Selective clamping during robot-assisted partial nephrectomy in patients with a solitary kidney: is it safe and does it help?

OBJECTIVES: To obtain the most accurate assessment of the risks and benefits of selective clamping in robot-assisted partial nephrectomy (RAPN) we evaluated outcomes of this technique vs those of full clamping in patients with a solitary kidney undergoing RAPN. PATIENTS AND METHODS: Data from institutional review board-approved retrospective and prospective databases from 2006 to 2019 at multiple institutions with sharing agreements were evaluated. Patients with a solitary kidney were identified and stratified based on whether selective or full renal artery clamping was performed. Both groups were analysed with regard to demographics, risk factors, intra-operative complications, and postoperative outcomes using chi-squared tests, Fisher's exact tests, t-tests and Mann-Whitney U-tests. RESULTS: Our initial cohort consisted of 4112 patients, of whom 72 had undergone RAPN in a solitary kidney (51 with full clamping and 21 with selective clamping). There were no significant differences in demographics, tumour size, baseline estimated glomerular filtration rate (eGFR), or warm ischaemia time (WIT) between the groups (Table 1). Intra-operative outcomes, including estimated blood loss, operating time, and intra-operative complications were similar in the two groups. Short- and long-term postoperative percentage change in eGFR, frequency of acute kidney injury (AKI), and frequency of de novo chronic kidney disease (CKD) were also not significantly different between the two techniques. CONCLUSION: In a large cohort of patients with solitary kidney undergoing RAPN, selective clamping resulted in similar intra-operative and postoperative outcomes compared to full clamping and conferred no additional risk of harm. However, selective clamping did not appear to provide any functional advantage over full clamping as there was no difference observed in the frequency of AKI, CKD or change in eGFR. Short WIT in both groups (<15 min) may have prevented identification of benefits in the selective clamping group; a similar study analysing cases with longer WIT may elucidate any beneficial effects of selective clamping.

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 (ß = -1.20, 95% confidence interval [CI] -5.45, 3.06; P = 0.582) and OC and MAC RPN (ß = -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.

The Impact of Arterial Clamping Technique in Robot-Assisted Partial Nephrectomy on Renal Function and Surgical Outcomes: Six-Year Experience at Siriraj Hospital, Thailand.

INTRODUCTION: Robot-assisted partial nephrectomy (RAPN) with different arterial clamping techniques has increasingly been performed to avoid ischemic injury to nephron. However, postoperative renal function remains controversial. We determine the impact of each renal arterial clamping on surgical and renal outcomes after RAPN. MATERIALS AND METHODS: Patients who underwent RAPN at Siriraj Hospital from 2010 to 2016 were retrospectively reviewed and stratified into 3 cohorts: main-clamp (MAC), selective-clamp, and off-clamp. RESULTS: Main, selective, and off-clamping were performed in 27, 38, and 12, respectively. Median tumor size and Radius, Exophytic or endophytic, Nearness to collecting system or sinus, Anterior or posterior, and Location relative to polar lines (RENAL) score were 3 cm and 7, respectively. Longer operative time was observed in MAC (p = 0.002) although estimated blood loss, transfusion rate, and complication were comparable. Warm ischemia time was not different between cohorts. However, number of patients with prolonged ischemia time in MAC were greater (p ≤ 0.01). All margins were negative. Median postoperative and latest glomerular filtration rate reduction were 3.8 and 5.3 mL/min/1.73 m2, respectively without significant difference between cohorts. On multivariable analysis, hypertension independently associated with reduced renal function preserved (p = 0.03). Median follow-up was 18 months. CONCLUSIONS: Our study is the first to report surgical and renal functional outcomes after RAPN in Southeast-Asian population. Based on our experience, clamping techniques does not impact on renal functions and complication rate was low even in small-volume center.

Anatomical study of renal arterial vasculature and its potential impact on partial nephrectomy.

