It has been shown that using the Mayo Adhesive Probability (MAP) Score, toxic fat is associated with longer operative time, increased blood loss and transfusion, and higher rate of conversion to both total nephrectomy and open surgery. Predictive factors of toxic fat include perirenal stranding and thickness (visible on preoperative CT scan), male gender, obesity, and hypertension. Therefore, it is worth considering in such cases other alternatives such as active surveillance or thermal ablation (when tumor parameters are appropriate for such approaches).
In the majority of cases the procedure is carried out by Professor Bensalah using the transperitoneal approach. The retroperitoneal approach is used occasionally, when the tumor is relatively small and located in the posterior aspect of the lower pole. Before commencing the procedure, no Foley catheter nor ureteral catheter are put in, and the patient is lying flat on his or her side, rather than “breaking” the bed. Following reflection of the colon, it is often useful to detect the ureter and follow it to the renal hilum. The perirenal fat overlying the tumor is left intact, and is used to mobilize the tumor and to apply traction while excising the tumor. When toxic fat around the kidney impedes perirenal dissection, intraoperative ultrasound is a valuable tool in directing the dissection toward the tumor.
Cold scissors are used to resect the tumor (in contrast to enucleation), along with a thin rim of overlying healthy renal parenchyma in order to assure negative resection margins. Shorter ischemia time is attained by the early unclamping of the renal artery. However, this technique is often associated with increased blood loss. The tumor bed is closed in two layers, using absorbable sutures and clips. A drain is generally skipped as it does not change the perioperative outcome, and is often associated with longer hospitalization and delayed patient mobilization. Intravenous opioids are avoided as patients are encouraged to ambulate and eat early on, and the majority are discharged on postoperative day 1 (unless complicated tumor or bleeding >500 mL).
Presented by: Karim Bensalah - Professor, Department of Urology, University of Rennes, France
Written by: Dr. Shlomi Tapiero, Department of Urology, University of California-Irvine, medical writer for UroToday.com. at the 36th World Congress of Endourology (WCE) and SWL - September 20-23, 2018 Paris, France