An apparatus and method for adjusting the orientation of a surgical viewing instrument, which may be used to view a patient target site and any intervening tissue from outside the body, as the position of the instrument is changed by a user. The instrument is attached to a robotic arm assembly and is...http://www.google.de/patents/US20010025183?utm_source=gb-gplus-sharePatent US20010025183 - Methods and apparatuses for maintaining a trajectory in sterotaxi for tracking a target inside a body
