Nephron sparing surgery has been accepted as a standard of care for T1a renal tumors. Although its acceptance level for peripheral tumors is high, the most centrally located tumors are still subjected to radical nephrectomy due to inherent technical reasons. Three basic anatomical facts may help perform partial nephrectomy in such difficult locations. One and the foremost is going into the natural sinus fat plane, which exists between the parenchymal lip and the hilar structures, and is familiar to most of us though extended pyelolithotomy. Second is the presence of a tough renal capsule along the parenchymal lip that goes into the hilum and gets attached to the calyceal neck separating parenchyma from the sinus fat. And the last one, renal masses are unlikely to infiltrate this plane at an early stage. Herein we present the technique of trans-sinus fat approach of laparoscopic partial nephrectomy (LPN) for centrally located tumors.
A standard three port transperitoneal renal access is achieved; an assistant's fourth port (5 mm) is added later. After complete extra Gerota mobilization of the kidney, the hilum is prepared for vascular control. Gerota's fascia with its fat is now divided all around the tumor. The hilar lip adjoining the parahilar mass is identified and cleared to allow entry to sinus fat plane. Healthy looking parenchyma is marked all around the tumor except medially, where the dissection extends into the renal sinus. Renal ischemia is then established and cortical incision is deepened all around the tumor. Initial cortical division allows the mass to be lifted away from the hilar structures allowing entry to the sinus fat plane. All major vessels entering this part of the mass can be identified, clipped and divided under vision. Gradually one reaches the calyceal neck or an infundibulum, which can be cut across. The peripheral cortical incision is then extended to the opposite side, and tumor is removed with good renal parenchyma around it. Standard nephropaxy follows to complete LPN.
This technique was used in 16 patients with T1 parahilar masses (midpole 5, lower polar 2, and upper polar 9). The size ranged from 2.5 to 7.5 cm. It could be successfully completed in 15 cases. One case with an upper polar mass was electively converted as it was not visualized properly due to its posterior location. Warm ischemia ranged from 15 to 37 min (average 23 min, <30 min in 14 cases). Average operating time (time from creating pneumoperitoneum to the placement of drain) was 145 min (125-240 min). An estimated blood loss was 250 ml (150-800 ml). Major complications occurred in three patients. Persistent urinary fistula (>2 weeks) required prolonged stenting and Foley's catheterization in two patients. Another patient with AV fistula and pseudoaneurysm required angioembolization, 4 weeks following the surgery. There were no positive margins.
Trans sinus-fat LPN for parahilar tumors is thus an anatomical approach and can safely be performed laparoscopically. It allows vascular control under vision, and provides a safe surgical margin at the depth of the tumor where it is more likely to be transgressed.