Systems and methods for performing surgical procedures and assessments

A surgical system for forming a path to a spinal target site via a trans-psoas approach, comprising:

• 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, the plurality of dilating cannulas comprising an outer dilating cannula fitting over another of the dilating cannulas when advanced in a trans-psoas path toward the targeted spine site,
• wherein a stimulation electrode is positioned on at least one of the dilating cannulas to deliver a stimulation signal for nerve monitoring proximate to a distal end of the dilating cannula when advanced in the trans-psoas path, the stimulation electrode being arranged in a fixed position relative to a longitudinal axis of the at least one dilating cannula such that the stimulation electrode rotates with the at least one dilating cannula when the at least one dilating cannula is rotated about the longitudinal axis.