A robotic surgical system for performing a surgical procedure within the body of a subject includes an elongate surgical instrument, a robotic controller configured to control the motion of the distal end portion of the surgical instrument, and a mechanomyography feedback system in communication with the robotic controller. The mechanomyography feedback system includes an elongate sphincter contraction sensor configured to monitor a physical response of a sphincter of the subject and to provide a mechanomyography signal corresponding to the monitored response. Additionally, the feedback system includes a processor configured to receive the mechanomyography signal, to determine if the received signal is indicative of an induced sphincter response, and to provide a control signal to the robotic controller if an induced sphincter response is detected.