Elsevier

European Urology

Volume 63, Issue 6, June 2013, Pages 1072-1081
European Urology

Surgery in Motion
Application of a Vasculature Model and Standardization of the Renal Hilar Approach in Laparoscopic Partial Nephrectomy for Precise Segmental Artery Clamping

https://doi.org/10.1016/j.eururo.2012.10.017Get rights and content

Abstract

Background

Clamping the segmental renal artery instead of the main renal artery during nephron-sparing surgery is a promising technique to decrease warm ischemia injury. Understanding vasculature characteristics and adopting an appropriate hilar approach to segmental arteries are essential to the technique.

Objective

To study the role of the vasculature model and to standardize the renal hilar approach in segmental renal artery dissection during laparoscopic partial nephrectomy (LPN).

Design, setting, and participants

A retrospective analysis of a consecutive series of 82 patients who underwent LPN with a precise clamping technique from December 2009 to June 2011 with a mean follow-up of 20 mo.

Surgical procedure

Three-dimensional dynamic renal vascular models were established based on dual-source computed tomographic angiography. Clamping number, clamping position, and a different hilar approach accessing target segmental arteries were determined preoperatively. Target arteries were dissected and clamped based on the model. Tumor excision and renorrhaphy were performed under regional parenchymal ischemia.

Outcome measurements and statistical analysis

Renal vascular characteristics and surgical outcomes were analyzed. The outcomes among different surgical approaches were compared using one-way analysis of variance test or Fisher exact test.

Results and limitations

All surgeries were performed successfully without converting to main renal artery clamping or radical nephrectomy. The median operative time was 90 min, and the mean clamping time was 24 min. The median estimated blood loss (EBL) was 200 ml, and six patients received blood transfusions. Five patients had hematuria without any intervention. One patient had a postoperative hemorrhage and received selective embolization intervention. Statistical analysis showed that appropriate surgical approaches chosen from the models led to comparable operative times, EBL, and complication rates. The limitation of the study lies on its retrospective feature.

Conclusions

A renal vasculature model provides effective orientation for a precise clamping technique. A standardized hilar approach based on the model optimizes the surgical procedure and leads to satisfactory surgical outcomes.

Introduction

Nephron-sparing surgery leads to less chronic kidney disease and fewer cardiovascular events compared with radical nephrectomy for patients with small renal tumors [1], [2], [3]. Minimizing warm ischemia injury is one technical focus to improve the functional outcomes of nephron-sparing surgery. For this purpose, one method is to decrease warm ischemia time (WIT). Recent literature confirmed that WIT remains an important modifiable feature associated with short- and long-term renal function [4], [5]. On the other hand, it is to reduce the warm ischemia area.

The main technique involved is selective artery clamping [6], [7], which potentially improves short-term postoperative renal function compared with main renal artery clamping [6]. Clamping of highly selective feeding arteries requires hilar microdissection [7], which is technically challenging without an understanding of the renal vasculature characteristics. The emergence of a high-quality three-dimensional vasculature model meets the requirements of precise clamping technique, which can orient the surgical procedure. Routinely dissecting target arteries from the posterior hilum was not effective enough, as some procedures needed converse to main renal artery clamping in our previous study [6].

Based on accumulated experience, we have set up a standard practice of an optimal hilar approach based on the vascular model to dissect target-feeding arteries. We present stepwise details on the application of the renal vasculature model and the standardized renal hilar approach in segmental renal artery dissection for the laparoscopic partial nephrectomy (LPN).

Section snippets

Methods and patients

We retrospectively analyzed a consecutive series of 82 patients who underwent LPN with precise segmental renal artery clamping from December 2009 to June 2011. The study was approved by the institutional review board of the Nanjing Medical University. Inclusion criteria for LPN were a single, organ-confined mass of 4 cm with a normal contralateral kidney. Patients with a 4- to 7-cm tumor were also included if resection was deemed technically feasible. All patients received dual-source computed

Results

Tumor characteristics, clamping numbers, and hilar approaches were analyzed before the operations based on the vasculature model (Table 1). The median tumor size was 3.0 cm, and 22% of the tumors were >4 cm. Polar, anterior, posterior, and striding tumors made up 24.4%, 28.0%, 18.3%, and 29.3% of the tumors, respectively. Clamping numbers were determined in the model. A single target artery was the most common, in 51.2% of all patients; three target arteries were the least common, in only 9.8% of

Discussion

Warm ischemia injury remains an important factor influencing postoperative renal function in nephron-sparing surgery [4], [5], [10]. Many novel techniques have emerged to minimize warm ischemia injury. One promising method is to convert global parenchymal ischemia to regional ischemia. Renal vascular segmentation provides the theoretical possibility of regional ischemia during nephron-sparing surgery. However, the variability of the renal vasculature and the complexity of the intrahilum

Conclusions

The renal vasculature model based on high-quality three-dimensional DSCT angiography provides important orientation for LPN with precise segmental artery clamping. Standardization of appropriate hilar approaches according to the model optimizes the surgical procedures and leads to satisfactory surgical outcomes.

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These authors contributed equally.

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