Difficult Operation Research Articles

#3988 MARS – A NOVEL SCORE TO PREDICT THE RISK OF ACUTE KIDNEY INJURY AFTER LIVING DONOR LIVER TRANSPLANT

Abstract Background and Aims Acute kidney injury is common in liver transplant recipients with adverse effect on graft and patient outcomes. There are many studies on incidence, risk factors and outcomes of AKI post-LT in deceased donors, there is paucity of data about AKI in living donor liver transplant recipients (LDLT). LDLT is a difficult and prolonged surgery with inherent risk to donors, so it practised in only few centres across the world however there is little data of AKI in living donor liver transplant recipients (LDLT). Method This prospective observational study was undertaken to assess incidence, risk factors, patient graft outcomes and to develop a novel prediction model to identify recipients at risk for post-transplant AKI at the earliest possible time point after living donor liver transplantation in a tertiary care large volume centre in northern India. Results Incidence of AKI in our study was 31.7% with 13.5% requiring renal replacement therapy. Male gender, history of hepatorenal syndrome, use of intraoperative inotropes (Indicating Post reperfusion injury), MELD score >14, preoperative proteinuria >0.5 gram/day & estimated GFR <90 ml/min/1.73 m2 were significant risk factors for AKI within 1 month post-LDLT in logistic regression model. We devised a risk prediction score (The MARS score) which had a sensitivity of 81.36%, specificity of 88.19%, positive predictive value of 76.9%, negative predictive value of 91.06% and overall accuracy of 86.02% to predict AKI. AKI was associated with longer hospital stay, higher mortality and led to higher occurrence of chronic kidney disease after a median follow up period of 724 (635 – 794) days. Conclusion Our risk model (MARS) with an AUC of 0.925 performed better than all previously reported scores in DDLT & LDLT .The variables in our AKI risk prediction are simple to extract and use making it favourable in resource limited settings where access to newer biomarkers of kidney injury is limited. There is a need to apply the score in other cohorts to validate its applicability.

Noise in the Operating Room as Indicator for Long and Difficult Surgeries

Abstract Background Noise pollution in the operating room (OR) has been shown to have adverse effects on the surgical team and has been linked to the occurrence of surgical site infections. Aims The aim of this study was to evaluate whether intraoperative sound levels were associated with postoperative complications. Methods Sound levels were measured during 407 procedures of patients undergoing elective or emergency surgery in four Swiss hospitals. Sound levels were registered every second in decibels dB(A). The percentage of time above 70dBA and the time-averaged sound levels were calculated. A standard questionnaire at the end of the surgery was used to evaluate subjectively perceived difficulty of the surgery and distraction during the procedure by the OR members. The POSSUM classification (“Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity”) was used to assess complexity of each procedure. Noise levels were then related to the occurrence of postoperative complications in multivariate regression models. Results Of the 294 patients included, 38% had any kind of postoperative complication. Intraoperative sound levels (percentage of time above >70dB(A) and time-averaged sound levels) were significantly higher for patients who developed a postoperative complication (0.7% versus 0.5%, respectively 60dB(A) versus 58dB(A), p-value < 0.01). Further, higher sound levels were significantly correlated with the duration and complexity of the procedure as well as subjectively perceived difficulty by the members of the surgical team. In a multivariate analysis including procedure- and patient-related factors, only the duration of the surgery was an independent predictor for postoperative complications. Conclusions Higher intraoperative sound levels were associated with an increased rate of postoperative complications. Here, we showed that this is likely the result of louder procedures being technically more challenging for the surgical team. Thus, increased sound levels may represent a surrogate marker for long and complex surgical procedures.

Barriers and facilitators to education access for marginalised non-citizen children in Malaysia: A qualitative study.

