Structural connectivity in children after total corpus callosotomy

Objectives: To investigate structural connectivity after total callosotomy. Methods: Deterministic fiber tracking (tractography) of whole brain white matter was performed on 13 epilepsy patients pre- and post-callosotomy. The analysis of structural connectivity was based on graph theory and network-based analysis with a focus on the inter- and intrahemispheric networks. Clinical demographic data including seizure patterns and outcomes were scored for the identification of correlations. Results: After total callosotomy, structural interhemispheric networks were significantly interrupted. Specific changes were observed in the structural intrahemispheric networks in both hemispheres: 3 edges presented with significant decreases in the left hemisphere, whereas 2 edges presented with significant decreases in the right hemisphere. No global changes were observed in the network density, average weighted strength, average characteristic path length, or global efficiency of intrahemispheric networks. The intrahemispheric hubs and nodal efficiency were minimal changed after callosotomy. Conclusion: While there was a significant decrease in structural interhemispheric connectivity post-callosotomy, we observed synchronously decremented changes of intrahemispheric edges in each hemisphere. This study suggests that white matter maintains the structural connectivity intrahemispherically although functional connectivity recovered after total callosotomy.