Introduction
(Article introduction authored by Conquest Editorial Team)
The field of transplant surgery has been transformed by robotic kidney transplantation (RKT). The benefits of minimally invasive surgery have been applied to the field of renal transplantation via robotic kidney transplantation (RKT). Techniques vary widely around the world, and standardization within evidence-based frameworks is needed to justify widespread use and assure safe and successful innovation.
Between 2010 and 2020, a comprehensive literature study was done to discover papers reporting on RKT approaches. So far, promising results have been documented, with specific benefits revealed for obese patients who would have been denied an open kidney transplant otherwise. In this review, the evolution of surgical techniques in RKT like gasless surgery, scarless surgery, RKT with multiple-vessel grafts, and robotic dual kidney transplantation are presented with perspectives on future developments.
Methods
A comprehensive literature search was conducted to identify all published evidence pertaining to techniques in RKT. As this is a rapidly evolving field, conference abstracts were included in the search as well as published papers. Search limits included English language and publications between 2010 and 2020. For guidance on RKT, National Institute for Health and Care Excellence (NICE) guidelines were reviewed as well as selected international guidance.
Healthcare databases searched included MEDLINE, EMBASE, PubMed, and NICE Evidence. Other databases include Cochrane Library, European Association of Urology, British Association of Urological Surgeons, Google, Google Scholar, BMJ Best Practice, UpToDate, and DynaMed.
In total, 119 sources of information were identified, which consisted of two guidelines, 37 published papers, and 80 conference abstracts. These were individually reviewed and only sources which reported specifically on technique in RKT were included.
A brief history of techniques in kidney transplant surgery
Successful kidney transplantation has been carried out for over 60 years and Figure 1 shows a timeline that outlines the progression of techniques from open to minimally invasive surgery.
The innovative procedure of LKT was compared to open kidney transplantation (OKT) and found to be feasible and safe in multiple studies.
It was not until the introduction of robotic surgery that the field of transplantation saw significant advancement. The evolution of surgical technique goes hand-in-hand with the evolution of surgical technology.
In the year 2000, the US Food and Drug Administration gave clearance for the use of the da Vinci Surgical System for use in general laparoscopic surgery. The main advantage of the robotic system was using Endowrist technology. This gave seven degrees of freedom to instruments, mimicking the movements of the human hand, and was therefore far more ergonomic than traditional laparoscopic instruments.
The use of the surgical system was adopted in urology, gynecology, and thoracic surgery. Just two years after its introduction to the market, it was used in kidney trans- plantation.
The first use of robotics in kidney transplantation
The use of robotics in kidney transplantation was first introduced in 2002 in Henri Mondor University Hospital, France by Hoznek et al.The robotic platform, the classic model of the da Vinci Surgical System, was used by the team for two main reasons.
Firstly, the precision of surgery could be enhanced through motion-scaling and increased dexterity of the robot.
Secondly, the prevalence of blood-borne infections including HIV, hepatitis B, and hepatitis C among hemodialysis patients can be significantly high. This may well be beneficial for the protection of surgeons from contracting blood-borne infections. For these reasons, the team aimed to demonstrate the feasibility of robotic-assisted kidney transplantation. The technique used the same principles as an OKT but with major modifications to incorporate the robot.
An incision was made in the left lower quadrant, held open using self-retaining retractors so that the robotic camera could be positioned above it. Two robotic arms were used to carry out the various steps of the procedure. A remote surgeon robotically performed the vascular dissection, vascular anastomoses, and ureterovesical anastomosis.
An assisting surgeon at the patient side was responsible for creating access to the vasculature, hemostasis and maintaining traction on the running sutures carried out robotically.
Mesenchymal stem cells (MSCs) in renal recovery
Giulianotti et al at the University of Illinois, USA, and Boggi et al at University Hospital of Pisa, Italy provided the first published experiences of RKT. They highlight- ed the benefits of RKT in obese patients who would have previously been denied an OKT. The University of Illinois selected obese patients in need of a transplant to assess whether RKT was appropriate for this patient population. They reported performing RKT in a 29-year-old woman with a BMI of 41 kg/m.
A peri-umbilical incision was used as it allowed for hand assistance in steps of the operation such as the vascular anastomoses, which would have been difficult given the poor exposure in obese patients. The postoperative course was uneventful, and the team, therefore, demonstrated the feasibility of RKT in a patient who would have otherwise been considered too high risk for a conventional open procedure.
