Often some countries are better at a particular surgery as the medical expertise is concentrated for that treatment. Many Third world countries have knowledge resources of diseases, which are seldom heard, in developed nations. Thus the expertise of dealing with such a disease is more and better.
For example, diseases related to mosquitoes, their identification, treatment as well as research is an expertise, which African countries boast of due to the Tropical weather. Instance of such a disease might take a long time to be diagnosed and treated in countries having extreme climates.
Medical Tourism is also another way to tap the medical expertise of a particular country.
Many patients from underdeveloped countries like Bangladesh, Nepal, etc also travel to other countries for Medical care.