If a bike has clip ons, can you mod to normal bars??

[Punkstig]

Without looking Genmar are one of very few companies that do clip on risers, you're looking at around £100, had a set on my T'cat, they only rose by 25mm but was a help.

It sounds like your back issue is long term so would it be worth investing in some gilles variobars?
Ok, not cheap but they would last a lifetime, unlimited adjustability and you can buy the correct size clamp for different sized fork tubes separately!