An electro-chemical surgical knife is detailed that in a single instrument provides both a chemically assisted mechanical dissector and an electrical knife. The chemically assisted mechanical dissector: includes a conductive mechanical instrument, a source, (7), of cleavage solution, a pump, (8), for feeding the cleavage solution to, a channel, (2), for transporting the cleavage solution to the operating location, and a flow controller, (8c), for controlling the volumetric feeding of cleavage solution by the pump to the channel inlet. The electric knife includes a source of high frequency AC electrical power, (5), for feeding AC current through an electric conductor, (3), to, an electrode, (6), formed by the conductive mechanical instrument and further comprises A second controller, (5c), for controlling the feeding of electric current to the electrode.
