How is partial nephrectomy nephron-sparing surgery (NSS) performed?

Updated: Mar 31, 2019
  • Author: Reza Ghavamian, MD; Chief Editor: Bradley Fields Schwartz, DO, FACS  more...
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According to the preference of the surgeon, a flank extraperitoneal or an anterior subcostal incision is used. A supine position with a tilt towards the contralateral side is the authors' preferred approach. Place a rolled towel underneath and lateral to the affected side, and slightly flex the table. Alternatively, when a flank incision is contemplated, the lateral decubitus position is used. Raise the kidney rest halfway between the iliac crest and the costal margin and flex the table. Flex the contralateral leg at the knee to provide stability and keep the ipsilateral lower extremity straight. Place pillows in between to cushion bony prominences. Wrap the outermost arm and place it on an armrest. Place an axillary roll underneath the dependent axilla to avoid brachial plexus injuries.

The authors' preferred approach, in the absence of previous abdominal surgery, is the anterior subcostal incision starting at the tip of the 12th rib, coursing 3 cm below the costal margin and extending across the midline to the opposite side when necessary.

Divide the falciform ligament after entering the peritoneum. The advantage of this incision is evaluation of the intra-abdominal viscera and excellent exposure of the renal vessels, especially in patients who are large or obese. The disadvantage is that the kidney is in the depth of the wound. The flank approach, using an extrapleural 11th or 12th rib incision, also provides excellent and rapid exposure to the kidney and the hilum and is a reasonable approach. However, in older patients or those with poor respiratory reserve, pulmonary complications are more common. This is due, in part, to increased pain associated with this incision compromising deep inspiration and subsequently leading to more atelectasis.

Optimal renal exposure is the key to a successful outcome. Mobilize the abdominal viscera accordingly and identify the kidney. Identify the renal pedicle and define the vasculature. Then, isolate the renal artery and place a vascular loop. Avoid excessive dissection and leave surrounding perivascular adventitial layers intact to serve as a cushion if application of a vascular clamp is contemplated. This reduces the risk of intimal damage to the artery, which can result in arterial thrombosis. Except for the fat directly overlying the tumor, dissect the perirenal fat free. Enucleation with a rim of normal parenchyma can be used for smaller lesions (< 3 cm) as depicted in the image below. Usually, renal occlusion is not necessary.

Enucleation with a rim of normal parenchyma. Enucleation with a rim of normal parenchyma.

Score the capsule with electrocautery. A plane is usually identified outside the pseudocapsule of the tumor and developed with the butt end of a scalpel handle or small Metzenbaum scissors. Then, excise the tumor with a combination of blunt and sharp dissection. While the assisting surgeon applies intermittent pressure, suture-ligate any bleeding vessel with 5-0 absorbable sutures.

Send a frozen section from the tumor crater bed, which represents the deep margin, to the laboratory. The crater is inspected for evidence of entry into the collecting system. If in doubt, 5 mL of indigo-carmine can be administered intravenously or intrapelvically (collecting system), and the tumor bed can be inspected for any leaks. Use thrombin-soaked Surgicel liberally to aid in hemostasis. When the defect is small, approximate the renal capsule to cover the defect with Gelfoam or Surgicel bolsters. If the defect is relatively large, close the parenchymal defect with exogenous Gore-Tex bolsters.

Larger lesions require temporary arterial occlusion and hypothermia. Preoperative definition of the renal vasculature is more imperative if a larger partial resection is contemplated. When in doubt, the appropriate segmental artery that supplies the tumor can be identified by injection of indigo-carmine as depicted in the image below. Leave the areolar tissue intact at the junction of the renal vein and the vena cava to provide increased stability of the renal vein. Initiate diuresis with intravenous mannitol and a loop diuretic (eg, furosemide) intraoperatively, with generous hydration before any interruption in the renal circulation. Infuse mannitol (12.5 g) intravenously 5 and 10 minutes before anticipated renal occlusion. This agent not only induces osmotic diuresis but also is a free-radical scavenger that can minimize ischemic insult from arterial clamping and the ultimate risk of postoperative acute tubular necrosis.

Segmental artery can be injected with indigo-carmi Segmental artery can be injected with indigo-carmine to delineate the supply area.