In Malaysia, marginalised non-citizen children are excluded from formal education at public schools. Recognising education as a fundamental human right, the barriers and facilitators to educational access among refugee and asylum-seeker, migrant, stateless and undocumented children in Malaysia were explored. Qualitative data were collected via 32 in-depth interviews with multiple stakeholders. Data were thematically analysed and organised at three socio-ecological levels. At the 'legislative and policy' level, the requirement of citizenship documents only allows some stateless children to access public schools. Yet, many informal learning centres are not state-endorsed, as they are unable to fulfil licensing criteria. Importantly, denying the right to work for adult refugees and other undocumented people demotivates the pursuit of education among children. At the 'individual and family' level, financial constraints constitute a major reason for school dropouts, especially through expectations on boys to work. Cultural norms partly contribute to the lower enrolment of Rohingya refugee girls in secondary education, but gender parity is maintained for most in primary education. Another factor is proximity to learning centres, which links to safety concerns and transportation costs. Those who accessed public schools reported bullying by local children, which parallels institutional discrimination against marginalised non-citizens. At the 'community and educational institutions' level, inadequate funding for learning centres limits their ability to invest in physical facilities, teachers' salaries and others. Despite difficult operating conditions, learning centres address diverse school readiness, educational backgrounds, and language competencies among students by having sensitised teachers, placement tests and preparatory classes at school entry, and options for vocational training. We propose the gradual inclusion of all children in public schools and the immediate state recognition and support of learning centres. Correspondingly, realising the 'Right to Work' for refugees and stateless peoples will be synergistic in advancing universal education access for all children.

Subtotal Cholecystectomy in Preventing Major Complications in Difficult Cholecystectomy Cases: A Comprehensive Single Center Study

ABSTRACT Background: Cholecystectomy is a commonly performed laparoscopic surgery but because of variability in anatomy, surrounding inflammation and fibrosis because of recurrent attacks of cholecystitis, can be a potentially difficult surgery. Laparoscopic total cholecystectomy in difficult gall bladder cases sometimes can cause severe complications. Laparoscopic subtotal cholecystectomy can be a bridge and a safe and feasible option between open subtotal cholecystectomy and laparoscopic cholecystectomy. Aim: To study indications, morbidity and clinical outcomes in patients undergoing subtotal cholecystectomy with laparoscopy or with open surgery. Settings and Design: It was a prospective observational study. Patients presenting with signs and symptoms of cholecystitis in either OPD or IPD and in emergency were included in this study. Materials and Methods: Total 38 patients who presented to our institute with clinical and ultrasonographic evidence of acute cholecystitis were included in the study. All patients underwent detailed and thorough clinical examination, laboratory investigations, ultrasonographic, and contrast enhanced computed tomography scan in selected patients. Based on intraoperative findings, decision of subtotal cholecystectomy either by laparoscopy or via open method was made. Various outcomes like intraoperative complications, postoperative complications and need of postoperative interventions, hospital stay, and returning to daily activity were observed and charted. Statistical Analysis: The data obtained were tabulated in Microsoft Excel and analyzed using SPSS version 17.0. Continuous variables were expressed as mean ± standard deviation value. Probability value (P value) was used to determine the level of significance. P value <.05 was considered as significant; P value <0.001 was considered as highly significant. Results: The common indications for subtotal cholecystectomy were severe cholecystitis with dense fibrous adhesions (97.4%), empyema (34.2%) or gangrenous gallbladder (31.6%), and Mirizzi syndrome (2.6%). Conversion rate was 21.1%. Morbidity rates were relatively low with subtotal cholecystectomy (bile leak 21.1%, sub hepatic collections 10.5%, retained stones 5.3%, paralytic ileus 18.4%, wound infection 7.9%, and common bile duct stricture 2.6%). Postoperative interventions were necessary in 18.4% of the cases (retained stones 5.3%, bile leak 7.9%, common bile duct stricture 2.6%, and subhepatic collection 2.6%). Mean duration of hospital stay was 7.5 days and returning to routine daily activity was 11.05 days. Conclusion: Subtotal cholecystectomy is a safe and feasible method for difficult gallbladder cases with a positive outcome. Laparoscopic subtotal cholecystectomy decreases the conversion rate in difficult gallbladder cases but it is not a substitute to open conversion if deemed necessary.

