Abstract： Background:Bipolar electro-coagulation has a reported efficacy in treating epilepsy involving functional cortex by pure electro-coagulation or combination with resection.However,the mechanisms of bipolar electro-coagulation are not completely known.We studied the acute cortical blood flow and histological changes after bipolar electro-coagulation in 24 patients with intractable temporal lobe epilepsy.Methods:Twenty-four patients were consecutively enrolled,and divided into three groups according to the date of admission.The regional cortical blood flow (rCBF),electrocorticography,the depth of cortex damage,and acute histological changes (H and E staining,neuronal staining and neurofilament (NF) staining) were analyzed before and after the operation.The t-test analysis was used to compare the rCBF before and after the operation.Results:The rCBF after coagulation was significantly reduced (P ＜ 0.05).The spikes were significantly reduced after electro-coagulation.For the temporal cortex,the depth of cortical damage with output power of 2-9 W after electro-coagulation was 0.34 ± 0.03,0.48 ± 0.06,0.69 ± 0.06,0.84 ± 0.09,0.98 ± 0.08,1.10 ± 0.1 l,1.11 ± 0.09,and 1.22 ± 0.11 mm,respectively.Coagulation with output power of 4-5 W completely damaged the neurons and NF protein in the molecular layer,external granular layer,and external pyramidal layer.Conclusions:The electro-coagulation not only destroyed the neurons and NF protein,but also reduced the rCBF.We concluded that the injuries caused by electro-coagulation would prevent horizontal synchronization and spread of epileptic discharges,and partially destroy the epileptic focus.