Learning curves of robot-assisted pedicle screw fixations based on the cumulative sum test

BACKGROUND In robot-assisted(RA)spine surgery,the relationship between the surgical outcome and the learning curve remains to be evaluated.AIM To analyze the learning curve of RA pedicle screw fixation(PSF)through fitting the operation time curve based on the cumulative summation method.METHODS RA PSFs that were initially completed by two surgeons at the Beijing Jishuitan Hospital from July 2016 to March 2019 were analyzed retrospectively.Based on the cumulative sum of the operation time,the learning curves of the two surgeons were drawn and fit to polynomial curves.The learning curve was divided into the early and late stages according to the shape of the fitted curve.The operation time and screw accuracy were compared between the stages.RESULTS The turning point of the learning curves from Surgeons A and B appeared in the 18th and 17th cases,respectively.The operation time[150(128,188)min vs 120(105,150)min,P=0.002]and the screw accuracy(87.50%vs 96.30%,P=0.026)of RA surgeries performed by Surgeon A were significantly improved after he completed 18 cases.In the case of Surgeon B,the operation time(177.35±28.18 min vs 150.00±34.64 min,P=0.024)was significantly reduced,and the screw accuracy(91.18%vs 96.15%,P=0.475)was slightly improved after the surgeon completed 17 RA surgeries.CONCLUSION After completing 17 to 18 cases of RA PSFs,surgeons can pass the learning phase of RA technology.The operation time is reduced afterward,and the screw accuracy shows a trend of improvement.

Learning curves of resection and reconstruction procedures in robotic-assisted pancreatoduodenectomy by a single surgeon:a retrospective cohort study of 160 consecutive cases

Background:Robotic-assisted pancreatoduodenectomy(RPD)has been routinely performed in a few of centers worldwide.This study aimed to evaluate the perioperative outcomes and the learning curves of resection and reconstruction procedures in RPD by one single surgeon.Methods:Consecutive patients undergoing RPD by a single surgeon at the First Affiliated Hospital of Sun Yat-sen University(Guangzhou,China)between July 2016 and October 2022 were included.The perioperative outcomes and learning curves were retrospectively analysed by using cumulative sum(CUSUM)analyses.Results:One-hundred and sixty patients were included.According to the CUSUM curve,the times of resection and reconstruction procedures were shortened significantly after 30 cases(median,284 vs 195 min;P<0.001)and 45 cases(median,138 vs 120 min;P<0.001),respectively.The estimated intraoperative blood loss(median,100 vs 50 mL;P<0.001)and the incidence of clinically relevant post-operative pancreatic fistula(29.2%vs 12.5%;P=0.035)decreased significantly after 20 and 120 cases,respectively.There were no significant differences in the total number of lymph nodes examined,post-operative major complications,or post-operative length-of-stay between the two groups.Conclusions:Optimization of the resection procedure and the acquisition of visual feedback facilitated the performance of RPD.RPD was a safe and feasible procedure in the selected patients.

Learning-Based Metaheuristic Approach for Home Healthcare Optimization Problem

This research focuses on the home health care optimization problem that involves staff routing and scheduling problems.The considered problem is an extension of multiple travelling salesman problem.It consists of finding the shortest path for a set of caregivers visiting a set of patients at their homes in order to perform various tasks during a given horizon.Thus,a mixed-integer linear programming model is proposed to minimize the overall service time performed by all caregivers while respecting the workload balancing constraint.Nevertheless,when the time horizon become large,practical-sized instances become very difficult to solve in a reasonable computational time.Therefore,a new Learning Genetic Algorithm for mTSP(LGA-mTSP)is proposed to solve the problem.LGA-mTSP is composed of a new genetic algorithm for mTSP,combined with a learning approach,called learning curves.Learning refers to that caregivers’productivity increases as they gain more experience.Learning curves approach is considered as a way to save time and costs.Simulation results show the efficiency of the proposed approach and the impact of learning curve strategy to reduce service times.

