Hanania subsequently became House Surgeon and Surgical Registrar at the Royal Northern Hospital in London from 1959-1961. He specialized in cardiovascular surgery and became a Fellow of the Royal College of Surgeons of England in 1961 (F.R.C.S.), the American College of Surgeons in 1971 (F.A.C.S.), the American College of Cardiology in 1977 (F.A.C.C.), the International College of Angiology in 1979 (F.I.C.A.) and the Royal Society of Medicine in 1980. He also became an Honorary Fellow of the Royal College of Surgeons in Ireland in 1980 (Hon. F.R.C.S.I.), the Royal College of Physicians and Surgeons of Glasgow in 1988 (Hon. F.R.C.S. Glasg) and the Royal College of Surgeons of Edinburgh in 1989.