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

2015 ◽  
Vol 122 (2) ◽  
pp. 419-432 ◽  
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.

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.

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

2012 ◽  
Vol 10 (5) ◽  
pp. 445-450 ◽  
Author(s):  
Eduard B. Dinca ◽  
Patricia de Lacy ◽  
John Yianni ◽  
Jeremy Rowe ◽  
Matthias W. R. Radatz ◽  
...  
Keyword(s):  
Arteriovenous Malformations ◽  
Lesion Volume ◽  
Bleeding Rate ◽  
Patients Âgés ◽  
Obliteration Rate ◽  
Telephone Interviews ◽  
Presenting Symptoms ◽  
Martin Grade ◽  
The Mean

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.

Multimodality treatment of posterior fossa arteriovenous malformations

2008 ◽  
Vol 108 (6) ◽  
pp. 1152-1161 ◽  
Author(s):  
Michael E. Kelly ◽  
Raphael Guzman ◽  
John Sinclair ◽  
Teresa E. Bell-Stephens ◽  
Regina Bower ◽  
...  
Keyword(s):  
Posterior Fossa ◽  
Arteriovenous Malformations ◽  
Multimodality Treatment ◽  
Neurological Complications ◽  
Cure Rate ◽  
Complete Obliteration ◽  
The Mean ◽  
Risk Of Hemorrhage ◽  
Negative Predictor

Object Posterior fossa arteriovenous malformations (AVMs) are relatively uncommon and often difficult to treat. The authors present their experience with multimodality treatment of 76 posterior fossa AVMs, with an emphasis on Spetzler–Martin Grades III–V AVMs. Methods Seventy-six patients with posterior fossa AVMs treated with radiosurgery, surgery, and endovascular techniques were analyzed. Results Between 1982 and 2006, 36 patients with cerebellar AVMs, 33 with brainstem AVMs, and 7 with combined cerebellar–brainstem AVMs were treated. Natural history data were calculated for all 76 patients. The risk of hemorrhage from presentation until initial treatment was 8.4% per year, and it was 9.6% per year after treatment and before obliteration. Forty-eight patients had Grades III–V AVMs with a mean follow-up of 4.8 years (range 0.1–18.4 years, median 3.1 years). Fifty-two percent of patients with Grades III–V AVMs had complete obliteration at the last follow-up visit. Three (21.4%) of 14 patients were cured with a single radiosurgery treatment, and 4 (28.6%) of 14 with 1 or 2 radiosurgery treatments. Twenty-one (61.8%) of 34 patients were cured with multimodality treatment. The mean Glasgow Outcome Scale (GOS) score after treatment was 3.8. Multivariate analysis performed in the 48 patients with Grades III–V AVMs showed radiosurgery alone to be a negative predictor of cure (p = 0.0047). Radiosurgery treatment alone was not a positive predictor of excellent clinical outcome (GOS Score 5; p > 0.05). Nine (18.8%) of 48 patients had major neurological complications related to treatment. Conclusions Single-treatment radiosurgery has a low cure rate for posterior fossa Spetzler–Martin Grades III–V AVMs. Multimodality therapy nearly tripled this cure rate, with an acceptable risk of complications and excellent or good clinical outcomes in 81% of patients. Radiosurgery alone should be used for intrinsic brainstem AVMs, and multimodality treatment should be considered for all other posterior fossa AVMs.

Novalis Shaped Beam Radiosurgery of arteriovenous malformations

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.

Surgical Risks Associated with the Management of Grade I and II Brain Arteriovenous Malformations

Neurosurgery ◽  
2004 ◽  
Vol 54 (4) ◽  
pp. 832-839 ◽  
Author(s):  
Michael Kerin Morgan ◽  
Andrew Michael Rochford ◽  
Antonio Tsahtsarlis ◽  
Nicholas Little ◽  
Kenneth Charles Faulder
Keyword(s):  
Arteriovenous Malformations ◽  
Adverse Outcome ◽  
Adverse Outcomes ◽  
Morbidity Rate ◽  
Low Grade ◽  
Imaging Features ◽  
Surgical Morbidity ◽  
Martin Grade ◽  
Eloquent Cortex

