A medical instrument assembly and robotic medical system are provided. The medical instrument comprises an outer probe having an elongated shaft, an inner probe having an elongated shaft coaxially disposed within the outer probe shaft, and actuating elements. The robotic medical system comprises the medical instrument assembly, a support on which the medical instrument assembly is slidably disposed, a user interface configured for generating at least one command, a drive unit coupled to the actuating elements, and an electric controller configured, in response to the command(s), for directing the drive unit to drive the actuating elements to independently effect movement of the outer and inner probes within at least one degree-of-freedom, and to linearly translate the medical instrument assembly along the support.