Robot-assisted Laparoscopic Partial Nephrectomy: Step-by-step Contemporary Technique and Surgical Outcomes at a Single High-volume Institution

EUROPEAN UROLOGY 62 (2012) 553 561 available at www.sciencedirect.com journal homepage: www.europeanurology.com Surgery in Motion Robot-assisted Laparoscopic Partial Nephrectomy: Step-by-step Contemporary Technique and Surgical Outcomes at a Single High-volume Institution Jihad H. Kaouk *, Ali Khalifeh, Shahab Hillyer, Georges-Pascal Haber, Robert J. Stein, Riccardo Autorino Section of Laparoscopic and Robotic Surgery, Glickman Urological and Kidney Institute, Cleveland Clinic, Cleveland, OH, USA Article info Article history: Accepted May 8, 2012 Published online ahead of print on May 29, 2012 Keywords: Nephron-sparing surgery Small renal mass Surgical technique Robot-assisted partial nephrectomy Please visit www.europeanurology.com and www.urosource.com to view the accompanying video. Abstract Background: Robotic technology is being increasingly adopted in urologic surgery. Objective: To describe a contemporary surgical technique and report cumulative surgical outcomes of robot-assisted laparoscopic partial nephrectomy (RALPN) at our tertiary care institution. Design, setting, and participants: Medical charts of consecutive patients who underwent RALPN between June 2006 and November 2011 were reviewed from a prospectively maintained, institutional review board-approved database. Surgical procedure: The main steps of our current surgical technique are described in this video tutorial: patient positioning and trocar placement; bowel mobilization; hilar dissection; tumor identification and demarcation; clamping of the hilum; tumor excision; renorraphy; hilar unclamping; and tumor retrieval. Outcome measurements and statistical analysis: Patients characteristics and main surgical outcomes were analyzed. Results and limitations: A total of 400 patients (mean age: 58.5 yr, mean body mass index: 30.7 kg/m 2 ) were included in this analysis. Mean renal tumor size was 3.17 cm (standard deviation [SD]: 1.64) and mean RENAL score was 7.2 (SD: 2). Six patients (1.5%) presented with a solitary kidney. Mean total operative time was 190.3 min (SD: 57), and mean warm ischemia time was 19.2 min (SD: 10.72). In 36 cases (9%), an unclamped hilum technique was used. After a mean follow-up of 12.4 mo (SD: 12.2), there was a decline of 9.2 ml/min per 1.73 m 2 (SD: 26.56) in estimated glomerular filtration rate. Most renal masses were malignant (74.5%), and the overall mean tumor size was 3.05 cm (SD: 1.66). Renal cell carcinoma with a clear cell histology represented the most frequent malignant diagnosis (64.4% of cases). A positive margin was observed in nine cases (2.25%). A total of 11 intraoperative complications (2.7%) occurred, and a conversion to open or laparoscopic PN was required in six cases (1.5%). A postoperative complication occurred in 61 cases (15.3%), the majority of them being low grade. Conclusions: The standardization of each surgical step has allowed for optimization of RALPN and ultimately improved its outcomes and expanded its indications. # 2012 European Association of Urology. Published by Elsevier B.V. All rights reserved. * Corresponding author. Glickman Urological and Kidney Institute, Cleveland Clinic, 9500 Euclid Avenue/Q-10, Cleveland, OH 44195, USA. Tel. +1 216 444 2976; Fax: +1 216 445 7031. E-mail address: kaoukj@ccf.org (J.H. Kaouk). 0302-2838/$ see back matter # 2012 European Association of Urology. Published by Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.eururo.2012.05.021

554 EUROPEAN UROLOGY 62 (2012) 553 561 [(Fig._1)TD$FIG] 1. Introduction Open partial nephrectomy (PN) continues to be the reference nephron-sparing surgery (NSS) procedure. Active surveillance and ablative technologies have emerged over the last few years as potential alternatives in selected patients [1,2]. Laparoscopic PN (LPN) has been mainly limited to experienced laparoscopic surgeons [3,4]. Robotic technology is being increasingly adopted in urologic surgery. Because of its unique features, the current robotic platform allows facilitation of a complex procedure such as LPN. Since the first report showing the feasibility of robot-assisted laparoscopic PN (RALPN) [5], a steadily increasing number of series has been reported [6]. Additionally, indications for RALPN have significantly expanded to include more challenging cases [7,8]. At our institution, an RALPN program was started in 2006 [9] and has been consistently implemented since [10 13]. In this paper, along with the accompanying video material, we describe our contemporary surgical technique and analyze corresponding cumulative surgical outcomes at our high-volume tertiary center. 