How to find "empty" buffer?

So I have lines(road network) and buffers around them. I need to find "empty bufers" whose lines is missing (pic below). Lines have attributes of buffer width, but it is incorect in some cases (dooes not match with actual buffer with). So creating/erasing with new polygons is not an option, since it will leave alot of trash polygons. Buffers is also dissolved in most cases.