Then, occlude the renal artery with an atraumatic vascular bulldog and wrap a plastic sheet around the kidney. The authors do not routinely occlude the renal vein because retrograde perfusion of the kidney might minimize the chance for postoperative acute tubular necrosis. It also allows for easier identification of renal veins for ligature in the parenchyma and differentiation from small tangential cuts in the collecting system at the time of resection.

Maintain liberal hydration throughout the procedure. Apply iced saline slush and cool the kidney to allow for adequate core renal hypothermia as depicted in the 1st image below. Then, resect the renal mass with a combination of blunt and sharp dissections with a 1- to 2-cm margin of normal renal parenchyma as depicted in the 2nd image below. Send frozen sections from the crater of the tumor bed to the laboratory. After the lesion is removed, suture-ligate the bleeding arteries and the visible bleeding veins with 4-0 absorbable sutures. Close the collecting system, if entered, with a 5-0 absorbable suture as depicted in the 3rd image below. If the collecting system is not easily identified, indigo-carmine can be injected into the renal pelvis to detect an obvious leak while the ureter is occluded.

Ice slush is applied to the isolated kidney, and t Ice slush is applied to the isolated kidney, and the core renal parenchymal temperature is lowered.
Wedge resection. Wedge resection.
The renal collecting system, if entered, is closed The renal collecting system, if entered, is closed and the edges of the defect are approximated manually.

With the assistant approximating the edges of the parenchymal defect as depicted in image #5 above, close the defect over a Surgicel/Gelfoam roll to aid in parenchymal pressure and hemostasis. Two strips of Gelfoam wrapped in Surgicel can be used to bolster the renal capsule along the edges of the defect to reduce the risk of tearing. Lay the 2 strips along the length of the defect on each side. Pass several 2-0 polyglycolic acid horizontal mattress sutures through the renal capsule, approximately 1 cm away from the edge of the parenchymal defect on each side, thereby incorporating the Gelfoam/Surgicel strips along each side of the defect as depicted in the image below.

Renal parenchymal repair using Gore-Tex graft. Renal parenchymal repair using Gore-Tex graft.

The parenchyma is malleable owing to arterial occlusion and should be closed along whichever axis allows for an easier approximation. Then, tie the interrupted sutures over the bolster. Place all sutures first. Have the assistant provide uniform and direct approximation while tying these sutures. Then, remove the arterial clamp and perfuse the kidney.

Large polar resections are approached in the same manner and are invariably performed best under regional hypothermia and arterial occlusion with core cooling. Usually, a transverse resection is required as depicted in the image below. These are usually larger lesions and require ligation of the segmental arteries and veins that supply the tumor and the corresponding section of the kidney. Carefully note the position of the ureter and the renal pelvis and close the collecting system with a running 5-0 absorbable suture. Because of the usually extensive resection, insertion of an indwelling double-J ureteral stent, placed antegrade intraoperatively or cystoscopically prior to open surgery, is advisable. Close the parenchymal defect as described above.

Segmental polar resection. Segmental polar resection.

Most partial nephrectomies are amenable to in situ techniques. With adequate cooling and exposure, 3 hours of safe ischemia is ample time for resection of almost all renal tumors. In the past, an indication for ex vivo (ie, bench) NSS was a centrally located tumor with concerns of adequate tumor excision and reconstruction. A recent study from a single center with extensive experience in NSS did not find the location of the tumor (central vs peripheral) to be a significant factor affecting outcome, especially in single, small, unilateral, and incidentally detected RCC.

Today, in experienced hands, bench surgery is usually not necessary. The most perceivable indication is the presence of a large central tumor in a solitary kidney. The technique involves a standard radical nephrectomy with particular attention to preserving the maximum length on the renal artery and vein. Administer intravenous mannitol (total 25 g) 5 and 10 minutes before removal and achieve maximum ureteral length with adequate adventitia.

Provide adequate hydration and administer furosemide liberally to maintain diuresis. After removal, perfuse the kidney with University of Wisconsin solution or Euro-Collin solution at 70°C via the renal artery and place the kidney in a shallow basin filled with cold saline slush. Resect the tumor. The frozen section analysis of the margins is obtained. Then, perform the reconstruction as described above. Infusion of the artery and vein with Euro-Collin solution before transplantation allows for identification and closure of small leaking vessels. Reimplant the reconstructed kidney in the contralateral iliac fossa with the standard renal transplantation technique as depicted in the image below. Stent and reimplant the ureter with a modified Lich-Gregoire technique.

Completed autotransplant. Completed autotransplant.

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