A Novel Mixed Precision Distributed TPU GAN for Accelerated Learning Curve

Deep neural networks are gaining importance and popularity in applications and services.Due to the enormous number of learnable parameters and datasets,the training of neural networks is computationally costly.Parallel and distributed computation-based strategies are used to accelerate this training process.Generative Adversarial Networks(GAN)are a recent technological achievement in deep learning.These generative models are computationally expensive because a GAN consists of two neural networks and trains on enormous datasets.Typically,a GAN is trained on a single server.Conventional deep learning accelerator designs are challenged by the unique properties of GAN,like the enormous computation stages with non-traditional convolution layers.This work addresses the issue of distributing GANs so that they can train on datasets distributed over many TPUs(Tensor Processing Unit).Distributed learning training accelerates the learning process and decreases computation time.In this paper,the Generative Adversarial Network is accelerated using the distributed multi-core TPU in distributed data-parallel synchronous model.For adequate acceleration of the GAN network,the data parallel SGD(Stochastic Gradient Descent)model is implemented in multi-core TPU using distributed TensorFlow with mixed precision,bfloat16,and XLA(Accelerated Linear Algebra).The study was conducted on the MNIST dataset for varying batch sizes from 64 to 512 for 30 epochs in distributed SGD in TPU v3 with 128×128 systolic array.An extensive batch technique is implemented in bfloat16 to decrease the storage cost and speed up floating-point computations.The accelerated learning curve for the generator and discriminator network is obtained.The training time was reduced by 79%by varying the batch size from 64 to 512 in multi-core TPU.

Cumulative sum analysis score and phacoemulsification competency learning curve

AIM： To use the cumulative sum analysis score（CUSUM） to construct objectively the learning curve of phacoemulsification competency.METHODS： Three second-year residents and an experienced consultant were monitored for a series of 70 phacoemulsification cases each and had their series analysed by CUSUM regarding posterior capsule rupture（PCR） and best-corrected visual acuity. The acceptable rate for PCR was 〈5%（lower limit h） and the unacceptable rate was 〉10%（upper limit h）. The acceptable rate for bestcorrected visual acuity worse than 20/40 was 〈10%（lower limit h） and the unacceptable rate was 〉20%（upper limit h）. The area between lower limit h and upper limit h is called the decision interval. RESULTS： There was no statistically significant difference in the mean age, sex or cataract grades between groups. The first trainee achieved PCR CUSUM competency at his 22 nd case. His best-corrected visual acuity CUSUM was in the decision interval from his third case and stayed there until the end, never reaching competency. The second trainee achieved PCR CUSUM competency at his 39^ th case. He could reach best-corrected visual acuity CUSUM competency at his 22 ^nd case. The third trainee achieved PCR CUSUM competency at his 41 st case. He reached bestcorrected visual acuity CUSUM competency at his 14 ^th case.CONCLUSION： The learning curve of competency in phacoemulsification is constructed by CUSUM and in average took 38 cases for each trainee to achieve it.

Does robot-assisted laparoscopic radical prostatectomy enable to obtain adequate oncological and functional outcomes during the learning curve?From the Korean experience

To estimate the short-term results of robot-assisted laparoscopic radical prostatectomy(RALRP)during the learning curve,in terms of surgical,oncological and functional outcomes,we conducted a prospective survey on RALRP.From July 2007,a single surgeon performed 63 robotic prostatectomies using the same operative technique.Perioperative data,including pathological and early functional results of the patient,were collected prospectively and analyzed.Along with the accumulation of the cases,the total operative time,setup time,console time and blood loss were significantly decreased.No major complication was present in any patient.Transfusion was needed in six patients;all of them were within the initial 15 cases.The positive surgical margin rate was 9.8%(5/51)in pT2 disease.The most frequent location of positive margin in this stage was the lateral aspect(60%),but in pT3 disease multiple margins were the most frequent(41.7%).Overall,53(84.1%)patients had totally continent status and the median time to continence was 6.56 weeks.Among 17 patients who maintained preoperative sexual activity(Sexual Health Inventory for Men≥17),stage below pT2,followed up for>6 months with minimally one side of neurovascular bundle preservation procedure,12(70.6%)were capable of intercourse postoperatively,and the mean time for sexual intercourse after operation was 5.7 months.In this series,robotic prostatectomy was a feasible and reproducible technique,with a short learning curve and low perioperative complication rate.Even during the initial phase of the learning curve,satisfactory results were obtained with regard to functional and oncological outcome.

