Hi! My Patterdale terrier (a little tasmanian devil) has chronic spinal pain, we think. She ruptured a disc at 4 which was operated on by the famous Irish vet, and she seemed fine for years although she was always cranky.
But chronic pain (IVDD) was the diagnosis of the 6th behaviourist I'd called upon for advice on her reactivity, a clinical vet behaviourist at Bristol University (Langham?) - they said her predatory aggression and explosive temper was caused by being in permanent pain, and that she she should go on a pain management program.
So she started on long term gabapentin and tramadol 4 years ago. Since then we've introduced amitriptyline and stopped the tramadol (I prefer to be able to fall back on it on her bad days); and we've experimented with a ketamine based one which I forget the name of, and most recently Pardale-V. Unfortunately she is unable to take the usual anti-inflammatories, they make her very poorly.
But she's almost 12, and seems permanently morose and grumpy. I can't tell if the meds are really helping her. She has tremors from nerve damage, some days worse than others, and although she doesn't have any serious deficits she is definitely weak in her hind legs and has poor proprioception at times. The muscles over her spine are rigid, I try to massage them and use heat packs but she just goes for me. She can only go for 20 mins walk a day, otherwise she loses coordination, falls over her feet and gets very tired. But she does enjoy her walks and it's one of the times she seems happy - she does still instigate a game every evening, although her preferred game is to attack us all and bark her head off. 
I think a grouchy temperament is common in these working terriers (she did work, before her accident), but she isn't a waggy, happy dog. She shakes and looks pained, ferociously and obsessively licks her feet, and snarls if you touch her hind legs or feet.
She recently had another course of steroids when the pain was bad, and in those 3 weeks her body was soft and relaxed, she wagged her tail more and she seemed brighter, and less snappy about her back end.
But the vet says there is "no indication that she should stay on steroids for the long term".
I know it's not ideal, but she's 12 - I'd rather she had one more year in less pain on steroids, which might trigger organ failure, than 3 more years with functioning organs but suffering in pain? When do we know she's had enough? I'll be heartbroken when she goes of course (I'll be THAT client sobbing), but I hate the idea of her suffering unnecessarily.
Our vet is brilliant, but I'm sure he gets sick of me.