About the Author: Marc Sindou, MD and DSc, DHC, is currently Professor Emeritus at the University of Lyon, France. He received his PhD degree on "Electrophysiological generators of the cerebral cortex in Humans" and his MD degree on "Dorsal Root Entry Zone as a target for pain surgery", in the seventies. After his neurosurgical training, he benefited from two Fellowships, first in Micro-neurosurgery in Kantonspital in Zurich with Pr. Gazi Yasargil, then for Functional Neurosurgery in MGH and Harvard University in Boston with Pr. William Sweet. Medical activity in Lyon was then directed to: 1) Functional Neurosurgery of Pain, Spasticity in Adults and Children, Epilepsy and Trigeminal Neuralgias; 2) Microsurgery of Giant Aneurysms, Meningiomas, Venous sinus repair and Cranial Nerve Vascular Compression Syndromes; 3) Neurophysiology applied to Neurosurgery. Surgical activity, together with his superb team and pupils, amounted at twenty-five thousands surgeries over a forty-year period of time. Medical and scientific experience has been published in 709 articles, 43 book-chapters and 7 books, and also through 185 invited-comments or editorials in International Journals. His Research Gate score is 47.60 (i.e, higher than 97.5 % of RG members), with h-index of 53 and h-index excluding self-citations of 48. He was a Founding member of the International Association for the Study of Pain (1976), the President of the World Society for Stereotactic and Functional Neurosurgery (1997-2001), a Vice-president of the European Association of Neurosurgical Societies (1999-2003), a European Teacher in the EANS Training Committee (1985-2014), the President of the French Speaking Neurosurgical Society (2007-2010). He is currently Co- Chairman of the Committee for "Stereotactic and Functional Neurosurgery" of the World Federation of Neurosurgical Societies. He delivered 331 invited-lectures in 59 different foreign countries. Among many international distinctions, he was awarded the European Lecture by the EANS in 2007, the Spiegel and Wycis Medal by the WSSFN in 2009, the Award of the Ten Masters in Neurosurgery by the World Federation of Neurosurgical Societies in 2009, and the Award of Top-neurosurgeon for CN disorders in 2018. He was honoured by 37 Visiting-Professorships, especially in the fields of Functional Neurosurgery and on the topic of Surgery in the DREZ, a concept that he introduced for Pain and Spasticity in 1974. He fully trained, in addition to several generations of french neurosurgeons, more than fifty foreign promising neurosurgeons, and still keeps fruitful collaboration with a large number of them.

George Georgoulis is a certified Neurosurgeon working at the General Hospital of Athens "G.Gennimatas", Department of Neurosurgery. He joined a fellowship program for Neurosurgery of Spasticity directed by Professor Sindou at Hôpital Neurologique "Pierre Wertheimer" Lyon, University of Lyon 1. He participates on the multidisciplinary team for Cerebral Palsy Children at the University of Athens. He is invited lecturer in several (pediatric) meetings, in particular the European Society of Pediatric Neurosurgery. His publications are cited in prestigious neurosurgical and neurological journals. Among general neurosurgery, his topics of interest are microsurgery for spasticity, intraventricular neuroendoscopy and intracranial meningiomas.