The Wind Release: Rasenshuriken is a variation of the Wind Release: Rasengan, similar to the Great Ball Rasengan being a variation of the standard Rasengan. Naruto first used this jutsu to defeat Kakuzu a former member of Akatsuki, destroying two of his hearts.
By manipulating the wind chakra of the Wind Release: Rasengan, Naruto was able to create four large points making the Rasengan appear as a giant shuriken, with the Rasengan in the center remaining a perfect sphere. The technique gives off a loud bell-like screech and is so powerful that it creates a storm around the area.
If the technique successfully makes contact, the victim becomes trapped in a giant vortex of countless microscopic wind chakra blades which attack the body on a cellular level so many times that even Kakashi Hatake is unable to count them all with his Sharingan eye. The wind chakra severs the chakra and nerve channels in the body, and if the circulatory system is damaged, it can't be repaired by any form of medical ninjutsu (in a manner similar to poison as stated by Tsunade).
The Rasenshuriken is a vastly dangerous and powerful jutsu, due to the fact that Naruto could not originally throw the Rasenshuriken as the name would have people believe; thus creating the problem of the user being partially caught in the blast and damaged like the victim, though at a lesser level (mainly the arm used to direct the technique). However, as of Naruto's fight with Pain, Naruto has learned to overcome the damage to his own body by throwing the Rasenshuriken, thus completing the technique as well as perfecting its use.
The technique has a "dense and quick-spinning" characteristic. The completed Rasenshuriken (with Senjutsu) appears more powerful. When first used upon collision Kakuzu's body was constantly pierced at a cellular level but remained somewhat intact. But, when thrown, Pain's Human path was cut so fast and so much that only less than half his head remained. The new version is also capable of slicing clean through a row of solid boulders and rocks.