  
Arteriovenous Malformations ◽  
Latency Period ◽  
Peripheral Dose ◽  
Target Delineation ◽  
Dose Volume ◽  
Dose Planning ◽  
Target Volumes ◽  
Risk Of Hemorrhage ◽  
Higher Doses

✓ Radiosurgery has proven useful in the treatment of small arteriovenous malformations (AVMs) of the brain. However, the volume of healthy tissue irradiated around large lesions is rather significant, necessitating reduced radiation doses to avoid complications. As a consequence, this can produce poorer obliteration rates. Several strategies have been developed in the past decade to circumvent dose–volume problems with large AVMs, including repeated treatments as well as dose, and volume fractionation schemes. Although success on par with that achieved in lesions smaller than 3 ml remains elusive, improvements over the obliteration rate, the complication rate or both have been reported after conventional single-dose stereotactic radiosurgery (SRS). Radiosurgery with a marginal dose or peripheral dose < 15 Gy rarely obliterates AVMs, yet most lesions diminish in size posttreatment. Higher doses may then be reapplied to any residual nidi after an appropriate follow-up period. Volume fractionation divides AVMs into smaller segments to be treated on separate occasions. Doses > 15 Gy irradiate target volumes of only 5–15 ml, thereby minimizing the radiation delivered to the surrounding brain tissue. Fewer adverse radiological effects with the use of fractionated radiosurgery over standard radiosurgery have been reported. Advances in AVM localization, dose delivery, and dosimetry have revived interest in hypofractionated SRS. Investigators dispensing ≥ 7 Gy per fraction minimum doses have achieved occlusion with an acceptable number of complications in 53–70% of patients. The extended latency period between treatment and occlusion, about 5 years for emerging techniques (such as salvage, staged volume, and hypofractionated radiotherapy), exposes the patient to the risk of hemorrhage during that period. Nevertheless, improvements in dose planning and target delineation will continue to improve the prognosis in patients harboring inoperable AVMs.

Outcomes of Radiosurgery for Brainstem Arteriovenous Malformations

Neurosurgery ◽  
2011 ◽  
Vol 69 (1) ◽  
pp. 45-52 ◽  
Author(s):  
Tomoyuki Koga ◽  
Masahiro Shin ◽  
Atsuro Terahara ◽  
Nobuhito Saito
Keyword(s):  
Arteriovenous Malformations ◽  
Additional Treatment ◽  
Surgical Morbidity ◽  
Factors Associated ◽  
Obliteration Rate ◽  
Early Results ◽  
Number Of Patients ◽  
The Mean ◽  
Risk Of Hemorrhage

Abstract BACKGROUND: Arteriovenous malformations (AVMs) in the brainstem yield a high risk of hemorrhage. Although stereotactic radiosurgery (SRS) is accepted, because of high surgical morbidity and mortality, outcomes are still unclear. OBJECTIVE: We previously reported the early results of SRS for brainstem AVMs. Here, we obtained data from a longer follow-up for a larger number of patients and present precise outcomes based on the latest follow-up data. METHODS: Forty-four patients with brainstem AVMs were treated by SRS. Outcomes such as the rates of obliteration, hemorrhage after treatment, and adverse effects were retrospectively analyzed. RESULTS: The annual hemorrhage rate before SRS was 17.5%. The mean follow-up period after SRS was 71 months (range, 2-168 months). The actuarial obliteration rate confirmed by angiography was 52% at 5 years. Factors associated with higher obliteration rate were previous hemorrhage (P = .048) and higher margin dose (P = .048). For patients treated with a margin dose of ≥ 18 Gy, the obliteration rate was 71% at 5 years. Persistent worsening of neurological symptoms was observed in 5%. The annual hemorrhage rate after SRS was 2.4%. Four patients died of rebleeding, and disease-specific survival rate was 86% at 10 years after treatment. CONCLUSION: Nidus obliteration must be achieved for brainstem AVMs because they possibly cause lethal hemorrhage even after SRS. Treatment with a high margin dose is desirable to obtain favorable outcomes for these lesions. Additional treatment should be considered for an incompletely obliterated nidus.

