Greater Renal Function Benefit from Enucleation Technique for More Complex Renal Tumors in Robot-Assisted Partial Nephrectomy

Abstract

Background: Tumor enucleation technique in robot-assisted partial nephrectomy (RAPN) reportedly contributes to renal function preservation. Which tumors and which part to utilize this technique have not been determined. Patients and Methods: This multi-institutional retrospective study included patients who underwent RAPN at tertiary surgery centers. Patients were first stratified into High, Intermediate, and Low categories based on renal nephrometry score. Patients were further classified into I/B-enucleation (I/B-E, I + B £ 1) and I/Bresection (I/B-R, I + B ‡ 2) groups based on surface-intermediate-base margin score. Perioperative outcomes, including percentile change in estimated glomerular filtration rate (eGFR), new-onset chronic kidney disease, complication rate, surgical margin, and trifecta achievement, were compared between the I/B-E and I/B-R groups in each category. Odds ratios (ORs) and b-coefficients were also compared.Results: Overall, 704 patients were included in this study. Relative decrease in eGFR was significantly lower for the I/B-E group in all three categories, with medians of 8.1%, 4.4%, and 3.2% in the High, Intermediate, and Low, respectively. In multivariate analyses, excision technique was independently associated with eGFR change in all three. b-coefficient was higher in the High (5.06) category than in the Low (3.17) or Intermediate (3.33). Across all three categories, significantly more patients attained trifecta with a difference of 34.0%, 18.3%, and 15.1% in the High, Intermediate, and Low categories, respectively (all, p < 0.05), with a higher OR in the High (5.91) category than in the Low (3.20) or Intermediate (2.48). No significant differences were found in operation time, amount of estimated blood loss, rate of positive surgical margin, or complications. Warm ischemic time was significantly longer for the I/B-E group in the Intermediate (18.0 minutes vs 16.0 minutes, p = 0.002) and Low categories (13.0 vs 11.0, p = 0.006), but not significant in High ( p = 0.344).Conclusions: I/B-enucleation in RAPN contributes to renal function preservation, and the impact was more emphasized in complex tumors.

Limited impact of warm ischemic threshold for partial nephrectomy in the robotic surgery era: A propensity score matching study

“…As recently described, enucleation required more WIT than resection, during tumor excision. 26 These data suggest that reserved renal mass volume might be of utmost importance in terms of renal function, although we could not carry out volumetric analysis due to a shortage of information. 6,21,23,26 The present result, that renal function recovery from AKI does not differ between two matched groups, might also be explained by the so-called "synergetic" relationship between ischemic time and surgical precision.…”

“…26 These data suggest that reserved renal mass volume might be of utmost importance in terms of renal function, although we could not carry out volumetric analysis due to a shortage of information. 6,21,23,26 The present result, that renal function recovery from AKI does not differ between two matched groups, might also be explained by the so-called "synergetic" relationship between ischemic time and surgical precision. 7 Furthermore, as the median WIT was 19.0 min and nowhere near the threshold of 30 min in the shorter group, even when matched for RENAL nephrometry score, some other measures to weigh surgical difficulty might be required.…”

New Trends in Robotic Retroperitoneal Partial Nephrectomy

“…A study by Ishiyama et al in 2021 compared the outcomes for 704 patients with T1 renal tumors who underwent RAPN either using the enucleation or standard resection technique. Their data showed that enucleation contributed to early preservation of renal function as measured by eGFR, without compromising oncological margins or patient outcomes (16). Interestingly, trifecta attainment was emphasized in patients with more complex renal tumors, whereby preservation of renal functions when compared to standard resection was most pronounced in the complex tumor group (16).…”