A percutaneous surgical system includes a plurality of tissue retractors configured to maintain a working space within soft tissue. The tissue retractors include a prong on their inner surfaces for engaging a ring member. The ring member maintains the position of the tissue retractors while also defining a number of channels inside the ring member. In one embodiment, the ring member includes concentric inner and outer walls connected by support walls. The inner wall defines an inner bore for supporting a working channel sleeve for the introduction of working instruments. A plurality of outer channels are defined between the inner, outer and support walls for the introduction of ancillary instruments to the surgical site. A manipulation tool is also provided that engages each tissue retractor for positioning the retractor within the patient.