OBJECTIVES: To validate Graves' classification of the intrarenal arteries and to verify the absence of collateral arterial blood supply between different renal segments, in order to maximize peri-operative and functional outcomes of partial nephrectomy. MATERIALS AND METHODS: The study was performed on 15 normal kidneys sampled from eight unembalmed cadavers. Kidneys with the surrounding perirenal fat tissue were removed en bloc with the abdominal segment of the aorta. The renal artery was injected with acrylic and radiopaque resins, with the specimen suspended in water. CT examination of the injected kidneys was performed to analyse the branches located deeply. After imaging acquisition, the specimens were treated with sodium hydroxide for removal of the parenchyma to obtain vascular casts. RESULTS: Ten casts (66.6%) showed the classic subdivision of the main artery into single posterior and anterior branches. With regard to the distribution of the segmental or second-order arteries, only two casts (13%) showed a pattern similar to that described by Graves, characterized by four segmental (second-order) branches coming from the anterior renal artery (apical, superior, middle and inferior). In the remaining 13 kidneys (87%) a different arterial vascular network was detected. In 10 casts (80%) a single renal segment was vascularized by two or more different branches coming from an artery leading to another segment (multiple vascularization). Multiple vascularization was observed in three (20%) apical segments, five (33%) superior segments, six (40%) middle segments, seven (47%) inferior segments and two (13%) posterior segments. CONCLUSIONS: This study shows that in the human kidneys the arterial vasculature is frequently different from that described by Graves. Moreover, in a significant percentage of cases, a single renal segment receives two or more branches that originate from an artery leading to another segment.

Renal function is the same 6 months after robot-assisted partial nephrectomy regardless of clamp technique: analysis of outcomes for off-clamp, selective arterial clamp and main artery clamp techniques, with a minimum follow-up of 1 year.

OBJECTIVE: To compare the renal functional outcomes, with >1 year of follow-up, of patients who underwent robot-assisted partial nephrectomy (RAPN) performed with different clamping techniques. PATIENTS AND METHODS: The peri-operative data of patients undergoing RAPN performed with different clamping techniques were retrospectively analysed (group 1: off-clamp, n = 23; group 2: selective clamp, n = 25; group 3: main artery clamp, n = 114). The main outcome measures were postoperative serum creatinine level, estimated glomerular filtration rate (eGFR) and percentage change in eGFR, the data for which were collected at periodic intervals during the first 12 months and annually thereafter, in addition to late eGFR value. Only patients with >1 year of follow-up were included in the analysis. RESULTS: The baseline characteristics of groups 2 and 3 were similar, while patients in group 1 had smaller sized tumours and lower tumour complexity. The median follow-up periods were 45 (group 1), 20 (group 2) and 47 (group 3) months. The median clamping times were 24.8 min in the main artery clamp and 18 min in the selective artery clamp groups. Group 2 had greater median blood loss volume (100 vs 500 vs 200 mL for groups 1, 2 and 3, respectively; P < 0.01) and a longer length of hospital stay (3 vs 4 vs 3 days for groups 1, 2 and 3, respectively; P = 0.02). No significant differences were found among the groups with regard to transfusion rates, positive surgical margin rates, complications, recurrence or mortality rates. Groups 1 and 2 had significantly less deterioration of postoperative renal function during the first 3 months after surgery (P = 0.04; percent change in eGFR -1.5, -2 and -8% for groups 1, 2 and 3, respectively), but this beneficial outcome was not observed after 6 months or for the latest eGFR measurement (P = 0.48; latest percent change in eGFR -3, -6 and -3.5% for groups 1, 2 and 3, respectively). In regression analysis, baseline eGFR, type of clamp procedure and tumour complexity score were predictive of normal renal function 7 days after surgery, while only baseline eGFR and age could predict it 1 year postoperatively. CONCLUSIONS: Off-clamp and selective artery clamp techniques result in superior short-term renal functional outcomes compared with the main artery clamp approach; however, after the 6th postoperative month, there were no significant differences regarding the functional outcome among the above surgical techniques, as long as the warm ischaemia time was 20-30 min.

Biophotonics-Intraoperative Guidance During Partial Nephrectomy: A Systematic Review and Meta-analysis.

CONTEXT: Partial nephrectomy (PN) with intraoperative guidance by biophotonics has the potential to improve surgical outcomes due to higher precision. However, its value remains unclear since high-level evidence is lacking. OBJECTIVE: To provide a comprehensive analysis of biophotonic techniques used for intraoperative real-time assistance during PN. EVIDENCE ACQUISITION: We performed a comprehensive database search based on the PICO criteria, including studies published before October 2022. Two independent reviewers screened the titles and abstracts followed by full-text screening of eligible studies. For a quantitative analysis, a meta-analysis was conducted. EVIDENCE SYNTHESIS: In total, 35 studies were identified for the qualitative analysis, including 27 studies on near-infrared fluorescence (NIRF) imaging using indocyanine green, four studies on hyperspectral imaging, two studies on folate-targeted molecular imaging, and one study each on optical coherence tomography and 5-aminolevulinic acid. The meta-analysis investigated seven studies on selective arterial clamping using NIRF. There was a significantly shorter warm ischemia time in the NIRF-PN group (mean difference [MD]: -2.9; 95% confidence interval [CI]: -5.6, -0.1; p = 0.04). No differences were noted regarding transfusions (odds ratio [OR]: 0.5; 95% CI: 0.2, 1.7; p = 0.27), positive surgical margins (OR: 0.7; 95% CI: 0.2, 2.0; p = 0.46), or major complications (OR: 0.4; 95% CI: 0.1, 1.2; p = 0.08). In the NIRF-PN group, functional results were favorable at short-term follow-up (MD of glomerular filtration rate decline: 7.6; 95% CI: 4.6, 10.5; p < 0.01), but leveled off at long-term follow-up (MD: 7.0; 95% CI: -2.8, 16.9; p = 0.16). Remarkably, these findings were not confirmed by the included randomized controlled trial. CONCLUSIONS: Biophotonics comprises a heterogeneous group of imaging modalities that serve intraoperative decision-making and guidance. Implementation into clinical practice and cost effectiveness are the limitations that should be addressed by future research. PATIENT SUMMARY: We reviewed the application of biophotonics during partial removal of the kidney in patients with kidney cancer. Our results suggest that these techniques support the surgeon in successfully performing the challenging steps of the procedure.

