Subjects will be selected from patients hospitalized in the Department of Neurosurgery of the IRCCS Mediterranean Neurological Institute Neuromed, according to specific inclusion criteria and undergoing surgery for disc disease. Subjects included in the study will be normotensive and hypertensive patients. Approximately 70 subjects of both genders (35 normotensive, 35 hypertensive) aged between 30 and 70 years old will be included in the study. All the enrolled patients must have an indication for neurosurgical intervention.