FIG. 1 is a left perspective view of a handle assembly for a surgical instrument showing our new design.

FIG. 2 is a left side view thereof.

FIG. 3 is a right side view thereof.

FIG. 4 is a bottom side view thereof.

FIG. 5 is a top view thereof.

FIG. 6 is a rear view thereof.

FIG. 7 is a front view thereof.

FIG. 8 is a left perspective view of a modified embodiment of the design shown in FIGS. 1-7.

FIG. 9 is a left side view thereof.

FIG. 10 is a right side view thereof.

FIG. 11 is a bottom side view thereof.

FIG. 12 is a top view thereof.

FIG. 13 is a rear view thereof.

FIG. 14 is a front view thereof.

FIG. 15 is a left perspective view of a second modified embodiment of the design shown in FIGS. 8-14.

FIG. 16 is a left side view thereof.

FIG. 17 is a right side view thereof.

FIG. 18 is a bottom side view thereof.

FIG. 19 is a top view thereof.

FIG. 20 is a rear view thereof.

FIG. 21 is a front view thereof.

FIG. 22 is a left perspective view of a third modified embodiment of the design shown in FIGS. 8-14.

FIG. 23 is a left side view thereof.

FIG. 24 is a right side view thereof.

FIG. 25 is a bottom side view thereof.

FIG. 26 is a top view thereof.

FIG. 27 is a rear view thereof; and,

FIG. 28 is a front view thereof.

The broken lines showing portions of a handle assembly for surgical instrument are included for the purpose of illustrating environmental structure and forms no part of the claimed design.