There was a topic about this that was closed but I have some new info that may help someone in the future.
I had some minor issues with emptying my bladder, after having a nerve trapped due to L5-S1. Basically it was a bit of trouble getting going, like the muscles "down there" were all tensed up. Since having the ALIF surgery two weeks ago, my bladder has been well and truly active [three to five times a night] and there are no problems with getting things going any more. I'm not dehydrated or anything as I do keep the fluids going to prevent blocking up from the Targin/Endone. So it looks like a success, though I hope the nerves get back to feeling normal soon as I am suffering some sleep deprivation from the constant getting up all night. Am speaking to my GP on Friday so if he has any suggestions about this I will let you guys know.