The invention relates to an instrument and a corresponding surgical method for the removal of a bone insert, for example for a shoulder prosthesis. The instrument is of the type comprising: a stem-like body (40) extending along a longitudinal axis (x-x) and provided with a proximal grip and a distal operating head (15) slidably associated with the stem-like body (40) for movement towards and away from each other; a cutting element (30) inside said operating head; and an end tip (16) protruding coaxially from said operating head. The following is also provided: a pushing mechanism (8), inserted inside said operating head and acting on said cutting element so as to displace it angularly from a rest position, where it is concealingly housed inside said end tip, to an operative position where it projects through a side opening in the end tip; said cutting element having an end extending substantially in a direction transverse to said longitudinal axis when in the operative position.