Quote Originally Posted by RasenDori
Because to cut it off requires that he touch it with his other hand. Also some of the flames were on his hand as well. It was a goner. I really do hope Shi has some hax move that will grow it back. Raikage's too cool to lose a hand to a punk like Sasuke.

EDIT:
http://www.onemanga.com/Naruto/464/13/
When did Kankurou become a cloud ninja? Looks like an assistant fucked up.
I know his hand was on fire, that's why I said he could have just cut his hand off. Oh well.

It wouldn't surprise me if they could regrow it back. We've seen medical ninjutsu regrow tissue before (Neji) and when Jiraya's arm was cut off he didn't seem to be panicking too much.