Joeky Senders

58 Chapter 3 Discussion VTE is one of the most common major complications and reasons for readmission, and ICH the most common reason for reoperation among patients undergoing craniotomy for a primary malignant brain tumor. This multicenter study provides novel and useful information regarding the timing of these events and identification of high-risk patients. The increased risk of VTE extends beyond the period of hospitalization, especially for PE, whereas ICH occurs predominantly within the first days after surgery. The VTE risk profile depends on the type of VTE (DVT versus PE events) and the clinical setting (during hospitalization versus after discharge). The patient population in this study was technically classified as those with a primary malignant brain tumor based on ICD-9 codes. Gliomas represent close to 80% of primary malignant brain tumors, 39 however, there is no standard ICD-9 code specific for glioma. The Central Brain Tumor Registry of the United States (CBTRUS) argues that multiple combinations of ICD histology codes can be used to define gliomas, and their approach was modeled in this study. 39 Therefore, these results are primarily applicable to glioma patients and should be put in the context of previous outcome research on glioma patients. Prior work Rolston et al. confirmed that the prevalence of VTE following a neurosurgical procedure as registered by the NSQIP registry has remained consistent over the last years. 53 This suggests that perioperative management has not improved effectively with regards to preventing VTE, despite the attention it receives in the neurosurgical literature. Several multicenter studies have previously investigated the short-term incidence of and risk factors for VTE after brain tumor surgery, 3,13,40-46 of which four studies focused on glioma patients. 3,13,40,42 From these studies, the rate of VTE following craniotomy is cited as 3.3-7.5% for glioma patients 3,13,40,42 and 2.3-4.0% for brain tumors patients in general, 41-43,45,47 with a follow-up ranging from solely the initial hospital stay to six weeks after surgery. The 30-day VTE rate was as high as 9.3% when asymptomatic DVTs were included as well. 3 These results are comparable to the VTE rates found in the current study and suggest a higher rate of VTE in glioma patients postoperatively compared to other brain tumors. Simanek et al. assessed the cumulative incidence of VTE over time after craniotomy for gliomas, demonstrating a major increase in the number of events in the first three