Abstract OBJECTIVE Grade I and II arteriovenous malformations (AVMs) have been considered safe to resect. However, unoperated low-grade AVMs have not been considered in previously reported series. The aim of this study was to examine all cases, both operated and unoperated, to identify any characteristics of low-grade AVMs that comprise a subgroup that might pose a relatively higher risk. METHODS A prospectively enrolled AVM database included 237 patients in Spetzler-Martin Grade I or II. These patients were analyzed on the basis of demographic characteristics, angiographic and magnetic resonance imaging features, clinical presentation, method of treatment, and outcome. RESULTS Surgery was performed in 220 patients in Spetzler-Martin Grade I or II. Seventeen patients did not undergo treatment because of poor neurological condition (six patients), patient refusal (nine patients), and perceived surgical difficulty (AVM size approaching 3 cm adjacent to Broca's area) (two patients). The overall surgical morbidity rate was 0.9%, and the mortality rate was 0.5%. Adverse outcomes occurred in 1 (0.6%) of 180 patients with AVMs located away from eloquent cortex and in 2 (5%) of 40 patients with AVMs adjacent to eloquent cortex. None of 28 surgical patients with deep venous drainage had an adverse outcome. All 219 patients who survived surgery underwent postoperative angiography that confirmed cure. No postoperative hemorrhage has occurred in 1143 patient-years of follow-up (mean follow-up, 5.3 yr). CONCLUSION When considering adverse outcome in the surgical series of Grade I and II AVMs alone, no statistical difference between non-eloquently located AVMs (0.6%) and eloquently located AVMs (5% adverse outcome) can be detected. However, consideration of all Grade I and II AVMs, both surgical and nonsurgical, may prove that a difference in outcome exists between these two groups masked by case selection. Generalization of the chances of adverse outcomes to all Grade I and II AVMs (both operated and unoperated) suggests that the risk of performing surgery on noneloquent brain in our series was 0.6% and that in eloquent brain could have been as high as 9.5%, had all such patients undergone surgery.

Radiosurgery for low-grade intracranial arteriovenous malformations

2014 ◽  
Vol 121 (2) ◽  
pp. 457-467 ◽  
Author(s):  
Dale Ding ◽  
Chun-Po Yen ◽  
Zhiyuan Xu ◽  
Robert M. Starke ◽  
Jason P. Sheehan
Keyword(s):  
Arteriovenous Malformations ◽  
Proportional Hazards ◽  
Cox Proportional Hazards ◽  
Low Grade ◽  
Surgical Morbidity ◽  
Radiation Induced ◽  
Prescription Dose ◽  
Martin Grade ◽  
Induced Changes

Object Low-grade, or Spetzler-Martin (SM) Grades I and II, arteriovenous malformations (AVMs) are associated with lower surgical morbidity rates than higher-grade lesions. While radiosurgery is now widely accepted as an effective treatment approach for AVMs, the risks and benefits of the procedure for low-grade AVMs, as compared with microsurgery, remain poorly understood. The authors of this study present the outcomes for a large cohort of low-grade AVMs treated with radiosurgery. Methods From an institutional radiosurgery database comprising approximately 1450 AVM cases, all patients with SM Grade I and II lesions were identified. Patients with less than 2 years of radiological follow-up, except those with complete AVM obliteration, were excluded from analysis. Univariate and multivariate Cox proportional-hazards and logistic regression analyses were used to determine factors associated with obliteration, radiation-induced changes (RICs), and hemorrhage following radiosurgery. Results Five hundred two patients harboring low-grade AVMs were eligible for analysis. The median age was 35 years, 50% of patients were male, and the most common presentation was hemorrhage (47%). The median AVM volume and prescription dose were 2.4 cm3 and 23 Gy, respectively. The median radiological and clinical follow-up intervals were 48 and 62 months, respectively. The cumulative obliteration rate was 76%. The median time to obliteration was 40 months, and the actuarial obliteration rates were 66% and 80% at 5 and 10 years, respectively. Independent predictors of obliteration were no preradiosurgery embolization (p < 0.001), decreased AVM volume (p = 0.005), single draining vein (p = 0.013), lower radiosurgery-based AVM scale score (p = 0.016), and lower Virginia Radiosurgery AVM Scale (Virginia RAS) score (p = 0.001). The annual postradiosurgery hemorrhage rate was 1.4% with increased AVM volume (p = 0.034) and lower prescription dose (p = 0.006) as independent predictors. Symptomatic and permanent RICs were observed in 8.2% and 1.4% of patients, respectively. No preradiosurgery hemorrhage (p = 0.011), a decreased prescription dose (p = 0.038), and a higher Virginia RAS score (p = 0.001) were independently associated with postradiosurgery RICs. Conclusions Spetzler-Martin Grade I and II AVMs are very amenable to successful treatment with stereotactic radiosurgery. While patient, physician, and institutional preferences frequently dictate the final course of treatment, radiosurgery offers a favorable risk-to-benefit profile for the management of low-grade AVMs.

Novalis Shaped Beam Radiosurgery of arteriovenous malformations

2004 ◽  
Vol 101 (Supplement3) ◽  
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.

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.

