Gamma Knife surgery for pediatric arteriovenous malformations: a 25-year retrospective study

Object The authors present their 25-year experience in treating pediatric arteriovenous malformations (AVMs) to allow comparisons with other historic studies and data in adults. Methods Data were collected from a prospectively maintained departmental database selected for age and supplemented by case note review and telephone interviews as appropriate. Results Three hundred sixty-three patients, ages 1–16 years (mean ± SD, 12 ± 3.2 years), underwent 410 treatments; 4 had planned 2-stage treatments and 43 were retreated subsequent to an initial partial response. Fifty-eight percent received general anesthesia for the procedure. Sixteen percent had previously undergone embolization. The most common presenting symptoms were as follows: hemorrhage (80.2%), epilepsy (8.3%; overall seizure prevalence 19.9%), and migrainous headaches (6.3%). Only 0.28% of the AVMs were incidental findings. The mean lesion volume was 3.75 ± 5.3 cm3 (range 0.01–32.8 cm3), with a median Spetzler-Martin grade of III (range I–V). The mean peripheral (therapeutic) dose was 22.7 ± 2.3 Gy (range 15–25 Gy), corresponding to a mean maximum dose of 43.6 ± 6 Gy (range 25–51.4 Gy). The obliteration rate was 71.3% in patients who received one treatment and 62.5% for retreated patients, with a mean obliteration time of 32.4 and 79.6 months, respectively. The overall obliteration rate was 82.7%. No follow-up data are as yet available for the 4 patients who underwent the staged treatments. Only 4 patients received peripheral doses below 20 Gy, and the AVM was obliterated in 3 of these patients. The other patients received 20, 22.5, or 25 Gy and had obliteration rates of 82.6%, 77.7%, and 86.3%, respectively. The bleeding rate postradiosurgery was 2.2%, and the cumulative complication rate was 3.6%, with radionecrosis being the most common complication (1.1%). Conclusions Surprisingly, there was no correlation (p = 0.43) between outcome and radiosurgical dose when that dose was between 20 and 25 Gy, thus suggesting that the lower of these 2 doses may be effective. Radiosurgery for pediatric AVM is safe and effective.

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Novalis Shaped Beam Radiosurgery of arteriovenous malformations

Journal of Neurosurgery ◽

10.3171/jns.2004.101.supplement_3.0425 ◽

2004 ◽

pp. 425-434

Author(s):

Alessandra G. Pedroso ◽

Antonio A. F. De Salles ◽

Katayoun Tajik ◽

Raymond Golish ◽

Zachary Smith ◽

...

Keyword(s):

Arteriovenous Malformations ◽

Peripheral Dose ◽

Content Type ◽

Obliteration Rate ◽

Shaped Beam ◽

Martin Grade ◽

The Mean ◽

Per Se ◽

Fine Print

Object. The authors studied outcomes and complications in patients who harbored arteriovenous malformations (AVMs) and underwent stereotactic radiosurgery involving the Novalis shaped beam unit. Methods. Between January 1998 and January 2002, 83 patients were treated with radiosurgery at University of California, Los Angeles. The mean patient age was 37.8 years. Forty-four patients completed follow up. There were 24 women. Sixteen patients underwent repeated radiosurgery. Embolization was performed in 13 patients and radiosurgery alone in 31. The mean follow-up period after embolization was 54.4 ± 21.9 months and 37.4 ± 14.6 months for radiosurgery alone. The mean peripheral dose was 15 Gy (range 12–18 Gy). The mean preradiosurgery lesion volume was 9.7 ± 11.9 ml for radiosurgery alone and 16.2 ± 11.3 ml for embolization. The AVMs in 13 patients (29.8%) were Spetzler—Martin Grade II, 12 (27.5%) were Grade III, eight (18.2%) Grade IV, and five (11.3%) were Grade V and VI each. Spetzler—Martin grade, volume, and peripheral dose were analyzed in consideration to outcome. A positive trend (p = 0.086) was observed between Spetzler—Martin grade and obliteration rate. Volume per se did not predict obliteration (p = 0.48). A peripheral dose of 18 Gy was shown to be the most important predictor for occlusion (p = 0.007). The overall obliteration rate was 52.5%. A transient complication was noticed in one case (2.3%) and but no permanent deficits due to radiosurgery have been detected so far. Three patients (6.8%) bled after radiosurgery. Conclusions. The range of the prescribed peripheral dose was narrow. An association between the mean peripheral dose of 15 Gy, high conformality, and homogeneous dose distribution permitted no permanent complications. Volume per se did not correlate with outcome. The next step will be to increase the peripheral dose shaping the beam and to achieve higher obliteration rates without increasing complications.