Indocyanine Green Imaging in Laparoscopic Cholecystectomy Plus Laparoscopic Common Bile Duct Exploration: A Suitable Option for Patients With Difficult Exploration (With Videos).

The clinical application of indocyanine green (ICG) fluorescence imaging technology in biliary surgery has gradually highlighted its role, and its role in laparoscopic cholecystectomy plus laparoscopic common bile duct exploration (LC+LCBDE) still needs to be further explored. Therefore, we evaluated the clinical value of ICG fluorescence imaging in LC+LCBDE. Data from 131 patients who underwent LC+LCBDE in our department between January 2019 and June 2021 were retrospectively collected and analyzed. Overall, 59 and 72 patients underwent ICG+LC+LCBDE and LC+LCBDE, respectively, and were assigned to the ICG (ICG+LC+LCBDE) and non-ICG (LC+LCBDE) groups based on their medical records. The clinical data of all patients were obtained, and the differences between the ICG and non-ICG groups were compared. A total of 131 patients successfully underwent surgery. There were no differences in baseline characteristics between the 2 groups. In terms of perioperative results, no significant between-group differences in biliary tract exposure before Calot's triangle dissection were noted; however, patients in the ICG group had better biliary tract observations after Calot's triangle dissection, shorter operative time, fewer complications, earlier postoperative exhaust, and lower hospital costs. ICG imaging can assist surgeons in determining biliary tract structures and injuries during surgery and in preventing operation-related bile leakage. ICG imaging is a technique worthy of promotion in difficult surgery.

Efficient Sign-Detection-Scheme Using Modular Computation Technique for the Moduli Set {2<sup>n</sup>-1, 2<sup>n</sup>, 2<sup>n</sup>+1, 2<sup>(n+1)</sup>-1, 2<sup>2n</sup>-5}

In computer arithmetic, one of the most important things to consider in hardware design is the ability of the system to detect and display numbers with their signs. This when properly managed will reduce errors and ensure hardware reliability. But interestingly, detecting and knowing the sign of a residue number during arithmetic operation is very difficult. Magnitude Comparison, Scaling and Number conversions are some of the other difficult operations in Residue Number System (RNS). Unlike the weighted number system, it is even extremely difficult to determine the sign of a number in an RNS architecture thereby hampering the full implementation RNS in general purpose computing. In this paper, an efficient sign detection algorithm for detecting the sign of a number in an RNS architecture is presented. In formulating the algorithms, X maximum, (X_max) is computed from the Dynamic Range, M=∏^k_i=1(m_i). Modular Computation Technique is employed as a converter to compute X from the residues (r₁, r₂, r₃) with respect to a given moduli set, say S= {m₁, m₂ ..., m_n}. X is positive if X-X_max<0 otherwise X is negative and the actual value is this case is computed as X-M. The moduli set {2ⁿ-1, 2ⁿ, 2ⁿ+1, 2⁽ⁿ⁺¹⁾-1, 2²ⁿ-5} is used for the system design implementation and for numerical illustrations. It is observed that the scheme effectively detects the sign of RNS numbers and theoretical analysis showed that simple hardware resources and low-power modular adders are used in the design. It is also observed that the scheme when implemented practically can help project RNS to be used in general purpose computing.

