Some reflections about history of stereotaxy.

The concept of stereotaxy is essentially based on functional topography, wh ich continuously evolved from We first observation by Hippocrates of a moto r deficit contralateral to an hemispheric wound, to the characteristic exam ple of Broca's speech area. The fate of a method depends on the need for it . When an outsider phenomenon, such as a pharmacological newcomer, occured, which brought, at least for a given period, a satisfactory solution, the n eed for the method disappeared and sent it in oblivion. At the same time, t he understanding that some pathologies, such as brain tumors, were not adeq uately taken care of by classical surgery and could eventually respond corr ectly to general treatments, such as chemotherapy or radiotherapy, induced the application of this forgotten, or near to be abandoned, method to a tot ally new field: this is what Talairach and his associates did when they int roduced the stereotactic biopsy, at a time where movement disorders needed less surgery as levodopa had come and provided a very attractive treatment When, on the contrary, it appeared that some forms of Parkinson's disease l ess responded to the drugs or were plagued by motor fluctuations and dyskin esias, Were could be a new need for surgery. However, complications became at that time unacceptable and the method was required to evolve towards new directions where efficacy goes with a negligible morbidity. This led event ually to new developments such as brain grafting or more recently high freq uency deep brain stimulation. Stereotaxy, like other methods, has experienc ed this type of fluctuation in ifs history and has on each occasion progres sed and acquired new skills and possibilities, far beyond what it was initi ally designed for.