Learning curves in minimally invasive esophagectomy

Surgical innovation and pioneering are important for improving patient outcome, but can be associated with learning curves. Although learning curves in surgery are a recognized problem, the impact of surgical learning curves is increasing, due to increasing complexity of innovative surgical procedures, the rapid rate at which new interventions are implemented and a decrease in relative effectiveness of new interventions compared to old interventions. For minimally invasive esophagectomy(MIE), there is now robust evidence that implementation can lead to significant learning associated morbidity(morbidity during a learning curve, that could have been avoided if patients were operated by surgeons that have completed the learning curve). This article provides an overview of the evidence of the impact of learning curves after implementation of MIE. In addition, caveats for implementation and available evidence regarding factors that are important for safe implementation and safe pioneering of MIE are discussed.

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.

3D image system improves the learning curve and contributes to medical education of rhinoplasty

Background: Rhinoplasty is a complex surgical procedure that requires critical analysis and precise design before surgery, making it a challenging operation for both the surgical team and medical educators. This study aimed to evaluate the impact of 3D design involvement on learning curves and to establish a more effective method for rhinoplasty education.Methods: Surgeons who participated in an educational program were divided into two groups. The experimental group was involved in the 3D design before the operation, and the control group was asked to review the rhinoplasty atlas. A self-assessment questionnaire was used to evaluate the learning curve of the eight rhinoplasty procedures for each surgeon, and the overall satisfaction rate data were also collected.Results: The self-assessment scores in both groups showed an increasing trend from the first to the eighth operation. The mean scores of the experimental group were significantly higher than those of the control group at the fifth operation(P=0.01). The satisfaction rate of the experimental group(91.7%) was higher than that of the control group(54.5%).Conclusion: The 3D imaging system can improve the learning curve and satisfaction rate of rhinoplasty education,proving that it is an easy and effective tool for medical education.

Current Status and Perspectives of External Versus Internal Pancreatic Duct Drainage during the Learning Curve of Laparoscopic Pancreaticoduodenectomy

Objectives: To summarize the current status and outlook of pancreatic duct drainage in the learning curve period of laparoscopic pancreaticoduodenectomy (LPD). Methods: By searching the literature related to the efficacy analysis of internal versus external pancreatic duct drainage in pancreaticoduodenectomy (OPD) and the learning curve period of laparoscopic pancreaticoduodenectomy in recent years at home and abroad and making a review. Results: Because of the complexity of the LPD surgical procedure, the high technical requirements and the high complication rate, it is necessary for the operator and his/her team to carry out a certain number of cases to pass through the learning curve in order to have a basic mastery of the procedure. In recent years, more and more pancreatic surgeons have begun to promote and use pancreatic duct drains. However, no consensus conclusion has been reached on whether to choose internal or external drainage for pancreatic duct placement and drainage in LPD. Conclusions: Intraoperative application of pancreatic duct drainage reduces the incidence of pancreatic fistula during the learning curve of laparoscopic pancreaticoduodenectomy. However, external pancreatic duct drainage and internal pancreatic duct drainage have both advantages and disadvantages, so when choosing the drainage method, one should choose the appropriate drainage method in conjunction with one’s own conditions, so as to reduce the incidence of complications.

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.

Learning curves of percutaneous endoscopic lumbar discectomy in transforaminal approach at the L4/5 and L5/S1 levels: a comparative study

