One of the more common and challenging complications of RAPN is intraoperative hemorrhage from the resection bed. This complication arises from inadequate or improper control of the renal vessels, which can result in poor operative visualization, increased risk of tumor violation and positive margins, urine leak, and conversion to open surgery or radical nephrectomy. Hemorrhage can result from either arterial bleeding and/or venous back bleeding, each of which presents unique challenges in management.

Prior to performing a RAPN it is imperative to review all available cross-sectional imaging to study the details of both the renal artery and vein as well as duplicates when present. This includes reviewing both axial and coronal images as both sets of images can provide nuances of the renal vascular anatomy and proximity to surrounding structures such as the collecting system as well as the tumor. Approximately 25% of patients have more than one renal artery. These arteries may be duplicates that have a similar caliber or they may be an accessory artery with a smaller caliber. Accessory arteries usually arise from the aorta and supply the poles. Right renal vein duplication is found in approximately 15–20% of cases, and it is infrequently duplicated on the left. Accessory renal veins are uncommon [8].

We routinely identify and skeletonize all renal arteries in preparation for clamping prior to tumor resection. Having a thorough understanding of the renal arterial “road map” from careful review of preoperative cross-sectional imaging is imperative so as to avoid unexpected arterial bleeding from a missed arterial vessel at the time of tumor excision. The authors strongly advise that a complete arterial clamping technique be used early in one’s experience as segmental arterial clamping often leads to more bleeding from adjacent areas of the kidney that remain perfused. However, with experience, a segmental arterial clamping technique can be selectively utilized based upon tumor size, location (e.g., polar vs midpole; exophytic vs endophytic vs mesophytic), proximity to adjacent structures (e.g., collecting system, hilar vessels), and overall tumor complexity. Another potential reason for arterial bleeding during tumor resection is due to inadequate coaptation of the artery by the laparoscopic bulldog clamps. This may be from incorporation of nearby adipose and connective tissue within the clamp or renal ostial calcifications, both of which may lead to incomplete occlusion of the artery by the bulldog clamp. This emphasizes the importance of prospectively skeletonizing the arteries down to the renal arterial adventitia as well as looking for the presence of renal ostial calcifications on preoperative imaging and clamping the vessel in a portion absent of calcifications. Furthermore, studies in porcine and human cadaver models have shown that differences in occlusion capabilities exist both within and between different laparoscopic bulldog clamps. In general, occlusion pressures are highest at the most proximal position on the clamp and lowest at the distal tip of the clamp. In addition, occlusive forces may decrease with increased duration of use [9, 10]. As a result of this, we routinely place two bulldog clamps on each artery to ensure adequate occlusion of blood flow.

Venous bleeding can also complicate RAPN. The influence of clamping the artery alone or the artery and the vein on renal function remains controversial in the literature [11–13]. The authors do not routinely clamp the renal vein during RAPN based upon the theoretical benefit that retrograde venous blood flow may provide partial oxygenation to the kidney; however, if excessive venous back bleeding is noted, a subsequent bulldog clamp is placed on the vein at that time. In our experience, the need to clamp the renal vein is uncommon in peripherally located tumors versus those located near the larger venous branches in the renal hilum. Perhaps paradoxically, in cases where the renal vein is clamped from the start and there is excessive venous back bleeding, we routinely unclamp the renal vein to allow venous blood to drain from the kidney which often decreases the bleeding at the resection bed. Taken together, the authors strongly recommend that all arteries and veins to the affected kidney be identified and skeletonized in preparation for clamping prior to tumor excision as attempts at identification and dissection of these vessels once bleeding occurs from the resection bed can be time-consuming and hazardous. Vessel loops can be placed around each vessel for easy and quick identification and access in case of bleeding.

There are several potential intraoperative complications related to kidney exposure at the time of RAPN affecting the bowel, spleen, pancreas, liver amongst the many major organs adjacent to the kidney.

For left-sided RAPN the descending colon must be mobilized off the entire surface of the kidney. For right-sided RAPN the ascending colon requires less mobilization as it is usually displaced medially on the surface of the lower pole of the kidney; however, one often has to mobilize the duodenum to adequately expose the renal hilum. In a meta-analysis, colonic and small bowel injuries have been reported to occur in up to 1.5 and 0.6% of laparoscopic radical nephrectomies, respectively [14]. Tanagho and colleagues reported a 0.1% risk of bowel injury in their series of RAPN [1]. In order to reduce the risk of bowel injury either directly or through thermal spread, we routinely incised the line of Toldt two centimeters lateral to the edge of the colon during our initial dissection and subsequent mobilization. Additionally, bowel injuries can occur as instruments are passed into the abdomen. As such, it is important for the assistant to carefully pass instruments and to notify the surgeon of any issues with passage such as perceived resistance.

