Stand-alone access system for minimally invasive spinal surgery

A retractor assembly for conducting minimally invasive surgery comprising:

• at least three retractor blades that are relatively articulable with respect to each other and are configurable in a self-supporting closed shape for defining a working channel to a surgical site,
• each of the retractor blades having a length and inner and outer surfaces joined by two side surfaces,
• the retractor blades being configurable such that the lengths of the retractor blades align in a substantially common direction along the working channel and the inner surfaces of the retractor blades face an interior of the working channel,
• the side surfaces between adjacent retractor blades comprising mating features configured to abut each other in the form of compression joints to temporarily interconnect the adjacent retractor blades and retain the retractor blades in a desired configuration surrounding the working channel and to constrain a collapse of the retractor blades into the working channel,
• wherein at least one of the retractor blades is configured to translate in the substantially common direction relative to the other retractor blades, and at least one of the retractor blades is configured to be pivoted relative to the other retractor blades such that an end of the retractor blade is moved away from a center of the working channel;
• interconnections between the retractor blades being limited to the mating features which are shaped to (a) permit relative angular motion between the retractor blades toward and away from the working channel over a continuum of positions along the lengths of the retractor blades and (b) permit relative translation between the retractor blades in the substantially common direction along the working channel.