Indications, Techniques, Outcomes, and Limitations for Minimally Ischemic and Off-clamp Partial Nephrectomy: A Systematic Review of the Literature

Microwave Scissors-Based Sutureless Laparoscopic Partial Nephrectomy Versus Conventional Open Partial Nephrectomy in a Porcine Model: Usefulness and Complications

BACKGROUND

This study aimed to compare the benefits and safety of microwave scissors-based sutureless laparoscopic partial nephrectomy (MSLPN) with those of conventional open partial nephrectomy (cOPN).

METHODS

Each kidney in nine pigs underwent MSLPN using microwave scissors (MWS) via transperitoneal laparoscopy or cOPN via retroperitoneal open laparotomy. The kidney's lower and upper poles were resected under temporary hilar-clamping. The renal calyces exposed during renal resections were sealed and transected using MWS in MSLPN and were sutured in cOPN. For MWS, the generator's power output was 60 W. Data on procedure time (PT), ischemic time (IT), blood loss (BL), normal nephron loss (NNL), and extravasation during retrograde pyelogram were compared between the two techniques.

RESULTS

The authors successfully performed 22 MSLPNs and 10 cOPNs. Compared with cOPN, MSLPN was associated with significantly lower PT (median, 9.2 vs 13.0 min; p = 0.026), IT (median, 5.9 vs 9.0 min; p < 0.001), BL (median, 14.4 vs 38.3 mL; p = 0.043), and NNL (median, 7.6 vs 9.4 mm; p = 0.004). However, the extravasation rate was higher in the MSLPN group than in the cOPN group (54.5 % [n = 12] vs 30.0 % [n = 3]), albeit without a significant difference (p = 0.265). Pelvic stenosis occurred in one MSLPN procedure that involved deep lower pole resection near the kidney hilum.

CONCLUSIONS

The study data show that MSLPN can improve intraoperative outcomes while reducing technical demands for selected patients with non-hilar-localized renal tumors. However, renal calyces, if violated, should be additionally sutured to prevent urine leakage.

On-clamp vs off-clamp robot-assisted partial nephrectomy for achieving modified trifecta: inverse probability of treatment weighting analysis from a high-volume tertiary robotic center

On-clamp partial nephrectomy for the surgical treatment of renal masses poses the risk of ischemia and greater post-operative renal function loss. Conversely, the off-clamp technique might enhance renal function preservation by avoiding any ischemia time. Nevertheless, the debate persists regarding the efficacy of the on- versus off-clamp partial nephrectomy in achieving better surgical, functional, and oncological outcomes. We retrospectively assessed the data from patients undergoing Robot-Assisted Partial Nephrectomy (RAPN) from 2016 and 2023 in a tertiary robotic center. Inverse probability of treatment weighting (IPTW) was used to account for selection bias in treatment allocation. The main objective of the study was assessing the achievement rates of a modified trifecta within the two groups. Multivariable logistic regression analysis (MLRA) was employed to assess the predictors of trifecta achievement. 532 patients were included in the analysis, of whom 74.1% vs. 25.9% underwent on- and off-clamp, respectively. Balancing the two groups for the main predictors of on-clamp surgery, there were no significant differences between on- and off-clamp in terms of estimated blood loss, transfusion rate, intra- and post-operative complications, positive surgical margins, and post-operative mean reduction of eGFR. Finally, no differences were found in the rate of "trifecta" achievement between on-clamp and off-clamp RAPN (24.6% vs. 21%, p = 0.82). At MLRA, off-clamp technique was not a predictor of trifecta achievement compared to the on-clamp technique (off-clamp vs. on-clamp, aOR 1.24, 95% CIs [0.65-2.36], p = 0.58). Our study revealed that clamping technique does not imply clinically relevant differences in reaching trifecta outcomes.

Renal and major clinical outcomes and their determinants after nephrectomy in patients with pre-existing chronic kidney disease: A retrospective cohort study

The consequences of partial nephrectomy (PN) compared to radical nephrectomy (RN) are less documented in patients with pre-existing chronic kidney disease (CKD) or with solitary kidney (SK). We assessed renal outcomes, and their determinants, after PN or RN in a retrospective cohort of patients with moderate-to-severe CKD (RN-CKD and PN-CKD) or SK (PN-SK). All surgical procedures conducted between 2013 and 2018 in our institution in patients with pre-operative estimated glomerular filtration rate (eGFR)<60 mL/min/1.73m2 or with SK were included. The primary outcome was a composite criterion including CKD progression or major adverse cardio-vascular events (MACE) or death, assessed one year after surgery. Predictors of the primary outcome were determined using multivariate analyses. A total of 173 procedures were included (67 RN, and 106 PN including 27 SK patients). Patients undergoing RN were older, with larger tumors. Preoperative eGFR was not significantly different between the groups. One year after surgery, PN-CKD was associated with lower rate of the primary outcome compared to RN-CKD (43% vs 71% p = 0.007). In multivariate analysis, independent risk factors for the primary outcome were postoperative AKI (stage 1 to stage 3 ranging from OR = 8.68, 95% CI 3.23-23.33, to OR = 28.87, 95% CI 4.77-167.61), larger tumor size (OR = 1.21 per cm, 95% CI 1.02-1.45), while preoperative eGFR, age, sex, diabetes mellitus, and hypertension were not. Postoperative AKI after PN or RN was the major independent determinant of worse outcomes (CKD progression, MACE, or death) one year after surgery.

Comparison of Perioperative, Functional, and Oncologic Outcomes of Open vs. Robot-Assisted Off-Clamp Partial Nephrectomy: A Propensity Scored Match Analysis

Off-clamp partial nephrectomy represents one of the latest developments in nephron-sparing surgery, with the goal of preserving renal function and reducing ischemia time. The aim of this study was to evaluate and compare the functional, oncologic, and perioperative outcomes between off-clamp robot-assisted partial nephrectomy (off-C RAPN) and off-clamp open partial nephrectomy (off-C OPN) through a propensity score-matched (PSM) analysis. A 1:1 PSM analysis was used to balance variables potentially affecting postoperative outcomes. To report surgical quality, 1 year trifecta was used. Univariable Cox regression analysis was performed to identify predictors of trifecta achievement. The Kaplan-Meier method was used to compare cancer-specific survival (CSS), overall survival (OS), disease-free survival (DFS), and metastasis-free survival (MFS) probabilities between groups. Overall, 542 patients were included. After PSM analysis, two homogeneous cohorts of 147 patients were obtained. The off-C RAPN cohort experienced shorter length of stay (LoS) (3.4 days vs. 5.4 days; p < 0.001), increased likelihoods of achieving 1 year trifecta (89.8% vs. 80.3%; p = 0.03), lower postoperative Clavien-Dindo ≤ 2 complications (1.3% vs. 18.3%, p < 0.001), and lower postoperative transfusion rates (3.4% vs. 12.2%, p = 0.008). At univariable analysis, the surgical approach (off-C RAPN vs. off-C OPN, OR 2.22, 95% CI 1.09-4.46, p = 0.02) was the only predictor of 1 year trifecta achievement. At Kaplan-Meier analysis, no differences were observed between the two groups in terms of OS (log-rank p = 0.451), CSS (log-rank p = 0.476), DFS (log-rank p = 0.678), and MFS (log-rank p = 0.226). Comparing RAPN and OPN in a purely off-clamp scenario, the minimally invasive approach proved to be a feasible and safe surgical approach, with a significantly lower LoS and minor rate of postoperative complications and transfusions as a result of improved surgical quality expressed by higher 1 year trifecta achievement.

Development and internal validation of a nomogram predicting 3-year chronic kidney disease upstaging following robot-assisted partial nephrectomy

PURPOSE

Aim of the present study was to develop and validate a nomogram to accurately predict the risk of chronic kidney disease (CKD) upstaging at 3 years in patients undergoing robot-assisted partial nephrectomy (RAPN).

METHODS

A multi-institutional database was queried to identify patients treated with RAPN for localized renal tumor (cT1-cT2, cN0, cM0). Significant CKD upstaging (sCKD-upstaging) was defined as development of newly onset CKD stage 3a, 3b, and 4/5. Model accuracy was calculated according to Harrell C-index. Subsequently, internal validation using bootstrapping and calibration was performed. Then nomogram was depicted to graphically calculate the 3-year sCKD-upstaging risk. Finally, regression tree analysis identified potential cut-offs in nomogram-derived probability. Based on this cut-off, four risk classes were derived with Kaplan-Meier analysis tested this classification.

RESULTS

Overall, 965 patients were identified. At Kaplan-Meier analysis, 3-year sCKD-upstaging rate was 21.4%. The model included baseline (estimated glomerular filtration rate) eGFR, solitary kidney status, multiple lesions, R.E.N.A.L. nephrometry score, clamping technique, and postoperative acute kidney injury (AKI). The model accurately predicted 3-year sCKD-upstaging (C-index 84%). Based on identified nomogram cut-offs (7 vs 16 vs 26%), a statistically significant increase in sCKD-upstaging rates between low vs intermediate favorable vs intermediate unfavorable vs high-risk patients (1.3 vs 9.2 vs 22 vs 54.2%, respectively, p < 0.001) was observed.

CONCLUSION

Herein we introduce a novel nomogram that can accurately predict the risk of sCKD-upstaging at 3 years. Based on this nomogram, it is possible to identify four risk categories. If externally validated, this nomogram may represent a useful tool to improve patient counseling and management.

