The nerosurgeon suggested need coflex spacers put in my back between l3-4 & l4-5. it is minimally invasive back surgery. i am 84 yrs old & at my age do i need these two metals in my back as i i am concerned it won't heal?

Those are spacers which were inserted with minimally invasive technique and there is no relationship with bone healing in recovery. If you suffer too much with nerve pain, it should be done. However, if pain can be controlled with med and physical therapy, i.e. tolerable, you can opt out the surgery. Although the procedure is minimally invasive, the risk is still there at your age. Good luck.