I have been using a night splint since October (5 months). I noticed almost immediate improvement, and am now almost afraid to go to bed without it for fear of what my foot will feel like in the morning. It's not the most comfortable thing, but I have gotten used to it - sort of. There is an alternatvie called the Strassburg Sock - it holds your foot in the same dorsiflexed position as the splint, and is reported to be more comfortable. I believe there is a link to more info about the sock on this Web Site.
You should definitely get a second opinion (from an orthopedic MD) before having any surgery. DPM's can help you, but they are often too quick to recommend surgery. Anyone on this site will tell you that cortisone shots and surgery are measures of last resort.
I assume you are doing all the "things" you need to do to care for your PF - not going barefoot, wearing good shoes that support your arches, wearing good socks that work with your shoe as a system, stretching, icing occasionally, exercising aerobically in ways that minimize the stress on your feet, etc. [You ARE doing these things, right?]
I have heard that using a cast is one of the most successful methods of treating severe cases of PF. I hope it will work for you. Just keep in mind that what works for some does not necessarily work for everyone. PF is very much an enigma in that respect.
I would encourage you to read the posts and the other info on this Web Site - there is a wealth of good information. It can help you with regard to your recovery and your expectations for PF.
Wishing you a steady and surgery-free recovery,