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Management of Arteriovenous Malformations by Stereotactic Radiosurgery: A Single Center Experience
Abstract and Figures
The aim of this monoinstitutional study is to evaluate the efficiency of stereotactic radiosurgery (SRS) in the management of arteriovenous malformations (AVM). Between June 1998 and July 2011, 51 patients with AVM were treated with linear accelerator-based SRS at our department. All patients were preevaluated for AVM size, location, neurological status, previous history of hemorrhage and Spetzler-Martin grading. Treated patients then underwent follow-up to evaluate obliteration and clinical status. Median followup time was 32 months (range; 20-93 months). Spetzler-Martin grade I-II and AVM sizes below 3 cm were associated with increased obliteration rate (p=0.01). The annual hemorrhage risk was 1.9%. No patients experienced deterioration of neurological status at follow-up. LINAC-based SRS is a safe and effective treatment modality in the management of cerebral AVMs. SRS comprises an effective alternative to surgery for the treatment of particularly small AVMs inaccessible with surgery.
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... In this context, microvascular surgical resection, endovascular embolization and radiosurgical treatment may be used for management of AVMs. Stereotactic Radiosurgery (SRS) has been utilized for management of several benign and malign indications with considerable success [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24]. In the context of AVMs, surgery offers effective management of AVMs in selected patients, however, radiosurgery may be considered when there may be an excessive risk of surgical complications for deep-seated lesions located at eloquent brain regions. ...
... In the context of AVMs, surgery offers effective management of AVMs in selected patients, however, radiosurgery may be considered when there may be an excessive risk of surgical complications for deep-seated lesions located at eloquent brain regions. Several studies have reported 3-year obliteration rates in the order of 60% to 90%, with safe and effective management of AVMs using SRS, even for larger lesions by use of staged procedures [2,3,8,[25][26][27][28][29][30]. ...
... SRS was performed after informed consent of the included patients and decision making for treatment with radiosurgery was decided by a multidisciplinary team of experts on neurosurgery, neuroradiology, and radiation oncology. Details of the radiosurgery procedure was described previously [8]. Briefly, a stereotactic head frame was affixed to the patients' skull under local anesthesia, supplemented with sedation if necessary. ...
Background: Cerebral arteriovenous malformations (AVMs) are rarely seen congenital vascular anomalies. AVMs may lead to intracranial hemorrages due to disorganized tangle of vessels. Lifetime risk of bleeding from AVMs may be significant given the diagnosis at typically earlier ages of the lifespan, and complications associated with hemorrhage may lead to substantial morbidity or mortality. Management of AVMs aims at eliminating or reducing the risk of subsequent bleeding. In this context, microvascular surgical resection, endovascular embolization and radiosurgical treatment may be used for management of AVMs.Objective: In this study, we assessed the incorporation of Magnetic Resonance Imaging (MRI) in treatment planning for AVM radiosurgery. Methods: We identified 25 patients receiving radiosurgery for AVMs at our institution. Radiosurgery target volumes generated by using CT-only based imaging and CT-MR fusion based imaging for each patient were evaluated.Results: Twenty five patients undergoing SRS for AVMs were evaluated for target volume determination in this study. Mean target volume was 4.9 cc (range: 1.3-15.9 cc) on CT-only imaging, 5.7 cc (range: 1.4-16.7 cc) on CT-MR fusion based imaging, and 5.9 cc (range: 1.4-16.9 cc) on consensus decision of all treating physicians with colleague peer review. Target definition based on CT-MR fusion based imaging was identical to the consensus decision of all treating physicians in majority of patients.Conclusions: Treatment planning for AVM radiosurgery may be improved by incorporating CT-MR fusion based imaging, which clearly should be supplemented with additional data from angiography. There is need for additional studies to establish a consensus on optimal target definition by multimodality imaging for SRS of AVMs.
