Partial Nephrectomy Treatment & Management

Prepare patients being considered for nephron-sparing surgery (NSS) for possible radical nephrectomy. Patients should be aware of the risk for possible temporary or permanent dialysis in the setting of a solitary functioning kidney undergoing surgical intervention. The optimal treatment is often determined intraoperatively. Optimal renal perfusion provided by a hydration regimen of approximately 200 mL/h or more of crystalloids overnight often is beneficial. Alternatively, same-day admission and hydration with a 1-L crystalloid bolus over an hour prior to the scheduled operation is also used. Prepare iced slush saline for intraoperative renal cooling in anticipation of arterial occlusion and regional hypothermia.

In most cases in which preoperative imaging is optimized and the correct incision is used, partial nephrectomy can be performed in situ. Temporary arterial occlusion and regional hypothermia are often necessary, depending on the size, location, and number of renal masses. Surgical options include enucleation with a rim of normal parenchyma, wedge resection, polar nephrectomy, or bench surgery and autotransplantation (ex vivo).

Several important principles exist for performing NSS for renal cell carcinoma (RCC). Early vascular control is the key for minimizing blood loss and for prompting renal hypothermia, when necessary, in cases in which it was not originally planned. Lower the surface and core renal temperature to minimize ischemic damage to the kidney. Intraoperatively, frozen section analysis of the resection margins is an important adjunct. Closure of the collecting system is mandatory to prevent fistula formation. In addition, inspect the entire remaining surface of the kidney to rule out multifocal RCC.

Do not hesitate to use temporary renal artery occlusion and hypothermia, even for relatively small lesions. This approach decreases intraoperative bleeding and, because of decreased tissue turgor, allows for palpation of the kidney for nonobvious intraparenchymal lesions that are not readily identifiable when the kidney is perfused. It also allows for better dissection of tumors, especially centrally located tumors, and assessment of the extent of involvement of contiguous intrarenal structures. Usually, only the renal artery is occluded, except in large centrally located tumors, in which the renal vein can be occluded to minimize bleeding and to allow for easier dissection and reconstruction.

Some surgeons have used intraoperative ultrasonography for evaluation of multifocality in select cases when preoperative imaging studies are equivocal or intraparenchymal nonpalpable tumors are suggested. In situations in which complex cystic lesions are encountered, ultrasonography can further characterize the lesion at the time of surgery. Ultrasonography can guide the incision in the renal capsule and identify the shortest and easiest access to the lesion that compromises and sacrifices the least amount of normal parenchyma. In one recent study, intraoperative ultrasonography did not add to preoperative CT scan or intraoperative inspection with regards to determining multifocality, but it did aid in determining the nature of intraparenchymal mass and the surgical approach.

Operative technique

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.

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.

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.

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.

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.

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. ^[5] 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.

With adequate preoperative planning, meticulous surgical technique, proper patient selection, and attention to detail, NSS can be performed with minimal morbidity and excellent outcomes for most patients selected. The role of partial nephrectomy in the setting of metastatic disease and a solitary kidney is not clearly defined. Certainly, this operation is contraindicated in the presence of nodal metastases. The use of intraoperative adjuncts such as ultrasonography and, especially, frozen section analysis is invaluable to the operating surgeon for prompt and effective decision making. The placement of a closed suction drain is essential after NSS.

Use of the described techniques provides a watertight closure of large parenchymal defects. Certainly, other traditional methods of closure (eg, closure of the parenchyma with horizontal sutures over the length of the defect with fat or Oxycel or closure with Gelfoam and Surgicel bolsters) have been successfully used. These methods depend on the strength of the renal capsule. Use of Gore-Tex allows for even distribution of tension along the length of the closure. Small bleeding vessels are easily tamponaded. Gore-Tex also allows the surgeon to tie the sutures with the desired tension without risking tear of the kidney capsule, especially when the arterial clamp is removed in transverse resections carried out for larger tumors.

