Dale, that is a really tough time you are having right now. It seems like you might be having more symptoms than just pudendal related issues -- with your leg giving out from under you, but not much showing up on the MRI. You might ask your docs if they definitively ruled out cauda equina syndrome and arachnoiditis.
Not sure what type of neuromodulation your physician is recommending -- sacral or direct pudendal nerve. Some people have gotten some relief from neuromodulation, but I think it's important to research the different options available. There are different approaches for having the leads implanted. Remember that if you have the neuromodulation leads implanted, you will not be able to have MRI's afterwards. So you may want to make sure you get the 3TMRI with the best resolution of all areas of the pelvis and spine and have cauda equina and arachnoiditis ruled out, before going the neurostimulator route.
You may also want to ask how they are going to administer the Botox if you try it -- whether it would be given into the bladder or into the pelvic floor muscles. I know a guy with some symptoms similar to yours who had Botox into the bladder and it just made things worse. Botox into the pelvic floor muscles might be worth a try if your pelvic floor muscles are in spasm. One way to find out if this could be effective would be to have injections of bupivocaine into the muscles first to see if that brings relief. This is a relatively inexpensive short acting drug with not many side effects. If it is effective in relieving your pain, then there is a good chance that Botox into those muscles would help. You could read more about this in Dr. Noor Gajraj's article on Botox. Keep in mind that Botox relaxes the muscle and can actually have the side effect of causing incontinence but it sounds like since you are already having incontinence, the overriding factor right now would be to relieve the pain and spasms. Botox typically only lasts a few months but when you are in a lot of pain, a few months of relief is worth it.
The fact that you are having unwanted erections when lying down (meaning the problem is positional) makes you wonder whether there is some sort of nerve entrapment. If you have unwanted sexual arousal with these erections, that is a condition called persistent genital arousal disorder (PGAD). You can read more about it here.
http://www.pudendalhope.info/sites/defa ... ne2013.pdf My PGAD was worse when lying down.
Keep your courage up and remember that eventually most people find some type of therapy that brings relief and allows them to enjoy life again.
Take care,
Violet
PNE since 2002. Started from weightlifting. PNE surgery from Dr. Bautrant, Oct 2004. Pain now is usually a 0 and I can sit for hours on certain chairs. No longer take medication for PNE. Can work full time and do "The Firm" exercise program. 99% cured from PGAD. PNE surgery was right for me but it might not be for you. Do your research.