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Summary Background Pediatric thoracoscopic lobectomy is a technically challenging procedure that may result in better pain control, better cosmetic results, and shorter hospital stay. However, data describing the learning curve of total thoracoscopic lobectomy (TTL) have yet to be obtained. To evaluate our learning curve for TTL in children, we reviewed the safety and efficiency of our initial experiences with TTL in pediatric patients with congenital lung malformation. Methods This was a retrospective study of all pediatric patients undergoing TTL between March 2011 and January 2017. Cumulative summation (CUSUM) analysis of operative time (OT) was used. Results One hundred patients were retrospectively analyzed and chronologically divided into three phases: the ascending (A), plateau (B), and descending (C) phases of CUSUM of OT. Phases A, B, and C comprised 35, 22, and 43 cases, respectively. OT decreased significantly from phases A to B (P = 0.035) and B to C (P = 0.019). Age and weight of patients both reduced significantly from phase A to B (p = 0.017 and p = 0.012, respectively), while the two measures did not vary from phase B to C (p = 0.987 and p = 0.874, respectively). Chest tube duration and length of hospital stay had similar trend. All complications occurred in five cases in phase A (5/35). Six cases were converted to open surgery (6%). Four conversions occurred within phase A and two in phase C (4/35 vs 2/43, p = 0.490). There were no mortalities. Conclusions Repeated standardized training plays a role in overcoming the learning curve for thoracoscopic lobectomy in children, and CUSUMOT indicates that a learning curve of approximately 57 cases is required in our institute.

Objectives To define the learning process of minimally invasive repair of pectus excavatum by the Nuss procedure through assessment of consecutive procedural metrics. Methods A single-center retrospective observational cohort study was conducted of all consecutive Nuss procedures performed by individual surgeons without previous experience between June 2006 and December 2018. Surgeons were proctored during their initial 10 procedures. The learning process after the proctoring period was evaluated using nonrisk-adjusted cumulative sum (ie, observed minus expected) failure charts of complications. An acceptable and unacceptable complication rate of 10% and 20% were used. Logarithmic trend lines were used to assess over-time performance regarding operation time. Results Two-hundred twenty-two consecutive Nuss procedures by 3 general thoracic surgeons were evaluated. Cumulative sum charts showed an average performance from the first procedure after being proctored onward for all surgeons, whereas surgeon B demonstrated a statistically significant complication rate equal to or less than 10% after 59 cases. Post-hoc sensitivity analyses using a stricter acceptable and unacceptable complication rate of 6% and 12% also showed an average performance for all surgeons. Although, the median time between consecutive procedures ranged from 7 to 35 days, no frequency–outcome relationship was observed. In addition, surgeons required the same average operation time throughout their entire experience. Conclusions After a 10-procedure proctoring period, repair of pectus excavatum by the Nuss procedure is a safe procedure to adopt and perform without a typical (complication based) learning curve while performing at least 1 procedure per 35 days.

Introduction: There are limited numbers of high-volume centers performing minimally invasive pancreatoduodenectomy (MIPD) routinely. Several approaches to MIPD have been described. Aim of this analysis was to show the learning curve of three different approaches to MIPD. Focus was on determining the number of cases necessary to obtain proficient level in MIPD. Patients and methods: Retrospective study wherein outcomes of 300 consecutive patients at three centers—at each center the initial 100 consecutive patients undergoing MIPD for malignant and benign tumors of the head of the pancreas and perimpullary area, performed by three experienced surgeons were collected and analyzed. Results: Overall, 300 patients after MIPD were included: the three different cohorts (laparoscopic n = 100, hybrid n = 100, robotic n = 100). CUSUM analysis of operating time in each center demonstrated that the plateau for laparoscopic PD was n = 61, for hybrid PDes was n = 32 and for robotic PD was n = 68. Median operative time for laparoscopic, hybrid, and robotic approaches was 395 min, 404 min, 510 min, respectively. Intraoperative blood loss for laparoscopic PD, hybrid PD, and robotic PD was 250 ml, 250 ml, and 413 ml, respectively. Delayed gastric emptying occurred 12% in laparoscopic cohort, 10% in hybrid, and 53% in robotic cohort. Major complications (Clavien-Dindo III/IV) rate for laparoscopic PD, hybrid PD, and robotic PD was 32%, 37%, and 22% with 5% death in each cohorts, respectively. Conclusion: This analysis of the learning curve of three European centers found a shorter learning curve with hybrid PD as compared to laparoscopic and robotic PD. In implementation of a MIPD program, a stepwise approach might be beneficial.

Summary Aim of the study To analyze the collective learning curve in the performance of safe liver resections, using the decrease of severe postoperative complications (SPC) as a proxy for overall safety competency. Material and Methods This was a retrospective analysis of a prospective database in the setting of a liver surgery program implementation in a tertiary center in Morocco. The 100 first consecutive cases of elective liver resections starting from January 1st, 2018 were included in the analysis. SPC were defined as CD > IIIa during the first 90 postoperative days. We used a cumulative sum (CUSUM) technique to determine the number of cases required to achieve safety competency. We then compared case characteristics before and after the learning curve completion. Results SPC occurred in 15 cases (15%), including 5 deaths (5%). The CUSUM chart revealed a learning curve completion at the 49th case, marked by an inflection point towards the decrease in SPC (24.5% vs 5.9%; P = 0.009). In period 2 (after), cases were associated with less diabetes, less synchronous digestive resection, more cirrhosis, and more prolonged preoperative chemotherapy. The rates of major resection (30.6% vs 29.9%; P = 0.89) and biliary reconstruction were comparable, as were the operating time, and estimated blood loss. Conclusion Approximately 50 cases were required to complete the learning curve and improve the overall safety of liver resection. In our setting, the learning curve chronology was consistent with collective measures, including team stabilization and protocol development.

Background Video-assisted thoracoscopic sympathectomy (VATS) is a common procedure unusually practiced by neurosurgeons due to lack of training. Objective To evaluate the learning curve for VATS in a young neurosurgeon with no previous experience in open sympathectomy techniques or extracranial endoscopic procedures. Methods This is a retrospective review and analysis of prospectively collected data in 50 consecutive cases admitted to our facility with the diagnosis of essential palmar and axillary hyperhidrosis operated by a neurosurgical trainee under strict supervision of 2 experienced mentors. After an initial training phase, cumulative sum mation (CUSUM) analysis was used to evaluate the surgical performance of the trainee in terms of operating time, blood loss, hospital stay and failures. Results Improvement in operating time was noticed after the first 20 cases with significant affection by changes in OR team. The blood loss was significantly improved after the first 10 cases with less sensitivity to changes in OR team. Hospital stay and failures were steady and within expected values throughout the study. Conclusion An average of 20 cases may be enough for a neurosurgeon with basal knowledge to attain technical competence in VATS sympathectomy. Mentored surgical training on VATS sympathectomy is a safe and effective training method with failures within expected limits. The experience of the OR team plays an important role in the rapid improvement and consistency of performance.

