Step-by-step Development of a Cold Ischemia Device for Open and Robotic-assisted Renal Transplantation

Surgical Strategies for Renal Transplantation: A Pictorial Essay

This pictorial essay aims to navigate through the complexities and challenges of renal transplantation (RT), by weaving together visual imagery with clinical insights within a comprehensive illustrative surgical guide. Herein, we provide a detailed visual exploration of the intricate anatomy and surgical processes necessary for both renal graft retrieval from the donor and also for an adequate implantation in the recipient. Regarding graft retrieval, after reviewing the relevant retroperitoneal surgical anatomy, and donor nephrectomy techniques, graft preservation and optimal backbench graft dissection principles were meticulously analyzed. Thereafter, the recipient surgical strategy for graft implantation was addressed, focusing on preoperative preparations, the site of implantation selection, exposure, operative bed dissection, graft revascularization, and urinary tract reconstruction. Careful donor and recipient selection, meticulous surgical execution, and rigorous postoperative management clearly hold a pivotal role in optimizing patient outcomes. Fostering a deeper understanding of the surgical nuances and clinical management practices that contribute to successful results post-RT, we hope to provide a useful practical tool for clinicians about to embark on the treacherous road of RT surgery. Innovative technologies and surgical practices that have already significantly improved the safety and effectiveness of RT stand testament to the importance of further scientific inquiry, conceptual developments, and clinical integration. Moving forward, it is essential that the medical community continues to refine these strategies and advocate for equitable access to transplantation, ensuring that advancements in the field translate into real-world benefits for all patients grappling with ESRD. The collaborative efforts of multidisciplinary teams are essential in addressing the complex clinical challenges associated with RT, with the ultimate goal of improving patient survival, enhancing graft longevity, and reducing healthcare disparities.

Continuous renal surface cooling technique (CSCT) in robotic-assisted kidney transplantation: technique and outcomes from a high-volume center: a prospective cohort study

BACKGROUND

Robot-assisted kidney transplantation (RAKT) surgery is an advanced minimally invasive technique, albeit with extended surgical and kidney ischemia time. To safeguard kidney function, the authors have devised a continuous surface cooling method (CSCT) for intraoperative kidney cooling.

MATERIALS AND METHODS

Patients receiving RAKT were divided into CSCT group and conventional group. The CSCT is a custom-designed apparatus composed of a single-layer plastic bag, featuring an inflow and an outflow that create a closed circuit for the continuous flow of cooling saline. The conventional group utilized ice slush for kidney graft cooling (Vattikuti Urology Institute-Medanta Technique, VUIMT). Patients who underwent open renal transplantation during the same period were also included in the study. All patients were subject to a minimum 2-month follow-up. And 1:3 propensity score matching was used to minimize selection bias.

RESULTS

A total of 144 patients underwent CSCT, 47 underwent VUIMT, and 196 underwent open surgery were included in the study, while after matching, 129, 43, 129 patients were included in the three groups, respectively. The median follow-up time was 19 months. None of the patients experienced delayed graft function, patient mortality, or graft loss. After introducing the kidney into the abdominal cavity for 20 minutes, the surface temperature of the kidney in the CSCT group was notably lower compared to the VUIMT group (15.42±0.88 vs. 21.74±2.53°C, P =0.001). This temperature disparity became more pronounced at 65 min (19.74±1.61 vs. 29.82±1.63°C, P <0.001). At both 3 and 7 days post-transplantation, creatinine levels in the VUIMT group were significantly higher than those in the CSCT and open surgery groups (at 3 days, 244.13±45.61 vs. 182.51±55.47 in CSCT group, P <0.001, or vs. 182.77±61.32 in the open surgery group, P <0.001; at 7 days, 162.42±54.86 vs. 143.11±44.32 in the CSCT group, P <0.001, or vs. 135.23±45.27 in the open surgery group, P <0.001). No differences were observed in blood creatinine, estimated glomerular filtration rate, and perioperative complications between the CSCT and open surgery groups.