... Symptoms of GJTs may cause substantial deterioration in the affected patients' quality of life and may warrant prompt management for alleviation or elimination of these symptoms. While surgery is typically utilized as the primary mode of management, complete surgical removal may not be feasible for selected patients due to critical location of some GJTs in close , and Stereotactic Body Radiation Therapy (SBRT) delivering high doses in one or a few treatment sessions have been utilized for management of several vascular disorders, functional disorders, malignant and benign tumors throughout the human body with encouraging therapeutic outcomes thanks to robust immobilization, precise target definition and treatment delivery under image guidance [1][2][3][4][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]. This contemporary treatment technique has been increasingly used as a noninvasive outpatient procedure with a condensed treatment schedule offering earlier return of patients to their daily activities. ...
... Radiosurgery in the form of Stereotactic Radiosurgery (SRS), Fractionated Stereotactic Radiation Therapy (FSRT), Hypofractionated Stereotactic Radiation Therapy (HFSRT), and Stereotactic Body Radiation Therapy (SBRT) has been judiciously utilized for management of several benign and malign conditions throughout the human body with encouraging therapeutic outcomes [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. For management of pituitary adenomas, several studies reported the safety and efficacy of radiosurgery [8,23,24]. ...
To report our experience of stereotactic radiosurgery (SRS) in consecutively treated patients with arteriovenous malformations (AVMs).
Of the 87 patients, 23 patients qualified and were treated with SRS as per predefined protocol according to AVM size, location, neurological status, prior bleeding, and the AVM score. All had Spletzer-Martin grade II/III and AVM scores <2.5. Patients underwent SRS using micromultileaf collimators delivering multiple noncoplanar fixed fields. Doses were prescribed using the Flickinger model. Patients were followed up with magnetic resonance angiography (MRA) and digitally subtracted angiography (DSA).
The mean nidus volume was 3.65 cc. The mean prescribed maximum dose was 22 Gy and the marginal dose was 19.24 Gy; 12 Gy normal brain volume was 8.39 cc and 12 Gy marginal volume was 5.03 cc. Mean dose to brain stem, pituitary hypothalamic axis, and optic chiasm was 2.5, 0.72, and 0.49 Gy, respectively. At a median follow-up of 22 months (range 1.5-71.2 months), 7 of 10 patients presenting with a neurological deficit showed significant improvement. All 15 patients who underwent MRA 1.5-2 years after SRS had no residual nidus yielding an MRA complete obliteration rate of 100%. Twelve patients also underwent a check DSA, which confirmed obliteration in 11 of them resulting in an accuracy of MRA of 92%. One patient after SRS had transient deterioration of motor power, which resolved completely after a short course of steroids and another had mild worsening of the hemiparesis. All patients are able to lead an active functional life.
Careful selection of cases suitable for SRS provides optimum obliteration rates with low toxicity.
Stereotactic radiosurgery successfully obliterates carefully selected arteriovenous malformations (AVM's) of the brain. In an initial 3-year experience using the 201-source cobalt-60 gamma knife at the University of Pittsburgh, 227 patients with AVM's were treated. Symptoms at presentation included prior hemorrhage in 143 patients (63%), headache in 104 (46%), and seizures in 70 (31%). Neurological deficits were present in 102 patients (45%). Prior surgical resection (resulting in subtotal removal) had been performed in 36 patients (16%). In 47 selected patients (21%), embolization procedures were performed in an attempt to reduce the AVM size prior to radiosurgery. The lesions were classified according to the Spetzler grading system: 64 (28%) were Grade VI (inoperable), 22 (10%) were Grade IV, 90 (40%) were Grade III, 43 (19%) were Grade II, and eight (4%) were Grade I. With the aid of computer imaging-integrated isodose plans for single-treatment irradiation, total coverage of the AVM nidus was possible in 216 patients (95%). The location and volume of the AVM were the most important factors for the selection of radiation dose. Magnetic resonance (MR) imaging was performed at 6-month intervals in 161 patients. Seventeen patients who had MR evidence of complete obliteration underwent angiography within 3 months of imaging: in 14 (82%) complete obliteration was confirmation being 4 months (mean 17 months) after radiosurgery. The 2-year obliteration rates according to volume were: all eight (100%) AVM's less than 1 cu cm; 22 (85%) of 26 AVM's of 1 to 4 cu cm; and seven (58%) of 12 AVM's greater than 4 cu cm. Magnetic resonance imaging revealed postirradiation changes in 38 (24%) of 161 patients at a mean interval of 10.2 months after radiosurgery; only 10 (26%) of those 38 patients were symptomatic. In the entire series, two patients developed permanent new neurological deficits believed to be treatment-related. Two patients died of repeat hemorrhage at 6 and 23 months after treatment during the latency interval prior to obliteration. Stereotactic radiosurgery is an important method to obliterate AVM's, especially those previously considered inoperable. Success and complication risks are related to the AVM location and the volume treated.
