ROBOT-ASSISTED TOTAL MESORECTAL EXCISION FOR RECTAL CANCER: COMPARISON OF SHORT TERM SURGICAL AND FUNCTIONAL OUTCOMES BETWEEN THE DA VINCI XI AND SI

Background Robotic rectal resection with the Da Vinci Si has been associated with low conversion rate, shorter learning curve and good functional outcomes. Nevertheless, the fixed position of the patient after docking and instrument collisions, represent some of its main drawbacks that could be overcome by the new Da Vinci Xi. The aim of this study is to compare surgical outcomes and postoperative autonomic function of robotic rectal resection with Total Mesorectal Excision (TME) for cancer, with the use of the new da Vinci Xi (Xi-RobTME group) and the da Vinci Si (Si-RobTME group), in a single surgeon experience. Methods The first consecutive 30 Xi-RobTME were compared with a case-matched Si-RobTME group, selected within our Institute database, comprising all cases performed between April 2010 and September 2016 by a single surgeon. Perioperative outcomes, prospectively collected in a dedicated database, were compared. The impact of minimally invasive TME on autonomic function and quality of life (QOL) was analyzed with 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 The docking and overall operative time were shorter in the Xi-RobTME group (23.5 min vs 17.5 min and 285 min vs 318 min, p<0,001 and p<0.05 respectively). A fully robotic approach with complete splenic flexure mobilitation (SFM) was used in 30/30 (100%) of the Xi-RobTME cases and in 7/30 (23%) of the Si-RobTME group (p <0.001). In the Si-RobTME group, a hybrid approach with complete 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. Ten of the 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. There were no differences in terms of conversion rate, mean hospital stay and pathological results (number of harvest lymph nodes, quality of mesorectum, distal margin) and in sexual and urinary scores between the two groups before and at 1 year after surgery. Conclusion The technical advantages offered by the new Da Vinci Xi seem to be mainly associated with 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 introduction of the new Xi platform