Old hardware removal with new fusion above in same surgery

I had an L4-5 fusion 11 years ago and the hardware hasn't given me any problems. I now am preparing for another fusion at L3-4. My surgeon is planning to take out my old hardware, then fuse the new area one level above. I do still have lower back pain and only got temp relief after the first surgery for 2 years. My most recent issue though is my left leg goes completely numb after standing only a few minutes. This has caused me to fall. I was an RN and so know all the complications of this surgery and don't think I want the old hardware taken out. I have osteopenia. I also don't want the extra anesthesia time and added complications that can occur. What do you think?