Repeat Radiosurgery for Intracranial Arteriovenous Malformations

Neurosurgery ◽  
2011 ◽  
Vol 70 (1) ◽  
pp. 150-154 ◽  
Author(s):  
John M. Stahl ◽  
Yueh-Yun Chi ◽  
William A. Friedman
Keyword(s):  
Initial Treatment ◽  
Arteriovenous Malformations ◽  
Intracranial Arteriovenous Malformations ◽  
University Of Florida ◽  
The Status ◽  
Median Volume ◽  
Radiation Induced ◽  
Prescription Dose ◽  
The University

Abstract BACKGROUND Despite a high success rate in the stereotactic radiosurgical treatment of intracranial arteriovenous malformations (AVMs) that cannot be safely resected with microsurgery, some patients must be managed after treatment failure. OBJECTIVE To provide an update on the use of repeat linear accelerator radiosurgery as a treatment for failed AVM radiosurgery at the University of Florida. METHODS We reviewed 103 patients who underwent repeat radiosurgical treatment for residual AVM at the University of Florida between December 1991 and December 2007. Each of these patients had at least 2 radiosurgical treatments for the same AVM. Patient information, including AVM nidus volume, prescription dose, age, and sex, was collected at the time of initial treatment and again at the time of retreatment. Patients were followed up after treatment with magnetic resonance, computed tomography, and angiographic imaging at standard intervals to determine the status of their AVM. The median follow-up after retreatment was 31 months. RESULTS Between the first and second treatments, the median AVM nidus volume was decreased by 69% (from a median volume of 12.7 to 4.0 cm3), allowing the median prescribed dose to be increased from 1500 cGy on initial treatment to 1750 cGy on retreatment. The final obliteration rate on retreatment was 65.3%. After salvage retreatment, 5 patients (4.9%) experienced radiation-induced complications, and 6 patients (5.8%) experienced posttreatment hemorrhage. CONCLUSION Repeat radiosurgery is a safe and effective salvage treatment for AVMs.

Stereotactic Radiosurgery for Brainstem Arteriovenous Malformations: A Multicenter Study

Neurosurgery ◽  
2017 ◽  
Vol 81 (6) ◽  
pp. 910-920 ◽  
Author(s):  
Or Cohen-Inbar ◽  
Robert M Starke ◽  
Cheng-Chia Lee ◽  
Hideyuki Kano ◽  
Paul Huang ◽  
...  
Keyword(s):  
Stereotactic Radiosurgery ◽  
Multicenter Study ◽  
Cranial Nerve ◽  
Arteriovenous Malformations ◽  
Maximum Dose ◽  
Latency Period ◽  
Medical Centers ◽  
Formidable Challenge ◽  
Radiation Induced

Abstract BACKGROUND The management of brainstem arteriovenous malformations (bAVMs) is a formidable challenge. bAVMs harbor higher morbidity and mortality compared to other locations. OBJECTIVE To review the outcomes following stereotactic radiosurgery (SRS) of bAVMs in a multicenter study. METHODS Six medical centers contributed data from 205 patients through the International Gamma Knife Research Foundation. Median age was 32 yr (6-81). Median nidus volume was 1.4 mL (0.1-69 mL). Favorable outcome (FO) was defined as AVM obliteration and no post-treatment hemorrhage or permanent symptomatic radiation-induced complications. RESULTS Overall obliteration was reported in 65.4% (n = 134) at a mean follow-up of 69 mo. Obliteration was angiographically proven in 53.2% (n = 109) and on MRA in 12.2% (n = 25). Actuarial rate of obliteration at 2, 3, 5, 7, and 10 yr after SRS was 24.5%, 43.3%, 62.3%, 73%, and 81.8% respectively. Patients treated with a margin dose &gt;20 Gy were more likely to achieve obliteration (P = .001). Obliteration occurred earlier in patients who received a higher prescribed margin dose (P = .05) and maximum dose (P = .041). Post-SRS hemorrhage occurred in 8.8% (n = 18). Annual postgamma knife latency period hemorrhage was 1.5%. Radiation-induced complications were radiologically evident in 35.6% (n = 73), symptomatic in 14.6% (n = 30), and permanent in 14.6% (n = 30, which included long-tract signs and new cranial nerve deficits). FO was achieved in 64.4% (n = 132). Predictors of an FO were a higher Virginia radiosurgery AVM scale score (P = .003), prior hemorrhage (P = .045), and a lower prescribed maximum dose (P = .006). CONCLUSION SRS for bAVMs results in obliteration and avoids permanent complications in the majority of patients.

