Editorial: Robotic Partial Nephrectomy: The Treatment of Choice for Minimally Invasive Nephron Sparing Surgery
Early in the adoption of robotic partial nephrectomy (RPN) as an alternative to laparoscopic PN (LPN) for the treatment of small renal masses, several of the current authors presented a similar comparison of LPN and RPN. They found RPN to result in shorter hospital stay, less blood loss, and shorter warm ischaemia time (WIT) compared with LPN [1]. They discovered that RPN outcomes were not dependent on the complexity of the tumour, which clearly impacted LPN results. They concluded that RPN is a safe and viable alternative to LPN and offered benefits even for experienced laparoscopic surgeons.
The current report in this edition of BJUI furthers the comparison of RPN and LPN and expands the assessment to include five high-volume centres of excellence in robotic surgery [2]. This retrospective, multi-institutional review of 1 185 RPN and 646 LPN represents the largest comparison to date of these two approaches for minimally invasive PN. Despite higher patient comorbidities and R.E.N.A.L. nephrometry scores in the RPN patients compared with the LPN group, there were fewer overall complications (16.2% vs 25.9%), a lower positive surgical margin rate (3.2% vs 9.7%) and a lower WIT (18 vs 26 min). They also found a much higher percentage of RPN patients (70% vs 33%) meeting the Trifecta criteria, defined as negative surgical margins, no perioperative complications, and a WIT of ≤25 min. Finally, the authors introduce a more stringent composite measure of ‘optimal outcomes’, which is the Trifecta with the addition of 90% estimated GFR preservation and no chronic kidney disease upgrading. They report 38.5% of RPN patients meeting optimal outcomes compared with 24.1% for LPN.
This study clearly demonstrates the superiority of RPN over LPN and is supported by other single-surgeon reports [3]. These results also exceed those reported for open PN with the added benefit of reduced hospital stay [4]. However, it is important to recognise that these results represent a mature experience with RPN by the leaders in the field of robotic renal surgery. Many of these authors pioneered the techniques currently used for RPN, and therefore these results may not apply to centres without the same experience or case volumes. One limitation of this report is the non-concurrent experience of LPN and RPN. The results of RPN came after an initial experience with LPN and therefore the outcomes of RPN may have benefitted from the lessons learned with LPN prior to RPN.
Reporting surgical outcomes as composite results, such as the Trifecta, allows for comparison between reports and sets an outcomes bar for future studies. Most composite measures include assessment of surgical margin status and complications, but there is no current agreement as to the optimal measure of renal functional outcomes. The current Trifecta used a WIT of ≤25 min as a measure of renal function impact, while the margin, ischaemia, and complications (MIC) score uses a WIT of <20 min [5], and others have used 90% renal parenchyma preservation as part of the Trifecta [6]. The impact of WIT on renal function has been questioned given the recently recognised importance of preserved renal parenchyma as an important predictor of renal function after PN [7]. Until there is consensus as to the best measure of renal function after nephron-sparing surgery, composite outcomes such as the Trifecta and the optimal outcomes as described by the authors will have limited utility.