CONCLUSION

The CSCT presents a significant advantage over the traditional VUIMT method in terms of kidney cooling and early postoperative kidney function preservation. Additional research is required to ascertain whether the CSCT can enhance the long-term prognosis of kidney transplant recipients.

Bradykinin induces acute kidney injury after hypothermic circulatory arrest through the repression of the Nrf2-xCT pathway

Postoperative acute kidney injury (AKI) is a common complication in patients undergoing deep hypothermic circulatory arrest (HCA); however, its underlying pathogenesis is unclear. In this study, we established a rat cardiopulmonary bypass model and demonstrated that hypothermia during HCA, rather than circulatory arrest, was responsible for the occurrence of AKI. By recruiting 56 patients who underwent surgery with HCA and analyzing the blood samples, we found that post-HCA AKI was associated with an increase in bradykinin. Animal experiments confirmed this and showed that hypothermia during HCA increased bradykinin levels by increasing kallikrein expression. Mechanistically, bradykinin inhibited the Nrf2-xCT pathway through B2R and caused renal oxidative stress damage. Application of Icatibant, a B2R inhibitor, reversed changes in the Nrf2-xCT pathway and oxidative stress damage. Finally, Icatibant reversed hypothermia-induced AKI in vivo. This finding reveals the pathogenesis of AKI after HCA and helps to provide therapeutic strategy for patients with post-HCA AKI.

Current status and future perspectives on robot-assisted kidney autotransplantation: A literature review

This review presents the latest insights on robot-assisted kidney autotransplantation (RAKAT). RAKAT is a minimally invasive surgical procedure and represents a promising alternative to conventional laparoscopic nephrectomy followed by open kidney transplantation for the treatment of various complex urological and vascular conditions. RAKAT can be performed either extracorporeally or intracorporeally. Additionally, a single-port approach can be performed through one small incision without the need to reposition the patient. Of 86 patients undergoing RAKAT, 8 (9.3%) developed postoperative > Grade 2 Clavien-Dindo (CD) complications. Although the feasibility of RAKAT was established in 2014, the long-term efficacy and safety along with outcomes of this surgical approach are still being evaluated, and additional studies are needed. With improvements in the technology of RAKAT and as surgeons gain more experience, RAKAT should become increasingly used and further refined, thereby leading to improved surgical outcomes and improved patients' quality of life.

Kidney stones in renal transplant recipients: A systematic review

INTRODUCTION

Lithiasis in renal graft recipients might be a dangerous condition with a potential risk of organ function impairment.

EVIDENCE ACQUISITION

A systematic literature search was conducted through February 2023. The primary objective was to assess the incidence of lithiasis in kidney transplant (KT) recipients. The secondary objective was to assess the timing of stone formation, localization and composition of stones, possible treatment options, and the incidence of graft loss.

EVIDENCE SYNTHESIS

A total of 41 non-randomized studies comprising 699 patients met our inclusion criteria. The age at lithiasis diagnosis ranged between 29-53 years. Incidence of urolithiasis ranged from 0.1-6.3%, usually diagnosed after 12 months from KT. Most of the stones were diagnosed in the calyces or in the pelvis. Calcium oxalate composition was the most frequent. Different treatment strategies were considered, namely active surveillance, ureteroscopy, percutaneous/combined approach, or open surgery. 15.73% of patients were submitted to extracorporeal shock wave lithotripsy (ESWL), while 26.75% underwent endoscopic lithotripsy or stone extraction. 18.03% of patients underwent percutaneous nephrolithotomy whilst 3.14% to a combined approach. Surgical lithotomy was performed in 5.01% of the cases. Global stone-free rate was around 80%.

CONCLUSIONS

Lithiasis in kidney transplant is a rare condition usually diagnosed after one year after surgery and mostly located in the calyces and renal pelvis, more frequently of calcium oxalate composition. Each of the active treatments is associated with good results in terms of stone-free rate, thus the surgical technique should be chosen according to the patient's characteristics and surgeon preferences.

