Take a garden hose with a leak in it. Fix the leak, and it could leak elsewhere along the hose.
My aorta blew out to 6.5cm and was replaced from the point of the graft to my heart up to the top of the aortic arch. For me there would only be one side where I could get another anuerysm since the other side of the repair is actually at my heart.
For you the surgeon could be saying they might remove the aneurysm and later another aneurysm could develop elsewhere on either side of that repair.
FYI my descending aortic dissection is managed to prevent anuerysms through medication. Should I develop another aneurysm then the remedy for me would be surgical intervention ie another surgery. Perhaps you also have medication to prevent or control any possible aneurysms?
Ask your surgeon for clarification.