One concern about the use of exogenous material has been postoperative tissue reaction that might occur, particularly when a repeat resection is contemplated in the future. In the authors' experience, Gore-Tex is relatively unreactive, and, although a pseudocapsule forms, the subsequent explorations have not been difficult and the inflammatory tissue reaction around the Gore-Tex has been minimal.

After NSS, patients are advised to return in 4-6 weeks for serum creatinine measurement and intravenous pyelography. In the absence of obstruction, the patient should undergo CT scanning every 6 months for 2 years and then yearly for the next 5 years, after which, the frequency is decreased to every 2 years. Chest radiography and measurements of serum calcium, alkaline phosphatase, liver function tests, and creatinine are obtained yearly for the initial 5 years and biannually thereafter. Some advocate the frequency of postoperative evaluation as dictated by the initial tumor stage, with less rigorous structured follow-up for low-stage, small tumors.

Most complications of nephron-sparing surgery (NSS) can be managed conservatively. However, the risk of a significant complication increases with the technical complexity of the case. Direct correlation exists between morbidity and the extent of NSS. The least morbidity occurs in enucleation and in situ conservative surgery, in which most tumors are smaller and peripherally located. In these patients, the morbidities of NSS parallel those of radical nephrectomy.

Accordingly, complication rates are higher in larger tumor resections in patients who have multifocal or bilateral tumors or in resections in patients with large tumors in a solitary kidney. Extracorporeal surgery is associated with increased risk of major complications, including renal vascular thrombosis and renal failure. These resections usually involve extensive manipulation of the renal vasculature and collecting system.

Hemorrhage

The most troublesome and common intraoperative complication of partial nephrectomy is excessive bleeding. In this respect, meticulous dissection, attention to detail, and ligation of intraparenchymal vessels are of paramount importance. Easy access to the renal hilum, provided by early identification and isolation of the renal artery, provides the additional safety of prompt arterial occlusion when excessive bleeding precludes a clear surgical field and adequate visualization. Postoperative hemorrhage is usually self-resolving and may be confined to the retroperitoneum or may be present with gross hematuria, decreased hematocrit, or flank ecchymosis. Treatment is expectant, consisting of volume resuscitation, serial hematocrits, and bedrest. Embolization is an option in the unusual case in which bleeding persists after conservative management and requires multiple transfusions. Reexploration is the last resort for severe intractable bleeding.

Not only is the intraoperative risk of bleeding relatively high (5-25%) with laparoscopic and/or robotic partial nephrectomy but the postoperative hemorrhage risk is not insignificant (1-15%). Mitigating this risk is very important for those surgeons performing this procedure, and the first step in doing so is identifying these risk factors. Richstone and colleagues present an overview of predictors that surgeons should be familiar with prior to performing this surgery and when counseling these patients prior to surgery. ^[6] Smoking and high American Society of Anesthesiologists (ASA) score were noted as risk factors for hemorrhagic complications in this study.

Urinary fistula

Recognized entry into the collecting system intraoperatively requires surgical repair. Failure to do so can result in postoperative urinoma. Risk factors include central location, larger tumor size, and increased complexity of the nephron-sparing operation. A small amount of urinary leakage is conceivably common and usually ceases spontaneously. Persistent drainage through the drain suggests a larger leak, which can still be managed expectantly. In the absence of ureteral obstruction, most leaks seal as more tissue healing occurs. If a urinoma forms after the flank drain has been removed, placement of a percutaneous drainage catheter in the urinoma is indicated to prevent abscess formation. Also, draining the collecting system with a percutaneous nephrostomy tube or, preferably, with a ureteral stent to seal the leakage site in the collecting system, is often helpful.

A study by Potretzke et al evaluated the incidence of and risk factors for a urine leak in robot-assisted partial nephrectomy. The study found that out of a database of 1,791 patients who underwent robot-assisted partial nephrectomy, urine leak was noted in only 14 patients (0.78%). A literature review by the same study found that the historical incidence of urine leak for open partial nephrectomy and laparoscopic partial nephrectomy ranged from 1.0% to 17.4% for open and from 1.6% to 16.5% for laparoscopic. ^[7]

Renal insufficiency

Most cases of renal insufficiency after NSS are the result of transient ischemia during surgery and usually resolve spontaneously. Attention to intraoperative measures to decrease the possibility of this complication, namely hydrating preoperatively, correcting electrolyte abnormalities, using mannitol, maintaining minimum arterial clamp time, and using surface hypothermia, is preventive.