Application of Robot Automation Technology Based on Machine Assisted and Artificial Intelligence in Distribution Network Overhead Line Engineering

INTRODUCTION: The development of artificial intelligence technology in the context of the intelligent era shows vigorous vigor and vitality, and artificial intelligence fusion of robotic automation technology can assist manpower to complete all kinds of difficult operations, distribution network overhead line as the current power transmission lines equipped with the main way for domestic power transmission and regional power safety is of great significance. OBJECTIVES: In order to reduce the labor intensity of operators, reduce the occurrence of power outages, and ensure the reliability of power supply, we discuss the application of robotic automation technology of machine-assisted and artificial intelligence in the distribution network overhead line project. METHODS: Distribution network with power operation intelligent robot will grid lines in the wave speed information through the sensor transmission to the computer system, the computer system will grid lines in the wave speed converted to the wave speed of the overhead line, can be mixed lines in the wave speed inconsistent problem to provide a good solution. RESULTS: At the scene of the work, the artificial intelligence distribution network power-carrying operation robot integrating artificial intelligence technology has a good application effect for the wiring in the distribution network overhead line project. CONCLUSION: Robot automation technology incorporates the advantages of artificial intelligence, can rely on sensor systems and computer systems to perceive and identify things, and can autonomously control their own behavior, automated processing of complex actions, with a certain degree of perception, planning and collaborative ability, can be applied to the distribution network overhead line project.

Pocket park in urban regeneration of China: Policy and perspective

Perched on the edge and corner of the city center, pocket parks transform urban vacant land into vibrant urban oases. It can greatly shorten the distance from citizens to the park, thereby promoting citizens' participation in outdoor activities and improving urban vitality. The construction of pocket parks in China started late. However, it has developed rapidly in recent years, which supports urban regeneration. A government document, published by the Ministry of Housing and Urban-Rural Development of the People’s Republic of China in 2002, promotes the construction of pocket parks. In the process of promoting the construction of pocket parks in Chinese cities, problems such as unclear construction standards, difficult operation and maintenance, blind copying, and emphasis on the landscape over the function have emerged. The aforementioned issues are elaborated and corresponding suggestions are pointed out in this short communication.

(413) Obturator Fenestration Technique for the Woody Indurated Penis

Abstract Introduction Performing penile implant surgery can be challenging especially in the presence of a woody indurated penis (e.g. post priapism, post infection, prolonged h/o ICI, etc.) The loss of corporal smooth muscle cells and excess of collagen deposition caused by corporal fibrosis can create challenges and increase risk of perforation, crossover and certainly infection. Clinically, these fibrotic corpora make placement of a penile prosthesis a difficult surgical procedure. Objective We demonstrate how the Obturator Fenestration Technique facilitates placement of a penile implant in the woody indurated penis. Methods 48 y/o male w/ Hx of a 3-day Priapism treated with a shunt at the time. Patient was not offered a penile implant until 8 months following event. At the time of penile implant surgery the urologist placed a malleable halfway up on the right corpora and did not attempt the other side and case was aborted. Physical examination revealed diffusely woody indurated corporeal tissue throughout the left corpora and distally on the right corpora Results Penile implant was successfully implanted using the obturator fenestration technique in the woody indurated penis in the patient with a previously failed attempt at implantation. Conclusions The use of the Obturator Fenestration Technique can help facilitate increasingly complex cases This can help reduce unnecessary complications and repeat revision surgery. However, there is a learning curve while using the Obturator Fenestration Technique and should not be performed by a novice surgeon We hope to improve our techniques and surgical approaches to improve surgical times and post-operative outcomes for the woody indurated penis Disclosure Any of the authors act as a consultant, employee or shareholder of an industry for: Coloplast, Boston Scientific

Turkish Dental Students’ Perceptions and Awareness of Dental Implant Education: A Questionnaire Study