Background and study aims Transoral incisionless fundoplication (TIF) is a safe and effective minimally invasive endoscopic technique for treating gastroesophageal reflux disease (GERD). The learning curve for this technique has not been reported. We studied the learning curve for TIF when performed by a gastroenterologist by identifying the threshold number of procedures needed to achieve consistent technical success or proficiency (consistent creation of TIF valve ≥ 270 degrees in circumference, ≥ 2 cm long) and efficiency after didactic, hands-on and case observation experience. Patients and methods We analyzed prospectively collected data from patients who had TIF performed by a single therapeutic endoscopist within 17 months after basic training. We determined thresholds for procedural learning using cumulative sum of means (CUSUM) analysis to detect changes in achievement rates over time. We used breakpoint analysis to calculate procedure metrics related to proficiency and efficiency. Results A total of 69 patients had 72 TIFs. The most common indications were refractory GERD (44.7 %) and proton pump inhbitor intolerance (23.6 %). Proficiency was achieved at the 18th to 20th procedure. The maximum efficiency for performing a plication was achieved after the 26th procedure, when mean time per plication decreased to 2.7 from 5.1 minutes (P Conclusions TIF can be safely, successfully, and efficiently performed in the endoscopy suite by a therapeutic endoscopist. The TIF learning curve is steep but proficiency can be achieved after a basic training experience and 18 to 20 independently performed procedures.

In this study, we consider the problem of detecting a change point in the conditional quantile of GARCH models. The task is essential in risk management as the conditional quantile is utilized to calculate the value-at-risk (VaR) of asset prices. We propose the cumulative sum (CUSUM) tests based on the residuals and derive their limiting distributions under mild conditions. We also demonstrate the validity of the tests by conducting Monte Carlo simulations, followed by a real data analysis of the exchange rate between the US Dollar and Korean Won and the Korea composite stock price index.

Purpose: Even though it is stated that external levator advancement (ELA) has a much longer learning curve than Müller muscle-conjunctival resection (MMCR) in the treatment of aponeurotic ptosis, there is no study in the literature regarding the learning curves of these two surgical techniques. We aimed to objectively determine the length of the learning curves of ELA and MMCR using cumulative sum (CUSUM) analysis.Methods: The first 30 unilateral ELA and the first 30 unilateral MMCR consecutively performed by a single surgeon were retrospectively reviewed. The CUSUM method was used to analyze the learning curves of ELA and MMCR based on operation times of consecutive surgeries and the clinical outcomes were compared.Results: CUSUM analyses revealed that the operation time stabilized after around 11 ELA surgeries and 12 MMCR surgeries and R2 value for ELA and MMCR were 0.93 and 0.91, respectively. There was no significant difference in these stratified analyses. Mean operation time was 45.7 minutes in the ELA group and 34.1 minutes in the MMCR group (p = 0.002). Total number of intraoperative complications was 37 in the ELA group and 16 in the MMCR group (p = 0.015). Symmetry success rate was significantly higher (p < 0.0001) and reoperation rate was significantly lower in the MMCR group (p = 0.045).Conclusions: Even though ELA is more challenging than MMCR, comparable learning curves indicate that surgeons in training need to be encouraged to perform both techniques. The challenges and obstacles that the surgeons in training face in these two techniques need to be analyzed in detail.

Objectives To evaluate the time course and caseload required to achieve proficiency by plotting the learning curve of video-assisted thoracoscopic sleeve lobectomy. Methods We reviewed 127 cases of video-assisted thoracoscopic sleeve lobectomy by a single surgeon at Shanghai Pulmonary Hospital to evaluate its learning curve using the cumulative sum (CUSUM) analysis. The changes of perioperative outcomes were assessed. Results The inflection points of the CUSUM curve were around case 30 and 90, according to which 3 phases were identified: Phase I, Phase II, and Phase III. Significant downtrends were observed regarding operative time (Phase I, 194 [173-233 minutes] vs Phase II, 172 [142-215 minutes] vs Phase III, 138 [117-164 minutes], P, Graphical abstract 30 cases are needed to lay the technical foundation and 90 cases are required to achieve proficiency. Significant improvements concerning the perioperative outcomes were observed as the learning curve developed. CUSUM, Cumulative sum; OT, operative time.

Background/Aims: Peroral endoscopic myotomy (POEM) has been increasingly used for achalasia in Latin America, where Chagas disease is prevalent, and this makes POEM more challenging. The aim of this study was to determine the learning curve for POEM in Latin America.Methods: Patients undergoing POEM in Latin America with a single operator were included from a prospective registry over 4 years. Non-linear regression and cumulative sum control chart (CUSUM) analyses were conducted for the learning curve.Results: A total of 125 patients were included (52% male; mean age, 59 years), of which 80 had type II achalasia (64%), and 38 had Chagas disease (30%). The average pre-procedure and post-procedure Eckardt scores were 6.79 and 1.87, respectively. Technical success was achieved in 93.5% of patients, and clinical success was achieved in 88.8%. Adverse events occurred in 27 patients (22%) and included bleeding (4 patients), pneumothorax (4 patients), mucosal perforation (13 patients), mediastinitis (2 patients), and leakage (4 patients). The CUSUM chart showed a median procedure time of 97 min (range, 45-196 min), which was achieved at the 61st procedure. Procedure duration progressively decreased, with the last 10 procedures under 50 min approaching a plateau (p-value

Single-port (SP) was recently implemented as an alternative robotic system for extraperitoneal radical prostatectomy (EPP). The primary aim of this study is to characterize the learning curve (LC) for the SP-EPP for an experienced multi-port (MP) robotic surgeon. All consecutive SP-EPP cases (N=150) performed by a single surgeon from initial experience in a high-volume tertiary care center were prospectively included. The cumulative sum Method (CUSUM) was used retrospectively to create the LCs for SP-EPP surgery based on several outcomes used to gauge the surgeon's performance relative to those previously obtained with the current gold standard (MP-Robot Assisted Radical Prostatectomy (MP-RALP);N=80). The evaluation of a surgical transition from MP to SP prostatectomy analyzed with the Statistical Process Control and the CUSUM method revealed a smooth and safe LC divided into four phases of 30-40 cases and a decrease of surgical time, blood loss and postoperative complication rate after the first learning phase.

