Nathan Beucler1,2, Arnaud Dagain3,4. 1. Neurosurgery Department, Sainte-Anne Military Teaching Hospital, 2 boulevard Sainte-Anne, 83800, Toulon Cedex 9, France. nathan.beucler@neurochirurgie.fr. 2. Ecole du Val-de-Grâce, French Military Health Service Academy, 1 place Alphonse Laveran, 75230, Paris Cedex 5, France. nathan.beucler@neurochirurgie.fr. 3. Neurosurgery Department, Sainte-Anne Military Teaching Hospital, 2 boulevard Sainte-Anne, 83800, Toulon Cedex 9, France. 4. Val-de-Grâce Military Academy, 1 place Alphonse Laveran, 75230, Paris Cedex 5, France.