How do I work my core after back surgery?

Pilates. I favor pilates over crunches swiss ball waterwork no leg lifts.
Compliance. Just make sure you are compliant with your surgeons recommendations. Once you are given the go ahead, you can either begin on your own or with a physical therapist. .
Depends on . Depends on the type of surgery and where you are postop in terms of time from surgery and whether tissues healed including if a fusion. However, isometric exercises can be started early and learned from a physical therapist but rehabilitation and activity should be guided by your surgeon.