A telscopic hand is needed so that the surgeon will operate his fingers and their motion will be duplicated inside the body by the arm. Since the late 1980s, such minimally invasive surgery has gained widespread acceptance due to reduced trauma, reduced recovery time and lower cost for the patient. Though it has some degree of articulation, there's really very little dexterity. The tip can only bend up to 90 degrees, and in only one direction. The maximum force should be similar with the maximum force of the human fingers.
External power is the human hand.
The instrument must be sterilizable before the operation or have a disposable tip. CO2 pneumatically actuated instruments for laparoscopy . However, on the laparoscopic cart, there is a tank of CO2 which is used to produce the gas-filled abdomen during the procedure. Like a leaf blower, but used to blow away and cut portions of body fat during surgery. Presently a pneumatic dissector is used with 50 psi CO2.