Longitudinal changes in renal parenchymal volume and function status after partial nephrectomy: a retrospective cohort study

BACKGROUND

The ipsilateral renal parenchymal volume (RPV) experiences a sharp decrease shortly after partial nephrectomy (PN), mainly due to surgical remove or devascularization of kidney tissue. However, the subsequent change of RPV and its association with glomerular filtration rate (GFR) fast decline remains unknown. Our objective was to investigate the change of ipsilateral RPV and renal function status from new baseline (1-12 months after PN) to latest follow-up (≥1 year) after PN, and to explore factors associated with ipsilateral RPV decrease rate and correlation between RPV decrease and GFR fast decline.

MATERIALS AND METHODS

A retrospective review of 367 patients with PN was conducted. Three-dimensional reconstruction of computed tomography (CT)/MRI images was performed for RPV calculation. Spectrum score was used to assess the degree of acute kidney injury (AKI) in the operated kidney after PN. GFR decline greater than 3 ml/min/1.73 m 2 /year was defined as GFR fast decline. One hundred fourteen patients underwent abdominal surgery was used as control. Predictive factors for subsequent decrease of RPV rate and GFR fast decline were evaluated by linear and logistic regression, respectively.

RESULTS

With a median interval time of 21.1 (interquartile range:13.8-35.5) months, median ipsilateral RPV significantly decreased from 118.7 (interquartile range:100.7-137.1) ml at new baseline to 111.8 (IQR: 92.3-131.3) ml at latest follow-up. The interval time [β: 1.36(0.71-2.01), P <0.001] and spectrum score [β: 5.83 (2.92-8.74), P <0.001] were identified as independent predictors of ipsilateral RPV decrease rate. GFR fast decline was observed in 101 (27.5%) patients. Annual ipsilateral RPV decrease rate [odds ratio:1.67 (1.05-2.67), P =0.03] and overweight [odds ratio:1.63 (1.02-2.60), P =0.04] were independent predictors of GFR fast decline.

CONCLUSIONS

Ipsilateral RPV experienced a moderate but significant decrease during follow-up after PN, especially in those with severer acute kidney injury. The presence of GFR fast decline was found to be associated with reduction of ipsilateral RPV, particularly in overweight individuals.

Assessing the Trade-off Between the Safety and Effectiveness of Off-clamp Robotic Partial Nephrectomy for Renal Masses with a High RENAL Score: A Propensity Score-matched Comparison of Perioperative and Functional Outcomes in a Multicenter Analysis

BACKGROUND

Tumors with a high nephrometry score represent a challenging surgical scenario for which robotic partial nephrectomy (RPN) is a primary option in expert hands.

OBJECTIVE

To compare perioperative and functional outcomes of off-clamp and on-clamp RPN in patients with renal masses with a high RENAL score (≥9).

DESIGN, SETTING, AND PARTICIPANTS

For this retrospective analysis, an RPN data set including 1604 patients treated at three institutions between 2003 and 2021 was queried for cases with a RENAL score ≥9.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

We used 1:1 propensity score matching (PSM) to select a cohort in which imbalances between the off-clamp and on-clamp groups were minimized. We used χ2 and Student t tests to compare categorical and continuous variables, respectively. The Kaplan-Meier method was used to compare the probability of having an estimated glomerular filtration rate (eGFR) ≥45 ml/min during follow-up. Univariable and multivariable analyses were performed to identify predictors of a trifecta outcome (negative surgical margin status, no Clavien-Dindo grade ≥3 complications, eGFR decline ≤30%) and of retaining eGFR ≥45 ml/min over time.

RESULTS AND LIMITATIONS

From an overall cohort of 354 patients (142 on-clamp, 212 off-clamp), a homogeneous PSM cohort of 78 patients in each group was selected (p ≥ 0.17). In the PSM cohort, operative time was significantly shorter in the off-clamp group (p < 0.001). There were no differences between the groups in the rates of severe complications (p = 0.32) and positive surgical margins (p = 0.24). The rate of trifecta achievement was significantly higher in the off-clamp group (83.3% vs 67.9%; p = 0.03). Warm ischemia time >20 min was independently negatively associated with trifecta achievement (odds ratio 0.32, 95% confidence interval 0.14-0.74). Moreover, the off-clamp group had a significantly higher probability of retaining eGFR ≥45 ml/min over time (3 yr: 95.9% vs 81.6%; p = 0.03); every 1-min increase in warm ischemia time reduced this probability by 1.3%.

CONCLUSIONS

We found a favorable trade-off between the benefits and risks of off-clamp RPN, with similar perioperative outcomes and a net benefit in terms of trifecta achievement and long-term renal function outcomes in comparison to on-clamp RPN.

PATIENT SUMMARY

The complexity of surgery for kidney tumors can be assessed using the RENAL score, which is a measure of the location and size of a kidney tumor. In a multicenter series of patients with tumors with a high RENAL score, we compared outcomes between strategies with (on-clamp) and without (off-clamp) clamping of kidney blood vessels during robot-assisted removal of part of the affected kidney. We found that off-clamp surgery results in better postoperative kidney function.

Long-term effect of acute ischemic injury on the kidney underwent clamped partial nephrectomy

GFR reaches a new baseline, primarily correlating with nephron-mass preservation, 1-12 months after partial nephrectomy (PN). However, does the ipsilateral GFR experience subsequent decline, and does acute ischemic injury has long-term effect on the operated kidney? 319 patients with two kidneys and unilateral clamped PN were analyzed. All had preoperative, new-baseline, and latest follow-up imaging/serum creatinine levels. Annual ipsilateral GFR decline rate (AIGDR) was defined as new-baseline GFR minus latest follow-up GFR normalized by new-baseline GFR, per year. Spectrum score was used to reflect the degree of acute ischemic injury in the operated kidney. 100 subjects searching for health screening served as controls. Predictive factors for AIGDR were assessed. The median AIGDR was 2.25%, significantly higher than controls (0.88%, p = 0.036). With some contralateral hypertrophy, the global annual GFR decline was similar to that of controls (0.81% vs. 0.88%, p = 0.7). Spectrum score correlated significantly with AIGDR (p = 0.037). These results support that acute ischemic injury has long-term effect on the operated kidney.

Risks and benefits of partial nephrectomy performed with limited or with zero ischaemia time

OBJECTIVE

To test the hypothesis that longer warm ischaemia time (WIT) might have a marginal impact on renal functional outcomes and might, in fact, reduce haemorrhagic risk intra-operatively.

PATIENTS AND METHODS

Data from 1140 patients treated with elective partial nephrectomy (PN) for a cT1-2 cN0 cM0 renal mass were prospectively collected. WIT was defined as the duration of clamping of the main renal artery with no refrigeration and was tested as a continuous variable. The primary outcome of the study was evaluation of the effect of WIT on renal function (estimated glomerular filtration rate [eGFR]) postoperatively, at 6 months and in the long term (measured between 1 and 5 years after surgery). The secondary outcome of the study was haemorrhagic risk, defined as estimated blood loss (EBL) or peri-operative transfusions. Multivariable linear, logistic and Cox regression analyses, accounting for age, Charlson comorbidity index, clinical size, preoperative eGFR and year of surgery, were used and the potential nonlinear relationship between WIT and the study outcomes was modelled using restricted cubic splines.

RESULTS

A total of 863 patients (76%) underwent PN with WIT and 277 (24%) without. The baseline median eGFR was 87.3 (68.8-99.2) mL/min/1.73m2 for the on-clamp population and 80.6 (63.2-95.2) mL/min/1.73m2  for the off-clamp population. The median duration of WIT was 17 (13-21) min. At multivariable analyses predicting renal function, longer WIT was associated with decreased postoperative eGFR (estimate: -0.21, 95% confidence interval [CI] -0.31; -0.11 [P < 0.001]). Conversely, no association between WIT and eGFR was recorded at 6-month or long-term follow-up (all P > 0.8). At multivariable analyses predicting haemorrhagic risk, clampless resection with no ischaemia time and PN with short WIT was associated with an increased EBL (estimate: -21.56, 95% CI -28.33; -14.79 [P < 0.001]) and peri-operative transfusion rate (estimate: -0.009, 95% CI -0.01; -0.003 [P = 0.002]). No association between WIT and positive surgical margin status was recorded (all P = 0.1).

CONCLUSION

Patients and clinicians should be aware that performing PN with very limited or even with zero WIT might increase bleeding and the need for peri-operative transfusion while not improving long-term renal function outcomes.

Functional recovery after partial nephrectomy: next generation analysis

OBJECTIVES

To provide a more rigorous assessment of factors affecting functional recovery after partial nephrectomy (PN) using novel tools that allow for analysis of more patients and improved accuracy for assessment of parenchymal volume loss, thereby revealing the potential impact of secondary factors such as ischaemia.

PATIENTS AND METHODS

Of 1140 patients managed with PN (2012-2014), 670 (59%) had imaging and serum creatinine levels measured before and after PN necessary for inclusion. Recovery from ischaemia was defined as the ipsilateral glomerular filtration rate (GFR) saved normalised by parenchymal volume saved. Acute kidney injury was assessed through Spectrum Score, which quantifies the degree of acute ipsilateral renal dysfunction due to exposure to ischaemia that would otherwise be masked by the contralateral kidney. Multivariable regression was used to identify predictors of Spectrum Score and Recovery from Ischaemia.

