[Prone position and operative posture in neurosurgery].

The most satisfactory method of prone positioning for the posterior approach to the spine and posterior fossa has been influenced by the necessity of providing good operating condition: prone position without abdominal and thoracic compression with a patient's head in the neutral position. Communication between the cava veins and the vertebral venous plexus explain that induce positioning can produce an excessive venous intraoperative bleeding with decreased surgical visibility. Furthermore venous return to the heart decreased resulting in some degree of impaired cardiac output. Hemodynamic disturbances of cerebral or spinal cord bloods flows can occurred.