The global diffusion of neurosurgery through academic mentorship chains

BACKGROUND: Neurosurgery emerged as a distinct clinical discipline in the early twentieth century, yet the mechanism by which this highly specialised craft spread across continents remains incompletely characterised. OBJECTIVE: To construct the first multi-continent academic genealogy of neurosurgery, mapping the diffusion from its founding centres, and the role of mentorship, war, and geography. METHODS: We conducted a systematic review of historical neurosurgical literature, supplemented by biographical records, departmental histories, and society archives. For each country, we identified the first trained neurosurgeon, their training lineage, and the year of the first dedicated department. Mentor-trainee relationships were mapped using the Academic Family Tree framework. RESULTS: We identified founding neurosurgeons across 33 countries. Most pre-1960 programmes traced within two or three generations to four hubs: Harvey Cushing in Boston, Herbert Olivecrona in Stockholm, Hugh Cairns in Oxford, and Norman Dott in Edinburgh. Japan represents an independent tradition shaped by German surgical literature and wartime experience. Sub-Saharan African founding neurosurgeons followed a distinct postcolonial pathway outside this genealogy. CONCLUSIONS: Neurological surgery spread globally through person-to-person mentorship rather than textbooks, conferences, or formal policy. World War I catalysed this process through cross-national surgical collaboration, underpinning international training programmes established after 1919. These findings inform contemporary surgical capacity-building in developing countries.