Occipital artery to middle cerebral artery bypass in pediatric moyamoya disease: rescue therapy after failed revascularization

OBJECTIVE Patients with pediatric moyamoya disease (PMMD) showing recurrent symptoms or decreased cerebral blood flow after initial revascularization therapy may require additional revascularization to improve their clinical condition. The authors evaluated the clinical and hemodynamic benefits of an occipital artery (OA)-middle cerebral artery (MCA) bypass for patients with PMMD who have undergone an initial revascularization procedure. METHODS The authors retrospectively identified 9 patients with PMMD who had undergone OA-MCA bypass between March 2013 and December 2017, and who had received a previous superficial temporal artery-MCA bypass. The following clinical data were collected: initial revascularization procedure, symptoms (presence or recurrence), pre-and postoperative cerebral blood flow and cerebrovascular reactivity (CVR) changes, posterior cerebral artery (PCA) stenosis, PCA-related and nonrelated symptoms, and latest follow-up. RESULTS Preoperatively, all patients (n = 9) suffered non-PCA-related recurrent symptoms, and 4 had PCA-related symptoms. At 1-year follow-up, all patients with PCA-related symptoms showed complete recovery. Additionally, 8 (89%) patients with non-PCA symptoms experienced improvement. Only 1 (11%) patient showed no improvement after the surgical procedure. The mean pre-and postoperative CVR values of the MCA territory were 14.8% and 31.3%, respectively, whereas the respective mean CVR values of the PCA territory were 22.8% and 40.0%. CONCLUSIONS The OA-MCA bypass is an effective rescue therapy to improve the clinical condition and hemodynamic changes caused by PMMD in patients who experience recurrent symptoms after initial revascularization.