Yes, and under the right circumstances, it can work great. It's important to get a good certified myofascial triggerpoint therapist - not just a PT who thinks they know what they're doing. The right training and experience make all the difference. Of course I can't make any promises; I'm not a doctor, and I don't know your particulars, but if your symptoms are caused by the piriformis muscle being in spasm, myofascial release may release that spasm and ease the pressure on the nerves. It may work for a long time, or temporarily (a few days) but the therapist should be able to show you how to help yourself if/when it happens again. It will hurt like cuss when they're doing it, and be sore afterward, and it will involve some stretching, but if it works (and IMO it's definitely worth a try) it'll be worth it.

http://www.myofascialtherapy.org/

Doc