Addressing the MSICS learning curve: identification of instrument-holding techniques used by experienced surgeons

AIM: To identify instrument holding archetypes used by experienced surgeons in order to develop a universal language and set of validated techniques that can be utilized in manual small incision cataract surgery(MSICS) curricula. METHODS: Experienced cataract surgeons performed five MSICS steps(scleral incision, scleral tunnel, side port, corneal tunnel, and capsulorhexis) in a wet lab to record surgeon hand positions. Images and videos were taken during each step to identify validated hand position archetypes.RESULTS: For each MSICS step, one or two major archetypes and key modifying variables were observed, including tripod for scleral incision, tripod-thumb bottom for scleral tunnel, underhand-index to thumb grip for side port, index-contact tripod for corneal entry, and tripodforceps for capsulorhexis. Key differences were noted in thumb placement and number of fingers supporting the instrument, and modifying variables included index finger curvature and amount of flexion.CONCLUSION: Identification of optimal hand positions and development of a formal nomenclature has the potential to help trainees adopt hand positions in an informed manner, influence instrument design, and improve surgical outcomes.

Learning curve for a surgeon in robotic pancreaticoduodenectomy through a“G”-shaped approach:A cumulative sum analysis

BACKGROUND Robotic pancreaticoduodenectomy(RPD)can achieve similar surgical results to open and PD;however,RPD has a long learning curve and operation time(OT).To address this issue,we have summarized a surgical path to shorten the surgical learning curve and OT.AIM To investigate the effective learning curve of a“G”-shaped surgical approach in RPD for patients.METHODS A total of 60 patients,who received“G”-shaped RPD(GRPD)by a single surgeon in the First Hospital of Shanxi Medical University from May 2017 to April 2020,were included in this study.The OT,demographic data,intraoperative blood loss,complications,hospitalization time,and pathological results were recorded,and the cumulative sum(CUSUM)analysis was performed to evaluate the learning curve for GRPD.RESULTS According to the CUSUM analysis,the learning curve for GRPD was grouped into two phases:The early and late phases.The OT was 480±81.65 min vs 331±76.54 min,hospitalization time was 22±4.53 d vs 17±6.08 d,and blood loss was 308±54.78 mL vs 169.2±35.33 mL in the respective groups.Complications,including pancreatic fistula,bile leakage,reoperation rate,postoperative death,and delayed gastric emptying,were significantly decreased after this surgical technique.CONCLUSION GRPD can improve the learning curve and operative time,providing a new method for shortening the RPD learning curve.

Evaluation of the learning curve of laser peripheral iridectomy:the 20^(th)case reaches the turning point

AIM:To explore the learning curve for ophthalmologists at the start of laser peripheral iridectomy(LPI)training.METHODS:The learning curve of 4 doctor groups without previous LPI experience was studied.Three main parameters of LPI were reviewed:total energy,argon energy and neodymium-doped yttrium aluminum garnet(Nd:YAG)energy.Procedures were evaluated in cohorts of 20 cases to identify the turning points of the three variables.RESULTS:There was no significant difference in terms of age or eye among the 4 doctor groups.There were stable trends on the learning curve for the Doctor A and C groups regarding total energy and argon energy.In addition,the turning points on the learning curve were determined after the 20th procedure for the Doctor B and D groups regarding total energy and argon energy.Moreover,the Nd:YAG energy was relatively stable since the first procedure.CONCLUSION:It requires approximately 20 procedures for a beginner to reach a turning point on the learning curve regarding LPI.It can serve as a point of reference or guideline for training beginners to perform LPI.

Impact of learning through credit and value creation on the efficiency of Japanese commercial banks

This study investigates the learning curve of commercial banks regarding the efficiency of credit and value creation.However,current empirical methods for accessing the learning curve in organizations are not suitable for use in financial institutions.Considering bank-specific characteristics,we introduce a dynamic learning curve using a cost function adjusted to capture learning-by-doing in banks.Using the model,we test several hypotheses on the impact of bank intermediary experience(learning)on the efficiency of credit and value creation in Japanese commercial banks.The findings show that bank intermediary learning significantly improves the cost efficiency gain in the gross value created,total credit created,and investment.However,bank intermediary experience has no significant effect on the efficiency of the economic value created for all the banks analyzed.These findings have practical implications for evaluating cost dynamics in bank credit and value creation,risk management,lending to the real sector,and shareholder value creation.

