Gamma Knife radiosurgery for cerebral arteriovenous malformations: a systematic review and meta-analysis

Cerebral arteriovenous malformations (AVMs) are rare vascular lesions that rupture at an approximate annual rate of 2–4% [ 1 ]. Annual haemorrhage rates range from < 1%, for unruptured superficially located AVMs, up to 33% in ruptured AVMs with deep, location and venous drainage [ 12 , 68 ]. Once haemorrhage occurs, the probability of experiencing new neurological deficit has been reported to be up to 50% and fatality ~ 10% [ 28 , 66 ]. Gamma knife radiosurgery (GKRS) is an established intervention predominantly favoured for small (< 3.5 cm), surgically high-risk or complex AVMs. Successful AVM GKRS is contingent on abolishing the risk of intracranial haemorrhage (ICH) via complete nidal obliteration, whilst limiting the development of new neurological deficit from radiation-induced changes (RICs) [ 9 , 26 , 69 ].