A key toward intelligent decision-making in industries lies in the ability to process and analyze vast quantities of business data. Concept drift and class imbalance are co-existing problems in real-life data sets, and the telecommunication sector is no exception. It has been discovered only recently that the problems of concept drift and class imbalance, which were thought to be totally independent, are correlated in many ways and they have adverse effects on each other. Cumulative Sum Detection Method (CusumDM), a simple and efficient method based on Cumulative Sum Charts, handles the problem of concept drift efficiently. However, the presence of class imbalance causes a decline in its performance. To facilitate intelligent customer churn prediction, this article proposes optimized two-sided Cusum churn detector (OTCCD), which is a significant improvement of CusumDM that handles the problems of class imbalance and concept drift by determining error rate of sliding windows alongside. This approach has been applied to the Call Detail Record (CDR) of a South Asian Telecom Company for churn prediction. Handling telecom data requires high-performance computing power and resource-aware intelligent methods due to the velocity and speed of the data. Presence of an extremely low number of churners creates class imbalance problems in CDR and abruptly, or gradually changing data distribution makes the churn data a rich source to target these problems. Prediction accuracy and mean evaluation time were the basis for verification of classification results, showing that OTCCD outperformed its antecedents CusumDM, Ensemble Drift Detection Method (Ensemble) and Adaptive Windowing (ADWIN) Change Detector by producing better accuracy.

The study compared a novel imageless robotic-assisted total knee arthroplasty (RATKA) and conventional TKA by considering (1) radiological outcomes, (2) outliers of radiological outcomes, and (3) learning curve. This prospective randomized controlled study performed by a single surgeon evaluated 152 patients (152 knees): 75 patients undergoing RATKA and 77 patients undergoing conventional TKA. Mechanical alignment, radiological implant positioning, and outliers were analyzed for radiological outcomes. Cumulative summation (CUSUM) analysis was used to assess the learning curve for operative time in RATKA. The RATKA had significantly better accuracy of knee alignment and component positioning than conventional TKA. The hip-knee-ankle axis and implant position outliers were significantly lower in the RATKA, with 94.7% of patients had achieved an overall mechanical alignment within 3° of a neutral mechanical axis. Changes in posterior condylar offset and joint line were significantly lower in the RATKA. A learning curve of seven cases for operative time was obtained for the RATKA. The imageless RATKA has better alignment accuracy with a short learning curve; thus, it presents an attractive option for TKA.

In the context of big data, multivariate processes must often be monitored in a timely and accurate manner. Usually, the distribution of process variables is unknown. This paper proposes a new stra...

Background Robotic gastrectomy (RG) for gastric cancer (GC) has gradually gained nationwide prominence following 2011 guidelines from the Japan Society for Endoscopic Surgery (JSES), including the surgeons' criteria and the proctor system. In this retrospective study, we examined the short-term outcomes of the initial series of RGs performed by second-generation operating surgeons trained within our institute. Methods Between January 2017 and April 2020, five surgeons each performed RG in 20 patients with clinical stage III or lower GC in accordance with the JSES guidelines. We evaluated both the rate of Clavien-Dindo grade II or higher morbidities and the console time required to reach the learning plateau via cumulative summation (CUSUM) analysis. Results We observed no mortality and 3% of morbidity following RG. Both the operative time (430 vs 387.5 min, P = 0.019) and console time (380 vs . 331.5 min, P = 0.009) were significantly shorter in the second 10 cases than in the initial 10 cases. We observed a remarkable trend in cases of distal gastrectomy (DG), in which the total operative time and console time were significantly shorter in the later cases. Our CUSUM analysis revealed that seven cases were required to achieve a learning plateau in RG when confined to DG. Conclusions Non-expert RG surgeons meeting the operating surgeon's criteria from the JSES who had trained under an expert RG surgeon safely performed RG in an initial 20 cases.

Background The electromagnetic navigation bronchoscopy (ENB) was increasingly used to mark small pulmonary nodules (PNs) for video-assisted thoracic surgery (VATS) resection due to high effectiveness and low risk. However, no study reports the learning curve of ENB-guided preoperative localization. In the study, we aimed to describe the learning curve of ENB-guided preoperative PNs localization initially. Methods Consecutive PNs cases that underwent ENB localizations between October 2018 and October 2019 by the same surgeon in our center were included in the study. The cumulative sum (CUSUM) method was used to analyze the learning curve of ENB localization. Results A total of 89 ENB localization from 64 patients were included in this study. The learning curve was divided into 3 phases: Phase I (the initial 11 cases), Phase II (the 12th to the 47th cases), and Phase III (the 47th to the 89th cases). The success rate of ENB localization has increased with the accumulation of operational experience in 3 phases (72.73%, 91.67%, and 97.62%, P=0.049). The distance from the ENB guide wire tip to the center of the lesion in Phase I was significantly longer than those in Phase II and Phase III (2.46±1.76 vs. 1.36±0.94 and 1.47±0.97 cm, P=0.014 and 0.027, respectively). Sex, bronchus sign, and learning curve phase were independent risk factors influencing operative time (OT) (OR =8.187, 18.847, and 13.920, respectively). Conclusions The technical competency, which is indicated by higher success rate, localization accuracy, and shorter OT, for ENB-guided preoperative PNs localization was achieved at the 47th operation.

Introduction Robotic-assisted surgery techniques are increasing in total knee arthroplasty (TKA). One crucial point is the prolonged time of surgery. The primary objective of this study was to determine the learning curve necessary to minimize the time of surgery. The secondary objective was to evaluate the accuracy of the implant alignment when using an imageless robotic system for TKA. Materials and methods In a case–control study, the first 70 consecutive robotic-assisted TKA procedures performed by a single senior surgeon were analyzed with regard to surgery time and implant alignment by comparing the intraoperative plan with the postoperative alignment. The evaluation of the learning curve with respect to surgery time was conducted using cumulative summation (CUSUM) analysis. The joint line height was measured with a new technique. Surgery time and joint line reconstruction were compared to 70 consecutive conventional TKA procedures. Results The learning curve for robotic TKA was completed after 11 cases. The learning curve did not influence the accuracy of joint line obliquity, joint line height, or limb alignment. The intraoperative plan designed for the robotic system was precisely implemented. The mean skin-to-skin time in the robotic group after the learning curve was completed did not differ from that in the manual group. A significant positive correlation was observed between the preoperative hip–knee–ankle angle and the postoperative distalization of the joint line in the robotic-assisted TKA group. Conclusion After completing the initial learning curve of 11 cases, the surgery time required to perform imageless robotic handpiece-assisted TKA was similar to that for the conventional technique. However, no learning curve was observed for the implant positioning when using the imageless robotic system. The implementation of the intraoperative plan was accurate up to