The initial move towards standardization of RKT
The Vattikuti-Medanta technique was the first report in RKT using robust evaluation for safety and effectiveness. This was achieved through adherence to the IDEAL (Innovation, Development, Exploration, Assessment, Long-term study) framework. This framework is now widely accepted as essential for the introduction and development of innovations in urological surgery.
The Vattikuti-Medanta technique pioneered the use of regional hypothermia to minimize warm ischemia time. Modified Toomey syringes were employed to instill ice-slush into the abdominal cavity via the GelPOINT device.
The ice slush was deposited around the kidney to maintain an average intra-operative kidney temperature of around 18–20 °C. This gave them more time to perform the vascular anastomoses robotically.
The authors reported that with increasing experience leading to reduced anastomotic time, regional hypothermia may not be required. However, during the initial learning curve, cooling the kidney can no doubt alleviate the pressure induced by the ticking warm ischemia clock. Abaza et al have reported on the Vattikuti-Medanta technique in a step-by-step article in which they high- lighted the ability to avoid re-docking the robot.
Sood et al have compared RKT using the Vattikuti-Med- anta technique to OKT. Functional outcomes were equivalent, with similar rejection rates and mean serum creatinine levels at six months. The same team published an IDEAL phase study which has shown lower complication rates in RKT (Fig 2).
Further developments in technique
Gasless surgery
Though the Vattikuti-Medanta technique has been the most widely adopted method for performing RKT, other techniques have been reported with positive outcomes. Tsai et al published their technique which used the arms of the robot to tent up the abdominal wall. This prevents- ed use of gas to create a pneumoperitoneum.
The insufflation gas was posited as a source of heat which may contribute to warm ischemia. By using the robotic arms to lift the abdominal wall and prevent heating of the kidney, the team concluded that they could therefore reduce the degree of warm ischemia.
Scarless surgery
Doumerc et al in France have also developed a technique building upon work by Modi et al in which the kidney is inserted trans-vaginally. This has corresponded with the widespread adoption of the Alexis dual-ring wound retractor. This wound retractor has been used in a range of both open and robotic urological procedures with promising results published, particularly in preventing wound infection.
Using the Alexis retractor, it has been demonstrated that the kidney can be both removed from the donor and inserted into the recipient trans-vaginally resulting in almost scarless surgery. However, there are limitations to this technique in that it is not suitable for nulliparous women due to lack of vaginal capacity.
RKT with multiple vessels
Graft kidneys with multiple arteries or, more rarely, veins can pose difficulty during back-bench preparation and in performing the anastomoses.
Grafts with multiple vessels (GMVs) are known to be associated with higher risks of complications and delayed graft function as compared to grafts with single vessels (GSVs). Yet long-term outcomes and patient survival with GMVs are comparable to single vessel grafts using the open technique.
With the current shortage of donor kidneys, GMVs therefore should not be regarded as an absolute contra-indication to transplantation and should still be utilized.
Robotic dual kidney transplantation
Dual kidney transplantation is well-recognized as a way of expanding the criteria for deceased donor transplantation. Dual transplant of these kidneys can optimize long-term function to that of a normal kidney.
Combining the overall benefits of RKT with dual kidney transplantation, therefore, has the potential for improving renal function long-term.
Robotic dual kidney transplantation (RDKT) has been pioneered by the team at H.L. Trivedi Institute of Transplantation Sciences, Ahmedabad, India, who have reported on performing RDKT in a series of 6 cases.
The team built on previous case reports and feasibility studies on cadavers. They used a unique technique in placing both kidneys on the ipsilateral iliac vessels.
The main limitation in RDKT in comparison to open dual kidney transplantation is prolonged operative time as multiple anastomoses are required which is time-consuming when performed robotically.
Conclusion
The advancement of RKT techniques has been encouraging, and the adoption of RKT as a safe and effective replacement to OKT looks to be a foregone conclusion. There have already been a number of procedures reported in the literature, with modifications based on patient and transplant characteristics. Steps in the operation have been changed for obese patients and those who want to avoid scarring.
Similarly, several approaches have shown outstanding success with GMVs and grafts with minimal nephron mass. To give a basic foundation, the Vattikuti-Med- anta technique has been the most extensively used.
As future surgeries are tailored more exactly to the enormous diversity of subtly varied patient and transplant features, this method will most likely change and be modified. As new procedures emerge in the future, it is critical to remember that patients will always take precedence over techniques.
