Effect of Different Surgical Positions on the Cerebral Venous Drainage: an Ultrasound Study on Neurosurgical Patients

The different positions used in neurosurgery for better accessibility to the operating field (park bench, prone) can impact cerebral venous drainage due to the effects of internal jugular venous outflow of blood, and may increase intracranial pressure. Excessive neck flexion and rotation in the park bench position, or flexion in the prone position, may lead to kinking or twisting of the internal jugular vein. This has been hypothesized as the major cause of disturbed venous drainage during surgery and may lead to neck swelling, brachial plexus injury, macroglossia (swollen tongue), delayed airway obstruction, and increases in intracranial pressure in postoperative patients. Optimal brain perfusion is best in the neutral position of the head, but surgery cannot always be performed in this position. Thus, we look to measure the internal jugular venous flow at different positions, as there have been few studies looking at this important contributing factor.