A comparison of effects of bipolar and monopolar electrocoagulation in brain.

Controlled bipolar and monopolar coagulation lesions were generated in the cerebral cortex of cats. Higher output powers were associated with larger lesions, while the lesion size was independent of the mode of coagulation. When cortical vessels were mobilized and coagulated for hemostasis, bipolar mode was associated with more rapid coagulation and less damage to the underlying brain. Higher output powers were not associated with larger lesions, probably because coagulation was more rapid. The neural damage resulting from radiofrequency current appears to be of thermal origin, and the blood-brain barrier dysfunction is a more sensitive measure of this damage than the stainable cellular changes.