Re: 2 surgeries L4-L5 blown disk again
Those are good questions to ask your spine surgeon. I couldn't venture a guess. It would depend on the size of the bulge, whether there is associated stenosis, the extent of nerve compression that the bulge might be causing, etc.
A fusion would only be recommended if the discectomy is creating instability at that segment.
Regarding ADR, it might be possible, but it would depend on how much has been trimmed away with your two preceeding surgeries. I guess there are a couple places that will do a two level ADR in the US, but it is not commonly done, and insurance carriers are getting balky about covering ADR. You would need to determine these things for the area in which you live.