Renal transplantation is the best treatment available for end-stage renal disease. Living renal transplantation has greatly expanded the number of kidneys available for the donor pool.19
Laparoscopic donor nephrectomy has become the gold standard procedure for those who wish to be living kidney donors.20
The operation has been proven to be technically feasible and demonstrates outcomes clinically comparable to those of open procedures.5
In addition, right-sided donor nephrectomy has also been shown to be equally efficacious in comparison to traditional left-sided harvests.16
RALDN is a technical variation of LDN that may provide for a shorter learning curve compared to that of standard laparoscopic nephrectomy.21–23
While the concern of utilizing LDN for retrieval of right-sided kidneys resulting in short renal veins leading to increased incidence of thrombosis and graft loss has been well documented, the advantages of robotic-assisted procedures have been suggested as a conduit to overcome the technical barriers associated with standard laparoscopy.18
Robotic systems are theorized to improve upon the limitations of pure laparoscopic surgery by providing enhanced visibility and flexibility as well as 3-dimensional vision with superior dexterity which provides for more efficient dissection of the renal hilum.23
Advantages of robotic-assisted techniques should theoretically translate into improved donor and recipient outcomes compared to LDN outcomes. We hypothesized that robotic-assistance may lead to lower blood loss, shorter operative times, and improved recipient outcomes. Because of our extensive prior experience with robotic renal surgery, we were comfortable with our patient and port positioning and did not have to overcome these aspects of the learning curve for this relatively high-stakes procedure. We primarily focused on right-sided RALDN, because we felt that autonomous dissection of the right kidney, particularly the upper pole and absence of accessory venous systems (ie, no lumbar vein or adrenal vein to identify or dissect), was easier compared to the left and thus was a more appropriate side on which to attempt our initial robotic-assisted donor nephrectomy procedures. If we had been able to demonstrate a significant positive impact of robotic-assistance, we would have proceeded to attempt left-sided robotic donor nephrectomies, with its higher colonic flexure and more complex accessory venous system.
In our study, EBL and OR times, 2 of the theorized goal outcomes associated with robotic surgery, showed improvement, but these results did not reach statistical significance. Alternatively, LOS and recipient eGFR at discharge were slightly worse with RALDN, although these results also did not reach statistical significance. Although serum creatinine levels were similar for both recipient groups at 1 year, when calculating the eGFR, recipients at 1 year posttransplant was significantly higher for RALDN patients compared to LDN. In view of the comparable serum creatinine levels and when considering our relatively small numbers, these results are difficult to interpret as being a true indication of more durable results with RALDN over LDN. It must be stressed that short-term intraoperative factors, such as EBL, OR time, and WIT, showed no benefit. Other clinical outcomes, including postoperative narcotic requirements as well as postoperative donor eGFR values were not significantly different between LDN and RALDN, demonstrating equal feasibility between both techniques ( and )
. In all patients, the operation was kept minimally invasive. There were no intraoperative complications including bleeding or bowel injuries, which can be associated with laparoscopic surgery.24,25
Understandably, these results may have been influenced by our young donor population with relatively low BMIs and low renal vascular complexity. In fact, our patient group had a lower incidence of dual vessels than the series published by Fettouh et al26
who reported on 79 patients, approximately 20% of whom had multiple renal arteries or veins. However, their complication rate was also very low and their mean EBL was 65mL, demonstrating that LDN can be safe even for donors with vascular anomalies.
The increased WIT in our RALDN group is undoubtedly related to the inefficacy of hilar control with extirpative robotic renal surgery. At the time of this manuscripts' writing, the da Vinci Robotic Surgical System does not yet have a stapler attachment, leaving the only devices for hilar control for the robotic surgeon to be either suture ligation or Hem-o-lok clip application, 2 methods that we believe to be unacceptably inferior. As a result, at the time of vessel ligation during RALDN, we had an assistant pass a vascular stapler through an accessory port to ligate the renal artery and vein, a process that was admittedly more awkward than with the laparoscopic counterpart, and thus may have translated into longer WITs. However, this difference did not reach statistical significance in our study nor did it adversely affect recipient allograft function. In addition, our results compare favorably to RALDNs performed by Hubert et al19
that showed an average WIT of 5.8 minutes in their cohort of patients. Still, in our study there was no improvement in the incidence of delayed graft function between the 2 groups, which occurred only once in either patient population.
Finally, the higher costs associated with robotics should be a determining factor when evaluating surgical techniques utilized in urologic surgery.27
When laparoscopic radical nephrectomy has been compared with open procedures, studies have shown that laparoscopy contributes an approximate $2000 to total hospital costs.28
A financial analysis specific to robotic surgery demonstrated that robotic-assistance incurs an additional $3200 in total hospital care dollars.29
These extra costs may be driven down if postoperative patient expenses can be reduced or if return to normal activity is faster. As robotic-assistance did not significantly improve postoperative patient parameters in our study, the higher costs associated with the use of robotics in our era of health-care financial awareness is another significant determining factor against RALDN.
Our study has several limitations that must be acknowledged. First, our low absolute number of patients can limit the demonstration of benefit of robotic-assisted donor nephrectomy. However, the absolute percentage of right-sided donor nephrectomies performed at our institution (16%) far exceeds the reported percentage of right-sided LDNs at several other major transplant centers in the United States.30
A larger number of study patients may drive some factors that did not reach statistical significance in our study to eventually show a difference between the 2 techniques. Second, a retrospective design inherently introduces selection bias in the study groups. Third, the theoretical advantages of RALDN over LDN during laparoscopic dissection may be better displayed in donor patients with complex renal vascular anatomy. In our study population, no donor patient in the RALDN group had >1 renal artery or vein. Patients with multiple renal vessels may be better suited for RALDN secondary to more efficient dissection of the renal pedicles compared to LDN, possibly leading to significantly shorter OR times or less EBL. Additionally, the addition of more advanced robotic surgical instrumentation, such as an endovascular stapler, may have a positive influence on some of the primary endpoints in our study. Finally, postoperative complications, such as deep vein thrombosis, pulmonary embolism, urinary tract infection, or wound infections were not reported in either group. Although these are generally limited in healthy donor patients undergoing minimally invasive surgery, subtle differences between RALDN and LDN may impact any or all of these factors.