Robotic-assisted laparoscopic partial nephrectomy : initial experience in Brazil and a review of the literature

ARTICLE INFO _______________________________________________________________ _____________________


ORIgINAL ARTICLE INTRODuCTION
The ubiquitous use of abdominal imaging modalities has resulted in an increase in the detection of incidental small renal masses (1).Surgical extirpation, especially open partial nephrectomy (OPn), is still the preferred treatment for small renal masses.Indeed, surgical extirpation is an established treatment for solid or complex cystic small renal masses, and it has oncologic control Context and Purpose: Partial nephrectomy has become the standard of care for renal tumors less than 4 cm in diameter.Controversy still exists, however, regarding the best surgical approach, especially when minimally invasive techniques are taken into account.Robotic-assisted laparoscopic partial nephrectomy (RALPn) has emerged as a promising technique that helps surgeons achieve the standards of open partial nephrectomy care while offering a minimally invasive approach.The objective of the present study was to describe our initial experience with robotic-assisted laparoscopic partial nephrectomy and extensively review the pertinent literature.Materials and Methods: Between August 2009 and February 2010, eight consecutive selected patients with contrast enhancing renal masses observed by CT were submitted to RALPn in a private institution.In addition, we collected information on the patients' demographics, preoperative tumor characteristics and detailed operative, postoperative and pathological data.In addition, a PubMed search was performed to provide an extensive review of the robotic-assisted laparoscopic partial nephrectomy literature.Results: Seven patients had RALPn on the left or right sides with no intraoperative complications.One patient was electively converted to a robotic-assisted radical nephrectomy.The operative time ranged from 120 to 300 min, estimated blood loss (EBL) ranged from 75 to 400 mL and, in five cases, the warm ischemia time (WIT) ranged from 18 to 32 min.Two patients did not require any clamping.Overall, no transfusions were necessary, and there were no intraoperative complications or adverse postoperative clinical events.All margins were negative, and all patients were disease-free at the 6-month follow-up.Conclusions: Robotic-assisted laparoscopic partial nephrectomy is a feasible and safe approach to small renal cortical masses.Further prospective studies are needed to compare open partial nephrectomy with its minimally invasive counterparts.comparable to that of radical nephrectomy (2).Furthermore, favorable outcomes and safety data suggest that patients who undergo partial nephrectomy have better renal function and are less likely to require renal replacement therapy than patients who undergo radical nephrectomy (3,4).
Because of the added morbidity of an open procedure, laparoscopic partial nephrectomy (LPn), which has demonstrated comparable perioperative and convalescent benefits, has emerged as a viable alternative to OPn (5).Unfortunately, LPn is technically challenging, and there is disagreement over the extent of problems related to renal function due to the long periods of ischemia required for tumor excision and intracorporeal sutured reconstruction (6).
In the past decade, many centers have successfully incorporated the da Vinci® robotic system in an attempt to perform complex reconstructive procedures with more precision, dexterity and rapidity.This system offers the surgeon an invaluable minimally invasive tool to overcome every challenge of LPn and preserve long-term renal function (7).We present our initial experience in robotic-assisted laparoscopic partial nephrectomy (RALPn) from a private institution in Brazil.In addition, we performed a detailed review of the pertinent literature.

MATERIALs AND METHODs
Between August 2009 and February 2010, eight consecutive patients (five males and three We also performed a PubMed search using the terms laparoscopic surgery, partial nephrectomy and robotic-assisted, and we compiled a detailed review of the pertinent literature.All articles with a series of patients were included.

RALPN Technique
The patients were placed in the flank position with the operative side facing up, and the operating table was partially flexed.The abdomen was insufflated with CO 2 via transperitoneal Veress needle access to a maximum pressure of 15 mmHg.The da Vinci® (Intuitive Surgical, Sunnyvale, CA) robot was then docked, and the entire procedure was performed robotically.Thirty-degree lens facing the down position were used in all cases.no ureteral catheters were placed.
After insufflation was observed, the colon was reflected medially, and the kidney was exposed from the lower pole to the upper pole.Gerota's fascia was dissected over the kidney, and the lesion was identified.In all cases but one (in which it was electively decided to convert to a radical roboticassisted procedure because of tumor location), a robotic-assisted partial nephrectomy was performed.
In all but two cases, which did not require hilar clamping, either the main artery or a polar artery was individualized for bulldog clamping.Laparoscopic bulldog clamps were placed across the full length of the renal arteries by the bedside surgeon.
Hot scissors were used to excise the mass, and all lesions were sent to pathology to create frozen sections.The collecting system was repaired with 3-0 polyglactin sutures in two cases.For renal reconstruction, we used a 2-0 polyglactin suture, which was placed through the capsule of the kidney and sequentially through the parenchyma of the operative bed (parenchymal sutures).Additional 0 polyglactin sutures were placed through the renal capsule and tied over a Surgicel bolster (capsular sutures).After releasing the bulldog clamp, intra-abdominal pressure was lowered to 5-10 mm Hg, and the operative field was carefully inspected.The tumor was placed in an organ bag, and a 15F Jackson-Pratt drain was placed around the kidney.

