Abstract :
Arteriovenous malformations (AVMs) are the results of angiogenesis disorders; they represent an anomalous communication between arteries and veins. They are uncommon vascular lesions that present with spontaneous intracranial hemorrhage (ICH), seizures, or headache that typically found in young adults. AVM is commonly treated by Gamma Knife surgery, where multiple fine beams of gamma photons are delivered in such a highly focused manner. A complete cure for each patient treated with technique has not yet been achieved. Many factors have been contributed to the likelihood of obliteration, such as the prescribed dose, AVM size, location in brain, patient’s, angioarchitecture, and the lack embolization history. Ninety subjects were included in the current study, their mean age is (31.18 ± 1.42) years. The bAVM were classified according to the volume into three groups, (< 5 cm3, 5-8 cm3, > 8cm3). The Spetzler-Martin grading scale was used for the estimation of the AVM nidus. The response of AVM (degree of sclerosis) to the gamma irradiation dose was estimated after six six months, one year, and 1.5 year. The mean irradiation dose of gamma was (18.87 ± 2.24) Gy. Margin dose ranging 16–25 Gy [10], isodose (50%) is commonly used for AVM treatment. Results: The volume of the AVM was significantly reduced after 1.5 year of the radiosurgery, where the first and the second AVM volumes’ groups showed a change in their mean volumes as compared to the original volume as shown in table 6. One year post radiosurgery, 3.7% of the total number of the treated cases (n=81), who were classified under the first AVM volume group, they showed a significant shrinkage of the AVM by less than 1 cm3 , while 67.9% of the second volume group showed variable percentages of scleroses as compared to the original volume before one year of radiosurgery, the amount of shrinkage ranged from less than 1 cm3 to more than 2 cm3 , the same effect of gamma dose was noticed wit the third AVM volume group, where 28.4% of the treated cases showed a significant decrease in the AVM volume with different responding percentages (p=0.018). The sclerosis of the larger volume bAVMs are of better response to the treatment by gamma knife radiosurgery, The rate of sclerosis is clearly related to time factor and can be noticed signifcanly after 1.5 year, with no significant sclerosis within the first six months of treatment.
