Comparing different pneumoperitoneum (12 Vs 15 mm Hg) pressures with cytokine analysis to evaluate clinical outcomes in patients undergoing Robotic-Assisted Laparoscopic Radical Cystectomy and Intra-Corporeal Robotic Urinary Diversion

Abstract

Background Robotic cystectomy is the mainstay surgical intervention for treatment-refractory non-muscle-invasive and muscle-invasive bladder cancer. However, paralytic ileus complicates the post-operative recovery, and may be a consequence of an inflammatory response associated with transient gut ischaemia. We have therefore investigated clinical, operative, and inflammatory biomarker associations between paralytic ileus in the context of robotic cystectomy and intra-corporeal ileal conduit urinary diversion. Methods Prospective patients referred for robotic cystectomy were consented and included in the study, whilst patients >75yo and converted to open procedure were excluded. The pneumoperitoneum pressure (PP) for carbon dioxide insufflation required to perform the procedure efficiently and safely was recorded (12mmHg or 15mmHg). We also recorded the post-operative days patients passed flatus and stools, whether they had ileus, as well as other standard clinical and demographic data. The expression of select pro- and anti-inflammatory cytokines was determined by multiplex analysis using a cytometric bead array with changes in profiles correlated with the pressures applied and with the existence of an ileus. Results Twenty-seven patients were recruited but only twenty were used in the study with 10 patients in each PP group. Seven patients were excluded all of whom had an extracorporeal ileal conduit formation. There were differences in the 40-minute shorter operative time and 1day shorter length of stay; as well as passing flatus 1 day and stools 1.5 days earlier in the 12mmHg compared to the 15mmHg group. More patients had ileus in the 15mmHg group (30% vs 10.0%). These were not statistically significant. Similarly, there were no statistical differences in the expression of pro-inflammatory cytokines at the two different pressures or between patient groups but there were outliers, with the median indicating non-symmetrical distribution. By comparison, anti-inflammatory cytokines showed some significant differences between groups, with IL-6 and IL-10 showing elevated levels post-surgery. No statistical difference was observed between pressures or the existence of an ileus, but the maximum levels of IL-6 and IL-10 detected in some patients reflect a pressure difference. Conclusions The initial findings of this novel scientific study indicated a higher risk of paralytic ileus post-robotic cystectomy when a higher pressure of 15mmHg is used compared to 12mmHg. Although further studies are required to establish the linkage between cytokine profile expression, pressure and ileus, our initial data reinforces the advantages of lower pressure robotic cystectomy and intra-corporeal urinary diversion in patient outcomes.