Relationship Between the Distance Between Ports and the Interference of Arms During Robot-Assisted Nephroureterectomy Using the Hinotori Surgical Robot System.

PURPOSE: We aimed to investigate the optimal port placement for robot-assisted radical nephroureterectomy (RANU) using the hinotori surgical robot system (HSRS), by considering the distance between ports and the number of interferences between the robotic arms.

METHODS

We retrospectively included seven consecutive patients undergoing RANU using HSRS between March and July of 2023. The distances between ports and the number of interferences between the robotic arms were analyzed from the log data. We illustrated the forceps' tips' location during RANU. The farthest part of the working range of the forceps' tips defined the target lesion. The relationship between perioperative data (e.g., port-to-port distance and target direction) and the number of interferences by the arm was analyzed using univariate and multivariate linear models.

RESULTS

The median total number of interferences per patient was 101, with a median of 62 from the kidney direction and 27 from the lower-ureter direction. The univariate analysis revealed the pure port-to-port distance (PPPD) (p = 0.02) and the port-to-port distance against the target (PPDT) (p < 0.001) as significant predictors of arm interference. In the multivariate analysis, only the increased PPDT showed to be significantly associated with interference reduction (estimate: -5.35, 95% confidence interval: -7.73, -2.96, p < 0.001).

CONCLUSION

In RANU using HSRS, with port placement near the outer edge of the rectus abdominis muscle, PPDT is a more important predictor of arm interference than PPPD; considering the assumed range of motion of the robotic forceps.