A plastic surgeon that specializes in belly button revision/umbilicoplasty?

I want to find a doctor that specializes in belly button revisions. My outie belly button is sagging after four children. I have a very minimal amount of loose skin above my belly button. I plastic surgeon examined me and recommended an umbilicoplasty. Do all plastic surgeons specialize in umbilicoplasties since they do a lot of work in the midriff area? If not, what do I ask/look for in a plastic surgeon to find the best surgeon possible for this procedure?