Adaptive Error Curve Learning Ensemble Model for Improving Energy Consumption Forecasting

Despite the advancement within the last decades in the field of smart grids,energy consumption forecasting utilizing the metrological features is still challenging.This paper proposes a genetic algorithm-based adaptive error curve learning ensemble(GA-ECLE)model.The proposed technique copes with the stochastic variations of improving energy consumption forecasting using a machine learning-based ensembled approach.A modified ensemble model based on a utilizing error of model as a feature is used to improve the forecast accuracy.This approach combines three models,namely CatBoost(CB),Gradient Boost(GB),and Multilayer Perceptron(MLP).The ensembled CB-GB-MLP model’s inner mechanism consists of generating a meta-data from Gradient Boosting and CatBoost models to compute the final predictions using the Multilayer Perceptron network.A genetic algorithm is used to obtain the optimal features to be used for the model.To prove the proposed model’s effectiveness,we have used a four-phase technique using Jeju island’s real energy consumption data.In the first phase,we have obtained the results by applying the CB-GB-MLP model.In the second phase,we have utilized a GA-ensembled model with optimal features.The third phase is for the comparison of the energy forecasting result with the proposed ECL-based model.The fourth stage is the final stage,where we have applied the GA-ECLE model.We obtained a mean absolute error of 3.05,and a root mean square error of 5.05.Extensive experimental results are provided,demonstrating the superiority of the proposed GA-ECLE model over traditional ensemble models.

Minimally invasive colorectal surgery learning curve

The learning curve in minimally invasive colorectal surgery is a constant subject of discussion in the literature.Discordant data likely reflects the varying degrees of each surgeon’s experience in colorectal,laparoscopic or robotic surgery.Several factors are necessary for a successful minimally invasive colorectal surgery training program,including:Compliance with oncological outcomes;dissection along the embryological planes;constant presence of an expert tutor;periodic discussion of the morbidity and mortality rate;and creation of a dedicated,expert team.

Role of robotic assistance in the learning of laparoscopy:Comparison of novice students’results in two FLS trials

Background: To investigate the learning curve of “robotic surgery” versus “conventional laparoscopy” in two trials of the FLS program in a population of medical students with no experience in laparoscopy. Methods: A prospective trial. Students, all novices in training and surgical practice, were randomized into 2 groups: the “traditional laparoscopy” group and the “robotic assistance” group. Students were evaluated during two tests from the FLS: peg transfer and intracorporeal knot tying. Results: The median laparoscopic knot completion time was significantly lower in the “robotic surgery” group (p = 0.038). Conclusions: Robotic assistance training in neophytes is effective in improving the completion time of laparoscopic knots.

Cost projections for microwave plasma CO production using renewable energy

Successful deployment of renewable fuel production requires substantial cost reduction along the entire value chain of the underlying manufacturing routes.To improve their performance,renewable fuel production technologies should follow a cost-reducing learning curve.In this article,we adopt recent evidence that learning-by-doing is directly influenced by the technology unit size and explore three scenarios for microwave plasma CO_(2)conversion in which the learning rate varies between 10%,15%,and 20%.Our projections reveal that the total investments required to deploy this CO_(2)conversion technology at an exajoule scale decline from 83 down to 23 billion euros under a 10%increase in the value of the learning rate.The CO_(2) production costs in 2050 amount to 247–346€(2019)/t CO_(2),in which the range is determined by the value of the learning rate.Even under substantial learning until 2050 the levelized CO production cost is unlikely to become competitive with conventional natural gas-based CO_(2) production processes,except when a CO_(2)tax is applied of up to 150€(2019)/t CO_(2).To optimally exploit effects of learning-by-doing,we recommend developing several CO production technologies simultaneously with multiple unit sizes,so as to improve the chance of ultimately selecting the process with the highest learning rate.