scholarly journals Radiosurgery for unruptured brain arteriovenous malformations in the pre-ARUBA era: long-term obliteration rate, risk of hemorrhage and functional outcomes

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Iulia Peciu-Florianu ◽  
Henri-Arthur Leroy ◽  
Elodie Drumez ◽  
Chloé Dumot ◽  
Rabih Aboukaïs ◽  
...  
Keyword(s):  
Functional Outcomes ◽  
Arteriovenous Malformations ◽  
Gamma Knife Radiosurgery ◽  
University Hospital ◽  
Line Treatment ◽  
First Line ◽  
Obliteration Rate ◽  
Risk Of Hemorrhage ◽  
First Line Treatment

AbstractThe management of non-hemorrhagic arteriovenous malformations (AVMs) remains a subject of debate, even more since the ARUBA trial. Here, we report the obliteration rate, the risk of hemorrhage and the functional outcomes after Gamma Knife radiosurgery (GKRS) as first-line treatment for non-hemorrhagic AVMs treated before the ARUBA publication, in a reference university center with multimodal AVM treatments available. We retrospectively analyzed data from a continuous series of 172 patients harboring unruptured AVMs treated by GKRS as first-line treatment in our Lille University Hospital, France, between April 2004 and December 2013. The primary outcome was obliteration rate. Secondary outcomes were the hemorrhage rate, the modified Rankin Scale (mRS), morbidity and epilepsy control at last follow-up. The minimal follow-up period was of 3 years. Median age at presentation was 40 years (IQR 28; 51). Median follow-up was 8.8 years (IQR 6.8; 11.3). Median target volume was 1.9 cm3 (IQR 0.8–3.3 cm3), median Spetzler-Martin grade: 2 (IQR 1–2), median Pollock-Flickinger score: 1.07 (IQR 0.82–2.94), median Virginia score: 1 (IQR 1–2). Median treatment dose was 24 Gy at 50% isodose line. Twenty-three patients underwent a second GKRS after a median time of 58 months after first GKRS. The overall obliteration rate was of 76%, based primarily on cerebral angiography and/or rarely only upon MRI. Hemorrhage during the post-treatment follow-up was reported in 18 (10%) patients (annual risk of 1.1%). Transient post-GKRS morbidity was reported in 14 cases (8%) and persistent neurological deficit in 8 (4.6%) of patients. At last follow-up, 86% of patients had a mRS ≤ 1. Concerning patients with pretherapeutic epilepsy, 84.6% of them were seizure-free at last follow-up. GKRS as first-line therapeutic option for unruptured cerebral AVMs achieves high obliteration rates (76%) while maintaining a high-level patient’s autonomy. All hemorrhagic events occurred during the first 4 years after the initial GKRS. In cases with epilepsy, there was 84.6% seizure free at last follow-up. Permanent morbidity was reported in only 4.6%.

Radiosurgery for Spetzler-Martin Grade III arteriovenous malformations

2014 ◽  
Vol 120 (4) ◽  
pp. 959-969 ◽  
Author(s):  
Dale Ding ◽  
Chun-Po Yen ◽  
Robert M. Starke ◽  
Zhiyuan Xu ◽  
Xingwen Sun ◽  
...  
Keyword(s):  
Arteriovenous Malformations ◽  
Latency Period ◽  
Cox Proportional Hazards ◽  
Favorable Outcome ◽  
Obliteration Rate ◽  
Presenting Symptoms ◽  
Prescription Dose ◽  
Martin Grade ◽  
Grade Iii

