Lower Incidence of Postoperative Acute Kidney Injury in Robot-Assisted Partial Nephrectomy Than in Open Partial Nephrectomy: A Propensity Score-Matched Study

A Novel Classification System of Renal Hilar Tumors for Surgical Guidance: Technique, Outcome, and Safety

BACKGROUND

This study was designed to develop an innovative classification and guidance system for renal hilar tumors and to assess the safety and effectiveness of robot-assisted partial nephrectomy (RAPN) for managing such tumors.

METHODS

A total of 179 patients undergoing RAPN for renal hilar tumors were retrospectively reviewed. A novel classification system with surgical techniques was introduced and the perioperative features, tumor characteristics, and the efficacy and safety of RAPN were compared within subgroups.

RESULTS

We classified the tumors according to our novel system as follows: 131 Type I, 35 Type II, and 13 Type III. However, Type III had higher median R.E.N.A.L., PADUA, and ROADS scores compared with the others (all p < 0.001), indicating increased operative complexity and higher estimated blood loss [180.00 (115.00-215.00) ml]. Operative outcomes revealed significant disparities between Type III and the others, with longer operative times [165.00 (145.00-200.50) min], warm ischemia times [24.00 (21.50-30.50) min], tumor resection times [13.00 (12.00-15.50) min], and incision closure times [22.00 (20.00-23.50) min] (all p < 0.005). Postoperative outcomes also showed significant differences, with longer durations of drain removal (77.08 ± 18.16 h) and hospitalization for Type III [5.00 (5.00-6.00) d] (all p < 0.05). Additionally, Type I had a larger tumor diameter than the others (p = 0.009) and pT stage differed significantly between the subtypes (p = 0.020).

CONCLUSIONS

The novel renal hilar tumor classification system is capable of differentiating the surgical difficulty of RAPN and further offers personalized surgical steps tailored to each specific classification. It provides a meaningful tool for clinical practice.

Surgical and functional outcomes of repeat robot-assisted laparoscopic partial nephrectomy compared with repeat open partial nephrectomy

OBJECTIVES

To examine the surgical and functional outcomes of patients who have undergone repeat open partial nephrectomy (reOPN) or robot-assisted laparoscopic partial nephrectomy (reRAPN).

METHODS

Until May 2022, 3310 patients with renal tumors underwent nephron-sparing surgery (NSS) at affiliated institutions. Of these, 22 and 17 patients who underwent reOPN and reRAPN, respectively, were included in this study.

RESULTS

No significant differences were found between the groups in terms of sex, age, comorbidities, recurrent tumor size at repeat NSS, interval from recurrence to initial NSS, and nephrometry score. ReRAPN had a shorter operative time (median: 138.0 vs. 214.0 min; p = 0.0023) and less estimated blood loss (median: 50.0 vs. 255.0 mL; p = 0.0261) than reOPN. The incidence of complications with Clavien-Dindo grade ≥ 2 was higher in the reOPN group than in the reRAPN group (31.8 vs. 5.9%; p = 0.0467). The mean decrease in the estimated glomerular filtration rate at 3 months postoperatively was not significantly different between the groups. The trifecta achievement rates in the reRAPN (64.7%) and reOPN (27.3%) groups were significantly different (p = 0.0194). On multivariate analysis, age and surgical method were significant predictors of trifecta achievement after partial nephrectomy.

CONCLUSIONS

There were no differences in postoperative renal functional outcomes between reOPN and reRAPN. ReRAPN is superior to reOPN in terms of surgical burden. Therefore, ReRAPN is an important minimally invasive surgery for recurrent renal cell carcinoma.

Oncological and functional outcomes of patients who underwent open partial nephrectomy for kidney tumor

OBJECTIVE

To report long-term functional and oncological outcomes of OPN Methods: We enrolled 182 patients who underwent consecutive OPN with a diagnosis of kidney tumor in our clinic between April 2002 and February 2020 and were selected from our prospective OPN database. Preoperative demographic and clinical characteristics, intraoperative and pathological results, and patients' postoperative functional and oncological follow-up data were retrospectively analyzed. Overall survival (OS) and disease- free survival (DFS) were evaluated using Kaplan-Meier survival analysis. The time-dependent variation between preoperative and postoperative functional results was statistically analyzed and presented in a graph.

RESULTS AND LIMITATIONS

The mean age was 54.4 ± 10.8 yr, and the median age-adjusted Charlson comorbidity index (ACCI) was 1 (interquartile range [IQR] 0-1). The mean tumor size was 3.1 ± 1.2 cm, and the median RENAL score was 6 (IQR 5-8). The most common malign histopathological subtype was clear cell carcinoma with 76.6%, and five cases (3.4%) had positive surgical margins (PSMs). The most common surgical techniques were the retroperitoneal approach (98.9%) and cold ischemia (88.5%). Estimated glomerular filtration rate (eGFR) preservation was 92% (80.8-99.3, IQR), which translates to 32% chronic kidney disease (CKD) upstaging. Acute kidney injury (AKI) was detected in 27 (14.8%) patients according to RIFLE criteria. The intraoperative complication rate was 5.5%, and the postoperative overall complication rate (Clavien-Dindo 1-5) was 30.2%. Major complications (Clavien-Dindo 3-5) were observed in 13 (7.1%) patients. The median oncological follow-up was 42 mo (21.3- 84.6, IQR), and the 5- and 10-yr OS were 90.1% and 78.6%, 5 and 10-yr DFS were 99.4% and 92.1%, respectively. No local recurrence was observed in 5 (3.4%) patients with PSMs; only one had distant metastasis in the 8th postoperative month. The retrospective design, the small number of patients who underwent PN based on mandatory indication, and one type of surgical approach may limit the generalizability of our findings.

