System and Methods for Performing Surgical Procedures and Assessments

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

• a dilating cannula having longitudinal axis, a distal end, a proximal end, and a length such that said proximal end extends beyond a skin surface when said distal end is positioned adjacent to said spinal target site via a trans-psoas approach to said spinal target site, said dilator being insulated along the entire length with the exception of at least one exposed electrical contact at said proximal end and an exposed stimulation electrode at said distal end, said stimulation electrode being exposed along only a radial portion of said distal end, said dilating cannula further including a reference mark viewable when said distal end of said dilating cannula is located between said skin surface and said spinal target site and indicative of the radial position of said exposed stimulation electrode;
• a stimulation clip having a first end attachable to said proximal end of said dilating cannula and a cable for establishing electrical communication between said stimulation clip and an electrical stimulator, said first end establishing electrical communication between said at least one electrical contact of said dilating cannula and said stimulation clip when said stimulation clip is attached to said dilating cannula.

The system of claim 14, further comprising a working corridor instrument that is slidable over the second dilating cannula to form a trans-psaos operative corridor to the spinal target site along said path created by said first dilating cannula.