Experience of one single surgeon with the first 500 robot-assisted laparoscopic prostatectomy cases in China's Mainland

Objectives: To summarize the experience of the first 500 robot-assisted laparoscopicradical prostatectomy (RALP) cases by one surgeon and analyze the influencing factorsof functional and oncological outcomes.Methods: Between April 2012 and October 2017, 500 patients who underwent RALP wereincluded and divided sequentially into five equal groups. Patients’ preoperative, perioperativeand postoperative outcomes were analyzed and evaluated, and the Kruskal-Wallis test wasused to analyze and compare the effect of surgeon experience by case.Results: There is a statistically significant reduction in operative time, intraoperative estimatedblood loss and postoperative hospital stay time (all p<0.001) with the increased experience.The results show that experience was the most important influencing factor in bothoperative time and blood loss. Pelvic lymph node dissection (PLND) might increase the operativetime. The total positive surgical margin (PSM) rate was 21.8%. The PSM rate in pT3 tumorswas significantly higher than that in pT2 tumors (12.0% vs. 37.1%, p<0.001). The 5-yearbiochemical recurrence (BCR)-free rate was 70.8%. The results of Cox regression showed thatpreoperative prostate-specific antigen (PSA), postoperative Gleason score (GS), and pathologicT stage were independent risk factors for BCR.Conclusion: After approximately 200 cases, the surgeon reached a plateau for RALP, but theoutcomes could still improve after more cases. The surgeon’s experience was the most importantinfluencing factor for both operative time and blood loss. PSM rate was mainly determinedby tumor stage rather than by operation experience.

Impact of Coronary Artery Anatomy in Arterial Switch Operation:In-hospital and Post-discharge Outcomes

Objective The influence of the coronary artery anatomy on the prognosis of patients receiving an arterial switch operation(ASO)is currently controversial,and the risk factors for this operation may change in more complicated patients.This study aimed to investigate the influence of coronary artery anomalies on the in-hospital and post-discharge outcomes of ASO in patients with transposition of the great arteries(TGA)and Taussig-Bing anomaly(TBA).Methods We retrospectively reviewed 206 patients who underwent ASO from January 2007 to December 2019.The median age at operation was 33[interquartile range(IQR):20–71]days.Median follow-up time was 7.2 years(IQR:4.0–10.3 years).Results Coronary anomalies were present in 86 patients(41.7%),with 9(4.4%)of them having a single coronary artery.Additional coronary features included intramural courses in 5(2.4%)patients,ostial stenosis in 1(0.5%)patient,and accessory coronary artery orifices in 5(2.4%)patients.There were 32(15.5%)in-hospital deaths and 8(4.6%)post-discharge deaths,yielding an overall survival of 81.3%,80.7%and 79.9%at 1,5 and 10 years,respectively.Mortality due to ASO has been drastically decreased since 2013.Patients with a single coronary artery had higher rate of in-hospital mortality,but this finding was not statistically significant.The earlier surgical era(OR:2.756)and a longer cardiopulmonary bypass time(OR:2.336)were significantly associated with in-hospital mortality,while coronary patterns were not.An intramural coronary artery(HR:10.034)and a patient age of older than 1 year at the time of ASO(HR:9.706)were independent predictors of post-discharge mortality.Conclusion ASO remains the procedure of choice for TGA with coronary anomalies with acceptable in-hospital and post-discharge outcomes in terms of overall survival and freedom of reoperation.However,intramural coronary artery is an independent risk factor for post-discharge mortality.Timely surgery within the 1st year of life helps improve overall midterm survival of ASO.

The assessment of endosonographers in training

Endosonography(EUS) has an estimated long learning curve including the acquisition of both technical and cognitive skills. Trainees in EUS must learn to master intraprocedural steps such as echoendoscope handling and ultrasonographic imaging with the interpretation of normal anatomy and any pathology. In addition, there is a need to understand the periprocedural parts of the EUS-examination such as the indications and contraindications for EUS and potential adverse events that could occur post-EUS. However, the learning process and progress vary widely among endosonographers in training. Consequently, the performance of a certain number of supervised procedures during training does not automatically guarantee adequate competence in EUS. Instead, the assessment of EUScompetence should preferably be performed by the use of an assessment tool developed specifically for the evaluation of endosonographers in training. Such a tool, covering all the different steps of the EUSprocedure, would better depict the individual learning curve and better reflect the true competence of each trainee. This mini-review will address the issue of clinical education in EUS with respect to the evaluation of endosonographers in training. The aim of the article is to provide an informative overview of the topic. The relevant literature of the field will be reviewed and discussed. The current knowledge on how to assess the skills and competence of endosonographers in training is presented in detail.

