Regional intensity of neurosurgical care and integration of aneurysm coiling in the United States

Aim: There is wide regional variability in the volume of procedures performed for similar surgical patients throughout the United States. We investigated the association of the intensity of neurosurgical care with the diffusion of the novel technology of cerebral aneurysm coiling. Methods: We performed a retrospective cohort study involving patients who underwent any neurosurgical procedure from 2005-2010 and were registered in the National Inpatient Sample (NIS) database. A sub-cohort of patients undergoing aneurysm clipping or coiling was also created. Regression techniques were used to investigate the association of the average risk-adjusted intensity of neurosurgical care with the average rate of coiling. Results: There were significant disparities in the rate of coiling among several states (ANOVA, P<0.0001). It ranged from 0.24 in Maryland, where clipping was very predominant, to 0.82 in Minnesota, where coiling was the main treatment modality used. In multivariate analysis, higher coiling rate was associated with increased age, higher income, rural hospital location, and small institution size. The Midwest was association with higher rate in comparison to the Northeast, whereas the West and the South had even lower rates. Increasing rate of coiling was associated with increasing intensity of neurosurgical care. There was a positive correlation of the average risk-adjusted intensity of neurosurgical care with the average rate of coiling per state (Pearson's p=0.43, P<0.001). Conclusion: We observed significant disparities in the rate of coiling in the United States. Increased intensity of neurosurgical care was positively associated with the integration of coiling in treatment of cerebral aneurysms.