Long-term complications after gamma knife surgery for arteriovenous malformations

Abstract

Object. The authors analyzed of the long-term complications that occur 2 or more years after gamma knife surgery (GKS) for intracranial arteriovenous malformations (AVMs). Methods. Patients with previously untreated intracranial AVMs that were managed by GKS and followed for at least 2 years after treatment were selected for analysis (237 cases). Complete AVM obliteration was attained in 130 cases (54.9%), and incomplete obliteration in 107 cases (45.1%). Long-term complications were observed in 22 patients (9.3%). These complications included hemorrhage (eight cases), delayed cyst formation (eight cases), increase of seizure frequency (four cases), and middle cerebral artery stenosis and increased white matter signal intensity on T2-weighted magnetic resonance imaging (one case of each). The long-term complications were associated with larger nidus volume (p < 0.001) and a lobar location of the AVM (p < 0.01). Delayed hemorrhage was associated only with incomplete obliteration of the nidus (p < 0.05). Partial obliteration conveyed no benefit. Delayed cyst formation was associated with a higher maximal GKS dose (p < 0.001), larger nidus volume (p < 0.001), complete nidus obliteration (p < 0.01), and a lobar location of the AVM (p < 0.05). Conclusions. Incomplete obliteration of the nidus is the most important factor associated with delayed hemorrhagic complications. Partial obliteration does not seem to reduce the risk of hemorrhage. Complete obliteration can be complicated by delayed cyst formation, especially if high maximal treatment doses have been administered.

Complications Following Linear Accelerator Based Stereotactic Radiation for Cerebral Arteriovenous Malformations

“…The obliteration rate and the percentage of satisfactory vs. less satisfactory outcomes reported in the present study generally correspond to the results in other recently published studies (9,10,13,17,18,21,22). Complete AVM occlusion was obtained in 80% of our patients, which is a relatively high figure compared with other reports.…”

“…Complications following radiation therapy typically occur as late events. Thus, inclusion of patients with a shorter follow-up period would give a falsely low incidence of radiation-related complications, because these often occur beyond 1 year after treatment (13). It has been reported that 82% of complications occur within the first 2 years and 92% within 3 years after treatment (15).…”

“…However, increasing radiation intensity and optimizing coverage of larger lesions within the border of effective radiation dose, also raises the risk of radiation complications (5). Recently, an increasing number of publications have focused on these risks (8,(10)(11)(12)(13)(14)(15)(16). A few centers have been able to analyze a large number of patients treated for cerebral AVMs with stereotactic radiation.…”

Radiosurgery of brain arteriovenous malformations in children

“…This is comparable to other reported rates of symptomatic and asymptomatic parenchymal changes on follow-up MR images after radiosurgery [25,37,41,43], suggesting that only in a small percentage these radiological changes result in neurological signs or symptoms, although long term data are to be awaited. It has been suggested that delayed cyst formation is associated with a higher maximal treatment dose, a larger bAVMvolume, complete nidus obliteration, and a lobar location of the bAVM [15]. While our series is too small to investigate long-term radiation-induced toxicity, it is interesting to note that in the case in which neurological damage due to radiation toxicity was seen, the bAVMvolume was relatively large, with a deep, non-cortical location, and therefore a bAVM-score larger than 2.…”

Gamma Knife®Radiosurgical Strategy for Pediatric High-Grade Arteriovenous Malformations: Advantages of Staged Radiosurgery Prior to Targeting Nidus Proximal to the Drainer

“…There are some high-grade (Spetzler-Martin grade [4][5] AVMs that have no chance for surgical resection or endovascular treatment and where only stereotactic radiosurgical procedures such as GKS can be considered. So far, in addition to the obliteration rate of the nidus, quite a lot of cases that developed radiation injury such as perinidal edema or cyst formation after stereotactic radiosurgery have been reported.…”