Cause analysis of transient neurological dificit after bypass surgery in moyamoya disease

Liao Yujun; Li Jingrun; Xu Bin

doi:10.11850/j.issn.1009-122X.2017.11.004

Abstract：Objective To investigate the mechanism of transient neurological dificit (TND) after superficial temporal artery (STA)-middle cerebral artery (MCA) anastomosis in moyamoya disease (MMD).Methods The clinical data of 49 surgery-treated hemispheres of MMD were analyzed retrospectively.The STA-MCA anastomosis with encephalo-duro-arterio-synangiosis (EDMS) was used for cerebral revascularization.Intraoperative indocyanine green (ICG) angiogram was used to demonstrate bypass patency and hemodynamics on the cortex.99mTc-ECD SPECT and territorial-Arterial Spin Labeling (t-ASL) MR scan were used for hemodynamic study.Results TND was observed from 2nd to 7th day after operation and sustained for 7.4 days in average,with an incidence of 34.7％ (17/49),manifested as aphasia,motor and sensory disturbance and epilepsy.All symptoms were relieved without neurological deficit at discharge after proper treatment.Perioperative SPECT study revealed 2 different types of changing pattern in cerebral hemodynamic:increased peffusion (7 hemispheres,characterized by hyperperfusion around the anastomosis site),and unbalanced perfusion (10 hemispheres,characterized by slightly increased or stable perfusion around the anastomosis site with adjacent hypoperfusion).The t-ASL study revealed blood-flow redistribution between bypass flow and initial flow,inducing a phenomenon of "watershed shift",and the location of new watershed was in accordance with hypoperfusion on SPECT.It's conceivable that flow disturbance in the new watershed may cause cerebral ischemia.Conclusions TND after STA-MCA anastomosis in MMD may be caused by hyperperfusion or cerebral ischemia induced by watershed shift.Perioperative hemodynamio analysis is of paramount significance in differential diagnosis and treatment.