RESULTS

In all, 409/189/72 patients had warm/cold/zero ischaemia, respectively, with median (interquartile range [IQR]) ischaemia times for cold and warm ischaemia of 30 (25-42) and 22 (18-28) min, respectively. The median (IQR) global preoperative GFR and new baseline GFR (NBGFR) were 78 (63-92) and 69 (54-81) mL/min/1.73 m2 , respectively. The median (IQR) ipsilateral preoperative GFR and NBGFR were 40 (33-47) and 31 (24-38) mL/min/1.73 m2 , respectively. Functional recovery correlated strongly with parenchymal volume preserved (r = 0.83, P < 0.01). The median (IQR) decline in ipsilateral GFR associated with PN was 7.8 (4.5-12) mL/min/1.73 m2 with loss of parenchyma accounting for 81% of this loss. The median (IQR) recovery from ischaemia was similar across the cold/warm/zero ischaemia groups at 96% (90%-102%), 95% (89%-101%), and 97% (91%-102%), respectively. Independent predictors of Spectrum Score were ischaemia time, tumour complexity, and preoperative global GFR. Independent predictors of recovery from ischaemia were insulin-dependent diabetes mellitus, refractory hypertension, warm ischaemia, and Spectrum Score.

CONCLUSIONS

The main determinant of functional recovery after PN is parenchymal volume preservation. A more robust and rigorous evaluation allowed us to identify secondary factors including comorbidities, increased tumour complexity, and ischaemia-related factors that are also independently associated with impaired recovery, although altogether these were much less impactful.

Comparison between minimally invasive partial nephrectomy and open partial nephrectomy for complex renal tumors: a systematic review and meta-analysis

BACKGROUND

The present study aimed to conduct a pooled analysis to compare the efficacy and safety of minimally invasive partial nephrectomy (MIPN) with open partial nephrectomy (OPN) in patients with complex renal tumors (defined as PADUA or RENAL score ≥7).

METHODS

The present study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement, Supplemental Digital Content 1, http://links.lww.com/JS9/A394 . We conducted a systematic search of the PubMed, Embase, Web of Science, and Cochrane Library databases until October 2022. MIPN and OPN-controlled trials for complex renal tumors were included. The primary outcomes were perioperative results, complications, renal function, and oncologic outcomes.

RESULTS

A total of 2405 patients were included in 13 studies. MIPN outperformed OPN in terms of hospital stay [weighted mean difference (WMD) -1.84 days, 95% CI -2.35 to -1.33; P <0.00001], blood loss (WMD -52.42 ml, 95% CI -71.43 to -33.41; P <0.00001), transfusion rates [odds ratio (OR) 0.34, 95% CI 0.17-0.67; P =0.002], major complications (OR 0.59, 95% CI 0.40-0.86; P =0.007) and overall complications (OR 0.43, 95% CI 0.31-0.59; P <0.0001), while operative time, warm ischemia time, conversion to radical nephrectomy rates, estimated glomerular decline, positive surgical margins, local recurrence, overall survival, recurrence-free survival, and cancer-specific survival were not significantly different.

CONCLUSIONS

The present study demonstrated that MIPN was associated with a shorter length of hospital stay, less blood loss, and fewer complications in treating complex renal tumors. MIPN may be considered a better treatment for patients with complex tumors when technically feasible.

Long-Term Renal Function Following Renal Cancer Surgery: Historical Perspectives, Current Status, and Future Considerations

Knowledge of functional recovery after partial (PN) and radical nephrectomy for renal cancer has advanced considerably, with PN now established as the reference standard for most localized renal masses. However, it is still unclear whether PN provides an overall survival benefit in patients with a normal contralateral kidney. While early studies seemingly demonstrated the importance of minimizing warm-ischemia time during PN, multiple new investigations over the last 10 years have proven that parenchymal mass lost is the most important predictor of new baseline renal function. Minimizing loss of parenchymal mass during resection and reconstruction is the most important controllable aspect of long-term post-operative renal function preservation.

Every decade counts: a narrative review of functional recovery after partial nephrectomy

OBJECTIVE

To provide a narrative review of the major advances regarding ischaemia and functional recovery after partial nephrectomy (PN), along with the ongoing controversies.

METHODS

Key articles reflecting major advances regarding ischaemia and functional recovery after PN were identified. Special emphasis was placed on contributions that changed perspectives about surgical management. Priority was also placed on randomized trials of off-clamp vs on-clamp cohorts.

RESULTS

A decade ago, 'Every minute counts' was published, showing strong correlations between duration of ischaemia and development of acute kidney injury (AKI) and chronic kidney disease after clamped PN. This reinforced perspectives that ischaemia was the main modifiable factor that could be addressed to improve functional outcomes and helped spur efforts towards reduced or zero ischaemia PN. These approaches were associated with strong functional recovery and some peri-operative risk, although they were generally safe in experienced hands. Further research demonstrated that, when parenchymal volume changes were incorporated into the analyses, ischaemia lost statistical significance, and percent parenchymal volume saved proved to be the main determinant. Cold ischaemia was confirmed to be highly protective, and limited warm ischaemia also proved to be safe. The reconstructive phase of PN, with avoidance of parenchymal devascularization, appears to be most important for functional outcomes. Randomized trials of on-clamp vs off-clamp PN have shown minimal impact of ischaemia on functional recovery.

CONCLUSIONS

The past decade has witnessed great progress regarding functional recovery after PN, with many lessons learned. However, there are still unanswered questions, including: What is the threshold of warm ischaemia at which irreversible ischaemic injury begins to develop? Are some cohorts at increased risk for AKI or irreversible ischaemic injury? and Which patients should be prioritized for zero-ischaemia PN?

Sutureless Purely Off-Clamp Robot-Assisted Partial Nephrectomy: Avoiding Renorrhaphy Does Not Jeopardize Surgical and Functional Outcomes

To compare outcomes of sutureless (SL) vs. renorrhaphy (RR) off-clamp robotic partial nephrectomy (ocRPN), we retrospectively analyzed procedures performed at our center, from January 2017 to April 2021, for cT1-2N0M0 renal masses. All the patients with a minimum follow-up < 1 month were excluded from the analysis. The trifecta rate defined surgical quality. Any worsening from chronic kidney disease (CKD) I-II to ≧ IIIa (from IIIa to ≧ IIIb, and from IIIb to ≧ IV) was considered as significant stage migration (sCKDsm). A 1:1 propensity score-matched (PSM) analysis minimized baseline imbalances between SL and RR cohorts in terms of age, gender, ASA score, baseline estimated glomerular filtration rate (eGFR), tumor size, and RENAL score. Logistic regression analyses identified predictors of trifecta achievement. Kaplan-Meier (KM) analysis assessed the impact of RR on significant chronic kidney disease sCKDsm-free survival (SMFS), while Cox regression analyses identified its predictors. Overall, 531 patients were included, with a median tumor size of 3.5 cm (IQR: 2.7-5); 70 (13%) presented with a cT2 mass. An SL approach was pursued in 180 cases, but 10 needed conversion to RR. After PSM analysis, patients receiving SL showed a higher trifecta rate (94% vs. 84%; p = 0.007). SMFS probabilities were comparable at KM analysis (log-rank = 0.69). Age (OR: 0.97; 95%CI: 0.95-0.99; p = 0.01), a RENAL score ≧ 10 (OR: 0.29; 95%CI: 0.15-0.57; p < 0.001), and RR (OR: 0.34; 95%CI: 0.17-0.67; p = 0.002) were independent predictors of trifecta achievement. Age (OR: 1.04; 95%CI: 1.003-1.07; p = 0.03) and baseline eGFR (OR: 0.99; 95%CI: 0.97-0.99; p = 0.05) independently predicted sCKDsm. Compared to RR, our experience seems to show that the SL approach significantly increased the probabilities of achieving the trifecta in the observed group of cases.

Purely Off-Clamp Laparoscopic Partial Nephrectomy Stands the Test of Time: 15 Years Functional and Oncologic Outcomes from a Single Center Experience

BACKGROUND

Nephron-sparing surgery represents the gold standard treatment for organ-confined renal tumors. We present 15-years of outcomes after off-clamp laparoscopic partial nephrectomy (ocLPN).

METHODS

a retrospective analysis was performed on patients who underwent ocLPN between May 2001 and December 2005. Baseline demographic, clinical, pathologic, surgical, functional and survival data were collected. The Kaplan-Meier method evaluated group-specific oncologic outcomes at 5, 10 and 15 years and the log rank test assessed differences between groups. The same analysis investigated the probabilities of developing a significant renal function impairment (sRFI) and achieving ROMeS. Cox analyses identified predictors of this latter tricomposite outcome.

RESULTS

We included 63 patients whose median tumor size was 3 cm (IQR:2-4). At 15 years, the chances of developing local recurrence, metachronous renal cancers or distant metastases were 2 ± 2%, 23 ± 6% and 17 ± 5%, respectively. Consequently, disease-free, cancer-specific and overall-survival probabilities were 68 ± 6%, 90 ± 4% and 72 ± 6%. MCRSS and UCISS well predicted oncologic outcomes. Overall, nine (14%) patients experienced an sRFI and 33 (52%) achieved ROMeS. Age (HR: 1.046; p = 0.033) and malignant histology (low-risk cancers HR: 3.233, p = 0.048) (intermediate/high risk cancers HR: 5.721, p = 0.023) were independent predictors of ROMeS non-achievement.

CONCLUSIONS

At 15 years from ocLPN, most of patients will experience both excellent functional and oncologic outcomes.

Effect of augmented reality navigation technology on perioperative safety in partial nephrectomies: A meta-analysis and systematic review

Aim

To evaluate the impact of augmented reality surgical navigation (ARSN) technology on short-term outcomes of partial nephrectomy (PN).

Methods

A systematic literature search was conducted in PubMed, Embase, Cochrane, and Web of Science for eligible studies published through March 28, 2022. Two researchers independently performed the article screening, data extraction and quality review. Data analysis was performed using Cochrane Review Manager software.

