As the storyline goes, WWE claims Zack Ryder suffered "a herniated disc" after being chokeslammed by Kane on last night's Raw Supershow. The official WWE website notes that Jerry Lawler's claim that Ryder sustained a "broken back" was a result of working off "unconfirmed reports." WWE.com goes on to note Ryder "remains hospitalized."
In reality, Ryder is not injured but this is all part of a storyline also involving John Cena and Eve.
You can read the kayfabe update at this link.