Recovery of renal function after open and laparoscopic partial nephrectomy

Background: Although oncologic outcomes appear to be similar after laparoscopic partial nephrectomy (LPN) and open partial nephrectomy (OPN), data on renal function are lacking.

Objective: To evaluate the change over time in renal function after LPN and OPN.

Design, setting, and participants: We identified 987 patients with a single sporadic tumor and a normal contralateral kidney who were treated by LPN (n=182) and OPN (n=805) between January 2002 and July 2009.

Intervention: All patients underwent LPN or OPN at Memorial Sloan-Kettering Cancer Center.

Measurements: Estimated glomerular filtration rate (GFR) was calculated using the abbreviated Modification of Diet in Renal Disease formula. We created a multivariable generalized estimating equations linear model that predicted GFR based on the time from surgery, preoperative GFR, tumor size, American Society of Anesthesiologists score, and ischemia time.

Results and limitations: Mean patient age, tumor size, and ASA score were similar between LPN and OPN patients. The baseline preoperative GFR was lower in the laparoscopic group (67 ml/min per 1.73 m(2) vs 73 ml/min per 1.73 m(2); p<0.001). The mean ischemia time was shorter after LPN than OPN (35 min vs 40 min, respectively; p<0.001). In a multivariable model, the interaction term between time from surgery and approach was statistically significant (p=0.045), indicating that there was a differential effect on recovery of renal function over time by approach. Laparoscopically treated patients maintained a slightly higher renal function than those treated via an open approach. The 2-mo and 6-mo predicted GFR for a typical patient increased slightly from 65 ml/min per 1.73 m(2) to 67 ml/min per 1.73 m(2), respectively, for those treated laparoscopically but remained constant at 62 ml/min per 1.73 m(2) after OPN.

Conclusions: Our data suggest that the surgical approach has a small effect on the recovery of renal function after partial nephrectomy. Laparoscopically treated patients maintained slightly higher renal function.