Trans-peritoneal vs. retroperitoneal robotic assisted partial nephrectomy in posterior renal tumours: need for a risk-stratified patient individualised approach. A systematic review and meta-analysis.

To systematically review world literature and compare peri-operative outcome including operating time (OT), estimated blood loss (EBL), warm ischemia time (WIT), length of stay (LOS) and complications between retroperitoneal robotic assisted partial nephrectomy (RP-RAPN) and trans-peritoneal robotic assisted partial nephrectomy (TP-RAPN) for posteriorly located renal masses. All randomised trials and observational studies comparing RP-RAPN and TP-RAPN for posteriorly located renal masses were considered. The GRADE approach (Grading of Recommendations Assessment, Development and Evaluation, GRADE) was used to rate the quality of evidence. 82 potential publications were identified. 3 were included in the review. All three studies were observational comparative studies. 347 and 550 patients underwent RP-RAPN and TP-RAPN, respectively, for posteriorly located tumours. There was statistically significant difference in LOS between the 2 techniques, favouring the RP-RAPN cohort: risk ratio (M-H, random, 95% CI), - 0.42 [- 0.67, - 0.18], p < 0.0006. There was no statistically significant difference in overall complication rates between the two techniques: risk ratio (M-H, fixed, 95% CI), 0.80 [0.49, 1.30], p = 0.37. There was no statistically significant difference in ≥ Clavien 3a complication rates between the two t echniques: risk ratio (M-H, fixed, 95% CI), 1.17 [0.62, 2.19], p = 0.63. OT, EBL, WIT and positive margin rates were similar for both approaches. The quality of evidence for complications, LOS and remaining outcomes were 'moderate', 'low' and 'very low', respectively, on GRADE approach. The current review suggests that the LOS with RP-RAPN are significantly lesser than TP-RAPN for posterior tumours. The RP-RAPN does not appear to offer any advantage over TP-RAPN for other peri-operative outcomes such as WIT, OT and EBL. The surgical margin rates and morbidity between the two approaches appear to be similar.