I am concerned about a surgery that was suggested to me recently. Disagnosted with L5-S1 spondylolysthesis. The procedure is posterior spinal fusion L5-S1 + TLIF and bone graft. I have never been operated on before in my life. I am 55 years old female in good heath. No colestherol, diabedis etc. What are the risks and the succes of this surgery ? I am in constant pain. Tried almoste everything, Chiropractor 4 years, injections etc..