Login to Access Video or Poster Abstract: MP59-10
Sources of Funding: none

Introduction

Renal volume losses near 20% are seen following partial nephrectomy for small renal masses despite minimizing resection margins to <1cm and ischemia time to <20minutes. The time course of volume loss is not well understood as immediate postoperative imaging is rarely obtained. This study compares volume loss immediately after surgery (day 3-4) to 4-6months after surgery._x000D_

Methods

Patients undergoing robotic partial nephrectomy for small renal masses with available imaging were included. Those with tumors <2cm or requiring postoperative embolization were excluded. Computed tomography (CT) imaging was available at three time points: preoperatively, post-operative day 3 or 4, and 4-6months. The post-operative day 3 or 4 scan was obtained prospectively to assess for asymptomatic pseudoaneurysms. A running base-layer and sliding clip cortical renorrhaphy were used. Philips Intellispace Portal was used to construct three-dimensional models of the operated kidneys using slice-by-slice semi-automatic segmentation. Manual exclusion of tumor volume and hilar structures was performed. Stata 13.1 was used to perform descriptive statistics and the Mann-Whitney U-test to compare volume losses._x000D_

Results

Twenty-three patients between January 2013 and March 2015 met criteria and were included. The median (IQR) age, BMI, and tumor diameter were 55years (41-62), 24.8kg/m2 (23-27), and 2.6cm (2.4-3.6), respectively. The nephrometry score median (IQR) was 6 (6-8). The percent male gender was 78%, and 61% were right sided. The operative time, warm ischemia time, and estimated blood loss were 178minutes (171-218), 20minutes (17-27), and 50mL (10-100). All tumors were renal cell carcinoma and had negative margins. There was one urine leak that did not require intervention. The preoperative, 3day, and 6month mean (SD) volumes for the operated kidney were 153.4cm³, (24), 149.6cm³ (24), and 127.4cm³ (25). The mean percent volume loss at 3days was 2.3% and at 6months was 14.6% (p-value < 0.0001).

Conclusions

The majority of volume loss after partial nephrectomy was not detected in the immediate postoperative period, but was seen by 4months. This supports the hypothesis of delayed atrophy from ischemia or reconstructive injury._x000D_

Funding

none