Visualization assembly 256 may comprise any of the variations described above, particularly the variation as described for FIGS. 24A and 24B. FIG. 28 shows a perspective view of another variation of end effector assembly 320 in which optionally shape-lockable elongate body 322 may comprise a separate visualization lumen 324 having a lumen opening 326 through which a guidewire 328 having a preset c