Patients should be aware of the risk of postoperative acute tubular necrosis and the possibility of temporary or permanent dialysis, especially in the setting of a solitary kidney. When recognized postoperatively, appropriate fluid and electrolyte management and use of dialysis (if necessary) can aid in the return of renal function. Stop nephrotoxic medications or alter the dosages. In one series, only 6.5% of patients progressed to end-stage renal disease requiring renal replacement therapy at an average of 8.2 years, of whom 5 had preoperative renal dysfunction. ^[8]

Lau et al from the Mayo Clinic have addressed the risk of chronic renal failure after partial nephrectomy versus radical nephrectomy with a normal contralateral kidney (unpublished data). This long-term series included 328 patients who were optimally matched for year of surgery, age, sex, renal function, and grade, stage, and size of tumor. The 10-year and 15-year local recurrence-free survival rates were 95% and 99% for partial and radical nephrectomy patients, respectively. Tumor in the contralateral kidney occurred in 1% of the patients in each group. The 10-year and 15-year cause-specific survival rates were 98% and 91%, respectively, for partial nephrectomy and 96% (10 y and 15 y) for radical nephrectomy; thus, no difference in outcome was observed.

More recently, Huang et al (2006) from the Memorial Sloan Kettering cancer center have suggested that radical nephrectomy places the patient in the realm equivalent to that of chronic kidney disease. ^[9] In this retrospective study, 662 patients with normal renal function and 2 healthy kidneys underwent elective partial or radical nephrectomy for a solitary tumor that was 4 cm or smaller. The glomerular filtration rate (GFR) was estimated using the abbreviated Modification in Diet and Renal Disease Study equation. Twenty-six percent of patients had renal failure prior to the operation.

Postoperatively, the 3-year probability that the patient would be free from a newly onset GFR of lower than 60 mL/min per 1.73 m² was 80% (95% CI, 73-85) after partial nephrectomy and 35% (28-43; P< 0.001) after radical nephrectomy; corresponding values for a GFR of lower than 45 mL/min per 1.73 m² were 95% (91-98) and 64% (56-70; P< 0.001), respectively.

Multivariable analysis showed that undergoing radical nephrectomy remained an independent risk factor for a newly onset GFR of lower than 60 mL/min per 1.73 m² (hazard ratio, 3.82 [95% CI, 2.75-5.32]) and 45 mL/min per 1.73 m² (11.8 [6.24-22.4]; both P< 0.001). They concluded that undergoing radical nephrectomy is a significant risk factor for the development of chronic kidney disease and may no longer be regarded as the criterion standard treatment for small renal cortical tumors.

Renal replacement therapy (ie, hemodialysis) was required more often in the nephrectomy series than in the NSS group. Furthermore, patients in the radical nephrectomy group had significantly higher serum creatinine levels (P = .003; 1.6 mg% vs 1.3 mg%) than in the nephron-preserving group. This series is particularly credible because of its long-term follow-up (15 y), and it presents compelling evidence that partial nephrectomy is associated with significantly less renal failure than ipsilateral radical nephrectomy in the presence of a contralateral normal kidney.

Other complications

Other complications can include infections or those attributable to anesthesia (eg, atelectasis and pneumonia). Appropriate antibiotic treatment and postoperative use of incentive spirometry can help to decrease incidence and to aid in management.