Objective. This study aimed to assess Turkish dental students’ awareness of and attitudes toward dental implant therapy, as well as the effectiveness of dental implantology lecture from their point of view.&#x0D; Materials and Methods. This study used a cross-sectional online survey. A total of 425 third-, fourth- and fifth-year dental students enrolled in Gazi University School of Dentistry during the 2020-2021 academic year were invited to participate in the survey anonymously and voluntarily. Following the descriptive part (age, gender, and education status), all the participants were asked 11 questions.&#x0D; Results. Total of 415 questionnaires were analyzed. The 3rd-year students stated that they were“ poorly” informed about dental implants (n=88, 64.7%), while the 4th- and 5th-year students were“ moderately” infromed (n=78, 54.2% and n=60, 44.4%, respectively) (p &lt; 0.001). All the students were believed that they needed to get more information during their undergraduate studies (p &lt; 0.01). More than half of all students preferred to have PhD or speciality training after graduation (p &gt; 0.05). Approximately 80% of all students believed that dentists should receive specialized training in order to practice implant dentistry (p &gt; 0.05).&#x0D; Conclusions. The results of this study show that some Turkish dental students find DI treatment a difficult operation and that they do not know enough about it. As a result, it is anticipated that improving the current curriculum will contribute to the course success and make dental students feel better prepared for dental implantology following graduation.

Development and validation of a preoperative difficulty scoring system for endoscopic resection of gastric gastrointestinal stromal tumor: a multi-center study

BackgroundEndoscopic resection (ER) is a promising technique for resecting gastric gastrointestinal stromal tumors (gGISTs); however, ER is technically challenging. This study aimed to develop and validate a difficulty scoring system (DSS) to determine the difficulty for ER of a gGIST.MethodsThis retrospective study enrolled 555 patients with gGISTs in multi-centers from December 2010 to December 2022. Data on patients, lesions, and outcomes of ER were collected and analyzed. A difficult case was defined as an operative time ≥ 90 min, or the occurrence of severe intraoperative bleeding, or conversion to laparoscopic resection. The DSS was developed in the training cohort (TC) and validated in the internal validation cohort (IVC) and external validation cohort (EVC).ResultsThe difficulty occurred in 97 cases (17.5%). The DSS comprised the following: tumor size ≥ 3.0 cm (3 points) or 2.0–3.0 cm (1 point); location in the upper third of the stomach (2 points); invasion depth beyond the muscularis propria (2 points); lack of experience (1 point). The area under the curve (AUC) of DSS in IVC and EVC was 0.838 and 0.864, respectively, and the negative predictive value (NPV) was 0.923 and 0.972, respectively. The proportions of difficult operation in easy (score 0–3), intermediate (score 4–5), and difficult (score 6–8) categories were 6.5%, 29.4%, and 88.2% in the TC, 7.7%, 45.8%, and 85.7% in the IVC, and 7.0%, 29.4%, and 85.7% in the EVC, respectively.ConclusionsWe developed and validated a preoperative DSS for ER of gGISTs based on tumor size, location, invasion depth, and endoscopists’ experience. This DSS can be used to grade the technical difficulty before surgery.

Multi-level graded facial emotion intensity recognition using MCANN for health care

Facial emotion recognition analysis is widely used in various social fields, including Law Enforcement for police interrogation, virtual assistants, hospitals for understanding patients’ expressions, etc. In the field of medical treatment such as psychologically affected patients, patients undergoing difficult surgeries, etc require emotional recognition in real-time. The current emotional analysis employs interest points as landmarks in facial images affected by a few emotions Many researchers have proposed 7 different types of emotions (amusement, anger, disgust, fear, and sadness). In our work, we propose a deep learning-based multi-level graded facial emotions of 21 different types with our proposed facial emotional feature extraction technique called as Deep Facial Action Extraction Units (DFAEU). Then using our Multi-Class Artificial Neural Network (MCANN) architecture the model is trained to classify different emotions. The proposed method makes use of VGG-16 for the analysis of emotion grades. The performance of our model is evaluated using two algorithms Sparse Batch Normalization CNN (SBN-CNN) and CNN with Attention mechanism (ACNN) along with datasets Facial Emotion Recognition Challenge (FERC-2013). Our model outperforms 86.34 percent and 98.6 percent precision.

