Introduction
Open kidney transplantation (OKT) is considered the gold standard treatment for end-stage renal disease as it is able to achieve a greater survival rate and a better quality of life in comparison to hemodialysis. The introduction of this surgical technique, in the second half of the last century, is considered a milestone in the history of surgery. The first successful cadaveric kidney transplantation was performed in 1953 and earned the Nobel Prize for Medicine in 1990 for Dr. Joseph Murray.
Despite the open technique being the standard approach in KT, minimally invasive alternatives have been introduced and carried out in many centers around the world, with the aim to reduce postoperative morbidity and improve surgical performance. The first step toward a less invasive surgery was the introduction of laparoscopy in kidney transplantation in 2009. , In 2013, the first large series of laparoscopic renal transplantation was published, enrolling 72 surgeries from living donors with a mean operating time of 224 minutes. Rewarming time was around 60 minutes, which was significantly longer than 30 minutes in the open surgery group. Functional outcomes were also compared to the standard technique, reporting comparable results in terms of graft and patient survival, with a median follow-up of 22 months. This new technique provided advantages in terms of wound infection and the need for analgesia, due to less postoperative pain with a subsequent faster recovery. Moreover, as a minimally invasive approach, better aesthetical results were observed. On the other hand, the procedure appeared challenging and needed robust expertise in laparoscopy to avoid reaching an unacceptable operative time. The anastomotic time was particularly challenging, with possible consequences for patients’ outcomes and graft survival. In fact, patients with end-stage renal disease have a higher risk of respiratory acidosis and hypertension due to carbon dioxide inflation of the peritoneum during long-time laparoscopic surgery. The obvious limitations of laparoscopic suturing techniques did not allow a widespread adoption of laparoscopic surgery for renal transplantation.
To overcome these limitations, robot-assisted kidney transplantation (RAKT) has shown promising results as a less invasive alternative to the open approach, with a minimal learning curve for surgeons experienced in robotic surgery.
Since the first RAKT performed in 2010, the surgical technique has been refined and standardized in highly experienced robotic centers around the world. Few authors have compared surgical and functional results with the open approach, showing possible advantages in selected cases, such as obese patients and multiple vessel grafts. , Furthermore, a structured program was developed in order to expand RAKT’s indication to deceased donors.
Robot-assisted kidney transplantation: Living donor
Background
Living donor nephrectomy
Around 20% of all kidney transplantations in Europe are performed using living donor grafts, while in the United States the percentage is up to 40%. A living donor’s kidney generally comes from familial or “emotionally related” donors. Compared to a deceased donor kidney, the use of a living donor graft has been shown to have advantages in terms of earlier graft function, longer graft survival, reducing waiting list. Furthermore, in the case of donation from a familiar ABO compatible, the receiver may take advantage of less aggressive immunosuppressive regimen. The left kidney is generally preferred for donation because of a longer renal vein, but in case of differing functions between the two kidneys, the kidney with the lower function is used. Until 1995, the standard surgical technique to extract the graft from the living donor was the open approach. This has been replaced by laparoscopic living donor nephrectomy. This newer procedure showed better results in terms of pain control, blood loss, hospital stay, and better aesthetic results, compared to the open technique.
Pushed by the minimal invasive revolution, in 2001 the Group of the University of Illinois (Chicago) reported the first series of robot-assisted laparoscopic donor nephrectomies, using the da Vinci Surgical System (Intuitive Surgical, Sunnyvale, CA). This new approach, despite its high costs, demonstrated to be feasible, reproducible, and safe. The vessels are usually divided with a da Vinci vascular stapler although an assistant-controlled stapler can also be used.
Living donor kidney transplantation
The first pure RAKT was performed in the United States in 2010. This technique was reproduced and refined by several authors. In 2014, Menon et al. described a standardized technique using a transperitoneal approach and guaranteeing regional hypothermia with the Vattikuti-Medanta technique. , In Europe, the first two RAKTs were performed in July 2015. In 2016, the European Association of Urology (EAU) Robotic Urology Session (ERUS-RAKT) formed a working group in order to follow RAKT’s outcomes. , To date in Europe, 11 centers joined the group with more than 300 procedures conducted with 1 year of follow-up, showing comparable outcomes with OKT.
