Comparing the effects of the Da Vinci Xi and Si robotic surgical systems on postoperative urological and sexual functions in rectal cancer surgery: a retrospective study

[Objectives] To compare the effects of the Da Vinci Xi and Si robotic surgical systems on postoperative urological and sexual functions in patients undergoing rectal cancer surgery. [Methods] We retrospectively analyzed the clinical data of 111 patients with primary rectal cancer who were admitted to Sun Yat-sen Memorial Hospital, Sun Yat-sen University and Guangdong Provincial Second People’s Hospital Affiliated to Jinan University from June 2020 to July 2024. The patients were divided into the Si group (underwent radical resection using the Da Vinci Si surgical system) and the Xi group (underwent radical resection using the Da Vinci Xi surgical system). Propensity score matching was used to match the patients’ general information. After 1∶1 propensity score matching, operative-related indicators (operation time, intraoperative blood loss, preventive ostomy, and surgical approach), pathological-related indicators (mesenteric integrity, pTNM stage, pT stage, pN stage, number of lymph nodes dissected, number of positive lymph nodes, pathological differentiation type, circumferential resection margin, proximal margin, and distal margin), recovery-related indicators (postoperative hospital stay, first postoperative defecation time, drainage tube retention time, anal function [assessed using the Wexner anal incontinence score], urological function [assessed using the international prostate symptom score], and sexual function [assessed using the international index of erectile function-5 for male and the female sexual function index for female]), and postoperative complications and deaths within 30 days were compared. [Results] There were no positive proximal margin cases or deaths within 30 days after surgery in either group. There were no significant differences between the two groups in preventive ostomy, surgical approach, mesenteric integrity, pTNM stage, pT stage, pN stage, number of lymph nodes dissected, number of positive lymph nodes, pathological differentiation type, circumferential resection margin, distal margin, postoperative hospital stay, first postoperative defecation time, drainage tube retention time, and total incidence of postoperative complications (P>0.05). The operation time was shorter and intraoperative blood loss was less in the Xi group than in the Si group (P<0.05). Before surgery, there were no significant differences in the international index of erectile function-5 scores for male patients, the international prostate symptom scores for male patients, and the female sexual function index scores for female patients between the two groups (P>0.05). After surgery, the international index of erectile function-5 scores for male patients and the female sexual function index scores for female patients decreased, while the international prostate symptom scores for male patients increased. The international prostate symptom scores for male patients in the Xi group was lower than that in the Si group (P<0.05). However, there were no significant differences in the international index of erectile function-5 scores for male patients and the female sexual function index scores for female patients between the two groups (P>0.05). There were also no significant differences in the proportions of male patients with moderate-to-severe sexual dysfunction, female patients with sexual dysfunction, and male patients with moderate-to-severe urological dysfunction between the two groups (P>0.05). [Conclusion] Compared with the Da Vinci Si surgical system, the Da Vinci Xi surgical system has shorter operation time and less intraoperative blood loss, which can better preserve the early postoperative urological function of male rectal cancer patients.