Impact of patient-specific three-dimensional printed liver models on hepatic surgery safety: a pilot study

BackgroundSimulation and navigation technologies in hepatobiliary surgery have been developed recently. In this prospective clinical trial, we evaluated the accuracy and utility of our patient-specific three dimensional (3D)-printed liver models as an intraoperative navigation system to ensure surgical safety. MethodPatients requiring advanced hepatobiliary surgeries during the study period were enrolled. Three cases were selected for comparison of the computed tomography (CT) scan data of the models with the patients' original data. Questionnaires were completed after surgeries to evaluate the utility of the models. Psychological stress was used as subjective data and operation time and blood loss as objective data. ResultsThirteen patients underwent surgery using the patient-specific 3D liver models. The difference between patient-specific 3D liver models and the original data was less than 0.6 mm in the 90% area. The 3D model assisted with intra-liver hepatic vein recognition and the definition of the cutting line. According to the post-operative subjective evaluation, surgeons found the models improved safety and reduced psychological stress during operations. However, the models did not reduce operative time or blood loss. ConclusionThe patient-specific 3D-printed liver models accurately reflected patients' original data and were an effective intraoperative navigation tool for meticulously difficult liver surgeries. Clinical trial registrationThis study was registered in the UMIN Clinical Trial Registry (UMIN000025732).

Improvement of esophagojejunostomy technique after total gastrectomy with overlap method: reduce the difficulty of surgery and shorten operation time.

Gastric cancer (GC) is one of the most malignant human cancers. Totally laparoscopic total gastrectomy (TLTG) is a difficult operation, especially esophagojejunostomy. Our team has adopted the method of suspending and pulling the esophagus with the visceral retractor and two needles of barbed wire interlocking to suture the common opening, which reduces the difficulty of the operation. From January to December 2020, 20 patients underwent TLTG with the overlap method by improved esophagojejunostomy technique and 20 patients with the traditional overlap method after TLTG were used as the control group. The surgery was performed using a five-trocar system. After lymphadenectomy, the esophagus was separated at least 2cm from the upper edge of the tumor. Improved esophagojejunostomy technique was completed by the following steps: (1) cutting end of the esophagus suspension; (2) jejuno-jejunostomy; (3) esophagojejunostomy; (4) close the esophagojejunum common incision opening. The results showed that the operative time, and anastomosis time of the modified group were shorter than those of the traditional group, There were no postoperative complications such as anastomotic leakage, anastomotic stenosis, duodenal stump fistula and Roux stasis syndrome in the both group. There was no statistically significant difference in postoperative complications between the two groups. Taken together, our modified esophagojejunostomy technique after total gastrectomy is feasible and safe. This procedure is an efficient method to shorten the operation time and reduce the difficulty of surgery in esophagojejunostomy of laparoscopic total gastrectomy.

Efficient Photo-Oxidation Leaching of Ni and Co in a Spent Lithium-Ion Battery Cathode by Homogeneous UV/H2O2

Existing lithium-ion battery (LIB) leaching and recycling techniques have been widely applied in industrial production despite problems, such as difficult operation, high cost, and heavy pollution. Herein, we propose a novel photochemical oxidation method to leach Co and Ni ions in spent LIB cathodes, achieving leaching efficiencies of 99.73 and 97.54% when irradiated with hydrogen peroxide as the oxidant in acetonitrile and dichloromethane as the solvent under UV light for 4 h. The oxidation mechanism of the reaction was investigated by a series of tests. Three free radical oxidation pathways that functioned together with the reaction mechanism were proposed. This study is the first to combine the UV/H2O2 photo-oxidation reaction with spent LIB recycling to achieve a universal, green, and simple operation path for metal recycling field in the future.

Clinical Outcomes After Ultra-Early Cranioplasty Using Craniectomy Contour Classification as a Patient Selection Criterion.