Laparoscopic totally extraperitoneal hernia repair (TEP) is a widely used treatment for inguinal hernia. Single-incision laparoscopic TEP (SILTEP) has attracted the attention of several surgeons, given its superior cosmetic results and patient satisfaction, as well as comparable outcomes to multiport surgery. Nonetheless, no relevant studies have evaluated the learning curve (LC) of SILTEP in terms of both operation time (OT) and surgical failure. Therefore, we aimed to investigate the LC of SILTEP for inguinal hernia. Medical records of 180 patients who underwent SILTEP performed by a single surgeon from a single institution between October 2012 and November 2017 were retrospectively reviewed. The LC was analyzed using the moving average method and cumulative sum control chart (CUSUM) for OT and surgical failure. Surgical failure was defined as the need for additional ports, open conversion, severe postoperative complications (Clavien–Dindo ≥ IIIa), and recurrence. Eight patients who underwent combined surgery or bilateral hernia repair were excluded from the OT analysis. From CUSUM graphs, the study period was divided into three phases: OT-phases 1 (1st–32nd), 2 (33rd–83rd), and 3 (84th–172nd) for OT and failure-phases 1 (1st–29th), 2 (30th–58th), and 3 (59th–180th) for surgical failure. Mean OTs were statistically different in the three OT phases (64.6 vs. 50.8 vs. 35.2 min; p

Introduction Robotic surgery has become a safe and effective approach for the treatment of pulmonary surgical pathology. However, the adoption of new surgical techniques requires the evaluation of the learning curve. The objective of this study is to analyze the learning curve of robotic anatomical lung resections. Methods Retrospective analysis of all robotic anatomical lung resections performed by the same surgeon between June 2018 and March 2020. The learning curve was evaluated using CUSUM charts to estimate trend changes in surgical time, surgical failure and the occurrence of post-operative cardiorespiratory complications throughout the sequence of cases. Results The study included a total of 73 cases. The median duration of all complications was 120 min (interquartile range: 90−150 min), the prevalence of surgical failure was 23.29%, while 4/73 patients had any postoperative cardiorespiratory complication. Based on the CUSUM analysis, the learning curve was divided into 3 different phases: phase i (from the first to the 14th intervention), phase ii (between the 15th and 30th intervention) and phase iii (from the 31st intervention). Conclusions The learning curve for robotic anatomical lung resections can be divided into 3 phases. The technical competence that guarantees satisfactory perioperative outcomes was achived in phase iii from the 31st intervention.

The preliminary results of an innovative surgical technique, which incorporated single-port three-dimensional (3D) videoscope and instruments for endoscopic nipple-sparing mastectomy (E-NSM), were reported. The medical records of patients who underwent single-port 3D E-NSM for breast cancer from August 2018 to September 2020 were analyzed, and the preliminary outcome of this procedure as well as the patient-reported aesthetic results are described in this article. The study enrolled 70 patients who received 80 procedures of single-port 3D E-NSM. The mean operation time was 158 ± 36 min, and the mean blood loss was 41 ± 26 ml. Three procedures (3.8 %) associated with delayed axillary wound-healing, eight cases of transient nipple ischemia (10 %), three cases of partial nipple ischemia/necrosis (3.7 %), and one case of total nipple-areolar complex (NAC) necrosis (1.3 %) were observed. No patient had margin involvement. Satisfaction rates of approximately 90 % were observed in terms of postoperative scar appearance, location, and length. Most of the patients (87.8 %) reported that they would choose the same operation again if given the chance to do so. The overall cost of a single-port 3D E-NSM was 7522 ± 470 U.S. dollars. According to cumulative sum (CUSUM) plot analysis, about 14 cases were needed for surgeons to familiarize themselves with single-port 3D E-NSM and immediate gel implant reconstruction and to decrease their operation time significantly in the initial learning phase. Single-port 3D E-NSM, a safe, efficient, lower-cost procedure, is associated with a good aesthetic result. It is a promising new technique for breast cancer patients indicated for mastectomy, but long-term oncologic safety follow-up evaluation still is needed.

Robot-assisted transabdominal preperitoneal inguinal hernia repair (rTAPP-IHR) is a safe and feasible approach for hernias of varying etiology. We aim to present a single surgeon’s learning curve (LC) of this technique based on operative times, while accounting for bilaterality and complexity. This is a retrospective cohort analysis of patients who underwent rTAPP-IHR over a period of 5 years. Patients who underwent primary, recurrent, and complex (previous posterior repair, previous prostatectomy, scrotal, incarcerated) repairs were included. Cumulative and risk-adjusted cumulative sum analyses (CUSUM and RA-CUSUM) were used to depict the evolution of skin-to-skin times and complications/surgical site events (SSEs) with time, respectively. A total of 371 patients were included in the study. Mean skin-to-skin times were stratified according to four subgroups: unilateral non-complex (46.8 min), unilateral complex (63.2 min), bilateral non-complex (70.9 min), and bilateral complex (102 min). A CUSUM-LC was then plotted using each procedures difference in operative time from its subgroup mean. The peak of the plot occurred at case number 138, which was used as a transition between ‘early’ and ‘late’ phases. The average operative time for the late phase was 15.9 min shorter than the early phase (p

Objective: This study explored whether all‐cause healthcare attendance rate post‐vaccination could detect the two historical influenza safety episodes occurring in 2010 and 2015 using a large de‐identified general practitioner (GP) consultations dataset. Methods: A retrospective observational cohort study was conducted using GP consultation data routinely collected from 2008 to 2017 in Victoria, Australia. Post‐vaccination GP consultation rates were monitored, over a 22‐week surveillance period each year that aligned with each year's influenza vaccination season, using the Observed minus Expected (O‐E) and the Log‐Likelihood Ratio (LLR) CUSUM charts. Days 1–7 post‐vaccination were considered as the risk period. The LLR CUSUM was designed to detect both a 50% and two‐fold rise in the odds of the baseline post‐vaccination GP consultation rates. Results: Over the 10‐year study period, more than 1.5 million seasonal influenza vaccines doses were administered to 295,091 persons. Overall, 1.29% had a GP consultation within one week of vaccination, but 98.53% of the consultations occurred in days 1–3 post‐vaccination. The LLR CUSUM chart detected significant increases in the weekly rates of post‐vaccination GP consultation in 2010 in children aged under ten years and in 2015 in adults aged 19–64 years. These increases were aligned by week, but one week earlier and by age category, with the historical adverse events following immunisation (AEFI) signals occurring in 2010 and 2015. However, in the absence of historical AEFI signals, increased rates of post‐vaccination GP consultations were identified in three of the eight influenza vaccination years. Conclusion: The crude post‐vaccination healthcare attendance rate has the potential to offer a sensitive proxy to monitor vaccine safety signal. Implications for public health: Vaccine safety monitoring using syndromic indicator has the potential to augment the existing surveillance systems as part of an integrated vaccine safety monitoring approach.