Nephron-sparing surgery (NSS) is now associated with improved technical success rates and long-term disease-free survival rates comparable to radical nephrectomy, especially in low-stage disease. Excluding hereditary renal tumors, the overall risk of local recurrence in modern partial nephrectomy series is 4-6%. Local recurrence rates are reported to be higher in patients with suspected disease (6.6%) versus incidental disease (1.1%). Incidental tumors are of lower size, grade, and stage. ^{[10, 11]}

Local recurrence after NSS represents, in part, growth of multifocal renal cell carcinoma (RCC) and not incompletely resected tumor. In a recent study of multifocality in RCC, the incidence rate of true unknown multifocality (at the time of surgery) was 6%, corresponding roughly to the local recurrence rates in the studies cited above. ^[12] The inherent risk of multifocality dictates a thorough inspection of the entire surface of the kidney at the time of operation. Certain pathologic patterns raise suspicion of multifocality, namely papillary RCC or mixed cell histological pattern.

NSS for RCC can achieve long-term tumor control, especially in the setting of a primary tumor smaller than 4 cm. In a recent study of 76 patients who underwent NSS, only 3 patients developed metastatic disease at a mean follow-up of 75 months. ^[13] Of the 51 patients who had a normal contralateral kidney, tumors were generally small and 49 patients had pathologic T1 or T2 tumors. Review of NSS data from 2 large centers reveals a 5-year cause-specific survival rate that approaches 90-95% for pathologic stage I RCC. ^{[14, 3]} As the pathologic stage of the renal lesion is increased, the risk of local recurrence and metastatic disease also increases.

Recently, several valuable reports regarding long-term follow-up and efficacy of this treatment modality were published. These recent, important, long-term studies on the efficacy of NSS serve to lead the way to expanding indications for NSS and are the first step in defining the new criterion standard for the treatment of RCC in appropriately selected patients with low-stage lesions of the appropriate size. ^{[8, 14, 3]}

To determine the clinical significance of early incidental detection of renal masses, one study compared patients who presented with one of the classic symptoms of RCC or subsequent metastases with patients who were asymptomatic in whom lesions were incidentally detected. ^[15]

From a large series of 633 patients, those with incidentally detected tumors had a significantly higher 5-year survival rate than those with symptomatic lesions (85.3% vs 62.5%). ^[15] The local and distant recurrence rates were also higher for symptomatic lesions. These findings correlate with a previous study by Licht et al on the results of NSS in incidental versus suspected RCC, in which the local recurrence rates were significantly lower (1% vs 6%) in the incidental group. ^[10] The 5-year cancer-specific survival rates were 94% versus 83% for incidental and suspected RCC, respectively. The higher survival rates in this series could be due to selection bias for NSS based on lower pathologic stage and size of the tumors. Nevertheless, the pattern is comparable.

Given that incidental tumors were of significantly lower grade and stage, current study, along with the increased detection of incidental renal tumors on cross-sectional imaging, serves to strengthen the place of NSS in the management of these lesions.

The Cleveland Clinic Group recently presented long-term results of partial nephrectomy for localized RCC with a minimum follow-up of 10 years. ^[8] This study of 107 patients revealed cancer-specific survival rates of 88.2% and 73% at 5 and 10 years, respectively. The study period dated back before 1988 and before the widespread use of cross-sectional imaging. The 10-year and 15-year local recurrence-free survival rates were 94% and 92%, respectively. The fact that 68% of patients were symptomatic at presentation, 31% had stage pT2 or higher tumors, and 90% had NSS for an imperative indication makes this study remarkable and adds more credence to NSS as a viable surgical option.

Nevertheless, the overall 10-year cancer-specific survival rate was 80%. The isolated local recurrence rate was 4%. When considering tumors smaller than 4 cm, the cancer-specific survival rate at 5 and 10 years was 98% and 92%, respectively. The cancer-specific survival rate was 100% for tumors smaller than 4 cm and a normal contralateral kidney, and no recurrences occurred.

Another recent large study evaluated the long-term efficacy of NSS using an analysis based on the new 1997 tumor, node, metastasis (TNM) staging system. ^[3] Patients who underwent a partial nephrectomy were compared to a group of patients who underwent radical nephrectomy and were matched in terms of age, sex, stage distribution, and follow-up time (mean 57 mo and 55 mo, respectively). The overall cancer-specific survival rates were 91.2% and 98% for radical nephrectomy and NSS patients, respectively, treated during the same time. The local recurrence rate was 2.7%.