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Novalis Shaped Beam Radiosurgery of arteriovenous malformations

Journal of Neurosurgery ◽

10.3171/sup.2004.101.supplement3.0425 ◽

2004 ◽

Vol 101 (Supplement3) ◽

pp. 425-434 ◽

Cited By ~ 17

Author(s):

Alessandra G. Pedroso ◽

Antonio A. F. De Salles ◽

Katayoun Tajik ◽

Raymond Golish ◽

Zachary Smith ◽

...

Keyword(s):

Arteriovenous Malformations ◽

Peripheral Dose ◽

Content Type ◽

Obliteration Rate ◽

Shaped Beam ◽

Martin Grade ◽

The Mean ◽

Per Se ◽

Fine Print

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Radiosurgery for Spetzler-Martin Grade III arteriovenous malformations

Journal of Neurosurgery ◽

10.3171/2013.12.jns131041 ◽

2014 ◽

Vol 120 (4) ◽

pp. 959-969 ◽

Cited By ~ 55

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.

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Outcomes of Radiosurgery for Brainstem Arteriovenous Malformations

Neurosurgery ◽

10.1227/neu.0b013e31821421d1 ◽

2011 ◽

Vol 69 (1) ◽

pp. 45-52 ◽

Cited By ~ 16

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.

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Staged radiosurgery for extra-large cerebral arteriovenous malformations: method, implementation, and results

Journal of Neurosurgery ◽

10.3171/jns/2008/109/12/s11 ◽

2008 ◽

Vol 109 (Supplement) ◽

pp. 65-72 ◽

Cited By ~ 28

Author(s):

Wen-Yuh Chung ◽

Cheng-Ying Shiau ◽

Hsiu-Mei Wu ◽

Kang-Du Liu ◽

Wan-Yuo Guo ◽

...

Keyword(s):

Mr Imaging ◽

Arteriovenous Malformations ◽

High Signal ◽

Minor Bleeding ◽

Cerebral Arteriovenous Malformations ◽

Presenting Symptoms ◽

Second Stage ◽

The Mean ◽

Cerebral Avms

Object The effectiveness and safety of radiosurgery for small- to medium-sized cerebral arteriovenous malformations (AVMs) have been well established. However, the management for large cerebral AVMs remains a great challenge to neurosurgeons. In the past 5 years the authors performed preplanned staged radiosurgery to treat extra-large cerebral AVMs. Methods An extra-large cerebral AVM is defined as one with nidus volume > 40 ml. The nidus volume of cerebral AVM is measured from the dose plan—that is, as being the volume contained within the best-fit prescription isodose. From January 2003 to December 2007, the authors treated 6 patients with extra-large AVMs by preplanned staged GKS. Staged radiosurgery is implemented by rigid transformation with translation and rotation of coordinates between 2 stages. The average radiation-targeted volume was 60 ml (range 47–72 ml). The presenting symptoms were seizure in 4 patients and a bleeding episode in 2. One patient had undergone a previous craniotomy and evacuation of hematoma. The mean interval between the 2 radiosurgical sessions was 6.9 months (range 4.5–9.1 months). The prescribed marginal dose given to the nidus volume in each stage ranged from 16 to 18.6 Gy. The expected marginal dose of total nidus was 17–19 Gy. Regular follow-up MR imaging was performed every 6 months. The mean follow-up period was 28 months (range 12–54 months). Results Most of the patients exhibited clinical improvement: relief of headache and reduced frequency of seizure attack. All patients had significant regression of nidus observed on MR imaging follow-up. Two patients had angiogram-confirmed complete obliteration of the nidus 45 and 60 months after the second-stage radiosurgical session. One patient experienced minor bleeding 8 months after the second-stage radiosurgery with mild headache. She had satisfactory recovery without clinical neurological deficit after conservative treatment. Conclusions These preliminary results indicate that staged radiosurgery is a practical strategy to treat patients with extra-large cerebral AVMs. It takes longer to obliterate the AVMs. The observed high signal T2 changes after the radiosurgery appeared clinically insignificant in 6 patients followed up for an average of 28 months. Longer follow-up is necessary to confirm its long-term safety.

