Department of ENT,Sikkim Manipal Institute of Medical Sciences,Sikkim Manipal University,Gangtok,India. Department of ENT,Sri Rama Chandra Medical College,Chennai,India. Department of ENT,Mon District Hospital,Nagaland,India. Department of ENT,Regional Institute of Medical Sciences,Imphal,India. Department of ENT,Jawaharlal Nehru Institute of Medical Sciences,Imphal,India. Department of Immunohaematology and Blood Transfusion,Regional Institute of Medical Sciences,Imphal,India.