I would suggest the same as Kimi: Get your hospital records. Read them over write up a list of questions to ask your neurologist. His/her saying that your LP was "relatively normal" doesn't say much. Get the LP results and bring them to the forum if you are comfortable and we can help you with your questions.
In the meantime, look around for another doctor that you can get another opinion from. Second opinions are important especially if you continue to have symptoms and no clear reason or diagnosis. You don't need to wait for it to happen again.
Take care of the other surgery that needs to be done, while you are still looking for an eplanation for what is happening with your legs.
Take care and please let us know if we can help you.
Did you ask what relatively normal ment? I would get a copy of the results to keep at home and probably get a second opinion depending on what the results were. I have a problem when Dr.'s speak in code. Hang in there, you are going to have to be your own advocate and be assertive to get answers. ~K