Devices, systems, and methods for providing a degree of freedom to a guide tube associated with a robotic surgical system. The surgical robot system may be configured to have six degrees of freedom associated with a vertical lift, rotation about a shoulder, rotation about an elbow, roll of a forearm, pitch of the end-effector, and rotation of a guide tube independent from the end-effector. The robotic surgical system allows for the proper orientation of an instrument in the guide tube along a trajectory to the operational site of a patient.