scholarly journals First experience of superselective embolization of renal arteries supplying the tumor with subsequent laparoscopic kidney resection

2021 ◽  
Vol 17 (3) ◽  
pp. 30-36
Author(s):  
V. L. Astashov ◽  
V. V. Shapovalov ◽  
V. V. Balanyuk ◽  
A. I. Zagorul’ho ◽  
D. V. Kozlov ◽  
...  
Keyword(s):  
Blood Loss ◽  
Renal Artery ◽  
Kidney Cancer ◽  
Renal Tumors ◽  
Two Stage ◽  
Second Stage ◽  
Superselective Embolization ◽  
Single Kidney ◽  
Functioning Kidney ◽  
Kidney Resection

Background. Patients with signs of tumor lesions in a single kidney or in the only one functioning kidney, with bilateral renal tumors are at high risk of functional failure or insufficiency of the kidney after surgery. Joint discussions with specialists in X-ray endovascular surgeries resulted in the development of a treatment algorithm for patients with localized kidney cancer who require organ-sparing surgery without ischemic kidney resection.Objective: to evaluation of the immediate results of two-stage surgical treatment of localized kidney cancer in patients with signs of tumor lesions in a single kidney or in the only one functioning kidney, with bilateral renal tumors, including superselective embolization of the artery supplying the tumor at the first stage, and laparoscopic kidney resection without renal ischemia parenchyma at the second stage.Materials and methods. This study included 5 patients with localized kidney cancer, who underwent two-stage treatment at Moscow Regional Oncology Dispensary between 24.03.2021 and 19.04.2021. The first stage included superselective embolization of the artery supplying the tumor; the second stage implied laparoscopic kidney resection 6-7 days following the first stage.Results. The median age of the patients was 62 years (range: 42-73 years). Four patients (80%) had unilateral kidney lesions, while 1 patient (20 %) had bilateral (synchronous) kidney cancer. The mean RENAL score was 8 (range: 6-10); patients were distributed as follows: score 4-6 in 40 %, score 7-9 in 40 %, and score >10 in 20 % of patients. At the first stage, patients underwent endovascular embolization of the branches of the renal artery. Patients had superselective embolization of either middle (n = 3; 60 %), upper (n = 1; 20 %), or lower (n = 1; 20 %) segmental arteries supplying the tumor. In one of them (20 %), we identified 3 large arterial branches; in another one (20 %), we identified 2 large arterial branches.At the second stage, we performed laparoscopic kidney resection. None of the patients required renal artery clamping, because there was an excellent visualization of the demarcation zone and no significant blood loss. The resection area was sutured in 1 case (20 %). In 2 individuals (40 %), a hemostatic sponge was installed in the removed tumor bed. In the remaining 2 cases (40 %), hemostasis was ensured by coagulation. The median blood loss was 100 mL (range: 50-200 mL). The postoperative period was uneventful in all patients. None of the patients developed symptoms of acute renal failure.Conclusion. Thus, superselective embolization of arteries supplying a kidney tumor has undeniable advantages in organ-sparing surgeries for patients with localized kidney cancer and some additional kidney problems, when organ preservation is crucial for patient's life.

Hypertensive nephropathy as an outcome of unilateral nephrectomy in kidney cancer

2020 ◽  
Vol 10 (3) ◽  
pp. 229-234
Author(s):  
Igor I. Titjaev ◽  
Sergey S. Andreev ◽  
Svetlana V. Andreeva ◽  
Konstantin V. Udalov ◽  
Denis S Kas’janov
Keyword(s):  
Blood Pressure ◽  
Kidney Cancer ◽  
Structural Damage ◽  
Plasma Pressure ◽  
Hypertensive Nephropathy ◽  
Cardiovascular Failure ◽  
Functional Changes ◽  
Adaptive Mechanisms ◽  
Single Kidney ◽  
Kidney Resection

Aim. To study the adaptive mechanisms of structural and functional changes in a single kidney after nephrectomy for kidney cancer. Materials and Methods. A total of 179 operations of two types were performed: nephrectomy and kidney resection in patients with cancerous lesions. Postoperative ultrasound was performed size control and dopplerography of the vessels of the contralateral single kidney, monitoring-control of blood pressure. Results. In case of kidney resection, the adaptive mechanisms controlling the volume of functioning tissue are preserved. The load on the organ remains minimal and physiological, and is not redistributed, blood pressure remains close to baseline. Nephrectomy does not lead to functional changes in a single kidney, but to adaptive and pathophysiological structural damage as a result of increased plasma pressure, organ reboot, its vicarious hypertrophy, which is accompanied by venous edema of interstitium as a pressure factor on the tissue, increased tone of arterioles, the development of secondary organ ischemia, circulatory hypoxia and increased blood pressure. All this fits into the clinical picture of hypertensive nephropathy. Conclusions. The potential risk of hypertension and hypertensive nephropathy in patients undergoing nephrectomy, compared with patients after organ-saving surgery, is significantly higher. One of the most important manifestations of hypertension in the elderly is a violation of the structure and function of target organs, which include: the brain, heart, blood vessels, kidney. Nephrectomy forms a pathological vicious circle, contributing to the development and further progression of renal and cardiovascular failure.