Objectives Failure to rescue (FTR) is defined by the number of deaths among patients experiencing major complications after surgery. In this report we analyze FTR and apply a cumulative sum control chart (CUSUM) methodology for monitoring performance in a large series of operated lung carcinoma patients. Methods Prospectively stored records of cases undergoing anatomical lung resection in one center were reviewed. Postoperative adverse events were coded and included as a binary variable (major, or minor complications). The occurrence of 30-day mortality was also recorded. Patients dying after suffering major complications were considered as FTR. Risk-adjusted CUSUM graphs using EuroLung1 and 2 variables were constructed for major complications and FTR. Points of plateauing or trend inversion were checked to detect intentional or non-adverted changes in the process of care. Results 2237 cases included. 9.1% cases suffered major complications. The number of cases considered as failures to rescuing was 46 (2.1% of the total series and 22.5% of cases having major complications). The predictive performance of EuroLung1 and 2 models was as follows: EuroLung1 (major morbidity) C-index 0.70 (95%CI: 0.66–0.73); EuroLung2 (applied to FTR) C-index 0.81 (95%CI: 0.750.87). CUSUM graphs depicted improvement in rescuing complicated patients after case 330 but no improvement in the rate of non-complicated cases until case 720. Conclusions FTR offers a complementary view to classical outcomes for quality assessment in Thoracic Surgery. Our study also shows how the analysis of FTR on time series can be applied to evaluate changes in team performance along time.

Study design and data analysis are two important aspects relevant to chronopharmacometrics. Blunders can be avoided by recognizing that most physiological variables are circadian periodic. Both ill health and treatment can affect the amplitude, phase, and/or period of circadian (and other) rhythms, in addition to their mean. The involvement of clock genes in molecular pathways related to important physiological systems underlies the bidirectional relationship often seen between circadian rhythm disruption and disease risk. Circadian rhythm characteristics of marker rhythms interpreted in the light of chronobiologic reference values represent important diagnostic tools. A set of cosinor-related programs is presented. They include the least squares fit of multiple-frequency cosine functions to model the time structure of individual records; a cosinor-based spectral analysis to detect periodic signals; the population-mean cosinor to generalize inferences; the chronobiologic serial section to follow the time course of changing rhythm parameters over time; and parameter tests to assess differences among populations. Relative merits of other available cosinor and non-parametric algorithms are reviewed. Parameter tests to compare individual records and a self-starting cumulative sum (CUSUM) make personalized chronotherapy possible, where the treatment of each patient relies on an N-of-1 design. Methods are illustrated in a few examples relevant to endocrinology, cancer and cardiology. New sensing technology yielding large personal data sets is likely to change the healthcare system. Chronobiologic concepts and methods should become an integral part of these evolving systems.

IntroductionThe aim of the present study was to investigate the learning curves of 2 trainees with different experience levels to reach proficiency in preoperative planning of the cup size based on learning curve cumulative summation (LC-CUSUM) statistics and a cumulative summation (CUSUM) test.Materials and methodsOne-hundred-twenty patients who had undergone primary total hip arthroplasty with a cementless cup were selected. Preoperative planning was performed by an experienced orthopedic surgeon. Trainee 1 (student) and trainee 2 (resident) planned the cup size. The trainees were blinded to the preoperative plan and the definitive cup size. Only after a cup size was chosen, the trainees were unblinded to the preoperative plan of the surgeon. LC-CUSUM was applied to both trainees to determine when proficiency in determining the appropriate cup size was reached. A CUSUM test was applied to ensure retention of proficiency.ResultsWith reference to the preoperative plan of the surgeon, LC-CUSUM indicated proficiency after 94 planning attempts for trainee 1 and proficiency after 66 attempts for trainee 2, respectively. Trainee 1 and 2 maintained proficiency thereafter. With reference to the definitive cup size, LC-CUSUM did not signal competency within the first 120 planning attempts for trainee 1. Trainee 2 was declared competent after 103 attempts and retained competency thereafter.ConclusionsLC-CUSUM/CUSUM allow for an individualized, quantitative and continuous assessment of planning quality. Based on LC-CUSUM statistics, the two trainees of this study gain proficiency in planning of the acetabular cup size after 50–100 attempts when an immediate feedback is provided. Previous experience positively influences the performance. The study serves as basis for the medical education of students and residents in joint replacement procedures.

In many educational assessments, items are reused in different administrations throughout the life of the assessments. Ideally, a reused item should perform relatively similarly over time. In reality, an item may become easier with exposure, especially when item preknowledge has occurred. This article presents a novel cumulative sum procedure for detecting item preknowledge in continuous testing where data for each reused item may be obtained from small and varying sample sizes across administrations. Its performance is evaluated with simulations and analytical work. The approach is effective in detecting item preknowledge quickly with group size at least 10 and is easy to implement with varying item parameters. In addition, it is robust to the ability estimation error introduced in the simulations.

Backgrounds/Aims Although it is difficult to master the surgical learning curve for treatment of perihilar cholangiocarcinoma (HCCA), there have been no studies on surgical outcomes between a novice and an experienced surgeon. Thus, the current study attempted to evaluate surgical outcomes from a single surgeon based on learning curve for surgical treatment of HCCA. Methods From January 2008 to December 2016, a single surgeon performed surgical treatment for 108 patients with HCCA at Severance Hospital, Seoul, Korea. Among them, 101 patients with curative surgical resection were included in this study. The learning curve was assessed by a moving average graph and CUSUM method using operation time. Surgical outcomes between the early period group (EPG) and the late period group (LPG) were compared according to learning curve. Results Operation time (603.17±117.59 and 432.03±91.77 minutes; p

Total Knee Arthroplasty (TKA) procedures incorporate technology in an attempt to improve outcomes. The Active Robot (ARo) performs a TKA with automated resections of the tibia and femur in efforts to optimize bone cuts. Evaluating the Learning Curve (LC) is essential with a novel tool. The purpose of this study was to assess the associated LC of ARo for TKA. A multi-center prospective FDA cohort study was conducted from 2017 to 2018 including 115 patients that underwent ARo. Surgical time of the ARo was defined as Operative time (OT), segmented as surgeon-dependent time (patient preparation and registration) and surgeon-independent time (autonomous bone resection by the ARo). An average LC for all surgeons was computed. Complication rates and patient-reported outcome (PRO) scores were recorded and examined to evaluate for any LC trends in these patient related factors. The OT for the cases 10–12 were significantly quicker than the OT time of cases 1–3 (p