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A treatment paradigm for high-grade brain arteriovenous malformations: volume-staged radiosurgical downgrading followed by microsurgical resection

Journal of Neurosurgery ◽

10.3171/2014.10.jns1424 ◽

2015 ◽

Vol 122 (2) ◽

pp. 419-432 ◽

Cited By ~ 41

Author(s):

Adib A. Abla ◽

William Caleb Rutledge ◽

Zachary A. Seymour ◽

Diana Guo ◽

Helen Kim ◽

...

Keyword(s):

Arteriovenous Malformations ◽

Primary Motor Cortex ◽

Young Patients ◽

High Grade ◽

Surgical Morbidity ◽

Treatment Paradigm ◽

Martin Grade ◽

The Mean ◽

Risk Of Hemorrhage

OBJECT The surgical treatment of many large arteriovenous malformations (AVMs) is associated with substantial risks, and many are considered inoperable. Furthermore, AVMs larger than 3 cm in diameter are not usually treated with conventional single-session radiosurgery encompassing the entire AVM volume. Volume-staged stereotactic radiosurgery (VS-SRS) is an option for large AVMs, but it has mixed results. The authors report on a series of patients with high-grade AVMs who underwent multiple VS-SRS sessions with resultant downgrading of the AVMs, followed by resection. METHODS A cohort of patients was retrieved from a single-institution AVM patient registry consisting of prospectively collected data. VS-SRS was performed as a planned intentional treatment. Surgery was considered as salvage therapy in select patients. RESULTS Sixteen AVMs underwent VS-SRS followed by surgery. Four AVMs presented with rupture. The mean patient age was 25.3 years (range 13–54 years). The average initial Spetzler-Martin grade before any treatment was 4, while the average supplemented Spetzler-Martin grade (Spetzler-Martin plus Lawton-Young) was 7.1. The average AVM size in maximum dimension was 5.9 cm (range 3.3–10 cm). All AVMs were supratentorial in location and all except one were in eloquent areas of the brain, with 7 involving primary motor cortex. The mean number of VS-SRS sessions was 2.7 (range 2–5 sessions). The mean interval between first VS-SRS session and resection was 5.7 years. There were 4 hemorrhages that occurred after VS-SRS. The average Spetzler-Martin grade was reduced to 2.5 (downgrade, −1.5) and the average supplemented Spetzler-Martin grade was reduced to 5.6 (downgrade, −1.5). The maximum AVM size was reduced to an average of 3.0 cm (downsize = −2.9 cm). The mean modified Rankin Scale (mRS) scores were 1.2, 2.3, and 2.2 before VS-SRS, before surgery, and at last follow-up, respectively (mean follow-up, 6.9 years). Fifteen AVMs were cured after surgery. Ten patients had good outcomes at last follow-up (7 with mRS Score 0 or 1, and 3 with mRS Score 2). There were 2 deaths (both mRS Score 1 before treatment) and 4 patients with mRS Score 3 outcome (from mRS Scores 0, 1, and 2 [n = 2]). CONCLUSIONS Volume-staged SRS can downgrade AVMs, transforming high-grade AVMs (initially considered inoperable) into operable AVMs with acceptable surgical risks. This treatment paradigm offers an alternative to conservative observation for young patients with unruptured AVMs and long life expectancy, where the risk of hemorrhage is substantial. Difficult AVMs were cured in 15 patients. Surgical morbidity associated with downgraded AVMs is reduced to that of postradiosurgical/preoperative supplemented Spetzler-Martin grades, not their initial AVM grades.

