I've had 3 lumbar spine surgeries to try to fix the source of spasm and pain since I was 16 years old.  I am currently 53.  My first fusion in 2013 was an L4-S1 with the large screws and rods.  A 2nd fusion in 2015 to fuse L2-L4.  And the final surgery in 2017 was to remove the hardware from the first surgery.  Also during that 2017 surgery, I was flipped over and given a C5-C7 fusion.  I never had pain coming from the neck, only numbness.  The spasms in the lumbar have been mostly corrected, however, the pain never went away.  Thus I ended up at a high of 408 mme per day, comprised of 120 mg / day Oxycodone (1.5 mme factor), 72 mg Extampza (1.5 mme factor), and 30 mg/day methadone (4 mme factor).  Getting rid of the Extampza was super easy with no withdrawal - I'm guessing because of the narcan within the capsule.  Getting rid of methadone caused migraines for about 6 months, but I haven't taken methadone since January.  After losing job in May of this year, and a gall bladder surgery in July of this year, I am left with no energy, no ability to generate endorphins, and no getting ahead of the pain at this dose level.  I need this crap out of my system and I really need the concept of hypersensitivity to pain to be accurate.