1. Department of Neurosurgery, Istanbul University, Istanbul Faculty of Medicine, Istanbul, Turkey;
2. Department of Neurosurgery, Istanbul Scoliosis and Spine Center, Florence Nightingale Hospital, Istanbul, Turkey;
3. Center for Spine Surgery and Pain Therapy, Center for Orthopedics and Traumatology of the St. Elisabeth Group-Catholic Hospitals Rhein-Ruhr, St. Anna Hospital Herne/Marien Hospital Herne University Hospital/Marien Hospital Witten, Herne, Germany