Hi. I Had A Severe Case Of Sciatica Five Years

Hi. I had a severe case of sciatica five years ago. It took me a year to recover to the point that I could stand up straight! In recent months, I've noticed sciatic pain returning, although not NEARLY as severe as five years ago. But I can't lay on my back for long, can't sit for long, without pain beginning in the lower part of my back and radiating down my left buttock and down my leg to my foot. Are there exercises that can, if not cure, minimize sciatica's recurrence?