My recent ct shows a pedicle screw has come loose entering the disc space between l4 and l5. how urgent is it that i have this corrected?

Below: It is impossible to give you an accurate answer without further information. Your question should be addressed to your DR who has all the information, and the xray results.

Depends on you: If you do not have any symptoms from this, there is no need for surgery. However, it would be hard to determine whether you are hurting from this because of your 5 spine surgeries and you likely have chronic pain syndrome. I am more concerned that the screw loosening is from failure to fuse. Thus can cause pain. You then should have revision surgery sooner than later.