One thing to consider with a bad back is how well you can carry the additional weight.
I am fused from T7-T11 after a helicopter assisted burst fracture at T9 in 1990. I still get massive pain from doing things like ironing and doing dishes. I also can't simply stand for long periods of time.
That said, I shoot weddings that involve many hours of standing, walking, moving and generally getting up and down. Somehow this is ok, though I still hurt like crazy at the end of the day. I can only do this because my camera bag goes around my waist with no load on my shoulders.
Back when I was doing the initial recovery from the crash, I used a cane quite frequently. While I never received any formal training with it, I do recognize that it can be a very effective weapon. I did consider buying one that had a sword hidden inside. Unfortunately the state I was in at the time would have really frowned severely on it if discovered... and I was often flying commercial and didn't want to potentially lose it before boarding a flight (such an item certainly would not be allowed today).
Ya know a small carbine might be appropriate in certain situations.
Best of luck to you!