REsuLTs
Perioperative data and final pathologic information are depicted in Tables 2 and 3, respectively.Three patients underwent RALPn on the left side, and four patients underwent RALPn on the right side.none of these patients had any intraoperative complications.One patient had a centrally located endophytic tumor near the renal hilar vessels.After hilum dissection and tumor exposure, we decided to electively convert the procedure to a robotic-assisted radical nephrectomy, which was conducted without any difficulties.Tumor sizes ranged from 15 to 35 mm, and most of the lesions were lower pole and exophytic cortical lesions.Operative time ranged from 120 to 300 min, EBL ranged from 75 to 400 mL and WIT ranged from 18 to 32 min (Table-2).There were no transfusions needed, no intraoperative complications and no adverse postoperative clinical events.In addition, hospital stays were only two to three days.Three patients required morphine derivatives, but only until the day after surgery.Four patients had renal cell carcinomas, grade 2 to 3. One patient (number 7) had his nephrectomy bed resection margin ampliated, and all pathological data of the final margins showed negative results in our series.There was one complex Bosniak category III cyst observed by a preoperative CT scan, but it turned out to be benign.We also observed one angiomyolipoma, which was indistinguishable from renal cell carcinoma on the preoperative CT scan, and two oncocytomas.Importantly, there were no recurrences at the six-month follow-up.

DIsCussION
The initial series of RALPn included patients with tumors ranging in size from 1 to 7.5 cm (the mean tumor size was 2.98 cm).The mean operative time, EBL and mean WIT are depicted in Table-4.Generally, the authors used a four-arm da Vinci® robotic system with a transperitoneal approach with regular hilum clamping and warm ischemia, with the robot docked at the begginning of the procedure.
Gettman et al. described one patient at the Mayo Clinic who experienced a positive margin, but there were no recurrences.Although one patient of the 13 in his series had prolonged ileus, there were no other significant postoperative complications (8).In another study, Kaul et al. described a slightly different lateral camera configuration with a 30° down lens during the operation; however, they still used an initial robotic-assisted approach.The Kaul et al. study re-  (10).
Bhayani and Das reported their initial experiences with a different sliding-clip renorrhaphy (i.e., Hem-O-Lock clips).The Hem-O-Lock clips slide into place under complete control of the surgeon seated at the console and are secured with a LapraTy clip (11,12).In the Bhayani and Das study, one patient was converted to open partial nephrectomy when the margins were not clear during intraoperative ultrasound, and another patient was converted to robotic-assisted cryoablation without complications (11).
The largest series of partial nephrectomy patients, which was published by Rogers et al., in-cluded 148 patients from six institutions.In these selected patients, surgery was performed by experienced laparoscopic urologists.There were only two conversions to OPn, and there were no longterm recurrences in their casuistics (13).There have been multiple studies involving the use of RALPn for complex and challenging cases, and detailed results are depicted in Table-5.neither conversions nor recurrences have been reported in the studies describing RALPn (14)(15)(16).
A highly experienced group has recently published their initial cases of partial nephrectomy without vascular hilar clamping, which minimized the risk of vascular injury and kidney ischemia associated with temporary arterial occlusion.The lack of vascular hilar control, however, resulted in a higher mean EBL compared with other contemporary series (Table-5) (17).
Current studies that compared LPn and RALPn are depicted in Table-6.Unfortunately, there are no randomized, controlled, prospective studies with adequate follow-up periods.A study by Caruso et al. in 2006 was the first observational study to compare LPn and RALPn, and they did not find any significant differences in operative time, ischemic time, EBL or hospital stay between the two groups (Table-6) (18).
A retrospective, case-matched comparison study that used an early unclamping technique in LPn and RALPn patients found that WIT was significantly higher for the RALPn group (21 vs. 14 minutes, p < 0.05); however, this study was limited by the small number of patients.Therefore, the results for WIT with the early unclamping technique were inconclusive (19).More recent studies have shown that WIT has been reduced as doctors gain more experience with RALPn.Their analysis demonstrated that RALPn resulted in shorter operative times, WITs and lengths of hospital stay compared with LPn (Table-6) (20)(21)(22).
The present study was the first robotic-assisted renal surgery series in Brazil.There are several inherent limitations of the present study because it was a prospective study with a small cohort of highly selected patients (with no control arms) who were only followed for a short period of time.nevertheless, the present study was able to show that RALPn is a safe and feasible option for the  Although OPn is currently considered to be the standard of care for the treatment of small renal tumors, intermediate oncologic outcomes for LPn are also excellent (23), and it is likely that oncologic outcomes are comparable between OPn, LPn and RALPn.Ischemic time is a major concern for renal function preservation, but this may not be an issue with RALPn because clamping times are less than 20 min and because RALPn also uses parenchymal clamping.Similar to LPn, RALPn causes less postoperative pain and decreases the length of hospitalization and active recovery.

CONCLusIONs
Robotic-assisted laparoscopic partial nephrectomy is a feasible and safe approach to re-

Table 1 -Patient Demographics.
globin values two days after surgery (but before discharge), length of stay, adverse clinical or surgical events (perinephric hematoma and urinary leakage), and the need for morphine derivatives.The pathology results were reviewed for tumor type, tumor size and margin status.A CT scan at the 6-month follow-up was indicated depending upon individual patient pathology.