Results

A total of 583 patients from eight studies were included in the analysis, with 313 in the ARSN-assisted PN group (AR group) and 270 in the conventional PN group (NAR group). ARSN-assisted PN showed better outcomes than conventional surgery in terms of operative time, estimated blood loss, global ischemia rate, warm ischemia time, and enucleation rate. However, there were no significant differences in the rate of Conversion to radical nephrectomy (RN), postoperative estimated glomerular filtration rate (eGFR), positive margin rate, and postoperative complication rate.

Conclusion

The utilization of ARSN can improve the perioperative safety of PN. Compared with conventional PN, ARSN-assisted PN can reduce intraoperative blood loss, shorten operative time, and improve renal ischemia. Although direct evidence is lacking, our results still suggest a potential advantage of ARSN in improving renal recovery after PN. However, as the ARSN system is still in an exploratory stage, its relevance in PN have been poorly reported. Additional high-quality randomized controlled trial (RCT) studies will be required to confirm the effect of ARSN on PN.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=301798, identifier PROSPERO ID: CRD42022301798.

Systematic Review of Comparative Studies of 3D Models for Preoperative Planning in Minimally Invasive Partial Nephrectomy

Background: The employment of 3-dimensional (3D) virtual models of the organs and tumors, obtained from conventional 2-dimensional (2D) imaging (i.e. computed tomography scan and magnetic resonance imaging) have already demonstrated an outstanding potential in urology, especially in renal surgery. Objectives: The aim of this systematic review is to provide an updated focus on the results obtained from the preoperative employment of 3D virtual imaging reconstructions in nephron sparing oncological surgery. Methods: A systematic literature search was conducted in April 2022 using Medline (via PubMed), Embase (via Ovid), Scopus, and Web of Science. The search strategy used PICO criteria and article selection was conducted in accordance with the PRISMA guidelines. The risk of bias and the quality of the articles included were assessed. A dedicated data extraction form was used to collect the data of interest. Results: The initial electronic search identified 471 papers, of which 13 ultimately met the inclusion criteria and were included in the review. 11 studies reported outcomes of virtual models, 2 studies focused on printed 3D models. In these studies, the application of 3D models for preoperative planning has been reported to increase the selective clamping rate and reducing the opening of collecting system, blood loss and loss of renal function. Conclusions: 3D virtual models seem to provide some surgical benefits for preoperative planning especially for complex renal masses. In the next future the continuous evolution of this technology may further increase its field of application and its potential clinical benefit.

3D renal model for surgical planning of partial nephrectomy: A way to improve surgical outcomes

OBJECTIVE

to evaluate the impact of 3D model for a comprehensive assessment of surgical planning and quality of partial nephrectomy (PN).

MATERIALS AND METHODS

195 patients with cT1-T2 renal mass scheduled for PN were enrolled in two groups: Study Group (n= 100), including patients referred to PN with revision of both 2D computed tomography (CT) imaging and 3D model; Control group (n= 95), including patients referred to PN with revision of 2D CT imaging. Overall, 20 individuals were switched to radical nephrectomy (RN). The primary outcome was the impact of 3D models-based surgical planning on Trifecta achievement (defined as the contemporary absence of positive surgical margin, major complications and ≤30% postoperative eGFR reduction). The secondary outcome was the impact of 3D models on surgical planning of PN. Multivariate logistic regressions were used to identify predictors of selective clamping and Trifecta's achievement in patients treated with PN (n=175).

RESULTS

Overall, 73 (80.2%) patients in Study group and 53 (63.1%) patients in Control group achieved the Trifecta (p=0.01). The preoperative plan of arterial clamping was recorded as clampless, main artery and selective in 22 (24.2%), 22 (24.2%) and 47 (51.6%) cases in Study group vs. 31 (36.9%), 46 (54.8%) and 7 (8.3%) cases in Control group, respectively (p<0.001). At multivariate logistic regressions, the use of 3D model was found to be independent predictor of both selective or super-selective clamping and Trifecta's achievement.

CONCLUSION

3D-guided approach to PN increase the adoption of selective clamping and better predict the achievement of Trifecta.

The Outcome of Sutureless in Partial Nephrectomy: A Systematic Review and Meta-Analysis

Purpose

To compare the effect of sutureless versus standard suture (double-layer suture) during renorrhaphy in laparoscopic or robotic-assisted partial nephrectomy on perioperative and renal function outcomes.

Methods

PubMed, Embase, and other sources were searched for randomized controlled trials or retrospective studies comparing sutureless partial nephrectomy versus standard suture partial nephrectomy. A systematic review and meta-analysis were performed by two reviewers independently.

Results

Five retrospective studies were included with a total of 634 patients. The results showed that there was a significant difference in the decline of estimated glomerular filtration rate (I² = 98.5%; WMD, -4.19 ml/min; 95% CI, -7.64 to -0.73; P < 0.001) and no significant difference in postoperative complications (I² = 0; RR, 1.31; 95% CI, 0.61 to 2.81; P = 0.623). A significant advantage in terms of operating time (I² = 53.9%; WMD, -29.08 min; 95% CI, -33.06 to -25.10; P = 0.069) and warm ischemia time (I² = 38.5%; WMD, -6.17 min; 95% CI, -6.99 to -5.36; P = 0.165) favored sutureless, while there was no significant difference in blood loss (I² = 58.1%; WMD, 3.10 ml; 95% CI, -39.18 to 45.38; P = 0.049).

Conclusion

Sutureless during renorrhaphy is feasible and safe compared with standard suture. Sutureless can shorten the operating time and warm ischemia time without increasing postoperative complications, and thus, it protects renal function.

On-Clamp vs. Off-Clamp Robot-Assisted Partial Nephrectomy for cT2 Renal Tumors: Retrospective Propensity-Score-Matched Multicenter Outcome Analysis

We compared perioperative outcomes after on-clamp versus off-clamp robot-assisted partial nephrectomy (RAPN) for >7 cm renal masses. A multicenter dataset was queried for patients who had undergone RAPN for a cT2cN0cM0 kidney tumor from July 2007 to February 2022. The Trifecta achievement (negative surgical margins, no severe complications, and ≤ 30% postoperative estimated glomerular filtration rate (eGFR) reduction) was considered a surrogate of surgical quality. Overall, 316 cases were included in the analysis, and 58% achieved the Trifecta. A propensity-score-matched analysis generated two cohorts of 89 patients homogeneous for age, ASA score, preoperative eGFR, and RENAL score (all p > 0.21). Compared to the on-clamp approach, OT was significantly shorter in the off-clamp group (80 vs. 190 min; p < 0.001), the incidence of sRFD was lower (22% vs. 40%; p = 0.01), and the Trifecta rate higher (66% vs. 46%; p = 0.01). In a crude analysis, >20 min of hilar clamping was associated with a significantly higher risk of sRFD (OR: 2.30; 95%CI: 1.13−4.64; p = 0.02) and with reduced probabilities of achieving the Trifecta (OR: 0.46; 95%CI: 0.27−0.79; p = 0.004). Purely off-clamp RAPN seems to be a safe and viable option to treat cT2 renal masses and may outperform the on-clamp approach regarding perioperative surgical outcomes.

Injectable adhesive self-healing biocompatible hydrogel for haemostasis, wound healing, and postoperative tissue adhesion prevention in nephron-sparing surgery

Nephron-sparing surgery is a well-established treatment in patients with T1a renal cell carcinoma; however, the complex suturing process prolongs warm ischaemia time, affects the preservation of normal renal parenchymal function, and causes avoidable postoperative tissue adhesion complications, including chronic abdominal pain, intestinal obstruction, and female infertility. Hence, the design of multifunctional biomaterials with haemostasis, postoperative wound management, and postoperative tissue adhesion prevention properties for nephron-sparing surgeries is urgently needed. In this study, a series of injectable adhesive multifunctional biocompatible hydrogels were designed based on the free-radical polymerisation of monomers acryloyl-6-aminocaproic acid (AA) and N-acryloyl 2-glycine (NAG), and the ionic coordination between Ca²⁺ and the abundant carboxyl groups in AA and NAG. AA/NAG/Ca (AA, NAG, and Ca refer to acryloyl-6-aminocaproic acid, N-acryloyl 2-glycine and calcium chloride, respectively) hydrogel exhibited good mechanical properties, swelling and adhesion properties, flexibility, in vitro blood-clotting ability, and cytocompatibility. In vivo experiments on liver injury models and rat/rabbit nephron-sparing surgery models elucidated that the AA/NAG/Ca hydrogel had haemostasis performance and wound healing properties that led to short bleeding time, reduced bleeding volume, and well-organised nephron structures. An abdomen-caecum adhesion model indicated that the AA/NAG/Ca hydrogel showed excellent anti-adhesion properties. In summary, this multifunctional hydrogel exhibited potential for improving haemostasis and wound management in nephron-sparing surgeries, showing potential for clinical application. STATEMENT OF SIGNIFICANCE: Extended warm ischemia time during nephron sparing surgery negatively affected postoperative renal function due to the need for hemostasis at the wound with abundant blood supply, and postoperative wound healing and additional adhesions caused by the surgical procedure deserve attention. Based on the efficient and stable adhesion properties of hydrogels and the ability to promote wound healing. Herein, a series of adhesive self-healing biocompatible hydrogels were prepared based on free-radical polymerization of acryloyl-6-aminocaproic acid (AA) and N-acryloyl 2-glycine (NAG) and the ionic coordination between Ca²⁺ with the abundant carboxyl groups in AA and NAG. AA/NAG/Ca hydrogel showed hemostasis property in nephron sparing surgery model, promote kidney wound healing, and could perform anti-postoperative adhesion efficacy in an abdomen-caecum adhesion model.