Comprehensive Overview of Innovative Strategies in Preventing Renal Ischemia-reperfusion Injury: Insights from Bibliometric and In silico Analyses

BACKGROUND

Ischemia-reperfusion Injury (IRI) is a complex pathophysiological process with severe consequences, including irreversible loss of renal function. Various intraoperative prevention methods have been proposed to mitigate the harmful effects of warm ischemia and kidney reperfusion.

AIM

This comprehensive analysis provides an overview of pharmacological agents and intraoperative methods for preventing and treating renal IRI.

METHODS

Our analysis revealed that eplerenone exhibited the highest binding affinity to crucial targets, including Aldehyde Dehydrogenase (AD), Estrogen Receptor (ER), Klotho protein, Mineralocorticoid Receptor (MR), and Toll-like Receptor 4 (TLR4). This finding indicates eplerenone's potential as a potent preventive agent against IRI, surpassing other available therapeutics like Benzodioxole, Hydrocortisone, Indoles, Nicotinamide adenine dinucleotide, and Niacinamide. In preventing kidney IRI, our comprehensive analysis emphasizes the significance of eplerenone due to its strong binding affinity to key targets involved in the pathogenesis of IRI.

RESULTS

This finding positions eplerenone as a promising candidate for further clinical investigation and consideration for future clinical practice.

CONCLUSION

The insights provided in this analysis will assist clinicians and researchers in selecting effective preventive approaches for renal IRI in surgical settings, potentially improving patient outcomes.

Living donor robotic-assisted kidney transplant compared to traditional living donor open kidney transplant. Where do we stand now? A systematic review and meta-analysis

BACKGROUND

Renal transplant is the standard of care for patients with end-stage renal disease (ESRD). Robotic-assisted kidney transplant (RAKT) has emerged as a safe minimally invasive approach with a lower complication rate than open kidney transplant (OKT). Concerns regarding ischemia times and graft function are still a matter of debate.

METHODS

Following PRISMA guidelines and PROSPERO registration CRD42023413774, a systematic review was performed in March 2023 on RAKT compared to OKT. Primary outcomes of interest were surgical times, ischemia times, blood loss, complication rates, and graft function. Data were analyzed using R version 4.2.2.

RESULTS

A total of nine studies comparing living donor RAKT to living donor OKT were included, totaling 1477 patients, out of which 508 underwent RAKT and 969 OKT. RAKT cases were highly selected as depicted in the manuscript. Cumulative analysis showed significantly longer total ischemic time (MD = 16.51; 95% CI = [9.86-23.16]) and rewarming ischemia time (MD = 11.24; 95% CI = [-0.46-22.01]) in RAKT group. No differences were found in total procedure time and time to complete anastomoses. Blood loss and transfusion rate were lower in RAKT group (MD = -53.68; 95% CI = [-89.78; -17.58]) and (RR = 0.29; 95% CI = [0.14; 0.57]), respectively. The meta-analysis revealed a lower rate of surgical site infection (SSI) (RR = 0.31; 95% CI = [0.19-0.52]) and symptomatic lymphocele (RR = 0.16; 95% CI = [0.06-0.43]) in RAKT. No difference in ileus rate was found. Pain scores were significantly lower in the RAKT group (MD = -1.14; 95% CI = [-1.59 - -0.69]; p ≤0.01). No difference in length of stay and hospital readmission were evidenced. Delayed graft function (DGF) and acute rejection rates were not different between interventions groups (RR =1.23; 95% CI = [0.40-3.74]) and (RR =0.96; 95% CI = [0.55-1.70]), respectively. No difference between groups in early graft outcomes are evident.

CONCLUSIONS

Our analysis suggests that RAKT is a minimally invasive, safe, and feasible procedure. It is associated with a lower complication rate and similar intraoperative, perioperative, and postoperative outcomes. Further quality studies are needed to confirm these findings.

