ion of another embodiment trial instrument. [0032]FIGS. 20A and 20B are a plan view and side view, respectively, of a distal portion of another embodiment trial instrument. [0033]FIGS. 21A and 21B are a plan view and side view, respectively, of a distal portion of another embodiment trial instrument. [0034]FIGS. 22A and 22B are a plan view and side view, respectively, of a distal portion of anothe