Operative technique
See the box that follows for special equipment required.
Robotic instruments
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Fenestrated bipolar forceps
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Monopolar scissors
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Potts scissors
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ProGrasp forceps
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Needle driver (×2)
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Black diamond micro forceps
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Scalpel
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Arterial punch
Sutures
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PDS 5/0
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Gore-Tex 6/0 (CV-6 TTc-9 or THc-12 needle)
Robotic or laparoscopic bulldog clamps (×4)
Laparoscopic scissors, suction device, graspers, Hem-o-lok clip appliers
GelPOINTToomey syringes
Living donor nephrectomy
The most common technique used to perform living donor nephrectomy is the transperitoneal laparoscopic approach. Considering its functional results are comparable to the open and robot-assisted approach, this technique shows a better cost-benefit ratio.
Bench table preparation
Once the donor nephrectomy is performed, the graft preparation is carried out on the bench table, located close to the operative bed. The kidney is immediately positioned in a metallic basin, together with ice slush, to reduce its temperature and is perfused with 1 L of a cold storage solution (Custodiol→, Celsior→, Institut Georges Lopez-1→). As soon as the kidney has been perfused, the vascular dissection starts. In the case of multiple vessels, their reconstruction is performed on the bench table. According to the preference of the surgeon, the ureter can be prestented with a double-J. At this time, in order to provide a low graft temperature during the rewarming time and to protect the kidney from injuries, it is packed into a cooling system consisting in a gauze filled with ice-slush and subsequently positioned inside the operative field, according to Vattikuti-Medanta technique. At the level of renal hilum, a window is opened on the gauze in order to carry out the anastomosis while the graft is kept cool ( Fig. 24.1 ). As the ice slush melts rapidly, every 15 minutes ice is added through the GelPOINT→ (Applied Medical, Rancho Santa Margherita, CA) via modified Toomey syringes in order to keep the graft temperature below 20°C during the anastomosis.
Patient and trocar positioning
Patient positioning changes according to the robotic system employed. The lithotomy position is provided with da Vinci Si→ or X→ system whilst the dorsal decubitus position is used in the case of da Vinci Xi→. Twenty to 30 degrees Trendelenburg is recommended. First, the pneumoperitoneum is created with a 12 mm camera port inserted in the supra-umbilical area. Alternatively, Verres needle puncture, optical trocar access, or Hasson technique (open) may also be used. Then, three 8 mm robotic ports are placed under vision and the robot is docked. The trocar disposition could minimally change according to the robotic system used.
If Da Vinci Si→ is used, the 8-mm port for arm 3 is positioned on the intersection between the line joining the pubis to arm 4 with the umbilicus-anterior superior iliac spine line. If RAKT is carried out with Da Vinci Xi→, the robotic ports are placed in line in a simple and reproducible scheme ( Fig. 24.2 ).
At this point, in order to introduce the graft in the abdominal cavity and to also allow the introduction of ice slush, a GelPOINT→ is positioned, replacing the camera trocar through a 6 to 8 cm periumbilical incision. The assistant port is placed through the GelPOINT. Transvaginal access has been proposed as an alternative mini-invasive technique in women. In some Centers AirSeal→ (Conmed, Utica, NY) system is used to maintain a constant and low pressure at 8 mmHg.
Transplant bed preparation
The external iliac vessels are carefully dissected and a retroperitoneal pouch is created by an incision of the peritoneum in order to allow graft covering after reperfusion (retroperitonealization).