Objective This study examined the learning curve for transseptal puncture (TSP) during transcatheter edge-to-edge mitral valve repair (TEER) performed by a dedicated mitral valve structural heart team. Effective TSP is mandatory for TEER but can be time-consuming and associated with complications including pericardial effusion and cardiac tamponade. Methods TSP was performed on 107 consecutive patients (76 ± 1 years, 52% male) undergoing TEER between 2014 and 2019. TSP was performed by each structural heart team member (1 cardiologist, 2 cardiac surgeons) on a rotating case-by-case basis. No team member had prior independent TSP experience. Data collected included total procedure time, TSP time (time elapsed between procedure start and septal crossing), and number of TSP attempts before successful puncture. Cumulative sum (CUSUM) of deviations from the mean across sequential cases were used to examine learning curves. Results Median total procedure time was 107 min, and the median TSP time was 14 min. Greater case number was significantly associated with both lower TSP time ( r s = −0.22, P = 0.022) and lower total procedure time ( r s = −0.29, P = 0.003). The majority of patients required only 1 TSP attempt (79%). There was a significant quadratic relationship between case number and the CUSUM for TSP time, with the learning curve peaking at 49 cases. Conclusions TSP for TEER has a substantial learning curve, requiring >50 cases to achieve acceptable efficiency. Even once proficiency is demonstrated, TSP remains a time-consuming component of TEER. Improvements in transseptal access technology may significantly decrease the time needed to master TSP and may improve the safety and precision of the procedure.

This systematic review and meta-analysis were conducted to compare the accuracy of component positioning, alignment and balancing techniques employed, patient-reported outcomes, and complications of robotic-arm assisted total knee arthroplasty (RATKA) with manual TKA (mTKA) and the associated learning curve. Searches of PubMed, Medline and Google Scholar were performed in October 2020 using PRISMA guidelines. Search terms included “robotic”, “knee” and “arthroplasty”. The criteria for inclusion were published clinical research articles reporting the learning curve for RATKA and those comparing the component position accuracy, alignment and balancing techniques, functional outcomes, or complications with mTKA. There were 198 articles identified, following full text screening, 16 studies satisfied the inclusion criteria and reported the learning curve of rTKA (n=5), component positioning accuracy (n=6), alignment and balancing techniques (n=7), functional outcomes (n=7), or complications (n=5). Two studies reported the learning curve using CUSUM analysis to establish an inflexion point for proficiency which ranged from 7 to 11 cases and there was no learning curve for component positioning accuracy. The meta-analysis showed a significantly lower difference between planned component position and implanted component position, and the spread was narrower for RATKA compared with the mTKA group (Femur coronal: mean 1.31, 95% confidence interval (CI) 1.08–1.55, ppp=0.004). There was no difference in arthrofibrosis, superficial and deep infection, wound dehiscence, or overall complication rates. RATKA demonstrated improved accuracy of component positioning and patient-reported outcomes. The learning curve of RATKA for operating time was between 7 and 11 cases. Future well-powered studies on RATKAs should report on the knee alignment and balancing techniques utilised to enable better comparisons on which techniques maximise patient outcomes.Level of evidence III.

Treatment of pancreaticobiliary pathology following Roux-en-Y gastric bypass (RYGB) poses significant technical challenges. Laparoscopic-assisted endoscopic retrograde cholangiopancreatography (LA-ERCP) can overcome those anatomical hurdles, allowing access to the papilla. Our aims were to analyze our 12-year institutional outcomes and determine the learning curve for LA-ERCP. A retrospective review of cases between 2007 and 2019 at a high-volume pancreatobiliary unit was performed. Logistic regression was used to identify predictors of specific outcomes. To identify the learning curve, CUSUM analyses and innovative methods for standardizing the surgeon’s timelines were performed. 131 patients underwent LA-ERCP (median age 60, 81% females) by 17 surgeons and 10 gastroenterologists. Cannulation of the papilla was achieved in all cases. Indications were choledocholithiasis (78%), Sphincter of Oddi dysfunction/Papillary stenosis (18%), management of bile leak (2%) and stenting/biopsy of malignant strictures (2%). Median total, surgical and ERCP times were 180, 128 and 48 min, respectively, and 47% underwent concomitant cholecystectomy. Surgical site infection developed in 9.2% and post-ERCP pancreatitis in 3.8%. Logistic regression revealed multiple abdominal operations and magnitude of BMI decrease (between RYGB and LA-ERCP) to be predictive of conversion to open approach. CUSUM analysis of operative time demonstrated a learning curve at case 27 for the surgical team and case 9 for the gastroenterology team. On binary cut analysis, 3–5 cases per surgeon were needed to optimize operative metrics. LA-ERCP is associated with high success rates and low adverse events. We identify outcome benchmarks and a learning curve for new adopters of this increasingly performed procedure.

Background Few studies have investigated the learning curves of minimally invasive donor nephrectomy (MIDN) using the cumulative sum (CUSUM) analysis. In addition, no study has compared the learning curves of the different surgical MIDN techniques in one cohort study using the CUSUM analysis. This study aims to evaluate and compare learning curves for several MIDN using the CUSUM analysis. Methods A retrospective review of consecutive donors, who underwent MIDN between 1997 and 2019, was conducted. Three laparoscopic-assisted techniques were applied in our institution and included for analysis: laparoscopic (LDN), hand-assisted retroperitoneoscopic (HARP), and robot-assisted laparoscopic (RADN) donor nephrectomy. The outcomes were compared based on surgeon volume to develop learning curves for the operative time per surgeon. Results Out of 1895 MIDN, 1365 (72.0%) were LDN, 427 (22.5%) were HARP, and 103 (5.4%) were RADN. The median operative time and median blood loss were 179 (IQR, 139–230) minutes and 100 (IQR, 40–200) mL, respectively. The incidence of major complication was 1.2% with no mortality, and the median hospital stay was three (IQR, 3–4) days. The CUSUM analysis resulted in learning curves, defined by decreased operative time, of 23 cases in LDN, 45 cases in HARP, and 26 cases in RADN. Conclusions Our study shows different learning curves in three MIDN techniques with equal post-operative complications. The LDN and RADN learning curves are shorter than that of the hand-assisted donor nephrectomy. Our observations can be helpful for informing the development of teaching requirements for fellows to be trained in MIDN.

