Ali A. Baaj, MD, Department of Neurological Surgery, Northwestern Medicine, Chicago IL USA Yu-Mi Ryang, MD, Helios Hospital Berlin-Buch, Department of Neurosurgery & Centre for Spine Therapy, Berlin, GermanySameh Abolfotouh, MD, MEDCARE Orthopedics and Spine Hospital, Dubai, United Arab EmiratesNader S. Dahdaleh, MD, Department of Neurological Surgery, Northwestern University, Chicago, IL, USAAvelino Parajón, MD, Department of Neurosurgery, Hospital Universitario Ramón y Cajal, Madrid, Spain