Systems and methods for performing surgical procedures. Such a system includes a cannula having proximal and distal portions. At least one carriage unit is slidably mounted within the proximal portion of the cannula for translation in axial directions of the cannula, and a tool has a shaft that is coupled to the carriage unit and protrudes through a port at the distal portion of the cannula. The tool has a working element mounted on a portion of the shaft that protrudes from the cannula to perform tasks within the cavity. A translation mechanism is provided for translating the carriage unit and its tool in the axial directions of the cannula, and a rotation mechanism is provided for rotating the tool about an axis of its shaft and relative to the first carriage unit. Rotation and translation mechanisms of each carriage unit are preferably individually and independently controlled.