Joeky Senders

38 Chapter 2 Implications Possible reasons for poorer prognosis in elderly patients with primary malignant brain tumors likely include medical comorbidities and a lower overall fitness level. 34,35 Increased BMI also corresponds to a lower overall fitness level and has been demonstrated to be a risk factor of postoperative morbidity and mortality in other surgical specialties too. 36 ASA-classification is based on comorbidity of patients before surgery. 37 Although the relationship between comorbidity and postoperative complications is intuitive, the current study validates ASA-classification as a meaningful way to risk stratify glioma patients before surgery. Both ASA class III and ASA class IV-V were predictive for almost all outcome measures. An incremental association between ASA classification and postoperative unfavorable outcomes is suggested because the odds ratios were generally higher for ASA class IV-V compared to ASA class III. The strongest association was found between ASA class IV-V and death within 30 days (odds ratio 5.95). Functional dependence is often associated with underlying comorbidity or motor deficits, but it is also associated with poor rehabilitation after surgery; therefore, functional outcome impacts postoperative morbidity and even long-term survival. 38 After ASA-classification, functional dependence was the most frequent and strongest predictor of postoperative morbidity and mortality. For all outcome measures except reoperation, the odds were twice as high among functionally dependent patients. Increased WBC can indicate infection, inflammation, and malignancy. 39,40 In the current study, an association was found between elevated WBC and preoperative steroid usage (p<0.001). Longer operative time results in a longer exposure to anesthesia and intraoperative risks; however, longer operative time also corresponds to surgical complexity, surgeon’s experience, and other patient factors. 41 Although many of these factors have been described in previous literature as predictors of worse long-term outcomes in brain tumor or cancer patients in general, the current study also identifies them as predictors of short-term morbidity and mortality among patients operated on for a primary malignant brain tumor. Most predictors are non-modifiable by surgeons; however, these results can help neurosurgeons and their multidisciplinary teams to identify high-risk patients for unfavorable outcomes after surgery. This may enable surgeons to tailor perioperative management to the risk profile of the individual patient. This is important because prophylactic treatment for one complication can increase the riskof other complications. For example, thromboprophylaxis can increase the risk of ICH. Optimizing the safety and efficacy of prophylactic strategies based on the risk profile of the individual patient can drastically reduce the rate of complications in the total population. Furthermore, targeting postoperative management can also reduce unnecessary healthcare costs.