Solitary kidneys and off-clamp nephron-sparing surgery: A model to explore modifiable predictors of renal decline

A renal mass in a solitary kidney (SK) provides a unique clinical model to assess renal function outcomes following off-clamp partial nephrectomy (ocPN), as the elimination of ischemia allows the isolated evaluation of baseline and intraoperative factors. This study aimed to identify predictors of functional deterioration in patients with SK treated by open, laparoscopic, or robotic ocPN.

From January 2011 to December 2023, 70 patients with SK undergoing ocPN were identified from an institutional renal cancer dataset. Outcomes were stratified by surgical approach: open (n = 27), laparoscopic (n = 11), and robotic (n = 32). Cox proportional hazards regression was used to assess predictors of progression to significant chronic kidney disease (sCKD, defined as CKD stage ≥3b). A P value <0.05 was considered statistically significant.

At a median follow-up of 62.7 months (interquartile range 35.9-79.7), estimated glomerular filtration rate and the incidence of end-stage renal disease remained comparable across surgical approaches (each P > 0.5). On multivariable analysis, discharge estimated glomerular filtration rate (hazard ratio [HR] 0.93; 95% confidence interval [CI] 0.89-0.98; P = 0.008) and the use of renorrhaphy over sutureless reconstruction (HR 2.77; 95% CI 1.004-7.64; P = 0.04) independently predicted sCKD progression.

In the absence of ischemia, postoperative renal function and reconstructive technique emerge as the main determinants of long-term decline. These findings emphasize the role of modifiable intraoperative factors in shaping functional outcomes after nephron-sparing surgery in SKs.