Transitioning from Da Vinci Si to Xi: assessing surgical outcomes at a high-volume robotic center

In the emerging field of robotics, only few studies investigated the transition between different robotic platforms in terms of surgical outcomes. We aimed at assessing surgical outcomes of patients receiving robot-assisted radical prostatectomy (RARP) and robot-assisted partial nephrectomy (RAPN) at a high-volume robotic center during the transition from Si to Xi Da Vinci surgical systems.

We analyzed data of 1884 patients undergoing RARP (n = 1437, 76%) and RAPN (n = 447, 24%) at OLV hospital (Aalst, Belgium) between 2011 and 2021. For both procedures, we assessed operative time, estimated blood loss, length of stay, and positive surgical margins. For RARP, we investigated length of catheterization and PSA persistence after surgery, whereas warm ischemia time, clampless surgery, and acute kidney injury (AKI) were assessed for RAPN. Multivariable analyses (MVA) investigated the association between robotic platform (Si vs. Xi) and surgical outcomes after adjustment for patient- and tumor-related factors.

A total of 975 (68%) and 462 (32%) patients underwent RARP performed with the Si vs. Xi surgical system, respectively. Baseline characteristics did not differ between the groups. On MVA, we did not find evidence of a difference between the groups with respect to operative time (estimate: 1.07) or estimated blood loss (estimate: 32.39; both p > 0.05). Median (interquartile range [IQR]) length of stay was 6 (3, 6) and 4 (3, 5) days in the Si vs. Xi group, respectively (p < 0.0001). On MVA, men treated with the Xi vs. Si robot had lower odds of PSM (Odds ratio [OR]: 0.58; p = 0.014). A total of 184 (41%) and 263 (59%) patients received RAPN with the Si and Xi robotic system, respectively. Baseline characteristics, including demographics, functional data, and tumor-related features did not differ between the groups. On MVA, operative time was longer in the Xi vs. Si group (estimate: 30.54; p = 0.006). Patients treated with the Xi vs. Si system had higher probability of undergoing a clampless procedure (OR: 2.56; p = 0.001), whereas the risk of AKI did not differ between the groups (OR: 1.25; p = 0.4). On MVA, patients operated with the Xi robot had shorter length of stay as compared to the Si group (estimate: - 0.86; p = 0.003), whereas we did not find evidence of an association between robotic system and PSM (OR: 1.55; p = 0.3).

We found that the Xi robot allowed for improvements in peri-operative outcomes as compared to the Si platform, with lower rate of positive margins for RARP and higher rate of off-clamp procedures for RAPN. Hospital stay was also shorter for patients operated with the Xi vs. Si robot, especially after robot-assisted partial nephrectomy. Awaiting future investigations-in particular, cost analyses-these results have important implications for patients, surgeons, and healthcare policymakers.