Vascular anastomosis
The first step is the anastomosis between the graft vein and the external iliac vein. Two clamps are placed on the external iliac vein in order to exclude this vascular tract from blood circulation and a longitudinal venotomy is performed. The end-to-side anastomosis is carried out with a continuous suture using a 6/0 Gore-Tex→ CV-6 TTc-9 or THc-12 needle (W.L. Gore and associates Inc., Flagstaff, AZ). Venous running suture starts from a tight knot at the cranial angle of the posterior wall of the vessel and goes on until the caudal angle, passing the needle in an outside–inside direction. Then, the needle is passed in an inside-outside direction to close the anterior wall of the vein. Prior to completion of the anastomosis, the lumen is flushed with a heparinized solution using a 4.8°F ureteric catheter. Finally, a clamp is placed on the graft vein and the two clamps are removed from the external iliac vein and placed on the external iliac artery.
As soon as the external iliac artery circulation is interrupted, arteriotomy may be realized with a cold linear incision that may be converted to a circular incision using a laparoscopic aortic punch. At this point, a continuous suture is performed similar to the venous technique ( Fig. 24.3 ). The peculiar difference of the arterial anastomosis is related to the first knot at the cranial angle, which is not tight until the needle has passed through the vessel. In fact, early tightening of the first knot could make the subsequent needle passage harder because of the smaller lumen of the artery than the vein. When the anastomosis is completed, a clamp is placed on the graft’s artery and the external iliac artery clamps are removed. If no signs of bleeding are observed, the graft’s vascular clamps are removed, and the reperfusion starts. Evaluation of the kidney’s reperfusion is primarily visual, but an ultrasound Doppler might be useful.
Ureteroneocystostomy
After reperfusion, ureteroneocystostomy is performed according to Lich-Gregoir technique using a Monocryl or PDS 5/0 (Ethicoin Inc., Cincinnati, OH) running suture. At this point, the retroperitonealization of the graft is performed with the aim to avoid pedicle torsion and facilitate future graft biopsies. The closure of the peritoneum is done with Hem-o-lock→ to guarantee peritoneal lymph reabsorption and decrease the risk of lymphocele.
Results
Menon et al. described for the first time a standardized technique for RAKT, with a total operative time of 214.1 ± 39.8 minutes and a rewarming time of 46.6 ± 9.3 minutes. These results were subsequently confirmed showing that a rewarming time less than 48 minutes correlated with better renal function recovery on postoperative day 30. In the first ERUS-RAKT including 147 procedures with a minimum 1 year of follow-up, optimal functional outcomes were reported with a median estimated glomerular filtration rate (eGFR) of 57.4 mL/min per 1.73 m 2 . An ERUS-RAKT update compared the first 120 cases with the following 171 cases showed a significantly shorter total surgical time in the second group (265 vs. 230 minutes, P = .005). 7.5% of patients experienced Clavien-Dindo ≥3 complications, 1.7% delayed graft function (DGF), 0.7% embolization, 1% transplantectomies performed for arterial thrombosis and 1% for vein thrombosis. In 2% of cases, a surgical exploration was required due to active bleeding; 0.7% of patients were affected by ileus requiring surgical exploration, 0.3% underwent transplantectomies performed for acute rejection. Late complications included 3% lymphoceles, 2% ureteric stenosis, 1% incisional hernias.
Few studies from referral centers analyzed the learning curve in RAKT. , In one study, after the first 34 procedures in a center, there was a 75% probability of achieving RAKT’s trifecta (no major intra/postoperative complications, no DGF, and rewarming time < mean + 2 standard deviation = 48.6 minutes).
Few authors compared the robot-assisted technique to the open approach with a lack of randomized control trials. In the latest retrospective series from Ahlawat et al. with a median follow-up of 2 years, graft postoperative function was comparable to the open technique despite a higher operative and rewarming time. Moreover, the robotic technique seemed to provide the following advantages:
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Lower intraoperative blood loss
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Reduced morphine-related analgesia administration postoperatively
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Lower symptomatic lymphocele incidence
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Lower wound infection rate.
( Table 24.1 ).