2. Patients and methods 2.1. Study population Medical charts of consecutive patients who underwent RALPN at the Cleveland Clinic between June 2006 and November 2011 were reviewed from a prospectively maintained, institutional review board approved database. Absolute and elective indications for RALPN have been applied and based on a variety of factors, including tumor factors (size, location, and relation with the hilum and collecting system), and patient factors (sex, comorbidities, body mass index [BMI], previous surgical procedures, presence of renal insufficiency or anatomic anomalies, and personal preferences). 2.2. Surgical technique A detailed illustration of the surgical technique for RALPN used at our institution can be found in the accompanying video material. 2.2.1. Preoperative planning and robotic instrumentation Tumor size, location, endophytic nature, and proximity to the collecting system are examined on preoperative abdominal computed tomography (CT) or magnetic resonance imaging and a RENAL nephrometry score is determined [19]. A comprehensive staging assessment is undertaken. Anticoagulants are discontinued for a week before the operation when feasible. A bowel preparation is done the day before surgery. The da Vinci surgical system (Intuitive Surgical Inc., Sunnyvale, CA, USA) is generally used in a three-arm configuration. The following robotic instruments are used: 308 down scope, ProGrasp forceps and Hot Shears monopolar curved scissors (both from Intuitive Surgical Inc., Sunnyvale, CA, USA), permanent cautery hook, and large needle driver. 2.2.2. Patient positioning, port placement, and robot docking The patient is positioned in a modified flank position at approximately 608. Pressure points are carefully padded with pillows and foam pads and the patient is secured to the table with a tape. The surgical table is mildly flexed and positioned in a slight Trendelenburg position. Fig. 1 Port configuration used during robot-assisted laparoscopic partial nephrectomy. (a) Right-side port placement. (b) Left-side port placement. C = 12-mm port for the robotic scope; R = 8-mm ports for the robotic instruments; A = 12-mm port for the assistant; L = 5-mm port for liver retraction. A transperitoneal approach is used. A similar port configuration is used for both right and left sides, as illustrated in Figure 1. The abdomen is insufflated to 15 mm Hg with a Veress needle at the lateral border of the rectus muscle across from the 12th rib. This serves later as the site for a 12-mm port through which the robot scope is inserted. An 8-mm robot port is placed at the lateral border of the ipsilateral rectus muscle, about 3 cm below the costal margin. A second 8-mm robot port is placed about 5- to 7-cm cephalad to the anterior superior iliac spine. An assistant 12-mm port is placed along the lateral border of the rectus muscle in the lower abdominal quadrant. On the right side, an additional 5-mm port is placed in the subxiphoid area to retract the liver. Port configuration can vary based on tumor location to optimize the working angles. For upper pole tumors, all the ports can be shifted 1- to 2-cm cephalad. Moreover, an extra 5-mm assistant port between the camera and the right robot port can be placed to allow the assistant better access to the operative field. For posterior tumors, all the ports can be shifted medially, as the kidney needs to be mobilized to allow access to its posterior aspect. The robot is positioned over the patient s shoulder so that its axis makes an obtuse angle in relation to the patient s axis to have the camera oriented in line with the kidney (Fig. 2). 2.2.3. Bowel mobilization On the right side, liver retraction is obtained by introducing a locking Allis clamp through the 5-mm subxiphoid port. With a Hot Shears monopolar curved scissors in the surgeons right hand and a ProGrasp forceps in the left hand, the peritoneum is sharply incised along the white line of Toldt. The bowel is mobilized medially, developing a plane anterior to Gerota s fascia and posterior to the mesocolon by using both sharp and blunt dissection. Attachments to the spleen or liver are released as necessary.