✓ An important factor in making a recommendation for treatment of a patient with arteriovenous malformation (AVM) is to estimate the risk of surgery for that patient. A simple, broadly applicable grading system that is designed to predict the risk of morbidity and mortality attending the operative treatment of specific AVM's is proposed. The lesion is graded on the basis of size, pattern of venous drainage, and neurological eloquence of adjacent brain. All AVM's fall into one of six grades. Grade I malformations are small, superficial, and located in non-eloquent cortex; Grade V lesions are large, deep, and situated in neurologically critical areas; and Grade VI lesions are essentially inoperable AVM's. Retrospective application of this grading scheme to a series of surgically excised AVM's has demonstrated its correlation with the incidence of postoperative neurological complications. The application of a standardized grading scheme will enable a comparison of results between various clinical series and ...
Objective:
The obliteration response of an arteriovenous malformation (AVM) to radiosurgery is strongly dependent on dose and volume. For larger volumes, the dose must be reduced for safety, but this compromises obliteration. In 1992, we prospectively began to stage anatomic components in order to deliver higher single doses to symptomatic AVMs > 15 ml in volume.
Methods:
During a 17-year interval at the University of Pittsburgh, 1040 patients underwent radiosurgery for a brain AVM. Out of 135 patients who had multiple procedures, 37 patients underwent prospectively staged volume radiosurgery for symptomatic otherwise unmanageable larger malformations. Twenty-eight patients who were managed before 2002 were included in this study to achieve sufficient follow-up in assessing the outcomes. The median age was 37 years (range, 13-57 yr). Thirteen patients had previous hemorrhages and 13 patients had attempted embolization. Separate anatomic volumes were irradiated at 3 to 8 months (median, 5 mo) intervals. The median initial AVM volume was 24.9 ml (range, 10.2-57.7 ml). Twenty-six patients had two stages and two had three-stage radiosurgery. Seven patients had repeat radiosurgery after a median interval of 63 months. The median target volume was 12.3 ml. (range, 4.2-20.8 ml.) at Stage I and 11.5 ml. (range, 2.8-22 ml.) at Stage II. The median margin dose was 16 Gy at both stages. Median follow-up after the last stage of radiosurgery was 50 months (range, 3-159 mo).
Results:
Four patients (14%) sustained a hemorrhage after radiosurgery; two died and two patients recovered with mild permanent neurological deficits. Worsened neurological deficits developed in one patient. Seizure control was improved in three patients, was stable in eight patients and worsened in two. Magnetic resonance imaging showed T2 prolongation in four patients (14%). Out of 28 patients, 21 had follow-up more than 36 months. Out of 21 patients, seven underwent repeat radiosurgery and none of them had enough follow- up. Of 14 patients followed for more than 36 months, seven (50%) had total, four (29%) near total, and three (21%) had moderate AVM obliteration.
