Continuous precise procedures are strictly required in microscopic neurosurgery. Holding the instrument in the best and identical position is important, and normally it is achieved by a surgeon's arm itself. The aim of the project is to develop an intelligent arm holding manipulator which follows surgeon's hand automatically. To achieve this object, we have developed an auto-adjusting arm holding manipulator named "EXPERT" for microsurgery which has 5 DOF passive control joint with powder brakes. In this paper, we reported one clinical study case using the system in cerebral blood vessel surgery. The system was used in blood vessel exposure and anastomosis task and it was confirmed that operational performance and stability of the mechanism was satisfactory for these kinds of precise surgery.
