I am just curious to know how he got around to it not tearing up his arm. He must be using the Sage Chakra somehow to protect himself.
It was explain http://www.onemanga.com/Naruto/415/15/, when using sage technique the user gets alot stronger thus making them recover at a faster rate and the fact that Naruto already heals at a faster rate because of the Kyuubi makes him withstand the after math of the rasenshuriken.