Differentiating reconstructive techniques in partial nephrectomy: a propensity score analysis.

INTRODUCTION: To assess whether volumetric measurements can differentiate functional changes between reconstructive techniques after partial nephrectomy. MATERIALS AND METHODS: One hundred and fifty-six patients undergoing partial nephrectomy for a single renal mass were retrospectively studied between 2008 and 2012. Computed tomography scans were available for volume calculations on 56 (18 non-renorrhaphy and 38 renorrhaphy). Institutional review board approval was obtained. The primary outcome was %volume loss in the operated kidney, which was calculated from three-dimensional reconstructions using a semiautomatic segmentation algorithm. Multivariable regression and propensity score analysis was performed. RESULTS: Volumetric analysis detected a difference in mean %volume loss between two-layer reconstruction (cortical renorrhaphy and base-layer) and base-layer only (15.6% versus 3.8%, p < 0.001). The mean %glomerular filtration rate (GFR) loss was also greater in the two-layer group (8.9% versus 2.4%, p = 0.03). Demographics were similar between groups except the two-layer group was older, had more males, and increased ischemia time. On multivariable regression the presence of two-layer closure (ß = -15.2%, p < 0.001) and tumor diameter (ß = -7.4, p = 0.004) were significant predictors of %volume loss while ischemia time (p = 0.88) was not. Two-layer closure remained a predictor on propensity-adjusted analysis (ß = -14.3, p = 0.004). The base-layer only group had two (5.3%) urine leaks and two (5.3%) bleeding complications. The two-layer group had two (1.7%) urine leaks and three (2.5%) bleeding complications (p = 0.23, 0.41). CONCLUSIONS: Volume loss calculated from CT scans can be used to monitor postoperative renal function. Techniques for renal reconstruction and tumor diameter are associated with volume and functional loss after partial nephrectomy and should be controlled for in future studies.

Feasibility of omitting cortical renorrhaphy during robot-assisted partial nephrectomy: a matched analysis.

BACKGROUND AND PURPOSE: To assess the safety of omitting cortical renorrhaphy during robot-assisted partial nephrectomy and measure preliminary functional outcomes. PATIENTS AND METHODS: Fifteen robot-assisted partial nephrectomies were performed with a running, base-layer suture for the collecting system and vessel hemostasis but without cortical renorrhaphy. The nonrenorrhaphy group was matched 1:2 by R.E.N.A.L. nephrometry score to a running, sliding-clip cortical renorrhaphy group retrospectively. Intraoperative blood loss, urine leaks, postoperative bleeds, and functional outcomes were evaluated. Predictors of %volume loss were evaluated using multivariable regression. RESULTS: No differences were seen between renorrhaphy and nonrenorrhaphy in sex (P=0.53), age (P=0.14), body mass index (P=0.08), Charlson score (P=0.44), tumor diameter (P=0.55), nephrometry score (P=0.77), preoperative glomerular filtration rate (GFR, P=0.63), or the amount of resected healthy kidney margin (P=0.21). Warm ischemia time was less for the nonrenorrhaphy group (P<0.002). One pseudoaneurysm necessitating embolization (1/30=3%) was seen in the renorrhaphy group compared with none in the nonrenorrhaphy group. No urine leaks occurred in either group. The median %GFR loss was 8.8% for renorrhaphy and 4.4% for nonrenorrhaphy (P=0.14) at a median follow-up of 4.1 months. The median %volume loss was 17 cm(3) for renorrhaphy and 9 cm(3) for nonrenorrhaphy (P=0.003). In a multivariable model, both cortical renorrhaphy (P=0.004) and tumor diameter (P=0.004) were predictors of %volume loss. CONCLUSION: Omission of cortical renorrhaphy appears feasible with no urine leaks or bleeding complications observed. The percent renal volume loss was improved by omission of cortical renorrhaphy. Reconstruction technique is important to control for when studying renal function after partial nephrectomy.