We propose an efficient statistical method (denoted as SSR-Tensor) to robustly and quickly detect hot-spots that are sparse and temporal-consistent in a spatial-temporal dataset through the tensor decomposition. Our main idea is first to build an SSR model to decompose the tensor data into a Smooth global trend mean, Sparse local hot-spots, and Residuals. Next, tensor decomposition is utilized as follows: bases are introduced to describe within-dimension correlation, and tensor products are used for between-dimension interaction. Then, a combination of LASSO and fused LASSO is used to estimate the model parameters, where an efficient recursive estimation procedure is developed based on the large-scale convex optimization, where we first transform the general LASSO optimization into regular LASSO optimization and apply FISTA to solve it with the fastest convergence rate. Finally, a CUSUM procedure is applied to detect when and where the hot-spot event occurs. We compare the performance of the proposed method in a numerical simulation study and a real-world case study, which contains a dataset including a collection of three types of crime rates for U.S. mainland states during the year 1965-2014. In both cases, the proposed SSR-Tensor is able to achieve the fast detection and accurate localization of the hot-spots., arXiv admin note: text overlap with arXiv:2001.11685

False power consumption data injected from compromised smart meters in Advanced Metering Infrastructure (AMI) of smart grids is a threat that negatively affects both customers and utilities. In particular, organized and stealthy adversaries can launch various types of data falsification attacks from multiple meters using smart or persistent strategies. In this paper, we propose a real time, two tier attack detection scheme to detect orchestrated data falsification under a sophisticated threat model in decentralized micro-grids. The first detection tier monitors whether the Harmonic to Arithmetic Mean Ratio of aggregated daily power consumption data is outside a normal range known as safe margin . To confirm whether discrepancies in the first detection tier is indeed an attack, the second detection tier monitors the sum of the residuals (difference) between the proposed ratio metric and the safe margin over a frame of multiple days. If the sum of residuals is beyond a standard limit range, the presence of a data falsification attack is confirmed. Both the ‘safe margins’ and the ‘standard limits’ are designed through a ‘system identification phase’, where the signature of proposed metrics under normal conditions are studied using real AMI micro-grid data sets from two different countries over multiple years. Subsequently, we show how the proposed metrics trigger unique signatures under various attacks which aids in attack reconstruction and also limit the impact of persistent attacks. Unlike metrics such as CUSUM or EWMA, the stability of the proposed metrics under normal conditions allows successful real time detection of various stealthy attacks with ultra-low false alarms.

Process monitoring techniques are of paramount importance in the chemical industry to improve both the product quality and plant safety. Small or incipient irregularities may lead to severe degradation in complex chemical processes, and the conventional process monitoring techniques cannot detect these irregularities. In this study to improve the performance of monitoring, an online multiscale fault detection approach is proposed by integrating multiscale principal component analysis (MSPCA) with cumulative sum (CUSUM) and exponentially weighted moving average (EWMA) control charts. The new Hotelling's T2 and square prediction error (SPE) based fault detection indices are proposed to detect the incipient irregularities in the process data. The performance of the proposed fault detection methods was tested for simulated data obtained from the CSTR system and compared to that of conventional PCA and MSPCA based methods. The results demonstrate that the proposed EWMA based MSPCA fault detection method was successful in detecting the faults. Moreover, a comparative study shows that the SPE-EWMA monitoring index exhibits a better performance with lower values of missed detections ranging from 0% to 0.80% and false alarms ranging from 0% to 21.20%.

This study analyzes the service quality of a University health clinic in Bekasi, WestJava, Indonesia. A control chart and capability analysis will be employed to analyzethe services' quality, especially registration processing time and the drug defect permonth. This study uses the CUSUM and EWMA control charts for detecting thesmall shifts in the processing time. The findings revealed that the current processesare in control and capable of meeting the current service level. There is only onepoint outside the upper limit. But it can be ignored/deleted since the assignablecause causes that event. This study gives direction for the Clinic to improve theservice quality.

Objective To analyze predictors that influence the learning curve of minimally invasive mitral valve surgery (MIMVS). Methods Patients who underwent MIMVS between March 2010 to March 2015 were retrospectively analyzed. Predictive factors that influence the learning curve were analyzed. Results One hundred and five patients were included in the analysis. Cardiopulmonary bypass (CPB) time in minutes was 158.72 +/- 40.98 and the aortic cross-clamp (ACC) time in minutes was 114.48 +/- 27.29. There were three operative mortalities, one stroke and five >2+ mitral regurgitation. ACC time in minutes was higher in the low logistic Euroscore II (LES) group (LES = 5 = 88.66 +/- 22.26),P = 5% = 41.66 +/- 17.14), (P

Muscle onset detection plays a key role in applications ranging from clinical to assistive technology. The Teager-Kaiser energy operator (TKEO) is an acknowledged tool used in surface electromyography (sEMG) signal conditioning for improving the performances of many change-point detection methods. Here, a TKEO extended version (ETKEO) was used to investigate its effects, for different SNR ranges, among a series of well-assessed algorithms, including a threshold-based one (TP). An optimization procedure on synthetic signals for the selection of the operator structure was also developed. The detection errors between TKEO and ETKEO, performed on real sEMG signals with SNR≤8 dB, showed significant ( ${p} ) overall improvements, not lower than 30%, when ETKEO was used. When compared with more robust techniques preconditioned by ETKEO as well, i.e., wavelet-, CUSUM- and profile likelihood maximization-based algorithms, the TP detector reached comparable performances for each SNR band, also for the lowest one. The results support the relevance of using ETKEO to improve onset analysis methods for a wide range of low SNR values, being particularly suitable for applications such as myoelectric motion intention detection. Moreover, the ETKEO adaptable structure suggests its use for other biological signals, presenting different characteristics with respect to sEMG signals.

Background Thoracoscopic repair of esophageal atresia with tracheoesophageal fistula (EA/TEF) remains technically challenging due to the rarity of these procedures. The aim of this study is to report our experience with thoracoscopic repair of type C EA/TEF and to evaluate the learning curve based upon the surgeon's skill level. Methods We retrospectively reviewed data of thoracoscopic EA/TEF repair performed in our center between October 2008 and May 2019. The learning curve was evaluated using the cumulative sum (CUSUM) method based on operative time. Results Of the 50 consecutive cases evaluated, the mean birth weight was 2634 ± 608 g and the median age at operation was 3 days (range, 1–29 days). The mean operation time was 144 ± 65 min. Anastomosis leakage occurred in 3 cases (6%) and strictures requiring balloon dilatations occurred in 16 cases (32%). The CUSUM analysis evaluated a learning curve of approximately 10 cases of thoracoscopic type C EA/TEF repair. A lower gestational age was associated with longer operation time. Conclusions Thoracoscopic repair of type C EA/TEF is a feasible and safe procedure. The number of procedures required to achieve a stable learning curve was 10. The learning phase may be shortened by adequate set-up under the supervision of an expert endoscopic surgeon. Type of study Retrospective Comparative Treatment Study. Level of evidence III

