A system for interchangeable retractor blades includes a shell, a first retractor blade, and a second retractor blade. The shell includes a rigid proximal end configured to attach to a surgical retractor and an opening, a distal closed end, and a pliable portion including a pocket in communication with the opening and extending along a length of the shell to the distal closed end. The first retractor blade includes a first geometry received through the opening into the pocket and that shapes the pliable portion to configure the shell in a first configuration. The second retractor blade includes a second geometry received through the opening into the pocket and that shapes the pliable portion to configure the shell in a second configuration.