My pet rat broke his spine

Question
I have two pet rats. Three days ago they escaped in the garden. Trying to catch them my boyfriend accidently caught the poor thing between the wall and a box. I think he broke his spine, the rat is dragging his back legs. I took him immediately to a vet, he said it can have a small percent chance to recover if he make him a 70euro injection. But if it doesn't he has to kill it. I made the injection,but nothing chanced in his condition, I didn't took him back to the vet. The rat is eating, is very active. From yesturday I noticed his lower part is very tense, it keeps his legs straight and I cannot put them stay normaly. Also I think he has no control when he is urinating. I really care about it. Please can u tell me what can I do? Is there any cure? And if not how can I make his life better? Thank u !

Answer
Give him time to heal.  If he is eating, trying to groom himself etc... let him live. A rat in pain will not eat, will screech and squeal etc.....  do you live in the UK?   I once rescued a rat that fell four feet down and broke his back and was unable to walk. He also dragged his back legs around.   I kept him in a single story cage, kept everything low for him so he can reach it, helped groom him using a human babys hair brush on his fur and gently massaged his scalp so he did not have anything cake on his scalp if he was unable to reach back and groom himself.   Also, be sure to wipe his penis and his genital area a few times a day with soft wet cotton to keep him clean.  Can he lift his tail or is his tail limp too?    
Your rat could be on steroids for a few days to see if that helps.  I wont tell you NOT to allow your rats to ever ever be free outside since it seems you have found this out.  not only can they escape but I bet you never knew that a large bird of prey will easily swoop down and grab your rat and take off with it never to see your precious pet again?  They also have been known to swoop down after small dogs too.  Thats how they eat, of course, swooping down after small animals as food and if they see your rat out free, they wont care if your out too, they will swoop right down and grab that rat before you can even realize what is happening.
The reason I say the rat can live like this is because it is not unusal for rats to develop hind leg paralysis as they age and they stop using their hind legs altogether.  Rats can adjust to extreme conditions and have a remarkable will to survive.  The vet wanted to put the rat down feeling he may have no quality of life and may be unhappy, but if he is eating, going poop and pee daily and you are more than willing to help with his daily life chores such as grooming him and keeping him clean if he cant, he will have a happy life with you.  Oh the rat that I had with a broken back lived for 3 and a half years!