Epidural didn't work. Will a spinal?

Hi

I am currently pregnant with my second and will be having an elective section due to a traumatic birth with my first. I had an epidural with first but it kept wearing off and so it had to be manually topped up by the on call anaesthetist. Obviously this wasn't always possible if they had been called into theatre. I was also left with a spinal headache and ended up in theatre for a blood patch. 

My worry is since I have had a previous bad experience with an epidural am I likely to experience the same thing with a spinal for a section? And has anyone experienced a spinal wearing off? Can that happen? If so what do they do?

Thanks