To summarize, a bedside method for assessment of changes of ventricle width/diameter of the optic nerve during clamping of EVD/LD is urgently needed and would facilitate the procedure, higher patient safety and lower costs. By now, there are some promising ultrasound methods (transcranial ultrasound with or without contrast enhancing agent to determine the width of the side and third ventricle, diameter of the optic nerve), which might substitute repeated CT scans but have not been evaluated for monitoring clamping of EVD/LD.