**3.1.2 Simple enucleation versus standard partial nephrectomy**

#### **3.1.2.1 Positive surgical margin rate**

Minervini (Minervini et al., 2011) retrospectively analysed 1519 patients operated for renal cell carcinoma to determine the impact of simple enucleation on oncologic outcomes: 982 underwent a standard partial nephrectomy versus simple enucleation in 537 cases. 25.9% of patients belonging to the standard partial nephrectomy group versus 21.3% of patients in the simple enucleation group had a renal cell carcinoma larger than 4 cm. PSM rate was significantly lower in the simple enucleation group (0.2%) versus the standard partial nephrectomy group (3.4%) (p<0.001).

#### **3.1.2.2 Cancer-specific survival rate**

For tumours smaller than 4 cm, pure enucleation provides long-term cancer-specific survival rates similar to RN and is not associated with a greater risk of local recurrence compared to partial nephrectomy (Carini 2006). Minervini (Minervini 2011) compared standard partial nephrectomy with simple enucleation: he could not find any significant difference between those 2 techniques after adjusting for cancer-specific survival probabilities: age at surgery (younger or older than 65 years), tumour stage (pT1a, pT1b or pT3a) and Fuhrman nuclear grades (1-2 versus 3). Patients who underwent a simple enucleation and had a Fuhrman nuclear grade 4 showed a significantly worse cancerspecific survival compared to patients who were treated with standard partial nephrectomy.

In another publication (Carini et al., 2006), Carini and Minervini reviewed 71 simple enucleations for renal cell carcinoma with diameter 4 to 7 cm. Median follow up was 74 months. There was no peri-operative mortality and no major complications requiring reintervention. Oncologic outcomes were acceptable: 5- and 8-year cancer-specific survival rates were 85.1% and 81.6%, respectively. Tumour stage had an impact on cancer-specific survival: 5-year cancer-specific survival rate was 95.1% for tumours of 4 cm, 83.3% for stage pT1b and 58.3% for stage pT3a tumours. He reported 10 patients (14.1%) with progressive disease but only 4.2% with local recurrence.

The Role of Nephron-Sparing Surgery (NSS) for Renal Tumours >4 cm 339

A critique to the laparoscopic approach remains that ischemia time is usually longer than in open procedure. In a European survey (Porpiglia et al., 2010), mean warm ischemia time was 25.7 minutes with a range 15-46 minutes. Cooling techniques in laparoscopy are time consuming. Clamping usually lasts from the beginning of the resection to the end of parenchymal suture. In order to reduce warm ischemia time, Nguyen (Nguyen et al., 2008) proposed to remove the clamp after the first layer of parenchymal suture. The remaining renorrhaphy is thus performed in the revascularized kidney. This technique decreases warm ischemia time by over 50%. There was a trend towards improved outcomes: less overall complications (16% vs. 22%), less postoperative renal haemorrhage (2% vs. 4%) and a decreased re-intervention rate (6% vs. 16%). However, those differences were not statistically significant. No patient had a positive resection margin, required open

The goal of efficient renorraphy is to reduce warm ischemia time. The type of suture

(running of interrupted) is not correlated with longer warm ischemia time.

conversion or showed renal dysfunction.

**3.2.1.4 Impact of parenchymal suture on renal function** 

Fig. 4-5. Examples of interrupted suture in open surgery.

Simple enucleation can be performed for tumours larger than 4 cm. Long-term outcomes are comparable to standard NSS.