Surgical and functional outcomes of robot-assisted versus laparoscopic partial nephrectomy with cortical renorrhaphy omission

To evaluate the surgical and functional outcomes between robot-assisted (CRO-RAPN) vs. laparoscopic (CRO-LPN) methods of cortical-renorrhaphy-omitting partial nephrectomy. Between July 2012 and June 2020, patients with localized clinical T1-2 renal masses who underwent CRO-RAPN or CRO-LPN were reviewed. The outcomes of the two groups were compared using propensity-score matching. Trifecta was defined as negative surgical margin, warm ischemic time < 25 min, and absence of complications of Clavien-Dindo grade III or more until three months postoperatively. The preservation rate of the estimated glomerular filtration rate (eGFR) was evaluated at six months postoperatively. Among 291 patients (CRO-RAPN, n = 210; CRO-LPN, n = 81) included in the study, 150 matched pairs of patients were analyzed. Compared to the CRO-LPN group, the CRO-RAPN group was associated with shorter warm ischemic time (13 min vs. 20 min, P < 0.001), shorter total operation time (162 min vs. 212 min, P < 0.001), less estimated blood loss (40 mL vs. 119 mL, P = 0.002), lower incidence of overall complications (3% vs. 16%, P = 0.001), higher preservation rate of eGFR at six months postoperatively (93% vs. 89%, P = 0.003), and higher trifecta achievement rate (84% vs. 64%, P = 0.004). CRO-RAPN contributed to shorter warm ischemic time, less blood loss, fewer complications, and higher preservation of renal function, all of which allowed this technique to achieve a higher rate of trifecta compared to CRO-LPN.

Changes in kidney function according to ischemia type during partial nephrectomy for T1a kidney cancer

To compare the postoperative estimated-glomerular-filtration-rate (eGFR) and parenchymal changes between cold ischemia and zero/selective ischemia for a T1a mass. We analyzed 104 patients who underwent open partial nephrectomy with cold ischemia (53) or zero/selective ischemia (51) for T1a between 2008 and 2018 to determine postoperative renal function changes and associated factors. Postoperative renal function was expressed as (postoperative-eGFR - preoperative-eGFR)/preoperative-eGFR × 100%. Parenchymal enhancement and thicknesses of the ipsilateral kidney as tissue changes were measured on postoperative CT to identify the correlation with the renal function change. Patients with 10% or 25% decrease in eGFR were significantly more in the cold ischemia group (p = 0.032, p = 0.006). On multivariable analysis, preoperative eGFR, ischemic type, and percent change of parenchymal thickness were identified to be significantly associated with postoperative 12 months renal function (B = - 0.367, p = 0.020; B = 6.788, p = 0.042; B = 0.797, p = 0.029). Change in parenchymal thickness was negatively correlated with changes in postoperative renal function (r = - 0.277, p = 0.012). Changes in eGFR were associated with a decrease in parenchymal thickness and the type of ischemic technique. Zero/selective ischemia during partial nephrectomy may have an advantage in preserving postoperative renal function compared to cold ischemia.

Clampless Laparoscopic Tumor Enucleation for Exophytic Masses Greater Than 4 cm: Is Renorrhaphy Necessary?

Objective: To demonstrate the safety of clampless 3D laparoscopic tumor enucleation (cLTE) for exophytic T1b kidney masses, avoiding suture to achieve hemostasis. Methods: Between January 2010 and January 2021, 241 consecutive patients with an exophytic renal tumor underwent sutureless cLTE. Patients with predominantly endophytic growth or tumors 4 mm closer to the collecting system less were excluded. In all cases, an attempt was made to accomplish surgery without suturing kidney parenchyma. Data were obtained from a retrospective review of history and physical examinations, operative and pathology reports, anesthesia records during the hospital stay, and follow-up visits. Results: Among 241 patients who underwent cLTE, 148 had cT1a and 93 had cT1b renal tumor. The median tumor size was 32 mm, and the median R.E.N.A.L. (radius exophytic/endophytic nearness anterior/posterior location) score was 6. Renorrhaphy was necessary in 5 cases. The median operative time (OT) was 100 minutes, and the estimated blood loss (EBL) was 150 mL. The median 24-hour decrease in hemoglobin was 1.8 g/dL. The median length of stay was 4 days. Nineteen patients had postoperative complications: 3 cases had Clavien-Dindo (CD) 3a or more, 6 had CD2, and 10 had CD1. Comparing the T1a and T1b groups, except for the median OT and the EBL, no significant differences were observed in all the other variables analyzed. In both groups, renal function was preserved after 1 year from surgery. Conclusion: Our experience showed that sutureless cLTE is safe and feasible for T1b tumors leading to radical oncological outcomes and preserving renal function.

A Modified Two-Layer Suture Technique for Transperitoneal Laparoscopic Partial Nephrectomy: Single-Center Clinical Experience

Purposes

This study aims to evaluate the feasibility and efficacy of a modified two-layer suture method during laparoscopic partial nephrectomy (LPN) by a comparative analysis with the traditional two-layer suture.

Methods

A total of 60 LPN patients were enrolled in this study, of which 30 patients received the modified two-layer suture method and the remaining 30 patients underwent the traditional two-layer suture. Then, surgical characteristics including operative time, warm ischemic time (WIT), estimated blood loss (EBL), and glomerular filtration rate (GFR) were recorded. Finally, univariable and multivariable linear regression analyses were used to evaluate the correlations of tumor characteristics, suture methods, and postoperative renal function.

Results

There was no significant difference between the two suture groups with respect to patient and tumor characteristics, postoperative creatinine level, and blood urea nitrogen (BUN) level. The modified suture group showed a significantly shorter clamping time and a less GFR level reduction than the traditional two-layer suture group (15 vs. 23 min; 42.32 ± 9.48 vs. 27.07 ± 7.88; p < 0.05). Additionally, the modified two-layer suture was an independent factor that influenced the clamping time and the level of GFR reduction.

Conclusion

The modified two-layer suture method is feasible and effective for LPN.

Three-dimensional (3D) reconstruction and navigation in robotic-assisted partial nephrectomy (RAPN) for renal masses in the solitary kidney: A comparative study

BACKGROUND

Numerous efforts were made to improve renal function and oncologic outcomes in surgery for patients with kidney cancer. We explored new robotic methods in solitary kidneys.

MATERIALS AND METHODS

We prospectively registered and included 16 patients in the 3D-robot-assisted partial nephrectomy (RAPN) group with a solitary kidney (anatomic or functional), and retrospectively identified 25 patients with a solitary kidney who received RAPN also operated by us for comparison.

RESULTS

The rates of global clamping reduced in the 3D-RAPN group (37.5% vs 76%)while selective rates were higher (56.2% vs 20%) (p = 0.028). The mean percentages of Scr increase (+20.2% vs +30.2%, p = 0.045) and eGFR reduction (-16.8% vs -27.1%) as well as rate of opening collecting systems (31.3% vs 72%, p = 0.010) were lower in 3D-RAPN group.

CONCLUSIONS

3D-RAPN less impaired the renal function of patients with a solitary kidney and showed superiority or non-inferiority in other evaluation indexes compared to conventional RAPN.

Comparison of Sutureless Versus Suture Partial Nephrectomy for Clinical T1 Renal Cell Carcinoma: A Meta-Analysis of Retrospective Studies

Background

Partial nephrectomy (PN) is the recommended treatment for T1 renal cell carcinoma (RCC). Compared with suture PN, sutureless PN reduces the difficulty and time of operation, but the safety and feasibility have been controversial. This meta-analysis was conducted to compare the function and perioperative outcomes of suture and sutureless PN for T1 RCC.

Methods

Systematic literature review was performed up to April 2021 using multiple databases to identify eligible comparative studies. According to the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) criteria, identification and selection of the studies were conducted. Meta-analysis was performed for studies comparing suture to sutureless PN for both T1a and T1b RCC. In addition, subgroup analysis was performed on operation time, warm ischemia time, estimated blood loss, and postoperative complications. Sensitivity analysis was used in analysis with high heterogeneity (operation time and estimated blood loss).

Results

Eight retrospective studies were included with a total of 1,156 patients; of the 1,156 patients, 499 received sutureless PN and 707 received suture PN. The results showed that sutureless PN had shorter operative time (I² = 0%, P < 0.001), warm ischemia time (I² = 97.5%, P < 0.001), and lower clamping rate (I² = 85.8%, P = 0.003), but estimated blood loss (I² = 76.6%, P = 0.064) had no difference. In the comparison of perioperative outcomes, there was no significant difference in postoperative complications (I² = 0%, P = 0.999), positive surgical margins (I² = 0%, P = 0.356), postoperative estimated glomerular filtration rat (eGFR) (I² = 0%, P = 0.656), and tumor recurrence (I² = 0%, P = 0.531).

Conclusions

In T1a RCC with low RENAL score, sutureless PN is a feasible choice, whereas it should not be overestimated in T1b RCC.

Robot-Assisted versus Laparoscopic Partial Nephrectomy for Giant Sporadic Renal Angiomyolipomas of ≥7 cm: A Propensity Score-Matched Analysis

Background

To compare the perioperative and functional outcomes between robot-assisted partial nephrectomy (RAPN) and laparoscopic partial nephrectomy (LPN) for giant sporadic renal angiomyolipomas (AMLs) of ≥7 cm.

Materials and Methods

Patients with sporadic renal AMLs of ≥7 cm who underwent RAPN or LPN in the First Affiliated Hospital of Nanchang University between 2015 and 2020 were retrospectively analyzed. Propensity score matching (1 : 1) was performed to adjust for potential baseline confounders. Perioperative and functional outcomes of the RAPN and LPN groups were collected and compared.

