The ornamental design for a surgical supportbar, as shown and described.
FIG. 1 is a front, top, left side perspective view of the surgical support bar in accordance with the present invention;
FIG. 2 is a front, bottom, left side perspective view thereof,
FIG. 3 is a front view thereof, wherein the rear view is a mirror image thereof,
FIG. 4 is a top view thereof;
FIG. 5 is a bottom view thereof;
FIG. 6 is a right side view thereof; and,
FIG. 7 is a left side view thereof.
The broken lines in the drawings show portions of the surgical support bar that form no part of the claimed design. In addition, the unshaded surfaces within the four circles and two obround shapes form no part of the claimed design.