Functional neurosurgery : from SEEG or invasive intracranial recordings in drug-resistant epilepsy to the therapeutic benefit of neuromodulation.

Functional neurosurgery is traditionally defined as opposed to its general counterpart, in that its main goal is to restore a deficient function in the absence of a vascular, tumoral, traumatic or infectious lesion. Most ironically, pioneers of functional neurosurgery, has often resorted to performing highly-selective, well-circumscribed, radiofrequency lesions to obtain a specific effect on key nodes of movement or pain brain circuitry. One key distinguishing feature of this specialty within the specialty resides in the fact that it also comprises invasive intracranial surgical procedures with purely exploratory purposes such as stereo-electro-encephalography, for instance. Such procedures constitute a truly unique opportunity to gain access to the brain signals and more generally to probe brain functions. Based on the breakthroughs in understanding the mysteries of brain that have been made possible by the analysis of these captured brain signals but also serendipitously, neuromodulation strategies have emerged for therapeutic purposes and now break down into all fields of functional neurosurgery and at all levels of central nervous system (peripheral nerve, spinal cord, basal ganglia or cerebral cortex). Neurosurgeons ,notably French ones, have played a key role in the emergence of these approaches and have significantly contributed to major breakthrough in neurosciences. Recently, advances in brain imaging along with technological refinements have considerably altered the landscape of the specialty, that is constantly evolving to the greatest benefit of patients suffering from drug-resistant epilepsy, chronic pain or movement disorder such as essential tremor or Parkinson’s disease.