Result

After propensity score matching, no statistically significant differences in baseline characteristics were found between the groups (41 vs. 41). Within the matched cohort, the warm ischemia time (WIT) in the RAPN group was significantly shorter than that in the LPN group (21 vs. 27 min, p < 0.001). In addition, the RAPN group was associated with improved postoperative renal function (72.8 vs. 69.8 mL/min/1.73 m², p=0.045). WIT and preoperative renal function are independent predictors of renal function at 6 months postoperatively, and renal score and operation method are independent predictors of WIT.

Conclusion

RAPN and LPN are safe and feasible minimally invasive treatments for sporadic giant renal AMLs, but RAPN is associated with shorter WIT and better postoperative renal functional preservation. WIT and preoperative renal function are independent predictors of renal function at 6 months postoperatively, while the RENAL score and surgical method are independent risk factors to WIT. For giant and complex renal AMLs, RAPN is the first choice when condition permits.

Minimally Invasive Partial Nephrectomy: Are All Clamps Created Equal? An Ex Vivo Model Simulation of Vascular Clampage

REASON FOR REVIEW

During the partial nephrectomy, clamping of the vascular pedicle before exision of the tumor is a key step in minimizing blood loss and maintaining adequate visualization. Different vascular clamping devices have been developed for minimal invasive surgery. However, there are no reports comparing them in turn of efficiency RECENT FINDINGS: We present an ex vivo experimental model, designed to demonstrate differences between the clamping devices. All clamps proved to function properly without any leakage at 90 and 120 mmHg, respectively. Our study and the ex vivo model prove that all available clamps are equally efficient at physiologic pressures.

Efficacy and safety of prophylactic superselective embolization for angiomyolipoma at the renal hilum

Objective

This study investigated the efficacy and safety of superselective transcatheter arterial embolization for angiomyolipoma at the renal hilum.

Methods

Between August 2012 and January 2015, 13 patients with 16 angiomyolipomas at the renal hilum underwent initial, prophylactic, superselective transcatheter arterial embolization. The patients were followed by computed tomography or magnetic resonance imaging, and volume-reduction ratios after embolization were measured.

Results

The mean or median post-embolization volume reduction ratios were 23% (follow-up duration, 1–2 months), 55% (3–6 months), 55% (7–12 months), 66% (1–2 years), 67% (2–3 years), and 54% (>3 years). After initial embolization, none of the 16 tumors bled or required surgery; two (13%) tumors recurred; and three (19%) tumors received repeat embolization. Estimated glomerular filtration rates were not decreased at medians of 7 days (near the time of discharge) and 39 days (first clinical follow-up) post-procedure, compared with baseline. Except for post-embolization syndrome, no procedure-related complications occurred.

Conclusions

Superselective embolization for renal hilar angiomyolipoma is safe and kidney-preserving, with good tumor volume reduction and bleeding prevention.

How to improve outcome in nephron-sparing surgery: the impact of new techniques

PURPOSE OF REVIEW

Nephron-sparing partial nephrectomy is the state of the art for localized small renal mass and it is gaining attention also for more advanced cases. In the present narrative review, we discuss the new developments that have occurred in the advancement of this approach over the past few years.

RECENT FINDINGS

Off-clamp, selective/superselective clamp and early-unclamping techniques are safe and feasible approaches, with potentially superior functional outcomes, and noninferior complications rate and oncological outcomes, when compared with main artery clamping. Renorrhaphy must preserve the physiological vascularization of residual parenchyma. Running sutures, particularly using barbed wires, shorten the operating and ischemia times. A further advantage could derive from avoiding a double-layer suture. Transperitoneal robot-assisted partial nephrectomy (RAPN) and retroperitoneal RAPN can be considered equivalent in terms of perioperative morbidity, functional and oncologic outcomes, regardless of tumor's location, thus the choice of the approach should be driven by the surgeon's expertise. Future improvements should be introduced by the single-port robotic surgery, which seems to be safe and feasibly also in an off-clamp manner.

SUMMARY

Significant advances have recently been achieved in nephron-sparing surgery technique. However, future studies with standardized reporting of these new techniques are needed to assess the real impact of them on early and long-term functional outcomes.

Meta grayscale adaptive network for 3D integrated renal structures segmentation

Three-dimensional (3D) integrated renal structures (IRS) segmentation targets segmenting the kidneys, renal tumors, arteries, and veins in one inference. Clinicians will benefit from the 3D IRS visual model for accurate preoperative planning and intraoperative guidance of laparoscopic partial nephrectomy (LPN). However, no success has been reported in 3D IRS segmentation due to the inherent challenges in grayscale distribution: low contrast caused by the narrow task-dependent distribution range of regions of interest (ROIs), and the networks representation preferences caused by the distribution variation inter-images. In this paper, we propose the Meta Greyscale Adaptive Network (MGANet), the first deep learning framework to simultaneously segment the kidney, renal tumors, arteries and veins on CTA images in one inference. It makes innovations in two collaborate aspects: 1) The Grayscale Interest Search (GIS) adaptively focuses segmentation networks on task-dependent grayscale distributions via scaling the window width and center with two cross-correlated coefficients for the first time, thus learning the fine-grained representation for fine segmentation. 2) The Meta Grayscale Adaptive (MGA) learning makes an image-level meta-learning strategy. It represents diverse robust features from multiple distributions, perceives the distribution characteristic, and generates the model parameters to fuse features dynamically according to image's distribution, thus adapting the grayscale distribution variation. This study enrolls 123 patients and the average Dice coefficients of the renal structures are up to 87.9%. Fine selection of the task-dependent grayscale distribution ranges and personalized fusion of multiple representations on different distributions will lead to better 3D IRS segmentation quality. Extensive experiments with promising results on renal structures reveal powerful segmentation accuracy and great clinical significance in renal cancer treatment.

Outcomes of gasless laparoendoscopic single-port partial nephrectomy in 356 consecutive patients: Feasibility of a clampless and sutureless technique

OBJECTIVES

To investigate the outcomes and feasibilities of gasless laparoendoscopic single-port clampless sutureless partial nephrectomy.

METHODS

We reviewed 356 consecutive patients with primary unilateral non-metastatic renal masses who underwent gasless laparoendoscopic single-port partial nephrectomy (2011-2018), which was performed retroperitoneally using a three-dimensional flexible endoscope, without vascular clamping or renorrhaphy in principle.

RESULTS

The median tumor size was 2.5 cm, and 213 (60%), 105 (29%), and 38 (11%) patients had peripheral, central, and hilar tumors, respectively. Clampless and sutureless partial nephrectomy was accomplished in 337 patients (95%), while eight (2%) and 16 (4%) patients required vascular clamping and renorrhaphy, respectively. The median operative time and blood loss were 220 min and 266 mL, respectively; eight patients (2%) received blood transfusion. Clavien-Dindo grade 3a complications occurred in 27 patients (8%); all these patients had urinary leakage treated with ureteral stent placement, one of whom also developed a postoperative pseudoaneurysm. Among 324 patients diagnosed with renal cell carcinoma, six (2%) had positive surgical margins, and one (0.3%) and seven (2%) developed metastatic and local recurrences, respectively. During a median follow-up of 54 months, no patient died from kidney cancer. The median percent decrease in estimated glomerular filtration rate at 3 months after surgery was 5.7%. No patient experienced postoperative acute renal failure, while one patient with preexisting renal impairment started dialysis at 70 months after surgery.

CONCLUSIONS

Clampless and sutureless partial nephrectomy can be safely accomplished in most patients undergoing gasless laparoendoscopic single-port surgery, yielding favorable oncological and functional outcomes.

Off-Clamp Robot-Assisted Partial Nephrectomy: Is There Something More to Achieve Optimal Trifecta Outcomes?

Objectives: To report trifecta outcomes of our "off-clamp" partial nephrectomy (PN) patients operated without main renal artery and/or any selective/superselective clamping. Materials and Methods: Between April 2008 and March 2020, 52 patients received "off-clamp" robot-assisted partial nephrectomy. Postoperative sixth month estimated glomerular filtration rate (eGFR) and eGFR decrease were considered for renal function evaluation. Patients with negative surgical margins, <15% postoperative eGFR decrease and absence of grade ≥2 Clavien-Dindo complications were reported to achieve trifecta outcomes. Results: Mean age and body mass index of the patients were 57.51 ± 12.99 years and 27.23 ± 4.35 kg/m², respectively. Mean preoperative hematocrit, serum creatinine, and eGFR were 42.01 ± 3.86%, 0.92 ± 0.28 mg/dL, and 85.26 ± 21.27 mL/min/1.73 m², respectively. Mean tumor size was 30.32 ± 13.64 mm. Mean PADUA and RENAL scores were 7.63 ± 1.46 and 6.21 ± 1.63, respectively. One patient had focal surgical margin positivity. Mean console time and estimated blood loss was 82.11 ± 38.51 minutes and 280.76 ± 278.98 mL, respectively. Complications were observed in two (4%) patients (one Clavien I, one Clavien IIIB). At postoperative sixth month, serum creatinine and eGFR were 0.95 ± 0.32 mg/dL and 83.65 ± 22.44 mL/min/1.73 m², respectively. Eventually seven patients had ≥15% postoperative eGFR decrease, one patient had grade ≥2 complication and one patient had positive surgical margin. Forty-three (83%) patients fulfilled trifecta outcomes. Conclusion: Off-clamp PN is important for optimal renal function preservation. Patient selection and additional operative measures along with experience in robotic procedure can contribute achievement of optimal trifecta outcomes.

