A combined electrical tissue sealing and mechanical tissue cutting instrument. The instrument has two opposing jaw members. A removable cartridge is positioned in one of the jaw members. The cartridge includes a tissue sealing electrode and a tissue cutter. As either the tissue sealing electrode or the cutter deteriorates with use, the cartridge is replaced with a new cartridge. Cartridges are configured with various electrode geometries to accommodate various associated electro-surgical units. One or more pressure sensors in the cartridge or in the instrument jaw that supports the cartridge provide an indication that a required clamping pressure exists between the jaw members to carry out the tissue sealing. A cut and seal controller allows various actions to be carried out when particular clamping pressures are sensed, or when an indication that tissue sealing is complete is sensed.