Jim mentioned recently he had a slip disk which was why the book stalled. Hoping it picks up now?
That is a real sucky injury, though at least it wasn't something life threatening. I've had it happen to me. As long as you don't require surgery it can be dealt with, with good long-term recovery possible, even though potential for further injury always remains.
Until the injury is dealt with, the pain can be very distracting and pain killers can dull any writer's ability to get work done. I required cortisone injections and I lost considerable weight after that to reduce the chance of reinjuring myself. My doctor tried other therapies before the cortisone injections, so I can understand how this situation has cost Jim a fair amount of work time.
In my case, this injury occurred over fifteen years ago and I haven't had any pain since then.
Good luck Jim!