Object Intracranial arteriovenous malformations (AVMs) are most commonly classified based on their Spetzler-Martin grades. Due to the composition of the Spetzler-Martin grading scale, Grade III AVMs are the most heterogeneous, comprising 4 distinct lesion subtypes. The management of this class of AVMs and the optimal treatment approach when intervention is indicated remain controversial. The authors report their experience with radiosurgery for the treatment of Grade III AVMs in a large cohort of patients. Methods All patients with Spetzler-Martin Grade III AVMs treated with radiosurgery at the University of Virginia over the 20-year span from 1989 to 2009 were identified. Patients who had less than 2 years of radiological follow-up and did not have evidence of complete obliteration during that period were excluded from the study, leaving 398 cases for analysis. The median patient age at treatment was 31 years. The most common presenting symptoms were hemorrhage (59%), seizure (20%), and headache (10%). The median AVM volume was 2.8 cm3, and the median prescription dose was 20 Gy. The median radiological and clinical follow-up intervals were 54 and 68 months, respectively. Univariate and multivariate Cox proportional hazards and logistic regression analysis were used to identify factors associated with obliteration, postradiosurgery radiation-induced changes (RIC), and favorable outcome. Results Complete AVM obliteration was observed in 69% of Grade III AVM cases at a median time of 46 months after radiosurgery. The actuarial obliteration rates at 3 and 5 years were 38% and 60%, respectively. The obliteration rate was higher in ruptured AVMs than in unruptured ones (p < 0.001). Additionally, the obliteration rate for Grade III AVMs with small size (< 3 cm diameter), deep venous drainage, and location in eloquent cortex was higher than for the other subtypes (p < 0.001). Preradiosurgery AVM rupture (p = 0.016), no preradiosurgery embolization (p = 0.003), increased prescription dose (p < 0.001), fewer isocenters (p = 0.006), and a single draining vein (p = 0.018) were independent predictors of obliteration. The annual risk of postradiosurgery hemorrhage during the latency period was 1.7%. Two patients (0.5%) died of hemorrhage during the radiosurgical latency period. The rates of symptomatic and permanent RIC were 12% and 4%, respectively. Absence of preradiosurgery AVM rupture (p < 0.001) and presence of a single draining vein (p < 0.001) were independent predictors of RIC. Favorable outcome was observed in 63% of patients. Independent predictors of favorable outcome were no preradiosurgery hemorrhage (p = 0.014), increased prescription dose (p < 0.001), fewer isocenters (p = 0.014), deep location (p = 0.014), single draining vein (p = 0.001), and lower Virginia radiosurgery AVM scale score (p = 0.016). Conclusions Radiosurgery for Spetzler-Martin Grade III AVMs yields relatively high rates of obliteration with a low rate of adverse procedural events. Small and ruptured lesions are more likely to become obliterated after radiosurgery than large and unruptured ones.

Long-term Outcomes of Stereotactic Radiosurgery for Arteriovenous Malformations in the Thalamus

Neurosurgery ◽  
2010 ◽  
Vol 67 (2) ◽  
pp. 398-403 ◽  
Author(s):  
Tomoyuki Koga ◽  
Masahiro Shin ◽  
Keisuke Maruyama ◽  
Atsuro Terahara ◽  
Nobuhito Saito
Keyword(s):  
Stereotactic Radiosurgery ◽  
Arteriovenous Malformations ◽  
Morbidity Rate ◽  
Long Term Outcomes ◽  
Surgical Morbidity ◽  
Obliteration Rate ◽  
Planning Software ◽  
Risk Of Hemorrhage

Abstract BACKGROUND Arteriovenous malformations (AVMs) in the thalamus carry a high risk of hemorrhage. Although stereotactic radiosurgery (SRS) is widely accepted because of the high surgical morbidity and mortality of these lesions, precise long-term outcomes are largely unknown. OBJECTIVE To review our experience with SRS for thalamic AVMs based on the latest follow-up data. METHODS Forty-eight patients with thalamic AVMs were treated by SRS using the Leksell Gamma Knife and were followed. Long-term outcomes including the obliteration rate, hemorrhage after treatment, and adverse effects were retrospectively analyzed. RESULTS The annual hemorrhage rate before SRS was 14%. The mean follow-up period after SRS was 66 months (range 6–198 months). The actuarial obliteration rate confirmed by angiography was 82% at 5 years after treatment, and the annual hemorrhage rate after SRS was 0.36%. Factors associated with higher obliteration rates were previous hemorrhage (P = .004) and treatment using new planning software (P = .001). Persistent worsening of neurological symptoms was observed in 17% and more frequently seen in patients who were treated using older planning software (P = .04) and a higher margin dose (P = .02). The morbidity rate for patients who received treatment planned using new software with a margin dose not more than 20 Gy was 12%. CONCLUSION SRS for thalamic AVMs achieved a high obliteration rate and effectively decreased the risk of hemorrhage, with less morbidity compared with other modalities. Longer follow-up to evaluate the risk of delayed complications and the effort to minimize the morbidity is necessary.