Systematic review of techniques and devices used to avoid warm ischemia time injury during kidney transplantation

PURPOSE

The lack of a reliable and reproducible technique to ensure a constantly low temperature of the graft during kidney transplantation (KT) may be a cause of renal nonfunction. The aim of this review was to assess all the methods and devices available to ensure hypothermia during vascular anastomosis in KT.

METHODS

A literature search was conducted through May 2022 using PubMed/Medline, Cochrane Library, Embase and Web of Science databases. Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines were followed to identify eligible studies. The review protocol was registered on PROSPERO (CRD42022326550).

RESULTS

A total of 20 studies reporting on four hypothermia techniques met our inclusion criteria. Simple instillation of cold serum is not sufficient, the graft reaching up to 33 ℃ at the end of warm ischemia time (WIT). Plastic bags filled with ice slush have questionable efficiency. The use of a gauze jacket filled with ice-slush was reported in 12/20 studies. It ensures a graft temperature up to 20.3 ℃ at the end of WIT. Some concerns have been linked to potentially inhomogeneous parenchymal cooling and secondary ileus. Novel devices with continuous flow of ice-cold solution around the graft might overcome these limitations, showing a renal temperature below 20 ℃ at all times during KT.

CONCLUSION

The gauze filled with ice slush is the most common technique, but several aspects can be improved. Novel devices in the form of cold-ischemia jackets can ensure a lower and more stable temperature of the graft during KT, leading to higher efficiency and reproducibility.

Insulating jackets thermally protect kidneys in an ex vivo model of second warm ischemia

BACKGROUND

Kidney transplantation is the current optimal treatment for suitable patients with end-stage renal disease. The second warm ischemic time (SWIT) is known to negatively impact delayed graft function, and long-term graft survival, and methods are required to ameliorate the impacts of SWIT on transplantation outcomes.

MATERIALS AND METHODS

This study primarily focused on determining the effect of a novel thermally insulating jacket on the thermal profile of the human kidney and quantifying the reduction in thermal energy experienced using this device (KPJ™). An ex vivo simulated transplantation model was developed to determine the thermal profiles of non-utilized human kidneys with and without KPJ™ (n = 5). Control kidney temperature profiles were validated against the temperature profiles of n = 10 kidneys during clinical kidney transplantation.

RESULTS

Using the ex-vivo water bath model, the thermally insulated human kidney reached the 15°C metabolic threshold temperature at 44.5 ± 1.9 min (vs control: 17.3 ± 1.8 min (p = 0.00172)) and remained within the 18°C threshold until 53.3 ± 1.3 min (vs control: 20.9 ± 2.0 min (p = 0.002)). The specific heat capacity of KPJ™ protected kidney was four-fold compared to the control kidney. The clinical temperature audit, closely correlated with the water bath model, hence validating this ex-vivo human kidney transplant model.

CONCLUSION

Intraoperative thermal protection is a simple and viable method of reducing the thermal injury that occurs during the SWIT and increasing the specific heat capacity of the system. Such technology could easily be translated into clinical kidney transplant practice.

The learning curve for open and minimally-invasive kidney transplantation: a systematic review

INTRODUCTION

There is lack of evidence on the impact of surgeons' learning curve on postoperative outcomes after open (OKT) or minimally-invasive (robot-assisted) kidney transplantation (RAKT). The aim of the review was to assess the learning curve (LC) for OKT and RAKT, focusing on intra-, perioperative and functional outcomes.

EVIDENCE ACQUISITION

A systematic review of the English-language literature published between 01/01/2000 - 10/12/2021 was conducted using the MEDLINE (Via PubMed), Web of Science and the Cochrane Library databases according to the principles highlighted by the EAU Guidelines Office and the PRISMA statement recommendations. The review protocol was registered on PROSPERO (CRD42022301132). The overall quality of evidence was assessed according to GRADE recommendations.