When considering pT1 lesions with the 1997 TNM criteria, tumors larger than 4 cm but smaller than 7 cm fared just as well as tumors smaller than 4 cm treated by NSS (100% survival rate). The survival rates of the patients with a 1997 pT1 lesion and a normal contralateral kidney did not differ, regardless of whether NSS or radical nephrectomy was performed (100% vs 97.5%). Partial nephrectomy was clearly less effective than radical nephrectomy when performed for lesions larger than 7 cm. Therefore, this study expands on the idea set forth by earlier studies that set the limit of tumor size at 4 cm or smaller, demonstrating the efficacy of NSS for lesions smaller than 7 cm.

Lau et al from the Mayo Clinic recently compared radical nephrectomy and NSS in the setting of a unilateral RCC and a normal contralateral kidney for the treatment of RCC. ^[14] In each cohort, 164 patients were matched optimally according to grade, stage, size, age, sex, and year of surgery. Overall median follow-up time was 3.8 ± 5.3 years. The cancer-specific survival rates between NSS and radical nephrectomy at 5, 10, and 15 years (98%, 98%, and 91% and 98%, 96%, and 96%, respectively) did not significantly differ. These results support an earlier matched cohort from the authors' institution that revealed similar cancer-specific outcome between NSS and radical nephrectomy for low-stage (< 4 cm) low-grade tumors. The local recurrence rate was only 2%, and that of contralateral recurrence was only 1%.

These 3 recent reports from 3 institutions at the forefront of the surgical treatment of RCC provide reassuring evidence on the efficacy of NSS. The survival data are comparable to earlier reports with shorter follow-up. The risk of local tumor recurrence, a concern after NSS, was 2-4%. This is in the low end of the range previously reported in the literature (0-10%) and could be attributable to incidental detection of low-grade low-stage tumors in the contemporary series. Likewise, the risk of multicentricity could conceivably be lower, an argument in favor of NSS in the current era. The risk of contralateral recurrence was low (1%). In a large study of 1213 patients who underwent radical nephrectomy, Dechet et al found this rate to be higher (4%), which could be attributable to larger higher-stage tumors in that historical review. ^[16]

Certain clinicopathologic features can predict outcome after NSS. A recent study found that patients with clear-cell RCC had a significantly worse cancer-specific survival rate than patients with papillary and chromophobe RCC. ^[17] The cancer-specific survival rates at 5 and 10 years were 94.4% and 91.5% for clear-cell RCC, respectively, and 99% for both papillary and chromophobe carcinoma. Tumor stage and grade were significantly associated with outcome in the clear-cell group.

With the advent of laparoscopy, the field of minimally invasive renal surgery is gaining wider acceptance. The use of laparoscopy provides a minimally invasive conduit to the delivery of certain treatment modalities (eg, cryotherapy, radiofrequency ablation [RFA]). Laparoscopic nephrectomy is feasible in experienced hands and is now an accepted modality for the treatment of renal cell carcinoma (RCC).

In an effort to reduce morbidity of open nephron-sparing surgery (NSS), laparoscopic partial nephrectomy has emerged as a viable alternative to open surgery. Hemostasis is the rate-limiting step in this procedure, especially for larger lesions. Various forms of energy and devices have been used to aid in hemostasis. Bipolar and monopolar cautery, harmonic scalpel, and argon beam coagulator have all been used. Various surgical hemostatic aids such as fibrin glue and BioGlue have also been used to aid in the closure and seal of the renal parenchymal defect. The challenge remains with the sizable renal tumor in which hilar control is necessary.

No reliable method of parenchymal cooling is currently available to allow sufficient time for excision of the tumor and closure of the defect. At centers of excellence, the open operation can be duplicated using hilar control with laparoscopic bulldogs and Satinsky forceps, sharp tumor excision, and suture repair and closure of the collecting system. This is a complex laparoscopic operation that requires expertise in expeditious intracorporeal suturing.