Retrospective analysis of a 10-year experience of stereotactic radiosurgery for arteriovenous malformations in children and adolescents

2002 ◽  
Vol 97 (4) ◽  
pp. 779-784 ◽  
Author(s):  
Masahiro Shin ◽  
Shunsuke Kawamoto ◽  
Hiroki Kurita ◽  
Masao Tago ◽  
Tomio Sasaki ◽  
...  
Keyword(s):  
Children And Adolescents ◽  
Arteriovenous Malformations ◽  
Univariate Analysis ◽  
Maximum Diameter ◽  
Content Type ◽  
Radiation Induced ◽  
Latency Interval ◽  
Risk Of Hemorrhage ◽  
Fine Print

Object. To obtain information essential to the decision to perform radiosurgery for arteriovenous malformations (AVMs) in children and adolescents, the authors retrospectively analyzed their experience with gamma knife surgery for AVMs in 100 patients ranging in age from 4 to 19 years. Methods. Follow-up periods ranged from 6 to 124 months (median 71 months), and the actuarial obliteration rates demonstrated by angiography were 84.1, 89.4, and 94.7% at 3, 4, and 5 years, respectively. Factors associated with better obliteration rates in univariate analysis included the following: a patient age of 12 years or younger; a mean nidus diameter of 2 cm or less; a nidus volume of 3.8 cm3 or less; a maximum diameter of the nidus less than 3 cm; and a Spetzler—Martin grade of III or less. Radiation-induced neuropathy was seen in four patients, and the risk factors were considered to be a nidus in the brainstem and a maximum radiation dose greater than 40 Gy. Hemorrhage developed during the latency interval in four patients, and one patient with a cerebellar AVM died of the hemorrhage. The annual bleeding rate was 1.5%. Feeding arteries located in the posterior cranial fossa and an AVM nidus located in the cerebellum were significantly associated with the risk of hemorrhage. After angiographically verified obliteration of the nidus, 51 patients continued to be observed from 1 to 110 months (median 67 months); hemorrhage developed in one patient 38 months after nidus obliteration. Conclusions. Radiosurgery is an acceptable treatment for small AVMs in children and adolescents in whom a higher obliteration rate can be achieved with lower risks of interval hemorrhage compared with the reported results in the general population. Careful follow-up observation seems to be required, however, even after angiographically verified obliteration.

scholarly journals Radiosurgery for Arteriovenous Malformations: the University of Toronto Experience

1997 ◽  
Vol 24 (2) ◽  
pp. 99-105 ◽  
Author(s):  
C. Young ◽  
R. Summerfield ◽  
M. Schwartz ◽  
P. O'Brien ◽  
R. Ramani
Keyword(s):  
Linear Accelerator ◽  
Normal Tissue ◽  
Arteriovenous Malformations ◽  
Ct Scanning ◽  
University Of Toronto ◽  
Enhanced Ct ◽  
The University ◽  
Dynamic Rotation ◽  
Explicit Derivation

ABSTRACT:Background:From July 1989 to February 1996, 130 patients underwent sterotactic radiosurgery. We report the results of the first 50 patients eligible for a minimum of three years of follow-up.Methods:Twenty women and 30 men, (mean age: 37.5 years) were treated by dynamic rotation on a 6 MV linear accelerator. Prior treatment was embolization in seventeen, surgery in three and embolization and surgery in six. All had DSA and enhanced CT scanning, while some had MRI. Forty-seven treatments used a single isodose. Restricting eloquent normal tissue to 15 Gy, margin doses (at 50 - 90% isodose) were 12 Gy (one patient); 15 Gy (sixteen patients); 20 Gy (31 patients); 25 Gy (two patients). Maximum diameters were: <1.5 cm (12 patients); < 2.0 cm (nine patients); < 2.5 cm (twelve patients); < 3.0 cm (thirteen patients; 3.0 cm (four patients).Results:Forty-five patients were evaluable at three years, with thirty-nine having angiography. Twenty-five had angiographically confirmed obliterations; two had parenchymal AVMs obliterated but with residual dural components; four had MRI evidence of obliteration (refused angiography). One patient acutely had a seizure; one patient (with hemorrhages, resection, and embolizations preceding two applications of radiosurgery, separated by 3.5 years) had worsening of memory.Conclusions:Our uncorrected (five patients unevaluable at three years) and corrected angiographically confirmed obliteration rates are 54% and 60% respectively. Our follow-up (98% accounting of cohort; 78% angiographic rate) and explicit derivation of denominators help delineate the efficacy of radiosurgery at these doses.

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