My wife is an athletic trainer, and I'm an avid Batman fan. At 1AM, watching Dark Knight Rises, this is what happens to my facebook status: "The worst potential injury Batman could have sustained and recovered from in a 5 month period is likely a vertebral rotation with a unilateral fracture. The manipulation preformed in the prison to fix his back excludes the possibility of a bilateral fracture resulting in the anterior translation of the vertebrae. The manipulation could be used for a posterior translation of the vertebrae, but the mechanism of injury caused by Bane would not result in a posterior translation."
To which I add, Batman's armor probably prevented the initial injury from being much worse than it could have been, and his motivation and intensity in recovery is much stronger than that of your average athlete. Keep in mind as well that the 5 month time frame is based on the nuclear decay rate parameter given in DKR (I will investigate that at a later time ha ha ha).