Object: Limited data exist to guide management of incidentally discovered pediatric moyamoya. Best exemplified in the setting of unilateral moyamoya, in which the unaffected side is monitored, this phenomenon also occurs in populations undergoing routine surveillance of the cerebral vasculature for other conditions, such as sickle cell disease (SCD) or neurofibromatosis Type 1 (NF1). The authors present their experience with specific syndromic moyamoya populations to better characterize the natural history of radiographic and clinical progression in patients with asymptomatic moyamoya.
Methods: The authors performed a retrospective review of the clinical database of the neurosurgery department at Children's Hospital Boston, including both nonoperative referrals and a consecutive series of 418 patients who underwent surgical revascularization for moyamoya disease between 1988 and 2010.
Results: Within the period of time studied, 83 patients were asymptomatic at the time of radiographic diagnosis of moyamoya, while also having either unilateral moyamoya or moyamoya in association with either SCD or NF1. The mean age at presentation was 9.1 years (range 1-21 years), and there were 49 female (59%) and 34 male (41%) patients. The mean follow-up duration was 5.4 ± 3.8 years (mean ± SD), with 45 patients (54%) demonstrating radiographic progression and 37 (45%) becoming symptomatic within this period. Patients with SCD had the highest incidence of both radiographic (15 patients [75%]) and clinical (13 patients [65%]) progression, followed by NF1 (20 patients [59%] with radiographic progression and 15 patients [44%] with clinical progression) and patients with unilateral moyamoya (10 patients [35%] with radiographic progression and 9 patients [31%] with clinical progression).
Conclusions: Radiographic progression occurred in the majority of asymptomatic patients and generally heralded subsequent clinical symptoms. These data demonstrate that moyamoya is a progressive disorder, even in asymptomatic populations, and support the rationale of early surgical intervention to minimize morbidity from stroke.