[(Fig._2)TD$FIG] EUROPEAN UROLOGY 62 (2012) 553 561 555 hilar vessels are circumferentially dissected to allow adequate placement of bulldog clamps. Occasionally, a Satinsky clamp is chosen for en bloc hilar occlusion. It is important not to miss early arterial branching that is more common on the right side, especially if a venous occlusion is planed, as this may lead to kidney congestion and may result in more bleeding. Once the main landmarks are identified at this stage, extensive manipulation of the ureter should be avoided to minimize risk of injuries or devascularization. If an early branching or bifurcation is suggested by the CT scan, the dissection can go medially. Countertraction, which the assistant can provide by using suction, is important at this step, and it is important to make sure that the artery is well surrounded. A hook can be used according to the surgeon s preference. Fig. 2 Operating room arrangement during robot-assisted laparoscopic partial nephrectomy. The robot is positioned over the patient s shoulder so that its axis makes an obtuse angle in relation to the patient s axis and the camera is oriented in line with the kidney. It is important to stay outside Gerota s fascia during bowel mobilization. On the right side there is no need for extensive mobilization of the bowel to expose the renal hilum. During the mobilization of the duodenum medially, the use of cautery is minimized. The gonadal vein is an important anatomic landmark when proceeding toward the renal hilum. On the right side, the gonadal vein is kept medially toward the vena cava, whereas on the left side, the gonadal vein is lifted along with the left ureter to expose the lower margin of the left renal hilum. 2.2.4. Hilum dissection Dissection proceeds along the psoas muscle with anterior elevation of the ureter and/or gonadal vein to identify the renal hilum (Fig. 3). The renal vein can be identified by tracing the gonadal vein proximally to its insertion in the renal vein on the left side or to its insertion in the inferior vena cava just caudal to the hilum on the right side. A flexible robotic Doppler probe (Vascular Technology Inc., Nashua, NH, USA) can be used to identify hilar vessels before clamping, especially in cases involving multiple renal arteries or early branching. The main [(Fig._3)TD$FIG] 2.2.5. Tumor exposure, identification, and demarcation Gerota s fascia is opened in an area far from the tumor to find the capsule, and dissection is performed along the renal capsule until the mass is exposed. The exposure is kept wide; a clue that one is approaching the tumor area is the presence of adhesions. The fat is then cleared circumferentially around the mass, allowing for visualization of 1 2 cm of normal parenchyma for future renal reconstruction. All attempts should be made to leave the overlying Gerota s fascia atop the mass to assist in histopathologic staging and also to use as a handle for retraction. A laparoscopic ultrasound probe, which is introduced, held, and maneuvered manually by the surgical bedside assistant, is used to plan the excision margins by allowing accurate identification of the location, depth, and borders of the tumor (Fig. 4). A recently introduced, drop-in, flexible, ultrasound probe (ProART Robotic Drop-In Transducer 8826; BK Medical, Peabody, MA, USA) was specifically developed for robotic surgery and can be directly controlled by the console surgeon by grasping a notch on its ventral aspect. Live intraoperative images are shown as a pictureon-picture display on the console screen using the TilePro functionality of the da Vinci surgical system. To define the border of the tumor, the ultrasound probe is oriented parallel to the tumor border. Margins of resection of the renal capsule are scored with cautery to delineate the resection boundaries. 2.2.6. Hilar control and tumor resection All necessary material, including sutures and instruments, are confirmed to be at hand before proceeding with this step. Before hilar occlusion, [(Fig._4)TD$FIG] Mannitol 12.5 g is given intravenously to aid in renal protection by Fig. 3 Main anatomic landmarks during right-side robot-assisted laparoscopic partial nephrectomy: Dissection proceeds along the psoas muscle with anterior elevation of the ureter to identify the renal hilum. IVC = inferior vena cava. Fig. 4 A laparoscopic ultrasound probe is used to plan the excision margins by allowing accurate identification of the location, depth, and borders of the tumor. Note that the ultrasound probe is moved parallel to the tumor margins with a translational movement and in different orientations to circumferentially delineate the resection margins.