EVIDENCE SYNTHESIS

Twelve studies were included in the qualitative analysis. Surgical competence in terms of operative and re-warming times was defined after 30 cases in OKT and after 11-35 cases in RAKT. Decreased complications rates were observed after 20-33 cases in OKT and 10-30 cases in RAKT. Optimal functional outcomes were achieved after 33 cases in OKT and 15-25 cases in RAKT. However, while a poor OKT experience did not influence the LC for RAKT, lack of robotic surgery exposure could lead to a longer LC for the robotic approach.

CONCLUSIONS

OKT and RAKT appear to have similar LCs and might require about 30 cases to achieve optimal surgical and functional outcomes. Previous expertise in OKT is warranted to shorten the LC for RAKT. Further research is needed to validate these thresholds using standardized reporting metrics.

Three-dimensional Augmented Reality-guided Robotic-assisted Kidney Transplantation: Breaking the Limit of Atheromatic Plaques

BACKGROUND

Robotic-assisted kidney transplantation (RAKT) has shown solid results as a minimally invasive alternative to the standard open approach (open kidney transplantation [OKT]). However, RAKT is still limited in those cases where the recipient's iliac vessels present atherosclerotic plaques, frequently found in elder patients and in those subjected to long-term hemodialysis. Unlike OKT, where the surgeon can palpate the arterial plaques, in minimally invasive surgery the haptic feedback is missing, making the vascular clamping and arteriotomy unsafe.

OBJECTIVE

To employ three-dimensional (3D) imaging reconstruction using augmented reality (AR) to intraoperatively locate the plaques during the crucial steps of kidney transplantation.

DESIGN, SETTING, AND PARTICIPANTS

Our study was conducted according to the Idea, Development, Exploration, Assessment, and Long-term follow-up (IDEAL) model for surgical innovation. Three-dimensional virtual models were obtained from high-accuracy computed tomography scan imaging and superimposed on the vessels during RAKT using the Da Vinci console software.

SURGICAL PROCEDURE

Three-dimensional AR-guided robotic-assisted kidney transplantation.

MEASUREMENTS

The correspondence of virtual models with the real anatomy of patients was assessed comparing vessels' and plaques' measures.

RESULTS AND LIMITATIONS

We tested the possibility of using the AR in the setting of vascular surgery by checking the correspondence of the virtual models to the real vessels. During the accuracy assessment, we investigated the anatomy of the iliac plaques and the capacity of the virtual models to correctly represent them. Finally, we tested the efficacy of the virtual model superimposition on the real vessels with plaques during RAKT in the recipients of living donor grafts. The main limitation consists in training needed to correctly superimpose virtual models on the real field.

CONCLUSIONS

The employment of 3D AR allowed surgeons to overcome one of the main limitations of RAKT, setting the foundation to expand its indications to patients with advanced atheromatic vascular disease.

PATIENT SUMMARY

The use of three-dimensional augmented reality guidance during kidney transplantation (KT) has the potential to "navigate" the surgeon during KT, allowing a safer procedure in patients with atheromatic vascular disease.

Small renal masses in kidney transplantation: overview of clinical impact and management in donors and recipients

Kidney transplantation is the best replacement treatment for the end-stage renal disease. Currently, the imbalance between the number of patients on a transplant list and the number of organs available constitutes the crucial limitation of this approach. To expand the pool of organs amenable for transplantation, kidneys coming from older patients have been employed; however, the combination of these organs in conjunction with the chronic use of immunosuppressive therapy increases the risk of incidence of graft small renal tumors. This narrative review aims to provide the state of the art on the clinical impact and management of incidentally diagnosed small renal tumors in either donors or recipients. According to the most updated evidence, the use of grafts with a small renal mass, after bench table tumor excision, may be considered a safe option for high-risk patients in hemodialysis. On the other hand, an early small renal mass finding on periodic ultrasound-evaluation in the graft should allow to perform a conservative treatment in order to preserve renal function. Finally, in case of a renal tumor in native kidney, a radical nephrectomy is usually recommended.