scholarly journals Laparoscopic removal of a kidney tumor after superselective embolization of the kidney vessels

2020 ◽  
Vol 21 (1) ◽  
pp. 65-69
Author(s):  
V. V. Zemlyansky ◽  
O. B. Zhukov ◽  
T. A. Kurmanov ◽  
Zh. D. Zhumagazin ◽  
A. M. Chinaliev
Keyword(s):  
Blood Loss ◽  
Tumor Resection ◽  
Tumor Diameter ◽  
Kidney Tumor ◽  
Feeding Artery ◽  
Loss Of Function ◽  
Kidney Tumors ◽  
Study Objective ◽  
Superselective Embolization ◽  
Kidney Resection

The study objective is to evaluate the effectiveness of using superselective embolization of the renal arterial bed prior to organ-preserving laparoscopic kidney tumor resection.Materials and methods. At the Center for Urology, Kidney Transplantation and Nephrology of the National Research Oncology Center (Nur-Sultan, Kazakhstan) between 2015 and 2019 laparoscopic kidney tumor resection was performed in 45 patients; in 9 patients with stage T1 kidney tumors, superselective embolization was also performed. Mean age of the patients was 54 years, mean tumor diameter was 2.8 cm. Localization near the kidney pole and presence of an artery isolatedly supplying the tumor were the main indications for superselective embolization of the feeding artery prior to kidney resection.Results. Mean blood loss was 280 ml. Complications characteristic of post-embolization period (pain, fever, arterial hypertension), as well as loss of function of the organ, were absent 3, 6 and 12 months after the procedure per laboratory and radiological examinations.Conclusion. Superselective embolization of the tumor feeding artery is an effective method allowing to minimize warm ischemia of the renal parenchyma and perform kidney resection with minimal blood loss.The authors declare no conflict of interest.All patients gave written informed consent to participate in the study and to the publication of their data.

Hand-assisted laparoscopic nephrectomy in morbidly obese patients

2020 ◽  
Vol 99 (6) ◽  
pp. 271-276
Keyword(s):  
Body Weight ◽  
Surgical Technique ◽  
Blood Loss ◽  
Hospital Stay ◽  
Kidney Cancer ◽  
The Body ◽  
Laparoscopic Nephrectomy ◽  
Morbidly Obese ◽  
Obese Patients ◽  
Morbid Obese

Introduction: Prevalence of obesity is 30 % in the Czech Republic and is expected to increase further in the future. This disease complicates surgical procedures but also the postoperative period. The aim of our paper is to present the surgical technique called hand-assisted laparoscopic nephrectomy (HALS), used in surgical management of kidney cancer in morbid obese patients with BMI >40 kg/m2. Methods: The basic cohort of seven patients with BMI >40 undergoing HALS nephrectomy was retrospectively evaluated. Demographic data were analyzed (age, gender, body weight, height, BMI and comorbidities). The perioperative course (surgery time, blood loss, ICU time, hospital stay and early complications), tumor characteristics (histology, TNM classification, tumor size, removed kidney size) and postoperative follow-up were evaluated. Results: The patient age was 38−67 years; the cohort included 2 females and 5 males, the body weight was 117−155 kg and the BMI was 40.3−501 kg/m2. Surgery time was 73−98 minutes, blood loss was 20−450 ml, and hospital stay was 5−7 days; incisional hernia occurred in one patient. Kidney cancer was confirmed in all cases, 48–110 mm in diameter, and the largest removed specimen size was 210×140×130 mm. One patient died just 9 months after the surgery because of metastatic disease; the tumor-free period in the other patients currently varies between 1 and 5 years. Conclusion: HALS nephrectomy seems to be a suitable and safe surgical technique in complicated patients like these morbid obese patients. HALS nephrectomy provides acceptable surgical and oncological results.

