Stereotactic Surgery

Abstract

Stereotaxis allows the precise localization of a point in the space based on the mathematical model proposed by Renee Descartes, which is defined by three plans: X, Y and Z. This concept was first used in Neurosurgery by Clarke and Horsley, who applied a stereotactic frame in animals to guide electrodes into the depth of the cerebellum to study neuronal function. Not until 1947, Spiegel and Wycis performed the first stereotactic procedure in humans, which was a thalamotomy for psychiatric disorder. Different frame systems to localize a deep brain structure three dimensionally were proposed. The arc centered system, developed by Lars Leksell in 1949, became the most commonly used. The ventriculography was the first great step on the development of stereotactic surgery. It provided the indispensable brain landmarks for the neurosurgeon to start the electrophysiological brain mapping. Functional and anatomic atlases of the brain were developed to guide the stereotactic operations. The development of computadorized tomography (CT) and magnetic resonance images (MRI) improved the targeting since the anatomy visualization became more detailed. The stereotaxis frameless became possible through the use of Neuronavigation. Stereotactic surgery is widely applied for morphological and functional procedures in the brain. Examples of morphological applications are brain biopsies, guided craniotomies for tumor resection and radiosurgery. Functional applications are implant of deep brain stimulators (DBS) or ablative lesions for movement disorder, pain, psychiatric diseases and epilepsy. The real time imaging can be provided when the procedures are performed in the interventional MRI.