## 3 Results
### Partial Nephrectomy  
Supplementary Table S1 lists the instruments used in the PN groups, their relative weights, and CO\({}_{2}\) production. Since the procedures in question are MIS, some instrumentation overlap existed. The total weight of the instruments utilized was 1669.4 g and 1637.4 g in groups A and B, respectively. In Group A, the plastic, metal, and composite fiber weights totaled 1225.2 g, 225.5 g, and 185.2 g, respectively. In Group B, the plastic, metal, and composite fiber weighed 1288.2 g, 152.5 g, and 133.2 g, respectively. The CO\({}_{2}\) emissions resulting from the production, disposal, and sterilization of the instruments were overall higher in Group B (12.14 kg vs. 9.04 kg, \(p\) = 0.02, 95% CI \(-\)4.04 to \(-\)2.16), with the majority of the emissions deriving from the plastic (Group B 8.37 kg vs. Group A 6.14 kg \(p\) = 0.01, 95% CI \(-\)2.87 to \(-\)1.59). The emissions from the metal and composite fiber components were higher in Group B, but the difference was not statistically significant. Summary statistics for instrument CO\({}_{2}\) consumption are summarized in Table 2.  
The power required for the robotic Xi Da Vinci system to function equals 3.5 kW/h, and considering an average surgical procedure time for RAPN in our institutions of 1.84 h, the resulting average CO\({}_{2}\) emissions equaled 2.27 kg in Group A. In contrast, in Group B, the laparoscopic Storz column operates at 0.6 kW/h, emitting 0.44 kg of CO\({}_{2}\) in 2.08 h of surgical time (\(p\) = 0.001, 95% CI \(-\)1.69 to 1.97). The power required for the OR to function equals to 3.0 kW/h, with the average time spent in it being 2.74 h in Group A and 3.1 h in Group B, with CO\({}_{2}\) emissions being higher in Group B (3.27 kg vs. 2.89 kg). The power required for a standard hospital room differs between summer and winter, with more power required in summer than in winter (0.75 kW/h vs. 0.6 kW/h, respectively) due to ventilation and air conditioning. On average, patients required 56.6 and 62.3 h of hospital stay in Groups A and B, respectively. In the winter, the CO\({}_{2}\) emissions were 11.97 kg and 13.17 in Groups A and B, respectively, and in the summer, they were 14.97 kg and 16.46 kg (\(p\) = 0.04, 95% CI \(-\)2.87 to \(-\)0.11) in Groups A and B, respectively. The total CO\({}_{2}\) emissions from energy consumption were 32.1 kg in Group A and 33.34 kg in Group B (Table 3).  
\begin{table}
\begin{tabular}{l c c c c} \hline  & **Group A** & **Group B** & \(p\)**-Value** & **Difference (95\% CI)** \\ \hline  & \multicolumn{4}{c}{_Weight, g_} \\ Plastics & 1225.2 & 1288.2 & **0.3** & \(-\)63.0 (\(-\)173.19 to 47.19) \\ Metal & 225.5 & 152.5 & **0.07** & 73.0 (56.13 to 89.87) \\ Composite fiber & 185.2 & 133.2 & **0.15** & 52.0 (37.86 to 66.14) \\ \hline
**Total** & 1669.4 & 1637.4 & **0.21** & **32.0 (\(-\)112.93 to 176.93)** \\  & \multicolumn{4}{c}{_CO\({}_{2}\) Emissions, kg_} \\ Plastics & 6.14 & 8.37 & **0.01** & \(-\)2.23 (\(-\)2.87 to \(-\)1.59) \\ Metal & 0.82 & 1.03 & **0.4** & \(-\)0.21 (\(-\)0.29 to \(-\)0.13) \\ Composite fiber & 2.07 & 2.73 & **0.16** & \(-\)0.66 (\(-\)0.87 to \(-\)0.45) \\ \hline
**Total** & 9.04 & 12.14 & **0.02** & \(-\)**3.1 (\(-\)4.04 to \(-\)2.16)** \\ \hline \end{tabular}
\end{table}
Table 2: Weights and CO\({}_{2}\) emissions of the partial nephrectomy groups. g: grams; kg: kilograms; CO\({}_{2}\): carbon dioxide.