ObesityHelp

Were you trying with Care-credit?  Not familiar with what is required for Mexico.

Is your bankruptcy fully discharged or are you still paying creditors?  You should be able to get it through some legit finance companies.  You are actually "less risk" because there are limitations on how often you can declare bankruptcy.  With a co-signer, you should be able to do it as well.  You may need to contact them directly and ask them to manually underwrite it.  

Your bigger problem is that any legit (or not so legit) finance companies will try and gouge you.  High interest rates with potentially other fees as well and likely no opportunity to for "interest free" periods or special offers that they offer to prime credit borrowers.   A co-signer won't help you with this.

The only way to not be treated as sub-prime is to have somebody take the loan out on your behalf.

 
I don't think employers will let you cash-out an active 401k.  You may be able to take a 401K loan depending on whether your employer has them available.  There are limits, like 50% and/or a specific dollar amount. There are some tax implications and other gotchas with this, so I suggest you do some research.  

It helps to contact those loan companies, banks, etc.  If you're bankruptcy has been discharged for a bit, you'll probably be able to get financed. I recognize the importance of the surgery, but be careful not to put yourself into a worse position while you are trying to heal.  Some of these loans could be as high as 30% interest with all kinds of fees.  Not telling you not to do it, but be careful not to over extend yourself.