Effect of an Airbag-selective Portal Vein Blood Arrester on the Liver after Hepatectomy: A New Technique for Selective Clamping of the Portal Vein.

OBJECTIVE: A novel technique was explored using an airbag-selective portal vein blood arrester that circumvents the need for an intraoperative assessment of anatomical variations in patients with complex intrahepatic space-occupying lesions. METHODS: Rabbits undergoing hepatectomy were randomly assigned to 4 groups: intermittent portal triad clamping (PTC), intermittent portal vein clamping (PVC), intermittent portal vein blocker with an airbag-selective portal vein blood arrester (APC), and without portal blood occlusion (control). Hepatic ischemia and reperfusion injury were assessed by measuring the 7-day survival rate, blood loss, liver function, hepatic pathology, hepatic inflammatory cytokine infiltration, hepatic malondialdehyde levels, and proliferating cell nuclear antigen levels. RESULTS: Liver damage was substantially reduced in the APC and PVC groups. The APC animals exhibited transaminase levels similar to or less oxidative stress damage and inflammatory hepatocellular injury compared to those exhibited by the PVC animals. Bleeding was significantly higher in the control group than in the other groups. The APC group had less bleeding than the PVC group because of the avoidance of portal vein skeletonization during hepatectomy. Thus, more operative time was saved in the APC group than in the PVC group. Moreover, the total 7-day survival rate in the APC group was higher than that in the PTC group. CONCLUSION: Airbag-selective portal vein blood arresters may help protect against hepatic ischemia and reperfusion injury in rabbits undergoing partial hepatectomy. This technique may also help prevent liver damage in patients requiring hepatectomy.

A Novel Three-dimensional Planning Tool for Selective Clamping During Partial Nephrectomy: Validation of a Perfusion Zone Algorithm.

BACKGROUND: Selective clamping during robot-assisted partial nephrectomy (RAPN) requires extensive knowledge on patient-specific renal vasculature, obtained through imaging. OBJECTIVE: To validate an in-house developed perfusion zone algorithm that provides patient-specific three-dimensional (3D) renal perfusion information. DESIGN, SETTING, AND PARTICIPANTS: Between October 2020 and June 2022, 25 patients undergoing RAPN at Ghent University Hospital were included. Three-dimensional models, based on preoperative computed tomography (CT) scans, showed the clamped artery's ischemic zone, as calculated by the algorithm. SURGICAL PROCEDURE: All patients underwent selective clamping during RAPN. Indocyanine green (ICG) was administered to visualize the true ischemic zone perioperatively. Surgery was recorded for a postoperative analysis. MEASUREMENTS: The true ischemic zone of the clamped artery was compared with the ischemic zone predicted by the algorithm through two metrics: (1) total ischemic zone overlap and (2) tumor ischemic zone overlap. Six urologists assessed metric 1; metric 2 was assessed objectively by the authors. RESULTS AND LIMITATIONS: In 92% of the cases, the algorithm was sufficiently accurate to plan a selective clamping strategy. Metric 1 showed an average score of 4.28 out of 5. Metric 2 showed an average score of 4.14 out of 5. A first limitation is that ICG can be evaluated only at the kidney surface. A second limitation is that mainly patients with impaired renal function are expected to benefit from this technology, but contrast-enhanced CT is required at present. CONCLUSIONS: The proposed new tool demonstrated high accuracy when planning selective clamping for RAPN. A follow-up prospective study is needed to determine the tool's clinical added value. PATIENT SUMMARY: In partial nephrectomy, the surgeon has no information on which specific arterial branches perfuse the kidney tumor. We developed a surgeon support system that visualizes the perfusion zones of all arteries on a three-dimensional model and indicates the correct arteries to clamp. In this study, we validate this tool.