556 [(Fig._5)TD$FIG] EUROPEAN UROLOGY 62 (2012) 553 561 [(Fig._6)TD$FIG] Fig. 6 Once the hilum is occluded, the tumor is resected along the previously scored margin using cold scissors. The defect can be covered with oxidized cellulose (Surgicel, Ethicon Inc., Somerville, NJ, USA) and a fibrin sealant (Evicel; Ethicon, Inc.; or Vitagel; Orthovita, Malvern, PA, USA). Gerota s fascia is closed by using Hem-o-Lok clips. Fig. 5 Hilar clamping can be performed using either (a) laparoscopic bulldog clamps or (b) a Satinsky clamp, which needs a dedicated port. 2.2.8. Specimen retrieval and closure A laparoscopic entrapment sac is introduced by the assistant; the specimen is placed in the sac and removed from an extended lower quadrant port site. Care must be taken to make the extraction incision large enough to avoid fracturing the specimen, possibly preventing accurate histopathologic examination for margin status and staging. All 12-mm incisions are closed with 0-Vicryl suture by using the Carter-Thomason device (Inlet Medical Inc., Eden Prairie, MN, USA). A Jackson-Pratt drain is placed through a lower lateral port. facilitating osmotic diuresis. Hilar clamping can be performed using either laparoscopic bulldog clamps or a Satinsky clamp (Fig. 5). If bulldog clamps are used, the renal artery is clamped first, and then the vein. In selected cases, resection may be performed by clamping the renal artery only. The Satinksy clamp needs a dedicated port and care must be taken to avoid collisions with other instruments. More recently, robotic bulldog clamps (Scanlan International, St. Paul, MN, USA), applied by the console surgeon using the robotic ProGrasp, have also become available. The hilum is occluded and the tumor resected along the previously scored margin using cold scissors (Fig. 6). The bedside assistant uses suction to clear the resection bed, enabling improved visualization while applying slight counter retraction, as needed. 2.2.7. Renorraphy Renorrhaphy is performed in two layers using robotic needle drivers. A 20-cm 2-0 Vicryl suture on an SH-1 needle (Ethicon Endo-Surgery, Somerville, NJ, USA) with a knot and Hem-o-Lok clip (Teleflex Medical, Kenosha, WI, USA) applied to the free end is used as a running suture of the tumor excision bed to oversew larger vessels and entries into the collecting system. The suture is brought through the renal capsule with the final throw and secured with two sliding Hem-o-Lok clips. The renal capsule is reapproximated using a continuous, horizontal mattress 0-Vicryl suture on a CT-1 needle with a sliding Hem-o-Lok clip [14] placed after each suture is passed through the capsule (Fig. 7). After the completion of renorraphy, the hilum is unclamped, and the renal excision bed is inspected for hemostasis with pneumoperitoneum pressure lowered to 6 mm Hg. Hem-o-Lok clips may be cinched down a little further to secure hemostasis. Whenever possible, the hilum is unclamped before capsular suturing in an early unclamping technique to minimize warm ischemia time (WIT). 2.3. Postoperative care and follow-up Intravenous fluids, analgesics, antibiotics, and prophylaxis for deep vein thrombosis are given per institutional protocol. Hemoglobin levels and hematocrit are monitored in the postoperative period. The Foley catheter and drain are usually removed on the morning after surgery; ambulation is encouraged, and the diet is advanced. 2.4. Data analysis Collected data included patient age, BMI, sex, race, American Society of Anesthesiologist (ASA) score, Charlson Comorbidity Index, maximum tumor size, operative time, WIT, estimated blood loss, intraoperative conversion rate, length of hospital stay, perioperative transfusion rate, tumor stage, rate of positive margins (calculated considering only patients with malignant diseases), pathologic data [15], tumor complexity according to the RENAL nephrometry score [16], and number of postoperative complications (Clavien classification) [17]. Descriptive analyses were used to describe the characteristics of the patient samples, expressed as the mean percentages and frequencies. 3. Results 3.1. Demographics A total of 400 patients were included in this analysis (Table 1). Standard deviation (SD) is given in parentheses. Mean age was 58.5 yr (SD: 11.9), BMI was 30.7 kg/m 2