Impact of surgical volume and resident involvement on patency rates after vasectomy reversaldA 14-year experience in an open access system

Objective:Evaluate the influence of fellowship training,resident participation,reconstruction type,and patient factors on outcomes after vasectomy reversals in a high volume,open access system.Methods:Retrospective review of all vasectomy reversals performed at a single institution from January 1,2002 to December 31,2016 was conducted.Patient and spouse demographics,patient tobacco use and comorbidities,surgeon training and case volume,resident participation,reconstruction type,and postoperative patency were collected and analyzed.Results:Five hundred and twenty-six vasectomy reversals were performed during the study period.Follow-up was available in 80.6%of the cohort and overall patency,regardless of reconstruction type was 88.7%.The mean time to reversal was 7.87 years(range of 0-34 years).The majority of cases included resident participation.Case volume was high with faculty and residents logging a mean of 37.0 and 38.7(median 18 and 37)cases respectively.Bilateral vasovasostomy was the most common reconstruction type(83%)and demonstrated a significantly better patency rate(89%)than all other reconstructions(p=0.0008).Overall patency and patency by reconstruction type were not statistically different among faculty surgeons and were not impacted by fertility fellowship training,resident participation or postgraduate year.Multivariate analysis demonstrated that increased time to reversal and repeat reconstructions had a negative impact on patency(p=0.0023 and p=0.043,respectively).Conclusions:Surgeons with a high volume of vasectomy reversals have outcomes consistent with contemporary series regardless of fellowship training in fertility.Patency was better for bilateral vasovasostomies.Patency was not negatively impacted by tobacco use,comorbidities,resident participation,or post-graduate year.

Four-year experience with more than 1000 cases of total laparoscopic liver resection in a single center

BACKGROUND Laparoscopic liver resection(LLR)has become a safe surgical procedure that needs additional summarization.AIM To review 4 years of total LLR surgeries,exceeding 1000 cases,which were performed at a single center.METHODS Patients who underwent LLR at West China Hospital of Sichuan University between January 2015 and December 2018 were identified.Surgical details,including the interventional year,category of liver disease,and malignant liver tumors prognosis,were evaluated.The learning curve for LLR was evaluated using the cumulative sum method.The Kaplan-Meier method was used to perform survival analysis.RESULTS Ultimately,1098 patients were identified.Hepatocellular carcinoma(HCC)was the most common disease that led to the need for LLR at the center(n=462,42.08%).The average operation time was 216.94±98.51 min.The conversion rate was 1.82%(20/1098).The complication rate was 9.20%(from grade II to V).The 1-year and 3-year overall survival rates of HCC patients were 89.7%and 81.9%,respectively.The learning curve was grouped into two phases for local resection(cases 1-106 and 107-373),three phases for anatomical segmentectomy(cases 1-44,45-74 and 75-120),and three phases for hemihepatectomy(cases 1-17,18-48 and CONCLUSION LLR may be considered a first-line surgical intervention for liver resection that can be performed safely for a variety of primary,secondary,and recurrent liver tumors and for benign diseases once technical competence is proficiently attained.

Combining robot-assisted surgical system and 3D visualization system for teaching minimally invasive vitreoretinal surgery

AIM:To investigate the feasibility of teaching minimally invasive vitreoretinal surgery with a robot-assisted surgical system and a three-dimensional(3D) visualization system.METHODS:Enucleated porcine eyes were established as an animal model for removing foreign bodies.Forty medical students were recruited to remove foreign bodies to compare the traditional microscope and the 3D system.One junior resident performed the surgical task with manual and robot-assisted operations on 20 porcine eyes for each group.One senior surgeon evaluated the retinal invasion by a graded injury degree.The learning curve for minimally invasive vitreoretinal surgery was described.RESULTS:Compared with the robot-assisted group,the injury degree was higher in the manual group.For the first ten surgeries,the manual and robot-assisted groups had injuries of 2.60±1.35(4 to 0) and 1.80±1.62(4 to 0),respectively.For the last ten surgeries,the injury degrees were 1.90±1.20(3 to 0) and 0.80±0.42(1 to 0).Considering the manual and robot-assisted groups together,95%,75% and 60% of the students considered surgical manipulation with the 3D visualization system to be more comfortable,easier and clearer,respectively.CONCLUSION:The robot-assisted surgical system and 3D visualization system may have value in teaching minimally invasive vitreoretinal surgery.