Open partial nephrectomy: current review

Partial nephrectomy (PN) is increasingly considered the gold standard treatment for localized renal cell carcinomas (RCCs) where technically feasible. The advantage of nephron-sparing surgery lies in preservation of parenchyma and hence renal function. However, this advantage is counterbalanced with increased surgical risk. In recent years with the popularization of minimally invasive partial nephrectomy (laparoscopic and robotic), the contemporary role of open PN (OPN) has changed. OPN has several advantages, particularly in complex patients such as those with a solitary kidney, multi-focal tumors, and significant surgical history, as well as providing improved application of renoprotective measures. As such, it is a technique that remains relevant in current urology practice. In this article we discuss the evidence, indications, operative considerations and surgical technique, along with the role of OPN in contemporary nephron-sparing surgery.

Laparoscopic and Robotic-Assisted Partial Nephrectomy: An Overview of Hot Issues

Laparoscopic partial nephrectomy and robot-assisted partial nephrectomy are attracting increased attention from urologists. They can achieve the same effect of oncology control as radical nephrectomy; moreover, they can offer better preservation of renal function, thus obtaining long-term living benefits. The indications are also expanding, making it possible for larger and more difficult tumors. Laparoscopic partial nephrectomy and robot-assisted partial nephrectomy can be performed by transperitoneal and retroperitoneal approaches, with their individual advantages and limitations. In addition, the renal tumor scoring systems have been widely used and studied in laparoscopic partial nephrectomy and robot-assisted partial nephrectomy. In -order to better preserve renal function, the zero-ischemia technique is widely used. The application of intraoperative imaging technology provides convenience and greater benefits. Besides, whether minimal invasive partial nephrectomy can be performed without stop antiplatelet treatment is still disputed. Clinicians perform substantial exploration and practice to achieve the "trifecta" of surgery: complete resection of the tumor, maximum protection of renal function, and no complications.

Head to Head Impact of Margin, Ischemia, Complications, Score Versus a Novel Trifecta Score on Oncologic and Functional Outcomes After Robotic-assisted Partial Nephrectomy: Results of a Multicenter Series

BACKGROUND

There is a paucity of data describing the ability of margin, ischemia, complications, score (MIC) and trifecta in predicting long-term outcomes of robotic-assisted partial nephrectomy (RAPN).

OBJECTIVE

To compare a novel trifecta (negative margins, no significant complications, and perioperative estimated glomerular filtration rate [eGFR] decrease ≤30%) versus standard MIC as predictors of oncologic and functional results in a large series of RAPNs.

DESIGN, SETTING, AND PARTICIPANTS

Between 2009 and 2019, a multicenter dataset was queried for patients with nonmetastatic renal masses who underwent RAPN at eight participating institutions.

INTERVENTION

RAPN.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

MIC and trifecta achievement were determined for the overall cohort and a subgroup undergoing off-clamp RAPN (ocRAPN), respectively. The overall survival (OS), recurrence-free survival (RFS), and new onset of end-stage renal disease (ESRD; defined as eGFR <30 ml/min) probabilities were assessed by the Kaplan-Meier method. Cox regression analyses were used to identify predictors of OS, RFS, and ESRD. For all analyses, two-sided p < 0.05 was considered significant.

RESULTS AND LIMITATIONS

Out of 1807 patients, MIC and trifecta were achieved in 71.1% (n = 1285) and 82.6% (n = 1492), respectively, and once restricted to the ocRAPN cohort, in 95.6% (n = 625) and 81.6% (n = 534), respectively. On Kaplan-Meier analysis, both MIC and trifecta achievement predicted higher OS and lower ESRD probabilities (all p < 0.014), while only trifecta achievement was a predictor of RFS probabilities (p = 0.009). On multivariable Cox regression, MIC did not predict any of the endpoints independently, while trifecta achievement was an independent predictor of higher OS (hazard ratio [HR] 0.4, 95% confidence interval [CI] 0.18-0.86; p = 0.019) and lower ESRD development probabilities (HR 0.32, 95% CI 0.15-0.72; p = 0.005).

CONCLUSIONS

Trifecta, initially described as comprehensive measures of perioperative outcomes, needs to stand the test of time. Compared with MIC, the recent trifecta was an independent predictor of clinically significant endpoints, namely, survival and ESRD development probabilities.

PATIENT SUMMARY

Our novel trifecta represents a reliable method for estimating survival and development of end-stage renal disease after robotic-assisted partial nephrectomy.

On-clamp versus purely off-clamp robot-assisted partial nephrectomy in solitary kidneys: comparison of perioperative outcomes and chronic kidney disease progression at two high-volume centers

BACKGROUND

Minimal literature describes the impact of hilar control on the progression to chronic kidney disease (pCKD) after robotic partial nephrectomy (RPN) in solitary kidneys (SK). The aim of this study was to compare purely off-clamp (ocRPN) vs. on-clamp robotic partial nephrectomy (onRPN) in SK and to identify predictors of pCKD at two high-volume centers.

METHODS

Between December 2013 and October 2019, 54 patients with SK underwent ocRPN and onRPN for renal tumors at two institutions. Baseline and perioperative data were analyzed. Newly onset of CKD stage 3b,4,5 (CKD3b,4,5) was assessed by Kaplan-Meier curves and compared for warm ischemia time (WIT) with the log-rank test. Cox regression analysis was used to identify predictors of pCKD.

RESULTS

At a median follow-up of 13 months (IQR 6.3-34), newly onset of CKD3b and CKD 4.5 were observed in 11.1% and 7.4% of patients, respectively. onRPN was associated with a higher risk of progression to CKD 3b,4,5 stages (P=0.034) and higher rate of perioperative complications (P=0.03). On univariable analysis eGFR at discharge (eGFRd), positive surgical margins status (PSM) and WIT were predictors of newly onset of CKD3b,4,5 (each P<0.05). Multivariable analysis identified eGFRd (HR 0.88; CI 95% 0.81-0.96) and WIT (HR 1.09; CI 95% 1.02-1.16) as independent predictors of pCKD (each P<0.01). Main limitations include the retrospective nature of the study, the short-term follow-up and the lack of data adjustment for parenchymal volume loss.

CONCLUSIONS

eGFRd and WIT during RPN are independent predictors of pCKD in SK. In this setting a critical reduction of WIT should be achieved according to the oncologic outcome. In patients with SK, WIT represents the only surgical modifiable factor of RPN for avoiding a quicker onset of pCKD.

Robotic Partial Nephrectomy with Indocyanine Green Fluorescence Navigation

Partial nephrectomy (PN) is a recommended type of treatment of localised renal tumors. Real-time intraoperative imaging technique, such as fluorescence imaging with indocyanine green (ICG) administration helps to improve intraoperative and postoperative outcomes in patients who underwent PN. Our work presents results of patients who underwent robotic PN with ICG navigation. A total of 37 patients underwent robotic PN with application of ICG between April 2015 and May 2019. A total amount of 5 mg of ICG was applied intravenously, and then robotic PN was performed with fluorescent imaging. ICG was used by the surgeon's decision according to unfavourable anatomical properties of tumor or to high R.E.N.A.L. nephrometry score. An exact border between perfused and nonperfused tissue was detected, and exact tumor's branch of the renal artery was clamped. Robotic PN with ICG-fluorescence imaging navigation was performed in 37 cases with a preoperative average diameter of tumor of 31 mm. The mean surgery time was 133 minutes, and the mean estimated blood loss was 190 mL. Arterial clamping was performed in 35 cases. The mean duration of warm ischemia was 14 minutes. Application of ICG enabled specific tumor-supplying vessel clamping in 25 cases. Two complications of grade II according to the Clavien-Dindo classification occurred intraoperatively, and one complication of grade III was observed. Renal function changes showed favourable results for the cases with superselective clamping. Finally, an administration of ICG eases superselective clamping of tumor-specific branch of renal artery and helps to preserve normal renal function with acceptable oncological results.

Impact of learning curve on perioperative outcomes of off-clamp minimally invasive partial nephrectomy: propensity score matched comparison of outcomes between training versus expert series

BACKGROUND

Off-clamp robotic partial nephrectomy (Off C-RPN) is a challenging technique, hard to teach since bleeding control is not easily reproducible in training settings. We compared perioperative outcomes of two propensity score matched (PSM) cohorts of patients undergone Off C-RPN by either a training or an expert surgeon in the same Institution.

METHODS

The prospectively maintained "renal cancer" database was queried for "off-clamp," "robotic," "partial nephrectomy" performed between January 2017 and June 2018. Achievement of main outcomes along the learning curve of training surgeon was assessed with logistic regression and Lowess analysis. A 1:1 PSM analysis generated two populations homogeneous for demographics, ASA score, tumor size, nephrometry score, baseline hemoglobin and estimated glomerular filtration rate (eGFR). Multiple tumors, and imperative indications were excluded. Categorical and continuous variables were compared by χ² and t-test.

RESULTS

Overall, 111 were treated by the expert, 51 by the training surgeon, respectively. Training surgeon experienced a significant decrease of console time (P=0.01). Patients treated by the expert surgeon had significantly larger tumors, higher PADUA and ASA scores (all P≤0.04). After applying the PSM, two cohorts of 29 patients, homogeneous for all baseline demographic and clinical variables (all P≥0.34) were selected. Hilar clamping was never necessary. Hospital stay, hemoglobin and eGFR at discharge, complication and positive surgical margins rates were comparable between the two cohorts (all P≥0.15).

CONCLUSIONS

Our results proved that the impact of learning curve on outcomes of Off C-RPN is negligible after completion of a proper training in minimally invasive surgery.

Study of Renal and Kidney Tumor Vascularization Using Data from Preoperative Three-dimensional Arteriography Prior to Partial Nephrectomy

BACKGROUND

In a cadaveric model with healthy kidneys, it has recently been highlighted that a single renal segment could be supplied by one or more arterial branches originating from an artery supplying another segment.

