Abstract: A pressure-responsive surgical tool assembly includes an inflatable enclosure and a pair of electrodes positioned therein. The electrodes are adapted to contact each other and operatively move away from each other under an increase of fluid pressure inside the enclosure until electrical contact is broken. An electrical lead is connected to each electrode for electrically monitoring the condition of electrode contact. A flexible tubing is connected to the enclosure to provide fluid flow therein to increase the pressure inside. A surgical tool overlies at least one of the electrodes and is adapted to transmit force applied from it to that associated electrode. Application of force by the tool initially causes the electrodes to contact each other and to remain in contact until the pressure inside the enclosure substantially balances the applied pressure from the tool whereupon electrode contact is broken.