1 Department of Orthopaedic Surgery, Centro Hospitalar do Alto Ave, Rua dos Cutileiros, Creixomil, 4835-044 Guimarães, Portugal. atiagobarbosa@gmail.com.
2 Department of Neurosurgery, Centro Hospitalar de São João, Alameda Professor Hêrnani Monteiro, 4200-219, Porto, Portugal. pereira.paulom@gmail.com. pedrodossantossilva@gmail.com. pedrommon@gmail.com. ruimcvaz@gmail.com.