[(Fig._7)TD$FIG] EUROPEAN UROLOGY 62 (2012) 553 561 557 Fig. 7 Renorrhaphy is performed in two layers using robotic needle-drivers: (a) 20-cm 2-0 Vicryl suture on an SH-1 needle with a knot and Hem-o-Lok clip applied to the free end is used as a running suture of the tumor excision bed to oversew larger vessels as well as entries into the collecting system; (b) the suture is brought through the renal capsule with the final throw and secured with two sliding Hem-o-Lok clips; (c and d) the renal capsule is reapproximated using a continuous, horizontal mattress 0-Vicryl suture on a CT-1 needle with a sliding Hem-o-Lok clip placed after each suture is passed through the capsule. (SD: 7.2), with a mean ASA score of 2.5 (SD: 0.5). Based on preoperative imaging, mean tumor size was 3.17 cm (SD: 1.64), and the mean RENAL score was 7.2 (SD: 2). In six cases (1.5%), the patient presented with a solitary kidney, and in 247 cases (62.2%), there was a history of previous abdominal or pelvic surgery. 3.2. Perioperative outcomes These are summarized in Table 2. Mean total operative time was 190.3 min (SD: 57), and mean WIT was 19.2 min (SD: 10.72). In 36 cases (9%), an unclamped technique was used. After a mean follow-up of 12.4 mo (SD: 12.2), there was a decline of 9.2 ml/min per 1.73 m 2 (SD: 26.56) in the estimated glomerular filtration rate. 3.3. Pathology The tumor pathology is detailed in Table 3. Most (74.5%) of the masses were malignant and the overall mean tumor size was 3.05 cm (SD: 1.66). Renal cell carcinoma with a clear cell histology represented the most frequent malignant diagnosis (64.4% of cases). The tumor stage was T1a and T1b in most cases. A positive margin was observed in nine cases (2.25%); one of these was a case of angiomyolipoma. Among the benign masses, oncocytoma was the most common (42.1% of cases). 3.4. Conversions and complications A total of 11 intraoperative complications (2.7% of cases) occurred (Table 4). In eight cases, the procedure was not completed as planned due to conversion to open or LPN (six cases, 1.5%) or to robotic radical nephrectomy (one case, 0.25%). A postoperative complication occurred in 61 cases (15.3%) (Table 5). The majority of these complications were low grade, with major (grade 3 and 4) complications occurring only in 3.2% of the entire cohort. There was no case of multiple organ dysfunction (grade 4b) or death (grade 5). 4. Discussion Careful patient selection is of utmost importance early in the surgeon s experience with RALPN. The ideal candidate

558 EUROPEAN UROLOGY 62 (2012) 553 561 Table 1 Demographics of the study cohort Table 3 Pathology Patients, no. 400 Age, yr Mean (SD) 58.5 (11.9) Median (IQR) 59 (51 67) Male patients, no. (%) 233 (58) BMI, kg/m 2 Mean (SD) 30.7 (7.2) Median (IQR) 29.2 (25.8 34) ASA score Mean (SD) 2.5 (0.5) Median(IQR) 3 (2 3) CCI Mean (SD) 4.2 (1.8) Median (IQR) 4 (3 5) Solitary kidney, no. (%) 6 (1.5) Previous abdominal surgery, no. (%) 248 (62) Preoperative creatinine, mg/dl Mean (SD) 0.96 (0.3) Median (IQR) 0.9 (0.7 1.1) Preoperative egfr, ml/min per 1.73 m 2 Mean (SD) 84.5 (30.7) Median (IQR) 85.16 (69.8 97.5) Tumor size, cm Mean (SD) 3.17 (1.64) Median (IQR) 2.8 (2 4) Tumor on right side, no. (%) 209 (52.3) RENAL score, n = 310 Mean (SD) 7.2 (2.0) Median (IQR) 7 (5 9) SD = standard deviation; IQR = interquartile interval; BMI = body mass index; ASA = American Society of Anesthesiology; CCI = Charlson Comorbidity Index; egfr = estimated glomerular filtration rate. All patients Malignant, no. (%) 298 (74.5) Benign, no. (%) 102 (25.5) Pathologic tumor size, cm Mean (SD) 3.05 (1.66) Median (IQR) 2.6 (1.9 3.9) Positive surgical margins, no. (%) 9 (2.25) Malignant, no. (%) RCC, clear cell 192 (64.4) RCC, papillary 67 (22.5) RCC, chromophobe 19 (6.4) RCC, mixed 8 (2.7) RCC, unclassified 9 (3) Other malignant 3 (1) RCC pathologic stage pt1a 215 (72.9) pt1b 58 (19.7) pt2 4 (1.4) pt3a 18 (6.1) Benign patients, no. (%) Oncocytoma 43 (42.1) Benign cyst 23 (22.5) Angiomyolipoma 22 (21.5) Adenoma 5 (4.9) Others 9 (8.8) SD = standard deviation; IQR = interquartile interval; RCC = renal cell carcinoma. Table 2 Perioperative outcomes Intraoperative variables Operative time, min Mean (SD) 190.3 (57) Median (IQR) 180 (150 210) Unclamped, no. (%) 38 (9.5) Early unclamping, no. (%) 80 (20) Warm ischemia time, min Mean (SD) 19.2 (10.72) Median (IQR) 19 (14 25) Estimated blood loss, ml Mean (SD) 260.2 (277.2) Median (IQR) 200 (100 300) would be a patient with predominantly exophytic T1a lesions, uncomplicated vascular anatomy, and a normal contralateral kidney. On the one hand, female patients present relative paucity of perirenal fat, which facilitates tumor dissection. On the other hand, posterior upper pole masses, especially on the right side; hilar masses; and deeply