Although robotic and laparoscopic techniques for partial nephrectomy have traditionally been used for less complex tumors smaller than 4 cm in size, indications for further use have expanded in recent years. Robotic assistance has proved useful for mobilization and intracorporeal suturing, decreasing clamp time, and making excision of tumors more precise and accurate. Even complex endophytic tumors can be safely removed in experienced hands.
The role of warm ischemia time on renal function outcomes is of much debate. Vascular clamping is commonly used in laparoscopic and robotic partial nephrectomy because it provides better visualization in a bloodless field. A large meta-analysis covering 91 papers revealed that renal function preservation is strongly associated with preoperative renal function and that warm ischemia time predicts long-term functional parenchyma. Twenty-five minutes has been used as a rough guideline for upper extent of warm ischemia time; however, a limited number of studies exist that expound that damage occurs before 25 minutes. Several studies have shown no compromise up to 40 minutes. Nonetheless, the shorter the time, the less chance of renal injury especially in cases of prior renal compromise from factors such as diabetes, hypertension, and other medical comorbidities.
Special circumstances, including previous surgeries, large tumor size, tumors that approach the hilum or are seen to be invading the collecting system on imaging studies, and the presence of a solitary kidney, may necessitate an open approach. Solitary kidney should be approached with extreme caution with appropriate case selection. If a prolonged clamp time is anticipated, an open approach with cold ischemia should be strongly considered. Laparoscopic partial nephrectomy is possible under most circumstances in which a tumor meets criteria to be stage T1a or T1b; however, pure laparoscopy requires significant skill with intracorporeal suturing and exposure.
Preoperative imaging should be performed with either a multiphase computed tomography (CT) angiogram or magnetic resonance imaging. These studies will give a detailed assessment of the vessels and delineate the tumor in relation to vessels and collecting system. It is important to note the presence of aberrant or multiple vessels before surgery. In some cases, contrast imaging is not possible because of poor renal function. In such cases, one must get as much out of the noncontrast imaging as possible.
At our institution, preoperative antibiotics are given according to the American Urological Association (AUA).
As presented by the AUA in its Best Practice Statement: A first- or second-generation cephalosporin is used for antibiotic prophylaxis, with the alternative being an aminoglycoside, in combination with ampicillin, or a fluoroquinolone. It is important to note that the FDA issued a strong warning against the use of fluoroquinolones in July 2016 as they have serious side effects. Perioperative use was not specifically addressed, so these antibiotics should be used with caution. Before surgery, a preoperative urine dipstick, urinalysis, and urine culture are performed to ensure that there is no active urinary tract infection. The patient should be consented for a possible open surgical approach in the event the tumor is not amenable to a minimally invasive approach but is to an open approach. In addition, total nephrectomy should be discussed in the event the tumor is not amenable to partial nephrectomy or there is a complication such as uncontrolled bleeding. Because these patients are at risk for thromboembolic events, we recommend preoperative use of 5000 units of subcutaneous heparin in conjunction with sequential compression devices.
Historically, mannitol’s use was indicated because of theories that it decreased the risk of renal dysfunction and lessened the effect of ischemia during clamp time. It is commonly used with donor nephrectomy. However, the paucity of research in this specific aspect of procedure has prompted studies to evaluate its effectiveness. Power et al’s review of 285 patients at their institution illustrated that use of intravenous (IV) mannitol did not improve renal function recovery compared with patients who did not receive the diuretic in the 6-month perioperative period.
Before the procedure, it is important to ensure that all necessary instruments are available and in the room. Dissection and tumor excision during robotically assisted partial nephrectomy can be carried out with a monopolar curved scissor or monopolar hook in the right hand and a Maryland bipolar or fenestrated bipolar in the left hand. For the renorrhaphy, needle drivers are used in both hands. If the surgeon elects to use the fourth arm, a fenestrated bipolar or ProGrasp may be useful for retraction and optimal positioning of the kidney.
After induction of anesthesia, placement of a 5-Fr ureteral catheter over a glidewire with a flexible cystoscopy can be performed before positioning. This is especially useful in endophytic or larger tumors when injury of the collecting system is more likely. A Foley catheter is then placed in the bladder. A syringe of methylene blue and IV tubing should be attached to the 5-Fr ureteral catheter and placed in an accessible position for the circulating nurse to inject during renorrhaphy so the surgeon can evaluate for collecting system injuries and guide repair. This step may be omitted for small peripheral tumors.