Conclusions:
Prospective staged volume radiosurgery provided imaging defined volumetric reduction or closure in a series of large AVMs unsuitable for any other therapy. After 5 years, this early experience suggests that AVM related symptoms can be stabilized and anticipated bleed rates can be reduced.
Stereotactic radiosurgery has been used to treat five arteriovenous malformations, in which surgical excision could not be carried out, using the “Co Gamma Unit.
The malformation could no longer be seen at angiography performed in the first case at 19 and 36 months and in another ease one year after therapy.
In the remainder 3 cases, no changes have been observed so far, but in two of them only one of several feeding arteries had been irradiated.
Between May, 1988 and August, 1993, 158 patients with arteriovenous malformations (AVMs) were treated radiosurgically at the University of Florida. A mean dose of 1560 cGy was directed to the periphery of the lesions, which had a mean volume of 9 cc (0.5 to 45.3 cc). One hundred thirty-nine of these individuals were treated with one isocenter. The mean follow-up interval was 33 months with clinical information available on 153 of these patients. Patients were followed until magnetic resonance (MR) studies suggested complete AVM thrombosis. An arteriogram was then performed, if possible, to verify occlusion status. If arteriography revealed any persistent nidus at 36 months posttreatment, the residual nidus was re-treated.
Outcome categories of AVMs analyzed included the following possibilities: 1) angiographic cure; 2) angiographic failure; 3) re-treatment; 4) MR image suggested cure; 5) MR image suggested failure; 6) patient refused follow-up evaluation; 7) patient lost to follow-up study; or 8) patient deceased. The endpoints for success or failure of radiosurgery were as follows: angiographic occlusion (success), re-treatment (failure), and death due to AVM hemorrhage (failure). Fifty-six patients in this series reached one of the endpoints. Successful endpoints were seen in 91% of AVMs between 1 and 4 cc in volume, 100% of AVMs 4 to 10 cc in volume, and 79% of AVMs greater than 10 cc in volume.
The more traditional measure of radiosurgical success, percentage of angiograms showing complete obliteration, was obtained in 81% of AVMs between 1 and 4 cc in volume, 89% of AVMs between 4 and 10 cc in volume, and 69% of AVMs greater than 10 cc in volume. A detailed analysis of the relationship of all outcome categories to size is presented.
Radiosurgery with external beam irradiation is an accepted treatment for small intracranial vascular malformations. It has been proven effective and safe for lesions with volumes of less than 4 cc. However, there is only some limited clinical data for malformations of grade 4 and grade 5, according to Spetzler and Martin.
At the Heidelberg radiosurgery facility equipped with a linear accelerator, 212 patients with cerebral arteriovenous malformations have been treated since 1984. Thirty-eight percent of the arteriovenous malformations treated were classified inoperable, 14% grade 5, 19% grade 4, and 29% grades 1-3. Radiation doses between 10 and 29 Gy were applied to the 80% isodose contour.
Above a threshold dose of 18 Gy, the overall obliteration rate was 72%. After 3 years, the obliteration rates were 83% with volumes of less than 4.2 cc, 75% with volumes of up to 33.5 cc, and 50% with volumes of up to 113 cc. Of the patients presenting with seizures and paresis, 83% and 56%, respectively, showed improvement, which correlated with the degree of obliteration. After a follow-up period of up to 9 years, the rate of radiation-induced severe late complications was 4.3%. In grade 5 lesions, the risk of side effects was 10%. No serious complications occurred if a maximum dose of less than 25 Gy was applied to treatment volumes of less than 33.5 cc.
The success of stereotactic high-dose irradiation of arteriovenous malformations depends on the dose applied. The incidence of radiation-induced side effects increased with the applied dose and treatment volumes. From our experience, doses of less than 25 Gy and treatment volumes of up to 33.5 cc are safe and effective. In the future, new techniques of radiosurgery with linear accelerators and dynamically reshaped beams will allow us to apply homogenous dose distributions. Additional use of magnetic resonance angiography for 3D treatment planning will help to identify the nidus more easily.