What is the safest treatment of a slipped disc. spine operation? ozone? yoga or acupressure?

It really depends on exactly what is wrong with your disc. Many people think they have a "slipped" disc and they don't. You need a MRI if you haven't had one yet.
Yoga can be good, but some poses can make the problem worse, so you need to find out the extent of the disc problem (is it a bulge, a herniation or an extrusion?)
Most people with even mild to moderate disc problems do not end up with back surgery, even after they see an orthopedic or neurosurgeon... good surgeons will tell you to exercise, go to physical therapy or try chiropractic first, and then if it doesn't get better, to come back & see them.

I see many non-surgical back pain patients & get a lot of referrals from the doctors in my city.
Go get a good evaluation of your back by a reputable chiropractor- find one who works well with other physicians.
I refer out when I need to, be it to physical therapy, orthopedist, neurologist, etc...
good luck.

i would consult my physican but i bet the doc will recommend surgery if it is bad
Yoga would be a high choose for me

Avoid surgery at all cost. Only appropriate if you are losing strength in your leg or are losing controls of bladder or bowels. 50% of backsurgery patients get worse or absolutely no better from surgery.

Acupuncturte will not replace or reduce the disc's pressure on spinal nerves.

See a Chiropractor trained in decompression therapy. Regardless of your MD'sd bias, results are encouraging with a much lower incidence of complication.

I know people that were unschooled about what Chiropractors are capable correcting being pleasantly suprised.

A chiropractor would be my first stop. They don't like surgery, and will work with you to avoid it. They manipulate your spine...it makes noise, but it doesn't really hurt. You'll need to see one frequently for a few weeks, tapering off as you heal.

Massage Therapy. I would not suggest doing yoga. With yoga, there is alot of stretching involved and I would hate for something to pop out on you or make something worse than what it is. I do not recommend Chiropractors either. Acupressure may be good.