Objectives： This study aimed to compare the learning curves of percutaneous endoscopic lumbar discectomy （PELD） in a transforaminal approach at the L4/5 and L5/S1 levels. Methods： We retrospectively reviewed the first 60 cases at the L4/5 level （Group I） and the first 60 cases at the L5/S1 level （Group II） of PELD performed by one spine surgeon. The patients were divided into subgroups A, B, and C （Group I： A cases 1-20, B cases 21-40, C cases 41-60; Group I1： A cases 1-20, B cases 21-40, C cases 41-60）. Operation time was thoroughly analyzed. Results： Compared with the L4/5 level, the learning curve of transforaminal PELD at the L5/S1 level was flatter. The mean operation times of Groups IA, IB, and IC were （88.75±17.02）, （67.75±6.16）, and （64.85±7.82） min, respectively. There was a significant difference between Groups A and B （P〈0.05）, but no significant difference between Groups B and C （P=-0.20）. The mean operation times of Groups IIA, liB, and IIC were （117.25±13.62）, （109.50±11.20）, and （92.15±11.94） rain, respectively. There was no significant difference between Groups A and B （P=0.06）, but there was a significant difference between Groups B and C （P〈0.05）. There were 6 cases of postoperative dysesthesia （POD） in Group I and 2 cases in Group IIA （P=-0.27）. There were 2 cases of residual disc in Group I, and 4 cases in Group II （P=0.67）. There were 3 cases of recurrence in Group I, and 2 cases in Group II （P〉0.05）. Conclusions： Compared with the L5/S1 level, the learning curve of PELD in a transforaminal approach at the L4/5 level was steeper, suggesting that the L4/5 level might be easier to master after short-term professional training.

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.

Learning curve of laparoscopy-assisted distal gastrectomy with systemic lymphadenectomy for early gastric cancer

AIM: To evaluate the nature of the 'learning curve' for laparoscopy-assisted distal gastrectomy (LADG) with systemic lymphadenectomy for early gastric cancer. METHODS: The data of 90 consecutive patients with early gastric cancer who underwent LADG with systemic lymphadenectomy between April 2003 and November 2004 were reviewed. The 90 patients were divided into 9 sequential groups of 10 cases in each group and the average operative time of these 9 groups were determined. Other learning indicators, such as transfusion requirements, conversion rates to open surgery, postoperative complication, time to first flatus, and postoperative hospital stay, were evaluated. RESULTS: After the first 10 LADGs, the operative time reached its first plateau (230-240 min/operation) and then reached a second plateau (＜200 min/operation) for the final 30 cases. Although a significant improvement in the operative time was noted after the first 50 cases, there were no significant differences in transfusion requirements, conversion rates to open surgery, postoperative complications, time to first flatus, or postoperative hospital stay between the groups. CONCLUSION: Based on operative time analysis, this study show that experience of 50 cases of LADG with systemic lymphadenectomy for early gastric cancer is required to achieve optimum proficiency.

The surgical learning curve for robotic-assisted laparoscopic radical prostatectomy： experience of a single surgeon with 500 cases in Taiwan, China

To analyze the learning curve for cancer control from an initial 250 cases （Group I） and subsequent 250 cases （Group II） of robotic-assisted laparoscopic radical prostatectomy （RALP） performed by a single surgeon. Five hundred consecutive patients with clinically localized prostate cancer received RALP and were evaluated. Surgical parameters and perioperative complications were compared between the groups, Positive surgical margin （PSM） and biochemical recurrence （BCR） were assessed as cancer control outcomes. Patients in Group II had significantly more advanced prostate cancer than those in Group I （22.2% vs 14.2%, respectively, with Gleason score 8-10, P = 0.033; 12.8% vs 5.6%, respectively, with clinical stage T3, P = 0.017）. The incidence of PSM in pT3 was decreased significantly from 49% in Group I to 32.6% in Group Ih A meaningful trend was noted for a decreasing PSM rate with each consecutive group of 50 cases, including pT3 and high-risk patients. Neurovascular bundle （NVB） preservation was significantly influenced by the PSM in high-risk patients （84.1% in the preservation group vs 43.9% in the nonpreservation group）. The 3-year, 5-year, and 7-year BCR-free survival rates were 79.2%, 75.3%, and 70.2%, respectively. In conclusion, the incidence of PSM in pT3 was decreased significantly after 250 cases. There was a trend in the surgical learning curve for decreasing PSM with each group of 50 cases. NVB preservation during RALP for the high-risk group is not suggested due to increasing PSM.

Optimal production lot sizing model in a supply chain with periodically fixed demand considering learning effect

This paper presents an optimal production model for manufacturer in a supply chain with a fixed demand at a fixed interval with respect to the learning effect on production capacity. An algorithm is employed to find the optimal delay time for production and production time sequentially. It is found that the optimal delay time for production and the production time are not static, but dynamic and variant with time. It is important for a manufacturer to schedule the production so as to prevent facilities and workers from idling.

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.

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.

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.

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.