The effect of centralization of caseload for primary brain tumor surgeries: Trends from 2001-2007

Background Improved patient outcomes have been associated with high-caseload hospitals for a multitude of conditions. This study analyzed adult patients undergoing surgical resection or biopsy of primary brain tumors. The aim of this study is two-fold: (1) to evaluate whether the trend towards centralization of primary brain tumor care in the US has continued during the period of between 2001 and 2007, and (2) to analyze volume-outcome effects. Methods Surgical volume trends of adults undergoing resection/ biopsy of primary supratentorial brain tumors were analyzed using the Nationwide Inpatient Sample. High- and low-caseload hospitals were defined as those performing in the highest and lowest quintile of procedures, respectively. Length of stay (LOS), mortality and discharge disposition were the main outcomes of interest. Results NIS estimated 124,171 patients underwent resection/ biopsy of primary supratentorial brain tumors between 2001 and 2007 in the US. The average number of annual resections in the highest 2 % and lowest 25 % caseload hospitals were 322 and 12 cases, respectively. Surgeries in high-caseload hospitals increased by 137 %, while those in low-caseload centers declined by 16.0 %. Overall, mortality decreased 35 %, with a reduction of 45 % in high- (from 2.2 % to 1.2 %) and 19 % in low- (from 3.2 % to 2.6 %) caseload hospitals. High-caseload centers had lower LOS than hospitals with lower caseload centers (6.4 vs. 8.0 days, p<0.001). Multivariate analysis showed that patients treated in low-volume hospitals had an increased risk of death (OR 1.8, CI: 1.2-2.7, p=0.006) and adverse discharge (OR 1.4, CI: 1.1-1.7, p=0.01). Conclusions Neurosurgical caseload at the nation's high volume craniotomy centers has continued to rise disproportionately, while low-caseload centers have seen a decrease in overall surgical volume. Over the time period between 2001 and 2007 there was a trend towards improved in-hospital mortality, LOS and discharge disposition for all hospitals; however, the trend is convincingly favorable for high-caseload hospitals.