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Gamma Knife surgery for large cerebral arteriovenous malformations

Journal of Neurosurgery ◽

10.3171/2010.7.gks101043 ◽

2010 ◽

Vol 113 (Special_Supplement) ◽

pp. 2-8 ◽

Cited By ~ 17

Author(s):

Hae Yu Kim ◽

Won Seok Chang ◽

Dong Joon Kim ◽

Jae Whan Lee ◽

Jin Woo Chang ◽

...

Keyword(s):

Gamma Knife ◽

Arteriovenous Malformations ◽

Lesion Size ◽

Primary Treatment ◽

Gamma Knife Surgery ◽

Treatment Modalities ◽

Obliteration Rate ◽

Complete Obliteration ◽

The Mean

Object Treatment of arteriovenous malformations (AVMs) is problematic due to many factors, including lesion size, lesion location, unacceptable complications, and negative outcomes. To overcome the limitation imposed by a large nidus volume, neurosurgeons have used Gamma Knife surgery (GKS) in a variety of ways, including combined with other treatment modalities, as volume-staged radiosurgery, and as repeat radiosurgery. We performed repeat radiosurgeries in patients who harbored large AVMs (> 30 cm3) and analyzed the AVM obliteration rates and complications. Methods The authors reviewed the cases of 44 patients at a single institution who underwent GKS between 1992 and 2007 for treatment of an AVM whose nidus was 30 cm3 or larger. The mean age of the patients was 27 years (range 4.5–62.3 years), and the median duration of follow-up was 109.4 months (range 27–202 months). The mean AVM nidus volume was 48.8 cm3 (range 30.3–109.5 cm3), and the mean radiation dose delivered to the margin of the nidus was 13.9 Gy (range 8.4–17.5 Gy). The authors determined complete AVM nidus obliteration based on findings on both MR images and digital subtraction angiograms. When they did not detect complete obliteration after GKS, they performed 1 or more additional GKSs separated by a minimum interval of 3 years. Results The overall obliteration rate following repeat GKS was 34.1%, and the estimated obliteration rate at 120 months was 41.8%. Three patients (6.8%) experienced hemorrhages after GKS, and 2 patients (4.5%) developed cysts. One patient (2.3%) experienced a newly developed seizure following GKS, and another patient (2.3%) was found to have radiation necrosis. Conclusions Even though complete obliteration of the large AVMs after repeat GKS took a long time, the complication rate was quite acceptable. In addition, the estimated obliteration rate at long-term follow-up was respectable. Repeat GKS should be considered as a primary treatment option for symptomatic large AVMs to overcome the limitation imposed on successful obliteration by the large volume of the nidus.

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Multimodality Treatment of Giant Intracranial Arteriovenous Malformations

Neurosurgery ◽

10.1227/01.neu.0000068700.68238.84 ◽

2003 ◽

Vol 53 (1) ◽

pp. 1-13 ◽

Cited By ~ 102

Author(s):

Steven D. Chang ◽

Mary L. Marcellus ◽

Michael P. Marks ◽

Richard P. Levy ◽

Huy M. Do ◽

...

Keyword(s):

