System and methods for performing surgical procedures and assessments

A surgical system for neural monitoring while forming an operative corridor in a trans-psoas approach to a spine, comprising:

• a control unit configured to receive user input regarding delivery of a stimulation signal to a stimulation electrode and to display on a color display device neuromuscular response data detected in response to the stimulation signal;
• a connector module that provides a plurality of EMG response channels and an electrical connection for at least one surgical access instrument, the connector module having a wire connection to the control unit so that the connector module is positionable apart from the control unit;
• a plurality of EMG electrodes connectable to the plurality of EMG response channels of the connector module, the EMG electrodes mountable relative to selected muscles;
• a sequential dilation access system comprising a plurality of dilating cannulas to form a trans-psoas corridor between a skin surface and a targeted spine site, at least one of the dilating cannulas fitting over another of the dilating cannulas when advanced in a trans-psoas path toward the targeted spine site;
• and
• a stimulation element electrically connectable to the connector module to deliver the stimulation signal proximate to a distal end of at least one of the dilating cannulas when advanced in the trans-psoas path toward the targeted spine site.