Abstract: A wrench for surgical use including a housing having an extension at the end of which there is a socket member having a slot through the wheel thereof with the socket member aligned with the corresponding slot in the free end of the extension to permit a nut on an extremely threaded rod to pass into the socket. The socket is peripherally toothed for engagement by a pair of worm gears disposed at respective sides of the socket member so that there is always driving engagement between the worm gears and socket member for rotating the socket member. Crank operated gears are exposed in the housing and are connected by drive shafts of the worm gears.A slidable nut retainer is disposed at each side of the extension and each is provided with a notch for reception of the threaded rod; the parts of the slidable nut retainer at the side of the notches, overlap the nut to prevent it from coming out of the socket.