1. Department of Neurosurgery, Cannizzaro Hospital, Via Messina 829, Catania,
2. Department of Neurosurgery, Hospital “San Gerardo,” Via G. B. Pergolesi 33, Monza, Italy,
3. Department of Amethyst Radiotherapy Center, San Giovanni Calibita Fatebenefratelli Hospital, Tiber Island, Rome,
4. Neurosurgery Unit, Highly Specialized Hospital and of National Importance “Garibaldi”, Piazza Santa Maria di Gesù 5, Catania, Italy.