1258 Most Roads Lead to Cushing: A Network Analysis Of Neurosurgical Training Lineages

INTRODUCTION: The mentorship and training relationships within the field of neurosurgery are pivotal in shaping the careers and influence of neurosurgeons. Understanding these relationships through network analysis can reveal key individuals and structural characteristics that drive the field's development. METHODS: A combined multi-directed and undirected network graph comprising neurosurgical training relationships was constructed, including edges between chair and trainee, program director and trainee, and peers from the same residency graduating within 5 years of one another. Graph level metrics were calculated and communities were detected via modularity maximization. Centrality metrics were calculated for a undirected subgraph of neurosurgical department chairs. RESULTS: The neurosurgical training network consisted of 8443 nodes and 259,445 edges, with a density of 0.0036, average degree of 61.5, 338 weakly connected components and 530 strongly connected components. We detected 394 communities (mean size 21.4 ± 59.9 members), with the 30 largest having 209.9 ± 69.1 members. Most of the members from the largest communities were from the same residency (60.28% ± 21.16). Harvey Cushing was dominant in closeness, betweenness and local-reaching centrality, highlighting his role as the quintessential neurosurgeon-influencer. Wilder Penfield had the top PageRank, demonstrating the breadth of his direct connections with other influential individuals. CONCLUSIONS: Our analysis reveals a sparse but highly connected network, typical of large real-world professional networks. This indicates that while there are many small groups of neurosurgeons who are closely interconnected, each is connected to a small fraction of the total. This suggests most neurosurgeons may not interact outside their immediate training hierarchy or peer group. The central positions and high influence of various chairmen suggest they have been pivotal in mentoring and connecting many neurosurgeons, contributing to the network's overall structure and dynamics. Future analyses will seek insights into the present-day importance of other key figures in neurosurgery.