No ischemia technique, parenchymal preservation and age are the most important determinants of renal function after partial nephrectomy.

OBJECTIVE: The aim of the present study was to compare the outcomes of Off-Clamp to On -Clamp approach during robot-assisted partial nephrectomy (RAPN). MATERIEL AND METHODS: Retrospective study of 940 patients who underwent a RAPN between 2007 and 2015 for cT1a tumors using On-Clamp or Off-Clamp approaches. Patient with solitary kidney or multifocal were excluded. Overall, 103 patients underwent Off-Clamp approach and 37 patients On-Clamp approach. We matched the patients in terms of tumor size, Charlson comorbidity index and R.E.N.A.L. score. At all, 309 patients from the On-Clamp were matched to the Off-Clamp group. We compared the clinic-pathological characteristics, perioperative morbidity and late functional outcomes between the 2 propensity score matched groups. Limitation included retrospective analysis. RESULTS: After matching, there were no difference in clinic-pathological characteristics in terms of gender, age, race, body mass index, Charlson comorbidity index, American Society of Anesthesiologists score, baseline estimated glomerular filtration rate (e-GFR), tumor size, R.E.N.A.L. score complexity, hilar (H) location between the 2 groups. Regarding perioperative outcomes; while operative time (P=0,4), estimated blood loss (P=0,28), Clavien grade III-IV complications (P=0,8) surgical reoperation (P=1), 30-day readmission (P=1), positive surgical margin (5,5% vs. 5,8%, P=0,9) were comparable between the 2 groups, there were significant difference in excisional volume loss (median, 7,08 vs. 3,51cm3, P<0,01), e-GFR decline (median, -9,7 vs. -2,2ml/min/1,73 m2, P<0,01), percent of e-GFR preservation (median, 87% vs. 97%, P<0,01), and CKD upstaging (36,5% vs. 23,3%, P=0,01), Off-Clamp approach (P=0,01), and age (P=0,02) were predictors of renal function preservation, whereas excisional volume loss (OR=1,035, CI 95% (1,015-1,06), P<0,01) predicted upstaging. CONCLUSION: RAPN for selected renal mass using Off-Clamp approach offered renal functional advantage over On-Clamp, without adding morbidities. While no ischemia technique was associated with less excisional volume loss, Off-Clamp approach, and age were independent predictors of renal function preservation. Clinical significance of these findings in various clinical settings will require further investigation.