Kidney tumors are being increasingly detected at smaller sizes1
and evidence is accumulating regarding the potential medical benefits of nephron sparing surgery,4, 5
supporting an increasing role of partial nephrectomy. LPN has demonstrated benefits compared to OPN in regards to blood loss and recovery with similar long-term renal functional and oncologic outcomes.4,5
LPN requires advanced skills in laparoscopy to accomplish tasks of tumor resection and renal reconstruction while minimizing warm ischemia times. Tumors located near renal hilar structures can add to the technical challenges of a LPN. Robotic assistance may facilitate the advanced maneuvers required to successfully perform partial nephrectomy for renal hilar tumors using a minimally invasive surgical approach. The magnified, 3-dimensional visualization and articulating robotic instruments can facilitate precise tumor resection and renal reconstruction for tumors near hilar structures. Our multi-institutional experience demonstrates the safety and efficacy of RPN in select patients with renal hilar tumors.
Although other reports have also demonstrated the safety and feasibility of RPN,7-11
ours is the first to address RPN specifically for renal hilar tumors. LPN for renal hilar tumors is described by Gill et al.6
However, these advanced surgeries were performed by one senior surgeon with considerable laparoscopic experience. Our study had more junior surgeons, with one immediately out of fellowship. Comparing our robotic experience for renal hilar tumors with this laparoscopic partial nephrectomy series, our mean warm ischemia time was shorter (28.9 vs. 36 minutes) with a similar mean tumor size (3.8 vs. 3.7 cm). We recognize that recent developments for LPN, such as the early unclamping technique described by Gill et al.,12
can significantly reduce warm ischemia times. Although this technique was not utilized in our series, as it had not yet been reported, we would anticipate similar benefits in warm ischemia time when applying this technique to RPN.
The risk of bleeding and arteriovenous fistula formation would theoretically be increased with hilar tumors. We feel that these potential complications can be avoided with precise sutured closure of the resection bed of the kidney, avoiding deep passes with large needles that could potentially increase the risk of an arteriovenous fistula or an excluded calyx. Robotic assistance facilitates suturing with a smaller RB-1 needle in these situations. We did not experience any episodes of major bleeding or other complications that required open conversion. However, if open conversion were to become necessary, the robot could be quickly undocked by removing the robotic instruments and clutching the robotic arms to pull attached robotic trocars from the abdomen. The robot could be pulled back several feet to allow room for the surgeon, who would be gowned and gloved by that time. We keep a gown and gloves available at all times for this reason. We also place a laparoscopic sponge in the abdomen prior to hilar dissection that can be used to pack bleeding vessels to help achieve hemostasis. We have performed a “dry run” exercise of undocking for open conversion in a porcine model in under 1 minute.
The two centers in this study used different camera positions and port strategies, each with relative advantages. The medial camera placement offers a global view of anatomical structures that simulates conventional laparoscopy. Lateral placement of the camera port placement may reduce arm collisions, provide more space for the assistant, and facilitate use of the fourth robotic arm to minimize dependence on the surgical assistant. The strategy of port placement and sutures used may vary based on surgeon preference.
Limitations of our study include its small sample size. However, we feel our experience illustrates the potential for robotic assistance to facilitate a minimally invasive approach for challenging renal hilar tumors. Potential disadvantages of RPN include the cost. We recognize that robotic assistance may not be practical for all partial nephrectomy cases. It was beyond the scope of this study to perform a detailed comparative cost analysis. If robotic assistance can facilitate a minimally-invasive and nephron-sparing approach in select patients with challenging renal hilar tumors that might otherwise require total nephrectomy or open surgery, then the benefits might justify the costs for this particular group of patients.
Our study is not designed to compare robotic assistance with the other approaches to partial nephrectomy. A comparison of OPN and LPN has already been described.4
Our study is intended to assess feasibility and short term outcomes of RPN for a select group of patients with renal hilar tumors. Further studies comparing RPN to other surgical approaches are warranted.