CONCLUSIONS

This study confirms excellent long-term oncologic and functional outcomes after OPN in a cohort of patients selected from a single institution. In light of the information provided by the literature and our study, our recommendation is to push the limits of PN under every technically feasible condition in the treatment of kidney tumors to protect the kidney reserve and achieve near-perfect oncological results.

Comparing the outcomes of open, laparoscopic and robot-assisted partial nephrectomy: a network meta-analysis

OBJECTIVE

To perform a systematic review and network meta-analysis (NMA) to determine the advantages and disadvantages of open (OPN), laparoscopic (LPN), and robot-assisted partial nephrectomy (RAPN) with particular attention to intraoperative, immediate postoperative, as well as longer-term functional and oncological outcomes.

METHODS

A systematic review was performed as per the Preferred Reporting Items for Systematic Reviews and Meta-Analyses-NMA guidelines. Binary data were compared using odds ratios (ORs). Mean differences (MDs) were used for continuous variables. ORs and MDs were extracted from the articles to compare the efficacy of the various surgical approaches. Statistical validity is guaranteed when the 95% credible interval does not include 1.

RESULTS

In total, there were 31 studies included in the NMA with a combined 7869 patients. Of these, 33.7% (2651/7869) underwent OPN, 20.8% (1636/7869) LPN, and 45.5% (3582/7689) RAPN. There was no difference for either LPN or RAPN as compared to OPN in ischaemia time, intraoperative complications, positive surgical margins, operative time or trifecta rate. The estimated blood loss (EBL), postoperative complications and length of stay were all significantly reduced in RAPN when compared with OPN. The outcomes of RAPN and LPN were largely similar except the significantly reduced EBL in RAPN.

CONCLUSION

This systematic review and NMA suggests that RAPN is the preferable operative approach for patients undergoing surgery for lower-staged RCC.

Robot-assisted laparoscopic versus open partial nephrectomy for renal cell carcinoma in patients with severe chronic kidney disease

OBJECTIVES

To compare surgical and functional outcomes between robot-assisted laparoscopic partial nephrectomy and open partial nephrectomy in patients with renal cell carcinoma with stage 4 chronic kidney disease.

METHODS

This was a retrospective analysis of 60 patients with stage 4 chronic kidney disease (estimated glomerular filtration rate 15-30 ml/min/1.73 m² ) who underwent partial nephrectomy for T1 renal cell carcinoma between April 2004 and April 2020. We compared perioperative outcomes according to the surgical approach. Multivariable analysis was performed to identify predictive factors for end-stage renal disease.

RESULTS

Robot-assisted laparoscopic partial nephrectomy and open partial nephrectomy were performed in 31 and 29 patients, respectively. The median age was 68 years and 17% of all patients were women. Patient and tumor characteristics did not differ between groups. The operative time (155.2 vs. 221.0 min, p < 0.0001) and the postoperative length of hospital stay (5.2 vs. 10.6 days, p = 0.0083) were significantly shorter, and the estimated blood loss was lower (53.4 vs. 363.2 ml, p = 0.0003) in the robot-assisted laparoscopic partial nephrectomy group than in the open partial nephrectomy group. Preoperative estimated glomerular filtration rate was the only significant predictor of end-stage renal disease after partial nephrectomy on multivariable analysis.

CONCLUSIONS

Both procedures preserved renal function in this patient cohort, delaying the requirement for postoperative dialysis. Furthermore, robot-assisted laparoscopic partial nephrectomy was associated with shorter operative time and postoperative length of hospital stay, as well as lesser estimated blood loss than open partial nephrectomy.

Predicting acute kidney injury following open partial nephrectomy treatment using SAT-pruned explainable machine learning model

Background

One of the most prevalent complications of Partial Nephrectomy (PN) is Acute Kidney Injury (AKI), which could have a negative impact on subsequent renal function and occurs in up to 24.3% of patients undergoing PN. The aim of this study was to predict the occurrence of AKI following PN using preoperative parameters by applying machine learning algorithms.

Methods

We included all adult patients (n = 723) who underwent open PN in our department since 1995 and on whom we have data on the pre-operative renal function. We developed a random forest (RF) model with Boolean satisfaction-based pruned decision trees for binary classification (AKI or non-AKI). Hyper-parameter grid search was performed to optimize the model's performance. Fivefold cross-validation was applied to evaluate the model. We implemented a RF model with greedy feature selection to binary classify AKI and non-AKI cases based on pre-operative data.

