What are the common side effects of reducing Prednisolone streroids gradually? I?

Sorry to hear of your inevitable and clical steroid side side effects. Very slow reduction should have few side effects. The biggest risk is infections failing to stimulate an adequate immune response as your adrenals will have stopped producing endogenous steroid. I am sure that you have a steroid card that warns you of the risks. Hope your surgery goes well and solves your problem.