64445, 64447 and 76942 modifiers

Modifiers 50 and 51 always seem to throw me. I need confirmation that I am using them correctly. Would like some feedback on the following please:

During bilateral ankle scopes, surgeon requested postop pain blocks using ultrasound guidance.

Anes did a total of 4 blocks (Popliteal 64445 and Saphenous 64447 on each foot). He used ultrasound guidance (76942) on all four blocks.

64445, 64447 and 76942 modifiers