Functional Outcomes after Selective Clamping in Robot-Assisted Partial Nephrectomy.

This study aimed to assess the risks and benefits of selective clamping in robot-assisted partial nephrectomy (RAPN). We retrospectively analyzed 372 patients who had undergone RAPN at our hospital between July 2010 and March 2021. After propensity score matching between the full and selective clamping groups, perioperative outcomes and postoperative preservation ratio of the estimated glomerular filtration rate (eGFR) were compared at 6 and 12 months of follow-up. After propensity score matching, we evaluated 47 patients from each group. While no significant differences were observed in surgical time, warm ischemia time, or incidence rates of all grades of complications between the two cohorts, the estimated blood loss (EBL) was significantly lower in the full clamping group than in the selective clamping group (30 vs. 60, p = 0.046). However, no significant intergroup differences were observed in the postoperative preservation ratio of eGFR at 6 or 12 months of follow-up (full clamping 94.0% vs. selective clamping 92.7%, p = 0.509, and full clamping 92.0% vs. selective clamping 91.6%, p = 0.476, respectively). Selective clamping resulted in higher EBL rates than did full clamping in RAPN. However, selective clamping provided no renal functional advantage over full clamping in our propensity-score-matched cohort.

The Impact of 3D Digital Reconstruction on the Surgical Planning of Partial Nephrectomy: A Case-control Study. Still Time for a Novel Surgical Trend?

INTRODUCTION: The purpose of this study was to evaluate the impact of 3-dimensional (3D) digital reconstructions of renal models on the arterial clamping approach during partial nephrectomy (PN). PATIENTS AND METHODS: Fifty-seven patients with T1 renal mass, referred for PN, were prospectively enrolled in 2 groups: Group 1 (n = 32) with revision of both 2-dimensional (2D) computed tomography (CT) imaging and 3D virtual model before surgery; Group 2 (n = 25) with revision of 2D CT imaging. Segmentation of the 3D models from preoperative high-quality CT scan was achieved using D2P software. In a sub-analysis of patients treated with PN with the on-clamp approach (n = 36), the effective intraoperative level of arterial clamping was compared with the preoperative planning. RESULTS: In the sub-group of patients referred to PN with the on-clamp approach, the intraoperative selective clamping was performed in 12 (57.1%) patients of Group 1 and in 2 (13.3%) cases of Group 2 (P = .01). The intraoperative management of the renal pedicle was done as preoperatively planned in 61.9% of patients in Group 1 and in 86.6% of cases in Group 2 (P = .1). CONCLUSION: The 3D-guided plan of PN allows to perform selective clamping in higher proportion of patients compared with the standard 2D-guided approach without increasing intraoperative and postoperative complications.

Superselective clamping of renal artery in laparoscopic partial nephrectomy: Primary experience sharing / 第二军医大学学报

Objective To evaluate the feasibility and safety of superselective renal artery clamping technique in laparoscopic partial nephrectomy and to assess its short-term effect on postoperative renal function. Methods Totally 23 patients, who were diagnosed as having renal malignant tumor and treated with transperitoneal laparoscopic partial nephrectomy by the same doctor at department of urology, Changhai Hospital from June 2013 to May 2014, were included in the present study. Superselective technique and traditional renal artery clamping technique were employed in group A (10 cases) and group B (13 cases), respectively. The operation time, intraoperative blood loss, postoperative renal function and other clinical parameters were compared between the two groups. Results Compared with group B, group A had significantly increased operation time ([257.60 ± 22.03] min vs [199.08 ± 36.70] min, P<0.05), intraoperative blood loss ([220 ± 57.01] mL vs [71.54 ± 30.51] mL, P<0.05) and postoperative incision drainage ([113.33 ± 24.82] mL vs [68.08 ± 28.88] mL, P<0.05), and there were no Grade III- complications such as massive bleeding or urinary leakage in the two groups. But patients in group A had slighter renal function damage postoperatively in the early stage compared with group B, as demonstrated by slighter eGFR decrease ([3.14 ± 7.22]% vs [15.26 ± 9.53]%, P<0.05) for a similar ischemic time ([28.60±8.17]) min vs ([27.85±6.16] min). Conclusion Superselective renal artery clamping does less harm to the kidney than traditional main renal artery clamping in laparoscopic partial nephrectomy, and it is worth further research for its benefit in early-stage renal function recovery postoperatively.