Evaluation of Gamma Knife treatment in management of intracranial arteriovenous malformations

Abstract

Brain arteriovenous malformations (BAVMs) are defined as the direct communication of arteries to abnormally tortuous and dilated veins without interposing capillaries. It can present with intracerebral hemorrhage (ICH) or they can be unruptured and present with symptoms resulting from mass effect or altered hemodynamics from direct shunting. in our series Symptoms leading to the diagnosis were hemorrhage in (64.8%) of patients, seizures in (34%) and it was of more than one year duration at time of gamma knife treatment in (22%) of patients, headaches in (25.9%), motor deficit in (21.3%), Steal symptoms in (2.7%), venous hypertension (2.7%) and it was an incidental discovery in (2.7%) of patients. Despite being an uncommon disease, BAVMs account for the majority of childhood hemorrhagic strokes and represent the most common cause of isolated, nontraumatic ICH in young adults. In patients with untreated BAVMs the annual hemorrhage rates are 2–4% (major morbidity 1.7%, mortality 1%, and combined morbidity and mortality 2.7% per year); however, the vast majority (71%) of these BAVMs had ruptured at initial presentation Three therapeutic modalities for arteriovenous malformation treatment (surgery, embolization, and radiosurgery) developed in the past years with specific tools, each tool with its own qualities The goal of stereotactic radiosurgery for cerebral AVMs is to obliterate the AVM nidus, decrease the risk of future hemorrhage, and improve seizure severity, headache, or other neurological deficits Complete AVM obliteration following radiosurgery generally takes 1–3 years and the risk of hemorrhage during this latency period becomes lower than untreated patients. In our series Obliteration rate following radiosurgery was 87% after 2 years of follow up. factors associated with a higher rate of total AVM obliteration included ; low Pittsburgh Scale, small AVM volume, frontal, ventricular and cerebellar location and non embolized AVMs. In our series symptomatic adverse radiation effects (AREs) (odema) developed after Gamma knife treatment occurred in 21.3% of patients. In 3.7% of them, a persistent clinical deterioration developed. In the other 17.5% of patients AREs were successfully managed with a short course of corticosteroids. Factors associated with a higher rate of AREs included Old age high Pittsburgh Scale, large AVM volume, high Prescription Dose, high Integral dose and parietal and frontal location