Various studies have compared the outcomes of laparoscopic partial nephrectomy to those of open NSS. In the Cleveland Clinic experience, the analgesic requirement, blood loss, average convalescence, and even surgical time (3 h vs 3.9 h) were lower in the laparoscopic group. ^[18] However, the warm ischemia time was 27.8 minutes vs 17.5 minutes. No kidney was lost because of warm ischemia, and the postoperative serum creatinine levels were similar (1.1 mg/dL vs 1.2 mg/). The laparoscopic group had 3 positive margin results as compared to none in the open group. In addition, fewer renal or urologic complications occurred in the open NSS group than in the laparoscopic group (2% vs 11%). Although laparoscopic partial nephrectomy with hilar control is promising, better techniques of renal cooling and intracorporeal suturing are necessary to decrease warm ischemia and decrease urologic complications.

Laparoscopic partial nephrectomy is an excellent choice for the incidentally detected small renal mass that is exophytic. In this scenario, in which the resection is more superficial, hemostatic agents such as fibrin glue (Tisseel, Baxter Healthcare Corporation, Irvine, Calif) and BioGlue can be used in addition to bipolar and argon beam coagulation. In these cases, especially when the tumor is not invading the collecting system, select superficial tumors require no parenchymal suturing.

Laparoscopic partial nephrectomy is a technically challenging procedure that requires surgical dexterity and advanced laparoscopic skills. To facilitate the learning curve, some authors have recently published their preliminary experience with robotic partial nephrectomy and have reported acceptable results. ^{[19, 20]}

Ficarra et al conducted a study using the Preoperative Aspects and Dimensions Used for an Anatomical (PADUA) classification and found that, after adjusting for the effects of surgeon experience, clinical tumor size, and upper collecting system repair, anatomical classification of anatomic tumor characteristics score for tumors were independent predictors of warm ischemia time and overall complications in patients who underwent robot-assisted partial nephrectomy. ^[21]

One drawback of the robotic approach for the surgically facile laparoscopist is that the operating surgeon is not in total control. The operator, from the robot console, has to rely on the proficiency of his or her bedside assistant in this time-sensitive operation. Certainly, most laparoscopic kidney surgeons do not view the surrender of total control as a positive in robotic partial nephrectomy.

A cost-comparison of open partial nephrectomy (OPN), laparoscopic partial nephrectomy (LPN), and robot-assisted LPN (RALPN) found that LPN results in shorter length of stay, making it more cost-effective than OPN. Lower instrumentation costs make LPN more cost-effective than RALPN despite the fact that RALPN results in shorter length of stay. ^[22]

The application of laparoscopy in treating renal lesions has generated interest in the delivery of other modalities such as cryotherapy and RFA. More data are available for cryotherapy. This modality can also be performed percutaneously, using MRI and CT guidance. The preliminary data are encouraging. During a mean follow-up period of 16 months, no patients in the series of Gill et al from the Cleveland Clinic had radiologic evidence of renal fossa, port site, or distant metastases. ^[23] In their series of 32 patients (34 tumors), no evidence of tumor was found at 3 and 6 months when a biopsy of the cryolesion was performed using ultrasound guidance. This was performed in 23 patients, 13 of whom had RCC diagnosed intraoperatively based on laparoscopic needle biopsy. Although not definitive or fool-proof, the short-term results are encouraging.

Another area of research is RFA, which is an evolving technology. Early data show excellent short-term and long-term tumor control in a porcine model. As with cryotherapy, additional studies and longer follow-up are needed.

These ablative procedures can be performed laparoscopically or percutaneously. An important limitation of these techniques includes the lack of pathologic specimens to allow for accurate histologic evaluation. As stated above, long-term results are largely unknown. Successful outcomes have been described as radiologic evidence of infarction, hemorrhage, reduction in size, or absence of growth on follow-up. Several investigators have expressed concern over tumor viability, especially at the periphery of the RFA lesion, based on treatment and immediate nephrectomy after RFA. Another limitation is the lack of long-term data. Only with 5- and 10-year data can we reliably compare the results with partial nephrectomy. Assessing recurrence based on enhancement on imaging or growth only is difficult. Biopsy of the ablated area is not reliable, as it samples a small area of the lesion.