Man, that's sad to hear. I went though something similar, though clearly not as bad as your girlfriend. I'm just now starting to feel back to normal, and its been 8 months since the injury. Backs take a very, very, long time.
There are many physical things I could tell you that have helped me. Actually the Cool Tip of the day today is one of the best:
"Today's training tip comes from Dr. Ryan Smith:
Sitting causes an increase in disc pressure. With prolonged sitting without low back support, this increased pressure is coupled with sustained low back flexion. This results in further increased disc loading forces, which can lead to injury. So, try to stand up and move around every 20 to 30 minutes to reduce this "tissue creep."
Also, use a towel roll to support the lumbar curve. Just roll up a towel, secure it with rubber bands, and place it at your low back. Make sure your butt is far back in your chair too. "
In my experience, get her a very nice chair - a computer chair that can swivel around, and one with an adjustable seat. Grab a small pillow or a towel, sit her far back in the chair, and shove the pillow down around the lower back, giving nice support.
Sitting may suck, but when you're stuck at home for months and it hurts to walk, either you're sitting in a bad position and watching tv/on the computer....or lying down with nothing but your thoughts. A bad chair to sit in will reverse progress. Get a good one.
The first thing I do in the morning is sit in that chair for a few minutes and my back actually relaxes into a proper lumbar curve... when I get up to walk around, I'm ready to go!
Another important thing is MAKE SURE she tries ALL the time to keep good posture!!!! Check out the articles on this site called Neanderthal No More 1-2or3 for an anatomy lesson in good posture. Learn it inside out!
Sleeping can be hard... you may have to force her to stop trying to cuddle with you when she sleeps and get her to sleep with her legs elevated (i will try to explain this, but i suck) so that the angle at her knee joint is 90 degrees and the angle at her hip joint is 90 degrees. --|__o How's that for an awesome picture?
If that is uncomfortable, get her to sleep on her side in a similar position with a pillow between her knees to keep stability in her hips.
Also, do you have an amazing bed? When I had my injury, I did all these things but they didn't help too much, cause my bed was a kids bed made for 14 and under. I am a cheapass and never bothered to get a new one as beds are expensive. Well I eventually decided that my body was deservedly the most expensive thing I own, and bought a very nice new bed. My symptoms started going away very quickly.
Christian33's advice is great about the pool! Being in water (as you know) makes you feel weightless and takes a LOT of pressure off the spine. Get her to start swimming a lot. Maybe take some classes just for fun and something to do!
Yoga is incredible, although many positions are probably bad for her at this point. Stretch the HELL out of the hip flexors, hamstrings, and calves. I've read that people with her specific injury tend to have weakness in the achilles tendon and surrounding area, so watch out for stretching the calves too hard or far.
Another stretch that has helped me so much but impossible for me to explain is called the Pigeon stretch in yoga...
imagine sitting in a chair. Take your right leg over your left as if you were crossing your legs. Not woman crossing, but man crossing... with your right foot/ankle over your left knee. Keep the back STRAIGHT! Bend forward with the goal of touching your stomach to your right shin. You should feel this basically in your right asscheek or so. You COULD do this lying with your back on the ground and your legs in the air, but I found that version to aggravate my hip flexors.
The best version for me is the next one. Imagine doing something similar on the ground. This time you arent on your back but facing the ground, like in a pushup position. Your left leg is straight back and your right leg is at about a 30 degree or less angle so your knee is pointing straight ahead of you... it looks somewhat like an arrow (---> long part = left leg, arrowhead = right leg). When you bend forward your goal is to touch your stomach to your right knee. STRAIGHT BACK!
Make sense? Look it up if it doesnt, its a great stretch... so is the chair version. Also, if the chair version hurts, she can try to do it dynamically from standing... just swing one leg up at a time into that position.
As for exercises, anything that doesn't bend the back or put any pressure on the spine... DO THEM. The faster she gets active the faster she will heal. Get the blood flowing and nutrients into the area.
Check out bodyweight exercises and joint exercises from Pavel Tsatsouline. Superjoints, Naked Warrior, and Relax into Stretch will show you some good exercises to use, and also the ultra important techniques for increasing intra-abdominal pressure.
Get her to try Janda situps (they were designed with back rehab in mind), and One-Legged Deadlifts, One-Legged Squats, Lunges. Glute and ham strength should be improved if it is a weak link. STREGTHEN her core muscles! Read up on abdominal strength and its relation to back health.
As for mobility exercises, if she can handle it, try dynamic stretching of the hip flexors by swinging one leg at a time to the back... kind of like kicking someone behind you while facing forward. Again i suck at describing things, sorry.
Obviously, if any of these exercises hurt (and I am talking about with good form) then don't do them! Just get her to do SOMETHING that gets the blood moving.
Also, what does she eat? Throw out all the garbage in the house, buy meat, vegetables, fruit. Eat food. Repeat. Eating a good diet will help the healing process along very much, and many foods have anti-inflammitory effects. Get her on FLAMEOUT, or at least GNC fish oil pills. I hope that you are knowledgable about nutrition, if not, read everything by Lowery and Berardi a few times.
Better yet, read it with your girlfriend.
Drug-wise... and I hate drugs... Celebrex seems to be the drug of choice for healing inflammation. Ask your doctor about it. Other than that, I don't know much about drugs. As I hate them!
moonjumper's hanging decompression exercises... they sound promising! I will try those out myself as well!
But I will tell you, all this stuff means nothing IF she is depressed and has no hope. You sound like a good man, sticking around for 3 years with almost no sex! Hahaha... but seriously, you probably already do this, but make her feel USEFUL!
When you cant work, have no income, cant have sex, cant go anywhere, cant do the things you are passionate about... for over a YEAR... you feel like "what the fuck is the FUCKING point?" Know what I mean? It sounds like your girlfriend sure does.
You need to get her MOTIVATED as hell to get this over with. The only way that can happen is if she knows she can BEAT IT. She can! Show her examples of people who have had horrible back problems and returned stronger than ever.
A few examples are the people responding to this thread, Frank Shamrock (frankshamrock.com), Bruce Lee (you better know him!).... actually while I'm talking about Bruce, rent the movie Dragon: The Bruce Lee story. A big part of it is (although exaggerated) the story of him almost being paralyzed and his wife forcing him to stop being a bitch and fight through it.
Rent movies that show people coming back from bad injuries, ANYTHING to light the proverbial fire under her ass and make her determined to beat this fucking back problem!
After that it will be your job to slow her down!
A long read yes, but I feel her pain... seems to be a common feeling here! Hopefully there is something in my post that will help. I wish her and you the best of luck!