As andym says, I did loads of swiss ball work to rehab my back. I was in a rigid plastic corset for 12 weeks while my back healed and by the end of that my core was shot.
Could recommend particular swiss ball exercises, but basically all of them are good! You can get one for home for pretty cheap (<£30) and there’s loads of exercise programs on the web for using them.
Any “normal” exercise (sit-ups, press-ups) becomes much, much harder when done on the ball, so be prepared to be humiliated at first!
My accident happened in July and my final visit to the specialist (neurologist) was just before Christmas. From previous sessions, I knew the types of range-of-movement tests he used to assess me, so I trained quite specifically towards those tests so that he would pass me fit to snowboard that winter! Got away for a trip over New Year and there was good powder. Bouncing up and down through powder turns hurt like hell, but I was loving every minute of it!