I would think anaerobic endurance lifting would be useful. Will your back let you do slow-squats and slow-dead lifts? If it will, pick a weight that you grit your teeth on, lifting to the count of 8-10 seconds up, 8-10 seconds down, no more than 6-10 reps per set, but many sets with little active rest in between (less than thirty seconds, maybe some jumping jacks or mountain climber calisthenics in between). I use this style to work on building burn, and pushing through it.
The slow lifting should also hit your arms, but for pushing, pending back, snag an exercise ball. Grab it like your doing a pushup, hands 3/4 the way to the sides, and hold a pushup mid-way for 60 seconds. My best is 45 seconds. I always like kettlebells too, but would keep it light if your back is nasty.
Hope my ideas were useful.