OBJECTIVE

To demonstrate occurrences of anatomical variations of renal vascularization and to analyze vascularization of renal tumors.

DESIGN, SETTING, AND PARTICIPANTS

This prospective monocentric study included all patients treated for a renal tumor between May 2015 and June 2017 by laparoscopic partial nephrectomy after superselective tumor embolization in a hybrid operating room.

INTERVENTION

Three-dimensional renal and tumoral arteriography with cone-beam computed tomography scan was performed, coupled with preoperative cross-sectional imaging. This procedure provided an accurate vascular anatomical mapping of the kidney and allowed further analysis of tumor vascularization.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Relation between anatomical variations of the vascularization and perioperative data was assessed. A χ² test or Fisher's test was used for qualitative variables, and a Student t test was used for quantitative variables.

RESULTS AND LIMITATIONS

Out of the 60 patients included, only 25 (42%) presented a standard vascular subdivision. In 26 patients (43%), tumors were supplied by more than one branch and in 20 patients (33%), there was a branch supplying the tumor from another segment. In these cases of multiple or multi-segmental tumor vascularization, tumor size, operative duration, and duration of embolization were significantly higher than in the case of standard vascularization. These complex tumors were more often located at the upper pole of the kidney or at the junction of the anterior and posterior vascular territories of the kidney. Limitations of this study include the low number of patients and its monocentricity.

CONCLUSIONS

This study confirms that renal vascularization frequently differs from Graves' reference model and that tumor vascularization can depend on several segmental branches. This vascular complexity explains surgical difficulties and must be taken into consideration when segmental arterial clamping is considered during partial nephrectomy.

PATIENT SUMMARY

We studied renal and tumor vascularization using three-dimensional preoperative arteriography data on tumor kidneys. We have shown that there is great variability in renal vascularization and that tumors can be vascularized branches that originate from an artery leading to another segment. This vascular complexity explains surgical difficulties and must be taken into consideration when segmental arterial clamping is considered during partial nephrectomy.

Surgical quality, cancer control and functional preservation: introducing a novel trifecta for robot-assisted partial nephrectomy

BACKGROUND

In order to improve standard reporting of outcomes after partial nephrectomy, different "trifecta" systems have been conceived. The subjective assessment of the included parameters and the unreliability for off-clamp procedures limited their reproducibility; their role in predicting functional and oncologic outcomes has never been assessed. We propose a new trifecta, based on standardized parameters, that summarizes PN outcomes regardless the clamping technique used and predicts main clinical outcomes.

METHODS

A retrospective analysis of a multicenter, multi-national dataset of patients with non-metastatic cT1-2 renal masses undergoing Robot-assisted partial nephrectomy was performed. Baseline demographic, clinical, pathologic and perioperative data were collected. Trifecta was defined as the coexistence of negative margins, no Clavien-Dindo ≥3 complications and ≤30% postoperative estimated glomerular filtration rate reduction. Univariable and multivariable regression analyses identified predictors of trifecta achievement. Kaplan-Meier method assessed differences in oncological outcomes between patients achieving trifecta or not. Univariable and multivariable Cox regression analysis identified predictors of newly onset chronic kidney disease stage ≥IIIa, recurrence-free and overall survival.

RESULTS

Overall, 1492 patients achieved trifecta. This cohort displayed significantly lower incidence of newly onset IIIa-V chronic kidney disease stages (all P<0.001), higher recurrence-free (P=0.009) and overall (P=0.014) survival probabilities. Patients achieving trifecta had a 65% reduced risk of developing newly onset stage IIIb-V Chronic Kidney Disease and a 55% reduced risk of overall mortality. Heterogeneity of surgical technique is a limitation.

CONCLUSIONS

This novel reproducible trifecta is based on standardized parameters and is an independent predictor of severe chronic kidney disease development and mortality.

Do patients with Stage 3-5 chronic kidney disease benefit from ischaemia-sparing techniques during partial nephrectomy?

OBJECTIVE

To analyse whether selective arterial clamping (SAC) and off-clamp (OC) techniques during robot-assisted partial nephrectomy (RPN) are associated with a renal functional benefit in patients with Stage 3-5 chronic kidney disease (CKD).

PATIENTS AND METHODS

The change in estimated glomerular filtration rate (eGFR) over time was compared between 462 patients with baseline CKD 3-5 that underwent RPN with main arterial clamping (MAC) (n = 375, 81.2%), SAC (n = 48, 10.4%) or OC (n = 39, 8.4%) using a multivariable linear mixed-effects model. All follow-up eGFRs, including baseline and follow-up between 3 and 24 months, were included in the model for analysis. The median follow-up was 12.0 months (interquartile range 6.7-16.5; range 3.0-24.0 months).

RESULTS

In the multivariable linear mixed-effects model adjusting for characteristics including tumour size and the R.E.N.A.L. (Radius; Exophytic/Endophytic; Nearness; Anterior/Posterior; Location) Nephrometry Score, the change in eGFR over time was not significantly different between SAC and MAC RPN (β = -1.20, 95% confidence interval [CI] -5.45, 3.06; P = 0.582) and OC and MAC RPN (β = -1.57, 95% CI -5.21, 2.08; P = 0.400). Only 20 (15 MAC, two SAC, three OC) patients overall had progression of their CKD stage at last follow-up. The mean ischaemia time was 17 min for MAC and 15 min for SAC. There was no benefit to SAC or OC in terms of blood loss, perioperative complications, length of stay, or surgical margins.

CONCLUSION

SAC and OC techniques during RPN were not associated with benefit in preservation of eGFR in patients with baseline CKD.

Study of kidney morphologic and structural changes related to different ischemia times and types of clamping of the renal vascular pedicle

Purpose

This study aimed to study morphological and renal structural changes in relation to different ischemic times and types of renal vascular pedicle clamping.

Methods

Sixteen pigs were divided into two groups (n = 8): Group AV - unilateral clamping of the renal artery and vein and Group A - unilateral clamping of the renal artery only, both with the contralateral kidney used as control. Serial biopsies were performed at 0, 10, 20, 30, 40, 50, 60, 70, 80, and 90 minutes after clamping.

Results

there is a correlation between the occurrence of renal damage as a function of time (p <0.001), with a higher frequency of Group A lesions for cellular alterations (vascular congestion and edema, interstitial inflammatory infiltrate, interstitial hemorrhage and cell degeneration), with the exception of in the formation of pigmented cylinders that were evidenced only in the AV Group.

Conclusion

the number of lesions derived from ischemia is associated with the duration of the insult, there is a significant difference between the types of clamping, and the AV Group presented a lower frequency of injuries than Group A. The safety time found for Group A was 10 minutes and for Group AV 20 minutes.

Effect of 3-Dimensional Virtual Reality Models for Surgical Planning of Robotic-Assisted Partial Nephrectomy on Surgical Outcomes: A Randomized Clinical Trial

IMPORTANCE

Planning complex operations such as robotic-assisted partial nephrectomy requires surgeons to review 2-dimensional computed tomography or magnetic resonance images to understand 3-dimensional (3-D), patient-specific anatomy.

OBJECTIVE

To determine surgical outcomes for robotic-assisted partial nephrectomy when surgeons reviewed 3-D virtual reality (VR) models during operative planning.

DESIGN, SETTING, AND PARTICIPANTS

A single-blind randomized clinical trial was performed. Ninety-two patients undergoing robotic-assisted partial nephrectomy performed by 1 of 11 surgeons at 6 large teaching hospitals were prospectively enrolled and randomized. Enrollment and data collection occurred from October 2017 through December 2018, and data analysis was performed from December 2018 through March 2019.

INTERVENTIONS

Patients were assigned to either a control group undergoing usual preoperative planning with computed tomography and/or magnetic resonance imaging only or an intervention group where imaging was supplemented with a 3-D VR model. This model was viewed on the surgeon's smartphone in regular 3-D format and in VR using a VR headset.

MAIN OUTCOMES AND MEASURES

The primary outcome measure was operative time. It was hypothesized that the operations performed using the 3-D VR models would have shorter operative time than those performed without the models. Secondary outcomes included clamp time, estimated blood loss, and length of hospital stay.

RESULTS

Ninety-two patients (58 men [63%]) with a mean (SD) age of 60.9 (11.6) years were analyzed. The analysis included 48 patients randomized to the control group and 44 randomized to the intervention group. When controlling for case complexity and other covariates, patients whose surgical planning involved 3-D VR models showed differences in operative time (odds ratio [OR], 1.00; 95% CI, 0.37-2.70; estimated OR, 2.47), estimated blood loss (OR, 1.98; 95% CI, 1.04-3.78; estimated OR, 4.56), clamp time (OR, 1.60; 95% CI, 0.79-3.23; estimated OR, 11.22), and length of hospital stay (OR, 2.86; 95% CI, 1.59-5.14; estimated OR, 5.43). Estimated ORs were calculated using the parameter estimates from the generalized estimating equation model. Referent group values for each covariate and the corresponding nephrometry score were summed across the covariates and nephrometry score, and the sum was exponentiated to obtain the OR. A mean of the estimated OR weighted by sample size for each nephrometry score strata was then calculated.

CONCLUSIONS AND RELEVANCE

This large, randomized clinical trial demonstrated that patients whose surgical planning involved 3-D VR models had reduced operative time, estimated blood loss, clamp time, and length of hospital stay.

TRIAL REGISTRATION

ClinicalTrials.gov identifiers (1 registration per site): NCT03334344, NCT03421418, NCT03534206, NCT03542565, NCT03556943, and NCT03666104.