Although not a technically difficult operation, cranioplasty is associated with high rates of complications. The optimal timing of cranioplasty to mitigate complications remains the subject of debate. To report outcomes between patients undergoing cranioplasty at ultra-early (0-6 weeks), intermediate (6 weeks to 6 months), and late (>6 months) time frames. We report a novel craniectomy contour classification (CCC) as a radiographic parameter to assess readiness for cranioplasty. A single-institution retrospective analysis of patients undergoing cranioplasty was performed. Patients were stratified into ultra-early (within 6 weeks of index craniectomy), intermediate (6 weeks to 6 months), and late (>6 months) cranioplasty cohorts. We have devised CCC scores, A, B, and C, based on radiographic criteria, where A represents those with a sunken brain/flap, B with a normal parenchymal contour, and C with "full" parenchyma. A total of 119 patients were included. There was no significant difference in postcranioplasty complications, including return to operating room ( P = .212), seizures ( P = .556), infection ( P = .140), need for shunting ( P = .204), and deep venous thrombosis ( P = .066), between the cohorts. Univariate logistic regression revealed that ultra-early cranioplasty was significantly associated with higher rate of functional independence at >6 months (odds ratio 4.32, 95% CI 1.39-15.13, P = .015) although this did not persist when adjusting for patient selection features (odds ratio 2.90, 95% CI 0.53-19.03, P = .234). In appropriately selected patients, ultra-early cranioplasty is not associated with increased rate of postoperative complications and is a viable option. The CCC may help guide decision-making on timing of cranioplasty.

The Surgical outcomes of fundus-first technique in lowering the rate of bile duct injuries and bleeding during open cholecystectomy that facing intraoperative difficulties: A single-center prospective study

Background: The problem of difficult gallbladder is not clearly defined and associated with real missing of therapeutic approaches that decreased morbidity. Moreover, the difficult gallbladder was reported as a contributing risk factor for biliary injury due to raised difficulty in surgical dissection within Calot’s triangle. The aim of this study is to determine the surgical outcomes of the open fundus-first cholecystectomy in lowering the rate of lethal intraoperative risks.&#x0D; Subjects and Methods: Our prospective study conducted during the period of January 2019 to December 2022 at Ibn Sina specialized hospital, Khartoum, Sudan, for two hundred and fifty-three patients underwent elective open fundus-first cholecystectomy for intraoperative difficulties.&#x0D; Results: the majority of cases had long-standing cholelithiasis with intraoperative difficulties revealed by pre-operative TUS and MRCP which required open fundus-first cholecystectomy in 173 (68.4%) of patients, (P-value &lt;0.05). The operative surgical time was 120 minutes in 103 patients (40.7%), (P-value &lt;0.05). During open cholecystectomy, variable intraoperative difficulties were found in all patients, (P-value &lt;0.05) and were divided into: (A) Contracted intra-hepatic gallbladder seen in 157 (62.1%) of cases; (B) Distorted anatomy within Calot's triangle seen in 135 (53.4%) of patients; and (C) Intraoperative bleeding from the liver bed was observed as bloody oozing form in 150 (59.3%) of cases. Our patients had minimal postoperative complications like mild wound infection in 8 (3.2%) of cases and mortality rate was zero. &#x0D; Conclusions: There is a need for appropriate therapeutic and preventive strategies in healthcare systems for safe dealing with difficult cholecystectomy. Unclear anatomy due to severe inflammatory dense adhesions at Calot’s triangle and CBD stones needing difficult surgeries are the most important limiting factors for fundus-first laparoscopic cholecystectomy. Hence, we humbly recommend an open approach of fundus-first cholecystectomy as safe surgical option to reduce the incidence of bile duct injuries and intra-operative bleeding.

