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.