An Enhanced Two Stage MMSE Equalizer for Coded FBMC/OQAM Systems

2019 ◽  
Vol 10 (1) ◽  
pp. 69-82 ◽  
Author(s):  
Mohammad Rizk Assaf ◽  
Abdel-Nasser Assimi
Keyword(s):  
Error Propagation ◽  
Channel Model ◽  
Error Correcting Codes ◽  
Two Stage ◽  
Probability Of Error ◽  
Second Stage ◽  
Different Types ◽  
Mmse Equalizer ◽  
And Performance ◽  
Ici Cancellation

In this article, the authors investigate the enhanced two stage MMSE (TS-MMSE) equalizer in bit-interleaved coded FBMC/OQAM system which gives a tradeoff between complexity and performance, since error correcting codes limits error propagation, so this allows the equalizer to remove not only ICI but also ISI in the second stage. The proposed equalizer has shown less design complexity compared to the other MMSE equalizers. The obtained results show that the probability of error is improved where SNR gain reaches 2 dB measured at BER compared with ICI cancellation for different types of modulation schemes and ITU Vehicular B channel model. Some simulation results are provided to illustrate the effectiveness of the proposed equalizer.

Personalised attraction recommendation for enhancing topic diversity and accuracy

2021 ◽  
pp. 016555152199980
Author(s):  
Yuanyuan Lin ◽  
Chao Huang ◽  
Wei Yao ◽  
Yifei Shao
Keyword(s):  
Real World ◽  
Information Overload ◽  
Two Stage ◽  
Misclassification Cost ◽  
Second Stage ◽  
Low Visibility ◽  
Recommendation Diversity ◽  
Optimisation Model ◽  
Definition Of ◽  
Improved Methods

Attraction recommendation plays an important role in tourism, such as solving information overload problems and recommending proper attractions to users. Currently, most recommendation methods are dedicated to improving the accuracy of recommendations. However, recommendation methods only focusing on accuracy tend to recommend popular items that are often purchased by users, which results in a lack of diversity and low visibility of non-popular items. Hence, many studies have suggested the importance of recommendation diversity and proposed improved methods, but there is room for improvement. First, the definition of diversity for different items requires consideration for domain characteristics. Second, the existing algorithms for improving diversity sacrifice the accuracy of recommendations. Therefore, the article utilises the topic ‘features of attractions’ to define the calculation method of recommendation diversity. We developed a two-stage optimisation model to enhance recommendation diversity while maintaining the accuracy of recommendations. In the first stage, an optimisation model considering topic diversity is proposed to increase recommendation diversity and generate candidate attractions. In the second stage, we propose a minimisation misclassification cost optimisation model to balance recommendation diversity and accuracy. To assess the performance of the proposed method, experiments are conducted with real-world travel data. The results indicate that the proposed two-stage optimisation model can significantly improve the diversity and accuracy of recommendations.

scholarly journals Two-stage multi-tasking transform framework for large-scale many-objective optimization problems

2021 ◽  
Author(s):  
Lu Chen ◽  
Handing Wang ◽  
Wenping Ma
Keyword(s):  
Large Scale ◽  
Original Problem ◽  
Optimization Problems ◽  
Reference Points ◽  
Optimization Strategy ◽  
Two Stage ◽  
Decision Space ◽  
Second Stage ◽  
Decision Variables ◽  
Objective Space

AbstractReal-world optimization applications in complex systems always contain multiple factors to be optimized, which can be formulated as multi-objective optimization problems. These problems have been solved by many evolutionary algorithms like MOEA/D, NSGA-III, and KnEA. However, when the numbers of decision variables and objectives increase, the computation costs of those mentioned algorithms will be unaffordable. To reduce such high computation cost on large-scale many-objective optimization problems, we proposed a two-stage framework. The first stage of the proposed algorithm combines with a multi-tasking optimization strategy and a bi-directional search strategy, where the original problem is reformulated as a multi-tasking optimization problem in the decision space to enhance the convergence. To improve the diversity, in the second stage, the proposed algorithm applies multi-tasking optimization to a number of sub-problems based on reference points in the objective space. In this paper, to show the effectiveness of the proposed algorithm, we test the algorithm on the DTLZ and LSMOP problems and compare it with existing algorithms, and it outperforms other compared algorithms in most cases and shows disadvantage on both convergence and diversity.

scholarly journals Deep learning for end-to-end kidney cancer diagnosis on multi-phase abdominal computed tomography

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Kwang-Hyun Uhm ◽  
Seung-Won Jung ◽  
Moon Hyung Choi ◽  
Hong-Kyu Shin ◽  
Jae-Ik Yoo ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Deep Learning ◽  
Kidney Cancer ◽  
Renal Tumor ◽  
Renal Tumors ◽  
Abdominal Computed Tomography ◽  
Wide Range ◽  
End To End ◽  
Multi Phase ◽  
Histologic Subtypes

