engleski

GAMMA KNIFE RADIOSURGERY IN TREATMENT OF BRAIN ARTERIOVENOUS MALFORMATIONS

Introduction: The primary goal of various therapeutic modalities for brain AVMs is to achieve complete obliteration of the nidus, eliminating the risk of cerebral hemorrhage. The aim of this report is to present experience and results with radiosurgical treatment of intracranial arteriovenous malformations in Gamma Knife Center Zagreb. Methods: Radiosurgery using Gamma Knife model C was performed on 156 patients with AVMs between January 2004 and June 2013. 121 patients were treated until June 2011 (minimal presumed follow-up of 2 years). 22 patients were lost from follow up and the data for remaining 99 patients were analyzed.The median patient age at the time of treatment was 36 years (range 8–66 years).The male to female patient ratio was 0.9:1. 47 patients (47, 5%) had previous bleeding, 46 patients (46, 4%) underwent prior embolisation and 2 patients (2%) were initially operated. Planning (target definition) was done based on stereotact. Treatment planning (target definition) was done based on stereotactic DSA and stereotactic MRI for all patients. The median AVM volume treated was 6.25 cm3 (range 0.2–20.4 cm3). The median peripheral Gamma Knife surgery dose was 21 Gy (range 17-25 Gy). Results: Complete obliteration was achieved in 93 patients (94%).Repeated radiosurgery was performed on 2 patients (2%), one patient refused re-treatment and remaining 3 patients without obliteration will be closely monitored until they reach 4 years follow up. In all patients obliteration was documented with MRI and in 26 patients (28%) obliteration was additionally documented with digital subtraction angiography. One patient had re- bleeding during latency period and recovered completely without additional therapy. One patient developed postradiosurgical cyst after proven obliteration with neurological worsening and underwent surgery as salvage therapy. Smaller volume AVMs and higher radiation dose resulted with a higher obliteration rate. The main limitation of this study is relatively low number of patients whose results were evaluated with DSA. Conclusion: Gamma Knife radiosurgery is rarely the method of first choice in treatment of brain AVMs, mainly because of latency period to obliteration, in which risk of haemorrhage still exists. In this study only one patient had re-bleeding after radiosurgery, and another required surgery as salvage therapy for postradiosurgical cysts formation. This makes radiosurgery safe treatment option for intracranial AVMs. High rate of obliteration and low risk of complications makes radiosurgery second best choice in treatment of brain AVMs.

Gamma Knife radiosurgery; Brain arteriovenous malformations; Nidus obliteration; Embolization; Pollock-Flickinger score

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