endophytic tumors can be more challenging, especially in patients with a solitary kidney or severely impaired baseline renal function [18]. Nevertheless, indications have been steadily expanded over the last few years. Successful outcomes have been reported for obese patients [19] and those with prior abdominal surgery [20] as well for challenging masses such Postoperative variables Length of stay, d Mean (SD) 3.6 (1.94) Median (IQR) 3 (3 4) Latest postoperative creatinine, mg/dl Mean (SD) 1.08 (0.39) Median (IQR) 1 (0.83 1.22) Change in creatinine, mg/dl Mean (SD) 0.11 (0.27) Median (IQR) 0.1 ( 0.01 to 0.2) Latest postoperative egfr, ml/min per 1.73 m 2 Mean (SD) 75.17 (23.3) Median (IQR) 74.4 (60.7 88.8) Change in egfr, ml/min per 1.73 m 2 Mean (SD) 9.2 (26.56) Median (IQR) 7.6 ( 18.86 to 0.54) SD = standard deviation; IQR = interquartile interval; egfr = estimated glomerular filtration rate. Table 4 Conversions and intraoperative complications Conversions, no. (%) To laparoscopic partial nephrectomy 4 (1) To open partial nephrectomy 2 (0.5) To robotic radical nephrectomy 1 (0.25) Intraoperative complications, no. (%) 11 (2.7) Vascular injury 5 Organ injury 4 Pleura injury 1 Reclamp 1 Postoperative, no. (%) 61 (15.3) Grade I 12 Grade II 36 Grade III 8 Grade IV 5 Grade V 0

EUROPEAN UROLOGY 62 (2012) 553 561 559 Table 5 Details of postoperative complications Overall, no. (%) Event (no.) Grade I 12 (3) Wound infection (1), ileus (10), metabolic (1) Grade II 36 (9) Transfusion (29), pneumonia (2), atrial fibrillation (2), DVT (2), PE (1) Grade III 8 (2) Angioembolization (1), pneumothorax (1), DVT/PE (4), Urine leak (2) Grade IV 5 (1.2) Temporary dialysis (1), atrial fibrillation (2), sinus bradycardia (1), pulmonary edema (1) Grade V 0 DVT = deep venous thrombosis; PE = pulmonary embolism. as hilar lesions [7], large tumors [8], complex lesions [10], and multifocal disease [11,12]. Notably, our study population presents a high mean BMI, a significant rate of patients with prior abdominal surgeries, and moderately to highly complex tumors. This reflects the referral pattern for our tertiary care institution, similar to what has been reported in large series from other major centers [6,8,21,22]. To optimally prepare the patient for the procedure, a thorough laboratory and imaging assessment is needed. This work-up also allows determining main tumor features, including tumor size, location, endophytic nature, and proximity to the collecting system, and establishing an objective parameter of tumor complexity, as based on of the currently available scoring systems [16,23,24]. It has been shown that anatomic tumor characteristics are independent predictors of WIT and overall complications [22,25]. In general, we witnessed an expanding range of indications for RALPN in our center, whereas other minimally invasive NSS treatment options have been offered to a more selected patient population [26]. A transperitoneal approach is the one most adopted for RALPN. In a few centers, a retroperitoneal approach has been described [27] and this may be an option of interest for patients with prior multiple abdominal surgeries or for posterior tumors. In case of transperitoneal approach in the setting of prior abdominal surgery, the Veress needle should be placed farthest from the previous incision. Eventually, a directvision placement of the initial trocar can be performed to maximize safety [20]. In obese patients, the entire port template can be shifted laterally, and in morbidly obese patients, extralong robotic trocars may be used [19,28]. Trocar configuration remains a key factor in the operative set up for standard laparoscopy, as it can affect the ergonomics of the procedure. A variety of configurations were described among the institutions pioneering the technique, each one with some recognized advantages and disadvantages [29]. The medial trocar configuration, implying a 308 down scope placed near the umbilicus, offers a wide viewing angle with a perspective that is familiar to the experienced laparoscopic surgeon [14,30]. Alternatively, a lateral camera position, with a 308 upscope, has been described [29,31]. One potential disadvantage can be the proximity of the scope to the kidney that may limit the surgical field. Our three-arm configuration involves the camera port and the two robotic ports at the level of the lateral edge of the rectus muscle. We spread them as much as possible to take advantage of the entire space and minimizing clashing. A four-arm approach has been suggested to allow the console