Should I Consider Disc Fusion Surgery While Having Degenerating Disc L4-L5 And Limited Mobility Despite Treatment?

Dr , I had Collapse disc l4-l5 age 80 . From last one year ,Stiffness and limited movement, casually jerk pain , as mri show degenerating change , but no numbness or severe pain. doctors are tried physiotherapy, spine injection , medicine but no relief . I can pull on in home but unable to walk , stand , sit for 5- 10 min . Dr told cure is disc fission, but hesitate to do due to age 80 , Dr pl advice , should I take risk of disc fussion . At this age or should pull on ?