Arteriovenous Malformations ◽

Multimodality Treatment ◽

Venous Drainage ◽

Neurological Deficits ◽

Maximum Diameter ◽

Morbidity Rate ◽

Presenting Symptoms ◽

Long Term Treatment ◽

Martin Grade

Abstract OBJECTIVE Giant arteriovenous malformations (AVMs) (i.e., those greater than 6 cm at maximum diameter) are difficult to treat and often carry higher treatment morbidity and mortality rates than do smaller AVMs. In this study, we reviewed the treatment, angiographic results, and clinical outcomes in 53 patients with giant AVMs who were treated at Stanford between 1987 and 2001. METHODS The patients selected included 20 males (38%) and 33 females (62%). Their presenting symptoms were hemorrhage (n = 20; 38%), seizures (n = 18; 34%), headaches (n = 8; 15%), and progressive neurological deficits (n = 7; 13%). One patient was in Spetzler-Martin Grade III, 9 were in Spetzler-Martin Grade IV, and 43 were in Spetzler-Martin Grade V. The mean AVM size was 6.8 cm (range, 6–15 cm). AVM venous drainage was superficial (n = 7), deep (n = 20), or both (n = 26). At presentation, 31 patients (58%) were graded in excellent neurological condition, 17 were graded good (32%), and 5 were graded poor (9%). RESULTS The patients were treated with surgery (n = 27; 51%), embolization (n = 52; 98%), and/or radiosurgery (n = 47; 89%). Most patients received multimodality treatment with embolization followed by surgery (n = 5), embolization followed by radiosurgery (n = 23), or embolization, radiosurgery, and surgery (n = 23). Nineteen patients (36%) were completely cured of their giant AVMs, 90% obliteration was achieved in 4 patients (8%), less than 90% obliteration was achieved in 29 patients (55%) who had residual AVMs even after multimodality therapy, and 1 patient was lost to follow-up. Of the 33 patients who either completed treatment or were alive more than 3 years after undergoing their most recent radiosurgery, 19 patients (58%) were cured of their AVMs. The long-term treatment-related morbidity rate was 15%. The clinical results after mean follow-up of 37 months were 27 excellent (51%), 15 good (28%), 3 poor (6%), and 8 dead (15%). CONCLUSION The results in this series of patients with giant AVMs, which represents the largest series reported to date, suggest that selected symptomatic patients with giant AVMs can be treated successfully with good outcomes and acceptable risk. Multimodality treatment is usually necessary to achieve AVM obliteration.

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Stereotactic radiosurgery for pediatric intracranial arteriovenous malformations: the University of California at San Francisco experience

Journal of Neurosurgery ◽

10.3171/jns.2002.97.1.0048 ◽

2002 ◽

Vol 97 (1) ◽

pp. 48-55 ◽

Cited By ~ 88

Author(s):

Matthew D. Smyth ◽

Penny K. Sneed ◽

Samuel F. Ciricillo ◽

Michael S. Edwards ◽

William M. Wara ◽

...

Keyword(s):

Partial Response ◽

San Francisco ◽

Arteriovenous Malformations ◽

University Of California ◽

Content Type ◽

Obliteration Rate ◽

The Mean ◽

The University ◽

Fine Print

Object. Stereotactic radiosurgery for arteriovenous malformations (AVMs) is an accepted treatment option, but few reports have been published on the results of this treatment in children. In this study the authors describe a series of pediatric patients with a minimum follow-up duration of 36 months. Methods. From 1991 to 1997, 40 children (26 boys and 14 girls) with AVMs were treated with radiosurgery at the University of California at San Francisco (UCSF). Follow-up information was available for 31 children (20 boys and 11 girls) in whom the median age at initial treatment was 11.2 years (range 3.4–17.5 years). The median follow-up duration was 60 months (range 6–99 months). Sixteen percent of the AVMs were Spetzler—Martin Grade II; 68%, Grade III; 10%, Grade IV; and 6%, Grade V. The mean volume of the AVMs was 5.37 cm3 and the median volume was 1.6 cm3. The mean marginal dose of radiation was 16.7 Gy and the median dose was 18 Gy (range 12–19 Gy). Angiography performed in 26 children confirmed obliteration of the AVM nidus in nine patients (35%), partial response in 16 patients (62%), and no response in one patient (4%). In five patients who refused angiography, magnetic resonance (MR) imaging revealed obliteration in two patients and partial response in three patients, bringing the overall obliteration rate associated with initial radiosurgery to 35%. Logistic regression analysis confirmed a significant correlation between marginal dose prescription and response (p = 0.025); in AVMs that received at least 18 Gy there was a 10-fold increase in the obliteration rate (63%) over AVMs that received a lower dose. Lesions smaller than 3 cm3 were associated with a sixfold increased obliteration rate (53%) over lesions larger than 3 cm3 (8%), but AVM volume was not a statistically significant predictor of response (p = 0.09). Twelve patients have since undergone repeated radiosurgery and are currently being followed up with serial MR imaging studies (in five cases, the AVM is now obliterated). During the follow-up period (1918 patient-months) there were eight hemorrhages in five patients, with a cumulative posttreatment hemorrhage rate of 3.2%/patient/year in the 1st year and a rate of 4.3%/patient/year over the first 3 years. There were two permanent neurological complications (6%) and no deaths in this study. Conclusions. The lower overall obliteration rate reported in this series is most likely due to the larger mean AVM volumes treated at UCSF as well as conservative dose—volume prescriptions delivered to children. Significantly higher obliteration rates were observed when a marginal radiation dose of at least 18 Gy was delivered. The permanent complication rate is low and should encourage those treating children to use doses similar to those used in adults.

