Complications of Therapies for Cerebral Arteriovenous Malformations in Children

Surgery

• Bleeding: Bleeding is the most immediate complication of surgery, and risks are magnified in smaller children, who have little reserve.  The loss of one-quarter of their blood volume can induce shock in children, and there may be rapid decompensation, which mandates careful monitoring and replacement of blood products by the operative team.
• Perfusion breakthrough: Normal perfusion pressure breakthrough is a phenomenon that is thought to occur after resection of high-flow AVMs in which the blood previously transmitted through the AVM is redirected to smaller, normal vasculature after the AVM has been removed, with subsequent inability of the vessels to handle the increased flow.  This can result in brain swelling, increased ICP, seizure, neurological dysfunction, or hemorrhage.  The problem may be minimized by staged preoperative embolization and rigorous blood pressure control postoperatively.
• Neurological deficits: Neurological deficits can occur after AVM resection, although specific rates are hard to derive, given the wide variability in AVM size and location.
• 0–12% morbidity rate: Overall, there is a low postoperative morbidity rate for low-grade (Grades I-III) Spetzler-Martin lesions (ranging from 0–12%), along with a high rate of complete obliteration (up to 100%), suggesting that surgical resection of these lesions is warranted, especially when performed in experienced centers( 39, 41–43).

Radiation Therapy

• Bleeding after treatment: The long delay between treatment and lesion obliteration in radiosurgery for AVMs means that the child is at risk of the complication of bleeding during this interval.  Patients with small (,<3 cm diameter), deep-seated lesions (in the basal ganglia, internal capsule, and thalamus) are the best candidates for radiosurgery.  A study of 42 children with lesions in these locations documented a 62% angiographic cure rate within 2 years (44). However, radiosurgery of AVMs in these sites has yielded a higher risk of rebleeding when compared to AVMs treated in other areas of the brain (45).  
• Radiation injury: Young children have risk of radiation-induced damage, including injury to the surrounding developing brain and potential for development of secondary malignancies.  These risks limit radiation use to older children in most cases.