Late morbidity and mortality following revascularization surgery for moyamoya disease in the pediatric population.

Objective: There are limited reports on long-term morbidity in pediatric patients who have undergone surgical revascularization for moyamoya disease (MMD). Here, the authors report long-term morbidity and mortality in a population of pediatric patients who underwent pial synangiosis for MMD from 1988 through 2016.
Methods: A single-center retrospective review of the hospital and personal operative databases of the senior authors was carried out to identify all patients who were treated for MMD at Boston Children's Hospital between 1988 and 2016, and who experienced any episode of late morbidity or mortality, which the authors defined as an event resulting in significant neurological deficit or death occurring more than 1 year after revascularization surgery. Hospital records were reviewed to determine pertinent demographic data, the initial mode of patient presentation, and associated comorbidities. Radiographic studies, when available, were reviewed for documentation of the diagnosis and for confirmation of the late complication, and the literature on this topic was reviewed.
Results: In total, 460 patients with MMD underwent surgery between 1988 and 2016 using the pial synangiosis surgical technique; 15 (3.3%) of these patients (9 females and 6 males) experienced documented late death (n = 14) or severe morbidity (n = 1). The median age at revascularization surgery was 8.0 years (range 1-21 years). The causes of these late complications were grouped into three etiologies: intraventricular or intracerebral hemorrhage (n = 8), systemic complications related to associated comorbidities or preoperative disabilities (n = 5), and the development of malignant brain tumors (n = 2). Four patients whose MMD was associated with a history of cranial radiation therapy died. These events occurred from as early as 2 years to as late as 27 years postoperatively.
Conclusions: The risk of late morbidities and mortality following pial synangiosis for MMD in the pediatric patient appeared to be low. Nevertheless, the occurrence of catastrophic cerebrovascular events, particularly intracerebral and intraventricular hemorrhage in the otherwise neurologically stable revascularized patient, was concerning. Although there is value in long-term surveillance of patients who have undergone surgery for MMD, from both a neurological and a general medical standpoint, particularly in patients with the risk factor of prior cranial radiation therapy, it is not clear from the data how the late deaths in this population could have been prevented.