Beekeeping is difficult with a bad back and can often cause a bad back.  Many
people and books recommend holding the smoker between the knees when working a
colony.  This may be convenient as you always know where to find it but it
reduces mobility and the ability to use the legs to their best advantage to do
most of the work in lifting heavy things and leaving more effort for the back
which isn't designed for the job.  Screw a coat hook to the back of the smoker
and hang it on the edge of a super or the belt or pocket.
You are working vertically, lifting supers up and lowering them.  Think
laterally.  Make a long hive, either with frames or a top bar hives.  Put it
on a stand to suit your height and you won't have to bend your back or lift
anything heavier than a frame of honey.  I hope this helps.
Chris Slade