for connecting a variety of surgical instruments for both minimally invasive surgery and for application in open surgery a push - button fastener is provided at the proximal end of the instrument to be connected in each case at the distal end of a shank part of an operating control device . furthermore , for connecting and actuating the function elements of the instrument connected in each case a mandrel assembly is provided at the proximal end of the instrument , the mandrel assembly being in turn mounted on and latched to a receiving part at the distal end of an adjuster mechanism actuatable by the operating control means . preferably , the mandrel assembly is tubular pin body slotted at its proximal end , having splined portions which is mounted on and latched to a contact pin guided and positioned in the shank part .