Initial Experience with the Use of a Robotic Stapler for Robot-Assisted Donor Nephrectomy

Introduction

Laparoscopy has generally been considered the gold standard method of performing living donor nephrectomies, ¹ as it offers patients a reduction in pain, estimated blood loss (EBL), and an improvement of esthetic results. ^2,3 Laparoscopy remains the most common method utilized for donor nephrectomies in the United States. ⁴ However, since the first description of robot-assisted laparoscopic donor nephrectomy for living donor renal transplantation, ⁵ the technique has gained popularity. The use of the robot has been supported by additional studies ^{6 –12} that note comparable postoperative complication rates while offering technical advantages to traditional laparoscopic surgery.

Although adaptations of robot-assisted laparoscopic donor nephrectomy have been made since its initial reporting, additional studies utilizing the approach confirm the feasibility and safety of the technique. ^{6 –9,13} Overall complication rates of robot-assisted and traditional laparoscopy have been found to be comparable. ¹² In addition, the robot-assisted technique has resulted in decreased postoperative length of stay that decreased the global cost of the procedure. ¹⁴ Furthermore, as much as 1 year postoperatively, the robot-assisted technique demonstrates comparable rates to the laparoscopic approach in terms of recipient outcomes, including delayed graft function, graft failure, and renal function. ¹¹

Similar to the advent and implementation of the laparoscopic technique, a learning curve does exist for the robot-assisted method. ⁷ Some evidence suggests, however, that the robotic approach offers a quicker learning curve ¹² compared to the laparoscopic technique. ¹⁵ Many urologists have embraced the technical advantages of the robotic approach, including improved dissection capabilities, more accurate graft preservation, improved visualization, and improved surgeon comfort. ^16,17 This poses the question: should we perform donor nephrectomies robotically? A study conducted by Giacomoni et al. ¹² suggested that during robot-assisted donor nephrectomies, the bedside assistant's hands caused more of a hindrance than a help when it came to achieving hemostasis in the abdominal cavity. The authors proposed that this pointed to the use of a totally robotic approach in the future. ¹²

Recent developments in robotic technology, such as the introduction of the da Vinci^® EndoWrist^® Stapler during the last two years, have provided the opportunity for increased robotic utilization during these surgeries. Our institution has adapted the use of this robotic stapler during a total of 10 living donor nephrectomy cases over the past year. With this case series, we aim to demonstrate the feasibility and safety of the use of robotic stapling for living-donor nephrectomies.

Materials and Methods

Ten cases of the da Vinci EndoWrist Stapler used during robot-assisted donor nephrectomy by a single surgeon are reported. Patient demographics were analyzed and are presented in Table 1. Cases were compared for relevant variables such as patient anatomy, EBL, postoperative complications, and graft function at discharge. Cost of robotic stapler versus the laparoscopic stapler (Endo GIA™ Stapler; Medtronic, Dublin, Ireland) is reported.

Results

A single surgeon performed all cases with the da Vinci EndoWrist Stapler. Patient population was composed of four males ranging in age from 21 years old to 61 years old and five females ranging in age from 38 years old to 61 years old. Each donor graft had a single artery and a single vein. Before stapling, each renal artery and vein were dissected circumferentially to the level of insertion at the aorta and inferior vena cava, respectively. In each case, a single vascular load was used for the taking of each vessel. Both left (N = 9) and right (N = 1) donor nephrectomies were performed in the series. The mean warm ischemia time was 3.19 minutes with a range of 0.5–6 minutes. EBL for the cases ranged from 13 to 100 mL with a mean blood loss of 44.8 mL.

No intraoperative complications and no immediate postoperative complications were observed in the study population with the exception of one case in which a donor had prolonged sedation secondary to intolerance of anesthesia, as well as postoperative urinary retention that required Foley catheter reinsertion. The length of stay for nine patients was 36 hours or less, while the aforementioned patient with complications had a stay of 3 days. All 10 patients have no significant complications to date requiring readmission or emergency department visit. Donor creatinine ranges from 0.78 to 1.58 mg/dL (mean 1.25 mg/dL), and donor glomerular filtration rate (GFR) ranging from 45 to >60 mL/min/1.73 sq m (mean 52.3), all have had adequate solitary kidney function. Graft function of all recipients is adequate to date with creatinine ranging from 0.86 to 2.55 mg/dL and GFR from 28 to >60 mL/min/1.73 sq m.

