Partial nephrectomy is the standard treatment option for small renal masses. The goal of partial nephrectomy is complete tumor removal with the preservation of renal function and no complications. Trifecta (total ischemia time <25 minutes, negative surgical margins, and no surgical complications) is widely used to evaluate success after partial nephrectomy. However, some patients experience acute kidney injury (AKI) even if they achieve trifecta. In the present study, we evaluated factors affecting AKI and subsequent renal function recovery after robot-assisted partial nephrectomy for clinical T1a renal masses.

One hundred and three patients who underwent robot-assisted partial nephrectomy for clinical T1a renal masses between September 2018 and February 2023 were evaluated. We defined AKI as an increased in the serum creatinine by ≥0.3 mg/dl or ≥50% from the preoperative value within the first postoperative 48 hours. We examined factors affecting AKI after RAPN and subsequent renal function recovery in patients with clinical T1a renal masses.

Among 103 patients, 95 (92%) achieved trifecta (Three patients had a total ischemic time ≥25 minutes, while 5 had surgical complications. All of these patients had negative surgical margins.). Among these 95 patients, 22 (23%) experienced AKI. Multivariate analysis identified age (p=0.04) and warm ischemic time (WIT) (p=0.004) as independent predictors affecting AKI. Patients in the AKI group were significantly older than the no AKI group (65.5 years vs. 62.0 years, p=0.034). WIT was significantly longer in the AKI group (21 min) than in the no AKI group (17 min) (p=0.04). We then evaluated 22 patients experienced AKI. Renal function was subsequently recovered in 17 (77%) of these patients 4-12 months after surgery. The proportion of patients with 2 or more of the 3 comorbidities (diabetes, hypertension, and cardiovascular disease) was significantly higher in the unrecovered group (100%) than in the recovered group (42%) (p<0.01).

Older age and longer WIT were independent risk factors for postoperative AKI, and the presence of comorbidities might influence subsequent renal function recovery. Surgeons need to reduce WIT when performing robot-assisted partial nephrectomy for older patients with comorbidities.