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Gamma knife radiosurgery as a single treatment modality for large cerebral arteriovenous malformations

Journal of Neurosurgery ◽

10.3171/jns.2000.93.supplement_3.0113 ◽

2000 ◽

Vol 93 (supplement_3) ◽

pp. 113-119 ◽

Cited By ~ 82

Author(s):

D. Hung-Chi Pan ◽

Wan-Yuo Guo ◽

Wen-Yuh Chung ◽

Cheng-Ying Shiau ◽

Yue-Cune Chang ◽

...

Keyword(s):

Gamma Knife ◽

Arteriovenous Malformations ◽

Radiation Treatment ◽

Gamma Knife Radiosurgery ◽

Consecutive Series ◽

Content Type ◽

Obliteration Rate ◽

Complete Obliteration ◽

Fine Print

Object. A consecutive series of 240 patients with arteriovenous malformations (AVMs) treated by gamma knife radiosurgery (GKS) between March 1993 and March 1999 was evaluated to assess the efficacy and safety of radiosurgery for cerebral AVMs larger than 10 cm3 in volume. Methods. Seventy-six patients (32%) had AVM nidus volumes of more than 10 cm3. During radiosurgery, targeting and delineation of AVM nidi were based on integrated stereotactic magnetic resonance (MR) imaging and x-ray angiography. The radiation treatment was performed using multiple small isocenters to improve conformity of the treatment volume. The mean dose inside the nidus was kept between 20 Gy and 24 Gy. The margin dose ranged between 15 to 18 Gy placed at the 55 to 60% isodose centers. Follow up ranged from 12 to 73 months. There was complete obliteration in 24 patients with an AVM volume of more than 10 cm3 and in 91 patients with an AVM volume of less than 10 cm3. The latency for complete obliteration in larger-volume AVMs was significantly longer. In Kaplan—Meier analysis, the complete obliteration rate in 40 months was 77% in AVMs with volumes between 10 to 15 cm3, as compared with 25% for AVMs with a volume of more than 15 cm3. In the latter, the obliteration rate had increased to 58% at 50 months. The follow-up MR images revealed that large-volume AVMs had higher incidences of postradiosurgical edema, petechiae, and hemorrhage. The bleeding rate before cure was 9.2% (seven of 76) for AVMs with a volume exceeding 10 cm3, and 1.8% (three of 164) for AVMs with a volume less than 10 cm3. Although focal edema was more frequently found in large AVMs, most of the cases were reversible. Permanent neurological complications were found in 3.9% (three of 76) of the patients with an AVM volume of more than 10 cm3, 3.8% (three of 80) of those with AVM volume of 3 to 10 cm3, and 2.4% (two of 84) of those with an AVM volume less than 3 cm3. These differences in complications rate were not significant. Conclusions. Recent improvement of radiosurgery in conjunction with stereotactic MR targeting and multiplanar dose planning has permitted the treatment of larger AVMs. It is suggested that gamma knife radiosurgery is effective for treating AVMs as large as 30 cm3 in volume with an acceptable risk.

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