http://www.naturaljointmobility.info/lowback.pdf
Not sure if this would fix the original poster's maybe rarer problem, but might help people who have the more common condition of lower back pain.
This talks about using exercises in a book called 'Treat your own back' by Robin Mckenzie to fix lower back problems.
After years of worsening pain I found the exercises in Mckenzie's book have removed all my pain.
Have a read, it might help!
I simply found out about the book by surfing the net and reading the reviews on amazon. And honestly it has fixed my problem and a couple of my friends.
P.S. My MRI scan showed two prolapsed discs before I started the exercises.