Tissue distractor devices, systems, and methods for soft tissue expansion in order to create a space between the tissue to improve visualization and for increased working space during surgery are disclosed. One method for separating soft tissues for cannula access to a treatment site within a patient body comprises providing a catheter having a tissue distractor on a distal end thereof and positioning the catheter between the soft tissues near the treatment site. Once properly positioned, the tissue distractor is expanded so as to separate the soft tissues. The tissue distractor is then elongated by mechanical actuation so as to provide cannula access to the treatment site. The cannula forms a working channel for surgical procedures, particularly minimally invasive surgical procedures.