AbstractIn 2020, it is estimated that 73,750 kidney cancer cases were diagnosed, and 14,830 people died from cancer in the United States. Preoperative multi-phase abdominal computed tomography (CT) is often used for detecting lesions and classifying histologic subtypes of renal tumor to avoid unnecessary biopsy or surgery. However, there exists inter-observer variability due to subtle differences in the imaging features of tumor subtypes, which makes decisions on treatment challenging. While deep learning has been recently applied to the automated diagnosis of renal tumor, classification of a wide range of subtype classes has not been sufficiently studied yet. In this paper, we propose an end-to-end deep learning model for the differential diagnosis of five major histologic subtypes of renal tumors including both benign and malignant tumors on multi-phase CT. Our model is a unified framework to simultaneously identify lesions and classify subtypes for the diagnosis without manual intervention. We trained and tested the model using CT data from 308 patients who underwent nephrectomy for renal tumors. The model achieved an area under the curve (AUC) of 0.889, and outperformed radiologists for most subtypes. We further validated the model on an independent dataset of 184 patients from The Cancer Imaging Archive (TCIA). The AUC for this dataset was 0.855, and the model performed comparably to the radiologists. These results indicate that our model can achieve similar or better diagnostic performance than radiologists in differentiating a wide range of renal tumors on multi-phase CT.

scholarly journals A Two-Stage Mono- and Multi-Objective Method for the Optimization of General UPS Parallel Manipulators

Mathematics ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 543
Author(s):  
Alejandra Ríos ◽  
Eusebio E. Hernández ◽  
S. Ivvan Valdez
Keyword(s):  
Genetic Algorithm ◽  
Performance Metrics ◽  
Tracking Error ◽  
Parallel Manipulators ◽  
Optimization Method ◽  
Statistical Hypothesis ◽  
Two Stage ◽  
Multi Objective ◽  
Second Stage ◽  
Conflicting Objectives

This paper introduces a two-stage method based on bio-inspired algorithms for the design optimization of a class of general Stewart platforms. The first stage performs a mono-objective optimization in order to reach, with sufficient dexterity, a regular target workspace while minimizing the elements’ lengths. For this optimization problem, we compare three bio-inspired algorithms: the Genetic Algorithm (GA), the Particle Swarm Optimization (PSO), and the Boltzman Univariate Marginal Distribution Algorithm (BUMDA). The second stage looks for the most suitable gains of a Proportional Integral Derivative (PID) control via the minimization of two conflicting objectives: one based on energy consumption and the tracking error of a target trajectory. To this effect, we compare two multi-objective algorithms: the Multiobjective Evolutionary Algorithm based on Decomposition (MOEA/D) and Non-dominated Sorting Genetic Algorithm-III (NSGA-III). The main contributions lie in the optimization model, the proposal of a two-stage optimization method, and the findings of the performance of different bio-inspired algorithms for each stage. Furthermore, we show optimized designs delivered by the proposed method and provide directions for the best-performing algorithms through performance metrics and statistical hypothesis tests.

scholarly journals Fast Two-Stage Computation of an Index Policy for Multi-Armed Bandits with Setup Delays

Mathematics ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 52
Author(s):  
José Niño-Mora
Keyword(s):  
Numerical Study ◽  
Arithmetic Operation ◽  
Bandit Problem ◽  
Index Policy ◽  
Two Stage ◽  
Second Stage ◽  
Whittle Index ◽  
Set Up ◽  
Computing Method ◽  
Special Case

We consider the multi-armed bandit problem with penalties for switching that include setup delays and costs, extending the former results of the author for the special case with no switching delays. A priority index for projects with setup delays that characterizes, in part, optimal policies was introduced by Asawa and Teneketzis in 1996, yet without giving a means of computing it. We present a fast two-stage index computing method, which computes the continuation index (which applies when the project has been set up) in a first stage and certain extra quantities with cubic (arithmetic-operation) complexity in the number of project states and then computes the switching index (which applies when the project is not set up), in a second stage, with quadratic complexity. The approach is based on new methodological advances on restless bandit indexation, which are introduced and deployed herein, being motivated by the limitations of previous results, exploiting the fact that the aforementioned index is the Whittle index of the project in its restless reformulation. A numerical study demonstrates substantial runtime speed-ups of the new two-stage index algorithm versus a general one-stage Whittle index algorithm. The study further gives evidence that, in a multi-project setting, the index policy is consistently nearly optimal.

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