Results

The best model obtained a 0.69 precision and 0.69 recall in classifying the AKI and non-AKI groups on average (k = 5). In addition, the model's probability to correctly classify a new prediction is 0.75. The proposed model is available as an online calculator.

Conclusions

Our model predicts the occurrence of AKI following open PN with (75%) accuracy. We plan to externally validate this model and modify it to minimally-invasive PN.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12911-022-01877-8.

Validation of predictive model for new baseline renal function after robot-assisted partial nephrectomy or radical nephrectomy in Japanese patients

PURPOSE

The study aim was to externally validate a new predictive model for new baseline glomerular filtration rate post-nephrectomy among Japanese patients.

MATERIALS AND METHODS

Patients with renal tumors who underwent radical nephrectomy or robot-assisted partial nephrectomy at a single Japanese institution in 2000-2020 were retrospectively analyzed. New baseline glomerular filtration rate is defined as the final estimated glomerular filtration rate within postoperative 3-12 months. The correlation/bias/accuracy/precision of the equation was examined by comparing the calculated new baseline glomerular filtration rate with the observed rate.

RESULTS

The study included 485 cases of radical nephrectomy, and 1030 cases of robot-assisted partial nephrectomy. The correlation/bias/accuracy/precision of the new equation predicting new baseline glomerular filtration rate were 0.86/-0.92/95.9/-5.65-3.62 in robot-assisted partial nephrectomy and 0.79/-1.02/87.8/-6.26-3.91 in radical nephrectomy, respectively. The fractional polynomial regression line approximated zero and its pointwise 95% confidence interval was considerably tight for the majority of both cohorts. The 95% confidence interval to discriminate new baseline glomerular filtration rates of ≥45 ml/min/1.73 m2 from receiver operating curves was 0.96 (0.95-0.97) and 0.89 (0.87-0.92) in robot-assisted partial nephrectomy and radical nephrectomy, respectively. Various preoperative factors including age, tumor size, complexity, body mass index, hypertension, and diabetes did not affect the predictive ability (correlation > 0.7) from the subgroup analysis.

CONCLUSION

The novel simple equation can accurately predict new baseline glomerular filtration rates after radical and robot-assisted partial nephrectomies in Japanese patients. This model will help physicians choose surgical treatments for renal tumors in daily clinical practice.

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

OBJECTIVES

To evaluate the association between extended (≥30 min) warm ischemic time and renal function in patients undergoing robot-assisted partial nephrectomy.

METHODS

This multi-institutional study retrospectively recruited 1131 patients who underwent robot-assisted partial nephrectomy. Patients were classified into shorter (<30 min; n = 1038) and longer (≥30 min; n = 92) groups based on the ischemic time required, and 1:2 propensity score matching was used to minimize selection bias. The perioperative outcomes, including acute kidney injury and trifecta attainment, and mid/long-term renal function were assessed before and after matching.

RESULTS

Patients in the longer group had tumors with a significantly larger diameter and RENAL nephrometry score. The decline in the nadir of the estimated glomerular filtration rate was significantly greater in the longer than the shorter group in the unmatched and matched cohorts (-16.2 vs -5.5%, P < 0.001; 15.5 vs -9.5%, P = 0.003, respectively). A higher incidence of acute kidney injury (9.8 vs 2.6%, P = 0.002) was observed in the longer group before matching, whereas the difference was comparable after matching. Before matching, the decline in estimated glomerular filtration rate at 6 months postoperatively was greater (-8.2 vs -5.1%, P = 0.005) and trifecta attainment was lower (50.0 vs 63.5%, P < 0.001) in the longer group. However, the differences were comparable for both the parameters between the groups in the matched cohort.

CONCLUSIONS

While extended warm ischemia during robot-assisted partial nephrectomy can be demanded in case of large and complex tumors, its impact on postoperative renal function is limited.

Three-dimensional Reconstruction of Renal Vascular Tumor Anatomy to facilitate accurate preoperative planning of partial nephrectomy

Objectives

To evaluate the role of three-dimensional (3D) reconstruction tumors and vessels of the kidneys in aiding the preoperative planning of partial nephrectomy.

Materials and methods

Patients with renal tumors to be treated with partial nephrectomy were included. Each patient underwent a preoperative computed tomography (CT) survey, and the reconstruction of each patient's 3D arteriography and 3D surface-rendered tumor was performed based on the CT images for preoperative surgical planning.

Results

A total of 6 patients, three with tumors of the right kidney and three with tumors of the left kidney, were enrolled in the study. The patients' mean age was 49.33 ± 4.03 years (range: 45-57 years), and their mean tumor size was 4.4 ± 1.84 cm (range: 2.2-6.8 cm). Four underwent robot-assisted laparoscopic partial nephrectomies, one underwent a traditional laparoscopic partial nephrectomy, and one underwent a radical nephrectomy through laparotomy. Their average postoperative hospital stay was 6.7 days (range: 3-10 days). No intraoperative or postoperative complications were noted. The renal function was preserved in all the patients, and none of the patients exhibited evidence of local recurrence during more than 6 years of follow-up.

Conclusions

3D arteriography fused with 3D surface-rendered tumor image navigation facilitates precise preoperative planning.