Mechanical and tribological behaviour of novel Al–12Si-based hybrid composites

Abstract Aluminium matrix composites with high abrasion resistance, which can adapt to high temperatures and difficult operating conditions, are needed in the automotive and aerospace industries. For this purpose, Al–12Si–TiB2–Al2O3 composites were developed with the addition of TiB2–Al2O3 ceramic reinforcements at different rates and Gr at a constant rate. High densities were achieved by using the hot pressing method with powder metallurgy. Microstructural analyzes (SEM, EDS, X-RD) of the produced samples were made. In addition, mechanical properties (hardness and three-point bending) were investigated. The best tribological features were determined with the help of Taguchi, ANOVA and the prediction model. As a result, with the addition of TiB2 and Al2O3 reinforcements to the Al–12Si matrix, significant increases in hardness occur. In the bending analysis, it was determined that the reinforcements made the hybrid composite strong up to a certain point. From a tribological point of view, the A3 hybrid composite showed the best wear performance. Test conditions were analyzed with the help of Taguchi L18 orthogonal array and analysis of variance (ANOVA). With the help of ANOVA, it was determined that the most effective factors on the response parameters were the applied load and MMC type.

АНАЛІЗ СПРЯЖЕННЯ Б'ЄФІВ ГІДРОТЕХНІЧНИХ СПОРУД ТРАНСПОРТНОГО БУДІВНИЦТВА З ДОРОЖНІХ ВОДОПРОПУСКНИХ ТРУБ В УМОВАХ ПЛОСКОЇ ЗАВДАЧІ

Introduction. Hydraulic structures of transport construction from road culverts are used to pass water under roadways and other structures. Some terrain features require the construction of a road culvert with a steep slope, which increases the velocity of the water and creates a high-energy flow at the outlet of the road culvert. This high-energy water can erode a natural riverbed. The most effective method of extinguishing excessive kinetic energy of the water flow is extinguishing with the help of a hydraulic jump. Problems. From the literature analysis, it was established that road culverts are in difficult operating conditions, which causes their premature destruction. Goal. It consists in the analysis of the conjugation of reach of hydrotechnical structures of transport construction from road culverts in the conditions of a flat task. Results. The analysis of the peculiarities of the conjugation of reach for road culverts in the conditions of a flat task was carried out, the influence of a number of factors on the length of the hydraulic jump was determined, and a methodological approach to solving the problems of conjugation of reach was given. Conclusions. The most effective method of extinguishing excessive kinetic energy of the water flow is extinguishing with the help of a hydraulic jump. However, the issues related to the kinematics of the flow in the area of the formation of the hydraulic jump and the question of its stability have been practically investigated, the controlling influence on the flow in the spreading zone of the structural elements of active type extinguishers for relatively wide and relatively narrow channels has been poorly studied. The performed analysis of the current state of the problem allows us to draw a conclusion about the imperfection of the existing methods of calculating the conjugation of biefs and the need to improve the existing calculation approaches.

3D Printing Model of a Patient's Specific Lumbar Vertebra.

Selective dorsal rhizotomy (SDR) is a difficult, risky, and sophisticated operation, in which a laminectomy should not only expose an adequate surgical field of view but also protect the patient's spinal nerves from injury. Digital models play an important role in the pre-and intra-operation of SDR, because they can not only make doctors more familiar with the anatomical structure of the surgical site, but also provide precise surgical navigation coordinates for the manipulator. This study aims to create a 3D digital model of a patient-specific lumbar vertebra that can be used for planning, surgical navigation, and training of the SDR operation. The 3D printing model is also manufactured for more effective work during these processes. Traditional orthopedic digital models rely almost entirely on computed tomography (CT) data, which is less sensitive to soft tissues. Fusion of the bone structure from CT and the neural structure from magnetic resonance imaging (MRI) is the key element for the model reconstruction in this study. The patient's specific 3D digital model is reconstructed for the real appearance of the surgical area and shows the accurate measurement of inter-structural distances and regional segmentation, which can effectively help in the preoperative planning and training of SDR. The transparent bone structure material of the 3D-printed model allows surgeons to clearly distinguish the relative relationship between the spinal nerve and the vertebral plate of the operated segment, enhancing their anatomical understanding and spatial sense of the structure. The advantages of the individualized 3D digital model and its accurate relationship between spinal nerve and bone structures make this method a good choice for preoperative planning of SDR surgery.