Lumbar Muscle Atrophy

A few years ago a specialist Spinal MRI showed my lumbar muscles had died and been replaced by a fibrus fatty tissue.

The specialist said there was nothing that I could do about it as they don't know why it happens.

So revisiting this problem and enquiring about exercises/weights that target my lumbar region, to see if I can build up some muscles there.

I included a pix of my lumbar region and don't know how you can tell (by looking at it) that the muscles have died.

I have had several lumbar operations and thought that they could be the reason my muscles died from the cuts, but these operations were 35 years ago.

I have periferal nerve damage in my legs which causes 24/7 pain, but scans show no senosis.

So it seems to me that walking is like climbing Mt Everest as using all other muscles to compensate for lumbar muscles not working. I use walking poles which really helps.

Any ideas on reactivating lumbar muscles?