surgeon to perform more tasks independently of the bedside assistant [32,33], especially in cases of complex tumors [34]. Identification of vascular structures represents a crucial and technically demanding step during renal surgery. The dissection of the renal hilum may pose a challenge because of the variable number and position of hilar vessels. Even if they help delineate hilar anatomy, preoperative imaging techniques are not always accurate [35]. Thus laparoscopic Doppler technology has been described for minimally invasive renal surgery and shown to reduce time and improve sensitivity for hilar dissection [36]. More recently, near-infrared fluorescence imaging after injection with indocyanine green has been described [37]. Minimizing WIT remains a key aspect of any NSS procedure [38]. Clamping of the renal hilum can be done using either laparoscopic bulldog clamps, a Satinsky clamp, or, more recently, robotically applied bulldog clamps, which is what we routinely use at our center. In selected cases, RALPN can be safely performed without renal hilar occlusion [39] or by an early unclamping technique [40]. This was applied in 9.5% and 20% of our cases, respectively. Renorraphy following tumor resection represents a key step of the procedure. Sliding-clip techniques were introduced and developed to allow more precise control and readjustment of the tension placed during suturing, while reducing the ischemia time. These techniques are now commonly adopted by several groups [21]. Over the years, we standardized our renorraphy technique, obtaining a significant improvement in the surgical outcomes [13]. In case of hilar tumors, we developed a specific novel renorraphy technique: the V-shaped hilar suture [41]. Some authors suggested that the use of barbed suture simplifies the renorrhaphy and improves efficiency, allowing for reduced WITs [42]. The placement of a laparoscopic Simon clamp across the renal parenchyma, 2 3 cm proximal to the resection line, to facilitate tumor excision has also been described [43]. A zero ischemia selective branch microdissection of the renal artery and vein coupled with carefully timed intraoperative reduction in blood pressure has also been proposed [44]. This study was intended to be focused on our surgical technique for RALPN and to report our cumulative outcomes. Notably, this represents the largest single-center series to date. Comparative analyses with other PN techniques as well as analysis of predictive factors of the surgical outcomes were not provided, and this can be regarded as a study limitation. 5. Conclusions Our technique for contemporary RALPN is detailed in this paper. The standardization of each surgical step has allowed

560 EUROPEAN UROLOGY 62 (2012) 553 561 optimization of the procedure and, ultimately, an improvement of its outcomes. The robotic approach offers the option of minimally invasive NSS, which is likely to duplicate the safety and effectiveness of the current reference open technique. Author contributions: Jihad H. Kaouk had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis. Study concept and design: Autorino, Kaouk. Acquisition of data: Hillyer, Khalifeh. Analysis and interpretation of data: Autorino, Kaouk. Drafting of the manuscript: Autorino. Critical revision of the manuscript for important intellectual content: Stein, Haber, Hillyer, Kaouk. Statistical analysis: Khalifeh. Obtaining funding: None. Administrative, technical, or material support: None. Supervision: Kaouk. Other (specify): None. Financial disclosures: Jihad H. Kaouk certifies that all conflicts of interest, including specific financial interests and relationships and affiliations relevant to the subject matter or materials discussed in the manuscript (eg, employment/ affiliation, grants or funding, consultancies, honoraria, stock ownership or options, expert testimony, royalties, or patents filed, received, or pending), are the following: Jihad Kaouk and Georges-Pascal Haber are consultants for Intuitive Surgical. Funding/Support and role of the sponsor: None. Acknowledgment statement: Tamara J Khashab voiced the video material accompanying this manuscript. Appendix A. Supplementary data The Surgery in Motion video accompanying this article can be found in the online version at http://dx.doi.org/10.1016/ j.eururo.2012.05.021 and via www.europeanurology.com. References [1] Ljungberg B, Cowan NC, Hanbury DC, et al. EAU guidelines on renal cell carcinoma: the 2010 update. Eur Urol 2010;58:398 406. 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