At our institution, the cost of using the robotic stapler in each case was $705, which includes the per-fire cost of using the EndoWrist Stapler, as well as the cost of the two stapler loads used in each case. The cost of use for a laparoscopic stapler (Endo GIA Stapler) with two white vascular loads (45 mm) would be $494.06.

Discussion

The cases reported demonstrate that the use of da Vinci EndoWrist Stapler offers feasible postoperative outcomes, including complications, length of stay, and recipient graft function at discharge. In addition to feasible patient outcomes, the da Vinci EndoWrist Stapler and the laparoscopic option (Endo GIA Stapler) both offer vascular loads (white cartridge) that are Food and Drug Administration approved. ^18,19 Both offer loads 45 mm in length, staple height of 2.5 mm, and close to 1 mm offering comparable dimensions. ²⁰ With similar closure dimension, and feasible patient outcomes, the use of a robotic stapler offers technical advantages to the surgeon compared to the laparoscopic stapler, including improved visualization, tremor reduction, and increased degrees of freedom.

The impact of the use of a robotic stapler on vessel length is unknown. An in vitro study of laparoscopic staplers concluded that the use of the Endo-TA stapler may allow for increased preservation of vessel length versus the Endo GIA stapler. ²¹ Ex vivo studies of the robotic stapler and the impact its use has on vessel length are absent and would be an interesting avenue for future study. In our series, however, adequate length of the artery and vein was achieved in all cases to complete both anastomoses without complication. While the length of the renal vein in right donor nephrectomies has traditionally been a concern, ²² we were able to complete a right-sided donor nephrectomy using the robotic stapler without compromising vascular length.

Moreover, the potential for device failure for the robotic stapler is not yet known. At least 65 cases of stapler failure have been reported during renal vascular control during laparoscopic nephrectomy. ²³ The most common mechanisms for stapler failure are staple line malformation and the stapler device locking up. ²⁴ These causes can be extrapolated to the robotic stapler. Clips were occasionally used during our dissections of the periarterial and perivenous tissues, and care was taken during our stapler application to avoid these, which could impact device closure and lead to misfire.

A previous study suggested that hand assisted stapling contributes to surgeon confidence, safety of the operation in terms of speed of removal, and control of unexpected bleeding. ⁹ However, with the well-documented learning curve of robot-assisted laparoscopic donor nephrectomy for living donor renal transplantation, ^6,7 we suggest that a similar learning curve is applicable to the use of robotic stapler.

Of note, the cost of the robotic stapler was marginally more expensive compared to a laparoscopic stapler at our institution, with a cost difference of ∼$200 per case. While the robotic stapler is more expensive, its adaption in the procedure offers a stepping stone to achieving a completely robotic approach. The laparoscopic approach requires a co-surgeon or resident physician to assist at the bedside, while the robotic approach could potentially open the door for an advanced practice provider or registered nurse first assistant to assist at the bedside. Taking of the vessels would be in complete control of the operating surgeon and offer more continuity. In addition, the surgeon would not have to undock the robot or rely on an assistant to secure the vessels, a critical part of the nephrectomy. This is an added benefit of the robotic approach and could be especially useful for centers with less experienced assistants.

The small sample size is one limitation of this study, but unavoidable in any early case series. As the study is only a single center, we offer only a single surgeon experience of the adaption of the da Vinci EndoWrist Stapler and note that experiences and results may differ at other institutions.

Conclusion

The use of a robotic stapler is feasible in terms of patient safety, technique, and cost in both left- and right-sided living-donor robotic nephrectomies. Further research is needed to confirm the benefit and safety of EndoWrist stapler use in robotic donor nephrectomies compared to laparoscopic stapler use. A retrospective comparative analysis or prospective study comparing these two techniques has not yet been performed and calls for additional research.