Subtotal obliteration of cerebral arteriovenous malformations after Gamma Knife surgery

2007 ◽  
Vol 106 (3) ◽  
pp. 361-369 ◽  
Author(s):  
Chun Po Yen ◽  
Peter Varady ◽  
Jason Sheehan ◽  
Melita Steiner ◽  
Ladislau Steiner
Keyword(s):  
Gamma Knife ◽  
Arteriovenous Malformations ◽  
Gamma Knife Surgery ◽  
Cerebral Arteriovenous Malformations ◽  
Peripheral Dose ◽  
Risk Of Bleeding ◽  
The Mean ◽  
Risk Of Hemorrhage ◽  
Early Filling

Object Subtotal obliteration of cerebral arteriovenous malformations (AVMs) after Gamma Knife surgery (GKS) implies a complete angiographic disappearance of the AVM nidus but persistence of an early filling draining vein, indicating that residual shunting is still present; hence, per definition there is still a patent AVM and the risk of bleeding is not eliminated. The aim of this study was to determine the risk of hemorrhage for patients with subtotal obliteration of AVMs. Methods After GKS for cerebral AVMs, follow-up angiography demonstrated a subtotally obliterated lesion in 159 patients. Of these, in 16 patients a subtotally obliterated AVM developed after a second GKS was performed for the partially obliterated lesion. The mean age of these patients was 35.2 years at the time of the diagnosis of subtotally obliterated AVMs. The lesion volumes at the time of initial GKS treatment ranged from 0.1 to 11.5 cm3 (mean 2.5 cm3). The mean peripheral dose used in the 175 GKS treatments was 22.5 Gy (median 23 Gy, range 15–31 Gy). To achieve total obliteration of the AVM, 23 patients underwent a new GKS targeting the proximal end of the early filling vein. The mean peripheral dose given in these cases was 23 Gy (median 24, range 18–25 Gy). The incidence of subtotally obliterated AVMs was 7.6% from a total of 2093 AVMs treated and in which follow-up imaging was available. The diagnosis of subtotally obliterated AVMs was made a mean of 29.4 months (range 4–178 months) after GKS. The number of patient-years at risk (from the time of the diagnosis of subtotally obliterated AVMs until either the confirmation of a total obliteration of the lesion on angiography or the time of the latest follow-up angio-graphic study that still visualized the early filling vein) was a mean of 3.9 years, ranging from 0.5 to 13.5 years, and a total of 601 patient-years. There was no case of bleeding after the diagnosis of subtotally obliterated AVMs. Of 90 patients who did not undergo further treatment and in whom follow-up angiography studies were available, the same early filling veins still filled in 24 (26.7%), and the subtotally obliterated AVMs were subsequently obliterated in 66 patients (73.3%). In 19 patients who underwent repeated GKS for subtotally obliterated AVMs and in whom follow-up angiography studies were available, the AVMs were obliterated in 15 (78.9%) and remained patent in four (21.1%). Conclusions The fact that none of the patients with subtotally obliterated AVMs suffered a rupture is not compatible with the assumption of an unchanged risk of hemorrhage for these lesions, and implies that the protection from re-bleeding in patients with subtotal obliteration is significant. Subtotal obliteration does not necessarily seem to be a stage of an ongoing obliteration. At least in some cases it represents an end point of this process, with no subsequent obliteration occurring. This observation requires further confirmation by open-ended follow-up imaging.

Factors related to complete occlusion of arteriovenous malformations after gamma knife radiosurgery

2000 ◽  
Vol 93 (supplement_3) ◽  
pp. 96-101 ◽  
Author(s):  
Jong Hee Chang ◽  
Jin Woo Chang ◽  
Yong Gou Park ◽  
Sang Sup Chung
Keyword(s):  
Gamma Knife ◽  
Arteriovenous Malformations ◽  
Gamma Knife Radiosurgery ◽  
Maximum Diameter ◽  
Content Type ◽  
Complete Occlusion ◽  
Factors Associated ◽  
Martin Grade ◽  
Fine Print

Object. The authors sought to evaluate the effects of gamma knife radiosurgery (GKS) on cerebral arteriovenous malformations (AVMs) and the factors associated with complete occlusion. Methods. A total of 301 radiosurgical procedures for 277 cerebral AVMs were performed between December 1988 and December 1999. Two hundred seventy-eight lesions in 254 patients who were treated with GKS from May 1992 to December 1999 were analyzed. Several clinical and radiological parameters were evaluated. Conclusions. The total obliteration rate for the cases with an adequate radiological follow up of more than 2 years was 78.9%. In multivariate analysis, maximum diameter, angiographically delineated shape of the AVM nidus, and the number of draining veins significantly influenced the result of radiosurgery. In addition, margin radiation dose, Spetzler—Martin grade, and the flow pattern of the AVM nidus also had some influence on the outcome. In addition to the size, topography, and radiosurgical parameters of AVMs, it would seem to be necessary to consider the angioarchitectural and hemodynamic aspects to select proper candidates for radiosurgery.

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