You won't be discounted for surgery if you are a smoker. They really don't care. Obviously if you were having surgery to correct something in your thorax or general respiratory system, they would probably advise you quit because you need surgery to correct it.. but they won't refuse an elective surgery on the basis of smoking. Your GP probably hates smokers and is intimidating you.

I don't think it would be a good idea to get coverage for a surgery and then drop it. Especially for spinal surgery -- it carries risks and you may have to do physical therapy afterwards.

Are you eligible for insurance/medicaid?