Outcome of Therapies for Intracranial Aneurysms in Children

Outcome after surgery

• Favorable outcomes in most children: A recent meta-analysis (13) including 560 patients found an overall rate of favorable outcomes of 84.5%, with similar rates following surgical (82.7%) and endovascular (88.3%) treatment. Significantly lower rates of favorable outcomes were found for children with ruptured aneurysms (77.5%) versus those with unruptured aneurysms (94.7%). No significant difference in the rate of favorable outcomes for surgical versus endovascular treatment was observed for either ruptured or unruptured aneurysms. Favorable outcomes in children with Hunt and Hess grades I to III versus grades IV to V subarachnoid hemorrhage were 88% and 44%, respectively. Similar rates of favorable outcomes were found for anterior versus posterior circulation aneurysms, saccular versus fusiform aneurysms, traumatic versus nontraumatic aneurysms, infectious versus noninfectious aneurysms, and teenage (13-18 years) versus younger (0-12 years) patients.
• Comparison with adults: About 60% of adult patients recover to their premorbid state after subarachnoid hemorrhage, whereas 15% experience poor outcome, and 25% die within 6 months (127,128). Cerebral vasospasm is a major determinant of outcome after aneurysmatic subarachnoid hemorrhage; its occurrence is linked to significantly increased mortality rate and decreased likelihood of good outcome (120).
• Obliteration rate: The complete obliteration rate is 90% in children (100,101).
• Risk of recurrence: The annual risk of recurrence is 2.6% in children (compared with less than 0.5% in adults) (101).
• Risk for de novo aneurysm formation or growth: The annual risk of de novo aneurysm formation or growth is 7.8% in children (compared with 1.8% in adults) (101).

Outcome after Endovascular Treatment

• Increasingly utilized: In a review of the literature on pediatric intracranial aneurysms published after 2000, the author (Thomas Beez) found endovascular treatment in 35% of pediatric aneurysm cases, including the application of stent-assisted procedures and flow diverters (78). This review also found a shift over time toward endovascular treatment of pediatric aneurysms; more than 50% of published aneurysm cases in the period between 2012 and 2015 were treated endovascularly (78). There may be a greater tolerance to the occlusion of a parent vessel for young children with aneurysms than adults with a similar aneurysm, potentially due to greater collateral cerebrovascular capacity.
• Clinical evidence: No randomized controlled trials comparing treatment options in pediatric aneurysms are published. However, single-center series indicate good results (10). Moreover, there currently exist no guidelines for deciding between microsurgical and endovascular treatment in children. Decisions must be made with respect to characteristics of individual aneurysms and parental preferences.
• Generalization from adult data: The International Subarachnoid Aneurysm Trial compared endovascular coiling with surgical clipping in ruptured aneurysms in adults in a prospective randomized fashion (129). The main finding was that the risk of dependency or death at 1 year was significantly lower in the endovascular group. Of note, the late rebleeding rate was 0.21% per patient-year in the endovascular group, compared with 0.063% in the surgical group (130). The observation that an increased risk of recurrent bleeding might exist from a coiled aneurysm is important when planning the treatment of a child, considering the higher life expectancy (100). Careful follow-up is thus recommended. The Barrow Ruptured Aneurysm Trial (BRAT), another prospective randomized trial, also found that patients assigned to surgical clipping had significantly worse outcomes (as measured by the modified Rankin Scale) as compared with those assigned to endovascular coiling at 1 year (131). However, after 1 year, the difference in outcomes between the two groups was not statistically significant (132,133).