For inserting a cage in the intervertebral disk space between two vertebrae, an instrument set includes a guide wire with a plurality of dilators that can be pushed over the guide wire and one over another, with a working sleeve and with a cage, in which the working sleeve is designed in its distal area such that it makes possible the fixation of its distal area in the direction of its extension with angular mobility or variable angular orientability of its proximal end.
