Comparison of Short Term Surgical and Functional Outcomes of Robot-Assisted Total Mesorectal Excision for Rectal Cancer with the da Vinci Xi vs Si

Background: The new Da Vinci Xi could overcome some of the main drawbacks of the Si, the fixed position of the patient after docking and instrument collisions. We compared surgical and functional outcomes of robotic rectal resection with Total Mesorectal Excision (TME) for cancer, between the da Vinci Xi (Xi-RobTME group) and the da Vinci Si (Si-RobTME group). Materials and Methods: The study group included the first consecutive 30 Xi-RobTME compared with a case-matched Si-RobTME group, performed between April 2010 and September 2016 by a single surgeon. Perioperative outcomes, autonomic function and quality of life, were compared. We used ICIQ-FLUTS and ICIQ-MLUTS (International Consultation on Incontinence–Female/Male Lower Urinary Tract Symptoms) and IIEF (International Index of Erectile Function)/FSFI (Female Sexual Function Index) questionnaires. Results: There was a significant difference between the two groups in the docking and overall operative time that were shorter in the Xi-RobTME group (23.5 min vs 17.5 min, p<0,001 and 285 min vs 318 min, p<0.05). In the Si-RobTME group, a hybrid approach with complete splenic flexure mobilization (SFM) was used in 12/30 cases (40%), while a fully-robotic approach was used in 18/30 cases (60%), of which 11 with partial SFM. In 30/30 (100%) of the cases in the Xi-RobTME group and 7/30 (23%) of the Si-RobTME group were performed with a fully robotic approach with complete SFM (p <0.001). 10/12 cases (83%) of Si-RobTME hybrid subgroup were males and the mean BMI was 25.1. The hybrid approach in males and patients with BMI>25 was necessary in 10 patients (45% vs 0%, p<0.001) and in 6 patients (37% vs 0%, p<0.05), respectively between Si-RobTME and Xi-RobTME groups. No differences in conversion rate, mean hospital stay and pathological results and in autonomic function before and at 1 year after surgery. Conclusion: The new Da Vinci Xi seem to offer technical advantages that could result in a shorter docking and operative time and with superior ability to perform a fully robotic approach, even in difficult patients such as male and obese. Conversion rate, pathologic and functional outcomes seems not to be improved, with the new Xi platform.