Changes in Kidney Volume after Robot-Assisted Partial Nephrectomy and Impact on Postoperative Renal Function

Area of Science:

• Urology
• Nephrology
• Surgical Oncology

Background:

• Robot-assisted partial nephrectomy (RAPN) is a common procedure for kidney tumors.
• Understanding post-operative kidney volume changes and their impact on renal function is crucial for patient management.
• Compensatory renal hypertrophy is a known phenomenon, but its dynamics after RAPN require detailed investigation.

Purpose of the Study:

• To quantify changes in kidney volume following robot-assisted partial nephrectomy (RAPN).
• To assess the impact of these volume changes on postoperative renal function, specifically estimated glomerular filtration rate (eGFR).
• To identify predictors of contralateral renal enlargement after RAPN.

Main Methods:

• Retrospective analysis of 58 patients who underwent RAPN.
• Kidney volumes were measured using contrast-enhanced CT scans pre- and post-operatively (1 week and 1 year).
• Multivariate analysis was employed to determine factors influencing changes in eGFR and total kidney volume.

Main Results:

• Significant kidney enlargement (operated, contralateral, and total) was observed 1 week post-RAPN.
• By 1 year, operated and total kidney volumes decreased, while contralateral kidney volume increased significantly.
• A 12.8% decrease in eGFR was noted at 1 year post-RAPN; age, ischemia time, and total kidney volume changes independently affected eGFR.

Conclusions:

• Contralateral kidney compensatory hypertrophy occurs after RAPN.
• Higher R.E.N.A.L. nephrometry score, L score, and smaller preoperative total kidney volume predict contralateral renal enlargement.
• These findings highlight the kidney's adaptive capacity and factors influencing functional recovery post-RAPN.