If an injury is noted intraoperatively, attempts can be made to repair the injury robotically. Small serosal injuries can often be managed with Lembert sutures as needed. A general surgery consultation should be considered for larger injuries. Fortunately, most injuries can be repaired by multilayer closure, rarely requiring bowel resection or diversion [15]. Missed bowel injuries often present in a delayed fashion and require multiple procedures to manage the injury [16]. As such having a heightened awareness of such injuries is prudent with immediate repair.

Splenic injury has been reported to occur in up to 1.3% of laparoscopic renal surgeries and up to 0.5% of RAPN series [1, 3, 14]. Prevention focuses on using gentle, blunt retraction of the spleen to minimize the risk of tearing the splenic capsule or injuring the spleen from direct, sharp injury. Complete mobilization of the spleen requires sharp dissection of its lateral attachments. The use of an oral gastric tube keeps the stomach decompressed which minimizes the risk of injury to the stomach while allowing the spleen to fall more medially as it is mobilized. Most capsular lacerations can be managed conservatively with the use of coagulation from a variety of energy sources (e.g., monopolar or bipolar electrocautery, argon beam electrocoagulation) or hemostatic agents [17, 18]. If the bleeding is not able to be controlled with the above methods and/or the injury is large, splenectomy may be necessary. However, the incidence of such an injury is rare as previously stated.

Pancreatic injuries are uncommon at the time of left-sided RAPN. They are reported to occur in <0.5% of left-sided laparoscopic upper tract procedures [19]. Prevention focuses on complete mobilization of the spleen and pancreas en bloc. If injury to the pancreas is recognized intraoperatively, a general surgery consultation should be obtained. Management usually consists of surgical repair of the injury if possible (e.g., laparoscopic stapling across the distal pancreas) and making the patient NPO, placing a nasogastric tube, total parenteral nutrition, somatostatin and percutaneous drainage. Delayed injuries often result in a patient presenting with abdominal pain, elevated serum amylase and lipase, and a fluid collection seen on imaging.

Diaphragmatic injuries have been reported in <1% of laparoscopic and robotic renal surgeries [1, 20]. During left-sided RAPN, the diaphragm can be injured during mobilization of the spleen or the upper pole of the kidney. For right-sided RAPN the diaphragm can be injured with mobilization of the liver. Judicious use of monopolar electrocautery while dissecting near the diaphragm is important as electrical transmission to the phrenic nerve can result in sudden contraction of the diaphragm with inadvertent sharp injury from nearby instrumentation. One should suspect an injury if they see billowing of the diaphragm. The anesthesiologist should be notified to monitor respiratory sounds and airway pressure. If recognized intraoperatively, the pleurotomy should be repaired with interrupted figure-of-eight sutures. Before final closure, air should be evacuated from the pleural cavity. This can be done with a laparoscopic suction device through the defect or by having anesthesia give a large inspiratory breath before securing the stitches [20]. A postoperative chest x-ray should be obtained to look for any evidence of a residual pneumothorax. If recognized postoperatively, a thoracostomy tube can be placed.

Hepatobiliary injuries have been reported in <1% of both laparoscopic upper tract surgeries and RAPN [1, 7, 21]. Minor tears of the capsule of the liver can either be observed or electrocautery can be used for hemostasis. Larger tears or injury to the parenchyma may require the argon beam coagulator to obtain hemostasis. Injuries to the gallbladder should prompt intraoperative consultation to a general surgeon for cholecystectomy. Similar to the spleen, the liver should be retracted with blunt force while using sharp dissection to release its lateral attachments.

Chylous ascites is a rare but potential complication of predominately left-sided renal procedures as the ascending intestinal lymphatics that drain into the cisterna chyli travel in the para-aortic location. It occurs as a result of lymphatic leakage that usually results during dissection of the renal hilar vessels (in particular the renal artery) along the aorta. In the process of skeletonizing the left renal artery, perivascular lymphatics are often disrupted that may lead to lymphatic leak if not clipped and secured. If large lymphatics are encountered, they should be directly clipped as electrocautery is generally insufficient at sealing lymphatic vessels. If chylous ascites develops postoperatively, it can usually be managed conservatively with a medium -chain triglyceride diet or total parenteral nutrition and somatostatin [22].

Vascular injuries can occur from inadvertent injury from Veress needle and trocar placement, sharp dissection, avulsion during dissection, thermal injury, and injury during robotic instrument exchange. Venous injuries are more common than arterial injuries.