Stereotactic methods are routinely used in neurosurgery for operations such as the aspiration of brain cysts, tumor biopsies and more recently to implant electrodes into brain targets. An integral part of this surgery is a mechanical device called a stereotactic frame (10) that has head holding clamps and bars which puts the head in a fixed position in reference to the coordinate system. Various methods of accurately aligning the frame have been used but a novel device and method are proposed that over-come at least some of the shortcomings of these current techniques. There is disclosed a removable frame attachment (30) that holds the frame in position but allows for fine adjustment, allowing a single operator to quickly and accurately position the frame. The attachment can be removed before surgery without moving the set position of the frame. The device comprises two or more arms (31,32) each arm being coupled to another at a point of intersection. At least one arm comprises a plurality of fixing means (35) and at least one arm is attached to the stereotactic frame (10) using gripping means (33).