Preoperative collateralization depending on posterior components in the prediction of transient neurological events in moyamoya disease

Changes in local cerebral blood flow (CBF) are a major cause of transient neurological events (TNEs) after revascularization for moyamoya disease (MMD); however, the influence of preoperative collateral pathway development on TNEs has not yet been investigated. This study included 28 hemispheres from 28 consecutive patients with MMD who underwent surgical revascularization, including a superficial temporal artery (STA) to middle cerebral artery (MCA) bypass, between January 2014 and March 2022. The collateralization pathways included the anterior communicating artery (AcomA) collaterals, posterior communicating artery (PcomA) collaterals, transdural collaterals, posterior pericallosal anastomosis, lenticulostriate anastomosis, thalamic anastomosis, and choroidal anastomosis. These collateral pathways were analyzed to identify predictive factors significantly associated with TNEs. TNEs were observed in 11 (39.3%) hemispheres. The development of posterior pericallosal anastomosis and choroidal anastomosis was a significant independent predictor of the occurrence of TNEs after bypass surgery for MMD (P = 0.01, OR 26.9, 95% CI 1.50–480.0; P = 0.002, OR 47.6, 95% CI 2.65–856.6). The development of choroidal and posterior pericallosal anastomosis could be reliable preoperative predictors of TNEs after bypass surgery for MMD. Our results provide useful information for future studies aimed at clarifying the mechanisms underlying TNEs.