TWO OLD AND simple concepts, a three-dimensional positioning stage and a coordinate system, were combined in 1906 to create a new one: the stereotactic method. For 25 years, it found little application until it was rediscovered for investigations in small animals. After the first human subcortical stereotactic procedure was performed in 1947, stereotactic methods found greatest application in the placement of subcortical lesions in the treatment of movement disorders. Rapid advances in the development of instrumentation, methods, and understanding of human neuroanatomy and neurophysiology resulted. However, a dormant period followed the introduction of L-dopa in 1968. The advent of computer-based medical imaging applied to the stereotactic method encouraged adaptation of stereotactic methods to the management of intracranial tumors, the rapid development of new surgical hardware, and the rediscovery of old methods and evolution of new ones for the treatment of movement disorders. In addition, the incorporation of computer systems as stereotactic surgical instruments further increased the capabilities of stereotactic methods. Radiosurgical applications increased with the proliferation of gamma units and the development of linear accelerator-based radiosurgical methods. Computers are used to fuse and reformat imaging databases for surgical planning, simulation, and frameless stereotactic intraoperative guidance. As a result, surgical procedures have become more effective in meeting preoperative goats and less invasive. Low-cost, high-speed, microprocessor-based workstation computers and intuitive user interfaces have increased the acceptance into mainstream neurosurgery. It is anticipated that a significant portion of neurosurgery, and probably most surgical procedures in general, will comprise computer-based interventions guided by volumetric imaging-defined data sets acquired preoperatively or by intraoperative imaging systems. The stereotactic surgery of the future may employ all or a combination of the following technologies: frameless stereotactic surgery, robotic technology, microrobotic dexterity enhancement, and telepresence robotics.