Proper positioning is imperative to avoid neuromuscular injuries. A modified flank position is used for laparoscopic and robotically assisted partial nephrectomy. The patient should be positioned over the kidney rest or the break in the bed in the event that it is necessary to raise the kidney; however, the bed should stay in the full nonflexed position with the kidney rest down unless indicated. The patient should be bumped approximately 30 degrees from the bed with the affected kidney’s side up; a medium bump or the cushion from the armboard can be used and should be placed behind the cervical spine and terminate at the small of the back. The arm on the ipsilateral side should be positioned on a floating armrest over the body with the shoulder in a neutral position. It is important to ensure that the position of the arm will not interfere with the left robotic arm. Additionally, the surgeon should ensure that the shoulder is at a neutral position and resting comfortably on the armrest without pressure on the shoulder joint to avoid neurapraxia. The bottom arm should be normally positioned on the armboard ( Fig. 13.1 ).
The bottom leg on the contralateral side to the affected kidney is bent with the top leg straight and pillows in between the legs. Alternatively, the legs can remain in the supine position with heel pads in place to avoid pressure on the heels.
We do not use an axillary role with the modified flank position described. However, use of an axillary roll is indicated when the full flank positioning is used. All pressure points should be checked again and padded. Foam pads cut in strips and silk tape are used to secure the patient to the bed at the level of the hips (ensuring not to apply pressure to the penis) and the lower legs and over the floating armboard. These should not overlie the knees and should be loose enough to allow a hand to slide under them without difficulty. The bed should be tilted left and right to ensure that there is no movement of the patient with change in bed position before prepping and draping.
The author prefers a transperitoneal approach for a majority of renal tumors because it provides more room and better visualization. Posterior tumors can also be accessed by this approach, but this requires more mobilization of the colon, spleen, and pancreas on the left and the colon and duodenum on the right to medially rotate the kidney. Very posterior tumors require complete mobilization of the kidney, especially the perirenal fat. To account for the new position of the kidney after medial rotation, the trocars may need to be shifted toward the contralateral side.
Alternatively, a retroperitoneal approach can be used for a posterior tumor or if there is a concern for intraabdominal adhesions when a patient presents with a history of multiple prior abdominal surgeries. This approach has been described in a previous chapter and should not be used unless the surgeon has marked experience with this approach.
Initially, a Veress needle is inserted perpendicularly to the fascia while pulling up on the fascia in the upper quadrant of the affected side. Marking of the port sites should be performed after the abdomen is insufflated. The camera and robotic arms are placed in a triangular formation as shown in Fig. 13.2 . In addition to the camera port and two robotic arms, there is an option to use the robotic third arm. The number of assistant ports inserted depends on the complexity of the tumor. A 12-mm assistant port is typically placed in the low midline between the medial ports in a position to ensure that it will not interfere with either the robotic arm or the camera arm. A paddle in the assistant port is used with regularity and has proven to be a very helpful tool for retraction of bowel during dissection. Additional assistant ports can be used as needed. It has been found useful to also use a 3-mm liver retractor for right-sided tumors; similarly, this can be used on the left side to lift the spleen.
Dissection and Mobilization
Mobilization of the kidney in the retroperitoneal or transperitoneal approach have been described in Chapter 12 for both left- and right-sided surgery. More mobilization of the kidney is usually required for the laparoscopic approach. Because laparoscopic instruments inherently lack articulating joints, it is important to provide adequate exposure so the kidney can be moved during cutting and suturing. Some instances may require the adrenal gland to be dissected off the kidney to adequately approach the tumor. Dissection of lumbar and gonadal vessels may also be necessary on the left side to visualize the renal artery and vein. During mobilization, the fourth arm may be helpful for retraction, but crowding of the robotic arms may limit use in thin patients in which case an assistant can be used. Special considerations should be taken for “sticky fat” around the kidney, requiring dissection directly onto the renal capsule away from the tumor site and extension of the dissection towards the tumor. This is a slow and tedious process that is necessary to adequately visualize the tumor. Failure to do so may result in inadvertent incision into the tumor capsule. The hilum can either be dissected robotically or laparoscopically ( Fig. 13.3 ). This depends on surgeon preference, and there are risks and benefits of each. Robotic dissection allows for use of instruments with more range of motion at the expense of haptic feedback. Pure laparoscopic dissection allows for haptic feedback but more limited instrument versatility. It must be noted that on the right side, the renal vein is shorter, and the surgeon must be aware of the adrenal vein; tearing this can cause significant bleeding and loss of visualization.