The use of surgical robots, particularly the Da Vinci robot, has seen a remarkable increase in the last years. According to producer reports, the number of systems has worldwide more than doubled since 2016 and went even up by a factor of four during the same time in Austria. However, the costs associated with these robotic systems are substantial and there is little evidence on the effectiveness of robot-assisted surgery (RAS). Robust evidence for improved patient outcomes compared to conventional surgical methods is scarce and only available for certain procedures, whereas operating times can be much longer and costs per procedure are much larger. While clear evidence exists for certain procedures that RAS can lead to better patient outcomes when they replace open surgeries, the evidence compared to conventional laparoscopy is less clear.
Based on Austrian DRG data for the years 2013-2023, this study investigates the causal effect of the availability of Da Vinci robots within a state (Bundesland) on various patient outcomes. We take advantage of the different timings in robot availability across states to identify the causal impact on patient outcomes by employing a difference-in-differences (DiD) approach for five procedures for which RAS is common (hernia repairs, cholecystectomies, hysterectomies, partial nephrectomies, and radical prostatectomies). To avoid selection bias, the effects of the availability of Da Vinci robots on overall patient outcomes for each procedure are assessed, independent of whether a particular patient was treated with or without a robot. We specifically analyze length of hospital stay and the proportion of minimally invasive surgeries as outcome variables. The model includes a time trend, age, gender and state fixed effects as controls.
The DiD analysis reveals that the availability of Da Vinci robots is associated with a statistically significant reduction in the length of hospital stays for certain procedures. For instance, the introduction of Da Vinci robots led to an average reduction by one day in hospital stays for radical prostatectomies. Additionally, the proportion of minimally invasive surgeries increased with the availability of Da Vinci robots, particularly for radical prostatectomies and partial nephrectomies. Additionally, mortality and readmission rates were considered. The analysis finds a significant reduction in mortality rates for inguinal or femoral hernia repairs and cholecystectomies with the introduction of Da Vinci robots, although these results should be interpreted with caution due to the low incidence of mortality in these procedures. The research design implies the assumption that availability of robots does not alter patient flows across states, which may introduce a bias in the efficiency of RAS. Robots were assumed to be available for all specialities, which may introduce a downward bias in the effectiveness of RAS.
This research provides evidence on the benefits of RAS for certain patient outcomes in Austria. The results of this study can support decision makers in comparing the benefits of this still relatively new technology with its costs.