3D-Printed Cold Preservation Device in Renal Autotransplantation for the Treatment of a Patient With Renal Artery Stenosis

Percutaneous transluminal angioplasty (PTRA) is a common treatment method for renal vascular disease (RVD). However, PTRA may not be effective in patients with abnormal vascular disease. Renal autotransplantation (RAT) has been used as an alternative therapy for these diseases. Restrictions due to intracorporeal kidney cold preservation and the renal function of intracorporeal RAT were not as well protected compared with open operation. We developed this technique of 3D-printed polylactide (PLA) cold jackets for laparoscopic complete intracorporeal RAT for the purpose of better protecting the renal function and determining the feasibility of this novel procedure. The procedure was successfully applied to a 51-year-old woman with bilateral renal artery stenosis. The operation time was 5 hours, and blood loss was 200 ml. The patient’s blood pressure remained constant throughout the operation, and the pressure was maintained at 120-140/70–90 mmHg without antihypertensive drugs 1 week after the operation. B-ultrasound showed that the blood flow signal of the transplanted kidney was normal and the boundary between the skin and medulla was clear. The patient was discharged 2 weeks after surgery. One year postoperatively, Doppler ultrasound of the autotransplant showed that the transplanted kidney was normal in size and shape. Radionuclide renal dynamic imaging revealed that the glomerular filtration rate (GFR) of the transplanted kidney was 36.9 ml/min. 3D-printed polylactide (PLA) cold jackets for laparoscopic complete intracorporeal RAT are a safe and effective method for the treatment of renal artery stenosis and represent a feasible method for preserving the renal function of severe renal artery stenosis patients; however, the technology is still at the exploratory stage and has room for further improvements.

Intracorporeal Versus Extracorporeal Robot-assisted Kidney Autotransplantation: Experience of the ERUS RAKT Working Group

BACKGROUND

Kidney autotransplantation is a useful technique to be reserved for cases in which kidney function is compromised by a complex anatomical configuration, such as long ureteral strictures and renal vascular anomalies not suitable for in situ reconstruction. Robot-assisted kidney autotransplantation (RAKAT) presents a novel, minimally invasive, and highly accurate approach.

OBJECTIVE

The aim of this study is to present the largest cohort of patients who underwent either extracorporeal (eRAKAT) or intracorporeal (iRAKAT) RAKAT, to confirm safety and feasibility and to compare the two approaches.

DESIGN, SETTING, AND PARTICIPANTS

We retrospectively analyzed prospectively followed patients undergoing eRAKAT and totally intracorporeal RAKAT in a total of three institutions.

SURGICAL PROCEDURE

Extracorporeal RAKAT and iRAKAT.

MEASUREMENTS

Surgical and functional outcomes of patients subjected to eRAKAT and iRAKAT were measured.

RESULTS AND LIMITATIONS

Between January 2017 and February 2021, 29 patients underwent RAKAT: 15 eRAKAT and 14 iRAKAT. No statistical difference in the preoperative data was recorded. The analysis of intraoperative variables showed a statistically significant difference between eRAKAT and iRAKAT in cold ischemia time (median [interquartile range {IQR}]: 151 [125-199] vs 27.5 [20-55]; p <  0.001) and total ischemia time (median [IQR]: 196.2 [182-241] vs 81.5 [73-88]; p <  0.001). However, faster renal function recovery in favor of eRAKAT was observed during the first 90 d, with comparable renal function at 1 yr. The 90-d Clavien-Dindo >2 complications were 13.8%. It is important to stress that RAKAT, and above all iRAKAT, should be performed by surgeons with experience in robotic renal, vascular, and transplant surgery.

CONCLUSIONS

Both eRAKAT and iRAKAT represent promising minimally invasive techniques in selected cases with acceptable ischemia time and comparable long-term operative outcomes.

PATIENT SUMMARY

In selected patients, both extra- and intracorporeal robot-assisted kidney autotransplantation represent valid alternatives in case of long ureteral strictures and renal vascular anomalies not suitable for in situ reconstruction.