Control charts are commonly applied for monitoring and controlling the performance of the manufacturing process. Usually, control charts are designed based on the main quality characteristics variable. However, there exist numerous other variables which are highly associated with the main variable. Therefore, generalized linear model (GLM)-based control charts were used, which are capable of maintaining the relationship between variables and of monitoring an abrupt change in the process mean. This study is an effort to develop the Phase II GLM-based memory type control charts using the deviance residuals (DR) and Pearson residuals (PR) of inverse Gaussian (IG) regression model. For evaluation, a simulation study is designed, and the performance of the proposed control charts is compared with the counterpart memory less control charts and data-based control charts (excluding the effect of covariate) in terms of the run length properties. Based on the simulation study, it is concluded that the exponential weighted moving average (EWMA) type control charts have better detection ability as compared with Shewhart and cumulative sum (CUSUM) type control charts under the small or/and moderate shift sizes. Moreover, it is shown that utilizing covariate may lead to useful conclusions. Finally, the proposed monitoring methods is implemented on the dataset related to the yarn manufacturing industry to highlight the importance of the proposed control chart.

Aims To illustrate the construction of statistical control charts and show their potential application to analysis of outcomes in children's surgery. Patients and methods Two datasets recording outcomes following esophageal atresia repair and intestinal resection for Crohn's disease maintained by the author were used to construct four types of charts. The effects of altering the target signal, the alarm signal and the limits are illustrated. The dilemmas in choice of target rate are described. Simulated data illustrate the advantages over hypothesis testing. Results The charts show the author’s institutional leak rate for esophageal atresia repair may be within acceptable limits, but that this is dependent on the target set. The desirable target is contentious. The leak rate for anastomoses following intestinal resection for Crohn's disease leak is also within acceptable limits when compared to published experience, but may be deteriorating. The charts are able to detect deteriorating levels of performance well before hypothesis testing would suggest a systematic problem with outcomes. Conclusions Statistical process control charts can provide surgeons with early warning of systematic poor performance. They are robust to volume–outcome influences, since the outcome is tested sequentially after each procedure or patient. They have application in a specialty with low frequencies of operations such as children's surgery. Type of study Diagnostic test. Level of evidence Level II.

Process monitoring of multivariate quality attributes is important in many industrial applications, in which rich historical data are often available thanks to modern sensing technologies. While mu...

Transanal total mesorectal excision (TaTME) is technically challenging even for experienced colorectal surgeons and there may be a higher risk of complications during learning. Determining when a surgeon is ready to safely perform this technique independently remains a matter of debate. Therefore, the objective of this study was to systematically summarize the available evidence regarding measures of proficiency in TaTME for rectal adenocarcinoma. A systematic search of MEDLINE, Embase, PubMed Epub records, Biosis previews, Scopus, and Cochrane Library databases was performed according to PRISMA guidelines. All English and French language studies published between 2010 and 2018 that described proficiency metrics for TaTME were included. Study heterogeneity precluded meta-analysis, and therefore qualitative synthesis was performed. The primary outcomes were the methodology and measures used to define proficiency, and the number of cases needed to achieve proficiency. Of 994 citations, five studies met inclusion criteria. Of these, only two used objective measures to define proficiency. These studies evaluated patient outcomes and defined proficiency through cumulative sum (CUSUM) analysis of the primary outcome(s): post-operative complications and TME quality. Two studies reported expert consensus to establish recommendations using a combination of electronic survey distributed to colorectal surgeons and consensus conferences with TaTME experts from 7 to 8 different countries. One study defined the learning phase as 16 months of TaTME practice, or the first 27 cases. Stated case volumes needed to achieve proficiency varied widely. Studies using objective outcome measures reported threshold volumes of 40 and 51 cases, respectively, while expert consensus studies recommended needing 6–30 procedures. Significant heterogeneity exists regarding the determination of proficiency benchmarks for TaTME. Expert consensus documents recommend lower case numbers to obtain proficiency than those defined by objective measures, suggesting greater experience may be required than generally thought.

Background Recently, robot-assisted kidney transplantation (RAKT) was recently introduced as renal replacement mini-invasive surgery. Objective To report surgical technique, including tips and tricks, and the learning curve for RAKT. Design, setting, and participants All consecutive RAKTs performed in the five highest-volume centers of the European Robotic Urological Society RAKT group were reviewed, and a step-by-step description of the technique was compiled. Surgical procedure Surgeries were performed with Da Vinci Si/Xi. The patient was placed in the lithotomy position. The Trendelenburg position was set at 20–30° and the robot was docked between the legs. Measurements Shewhart control charts and cumulative summation (CUSUM) graphs and trifecta were generated to assess the learning curve according to rewarming time (RWT), intra/postoperative complications, and renal graft function (glomerular filtration rate) on days 7 and 30, and at 1 yr. Linear regressions were performed to compare the learning curves of each surgeon. Results and limitations Arterial anastomosis time was below the alarm/alert line in 93.3%/88.9% of RAKTs, while venous anastomosis time was below the alarm/alert line in 88.9%/73.9%. The nonanastomotic RWT exceeded +3 standard deviation (SD) in 24.7% of procedures and +2SD in 37.1%. In only 46% cases, the RWT was below the alert line. The ureteroneocystostomy time was below +2SD and +3SD in 87.9% and 90.2% of cases, respectively. CUSUM showed that the learning curve for arterial anastomosis required up to 35 (mean = 16) cases. Complications and delayed graft function rates decreased significantly and reached a plateau after the first 20 cases. Trifecta was achieved in 75% (24/32) of the cases after the first 34 RAKTs in each center. Conclusions A minimum of 35 cases are necessary to reach reproducibility in terms of RWT, complications, and functional results. Patient summary Robot-assisted kidney transplantation requires a learning curve of 35 cases to achieve reproducibility in terms of timing, complications, and functional results. Synergy between the surgeon and the assistant is crucial to reduce rewarming time. High-grade complications and delayed graft function are rare after ten surgeries. Hands-on training and proctorship are highly recommended.

Background The purpose of this study was to evaluate surgical outcomes of kidney transplantation (KTX) based on surgeon volume and surgeon experience, and to develop the learning curve model for KTX using the cumulative sum (CUSUM) analysis. Methods A retrospective review of 1466 consecutive recipients who underwent KTX between 2010 and 2017 was conducted. In total, 51 surgeons, including certified transplant surgeons, transplant fellows and surgical residents were involved in these procedures using a standardized protocol. Outcomes were compared based on surgeon volume (low [1–30] versus high [31≥] volume) and surgeon's type (consultant surgeons, fellows or residents). Results Operative time (129 versus 135 min, P < 0.001) and warm ischemia time (20.9 versus 24.2 min, P < 0.001) were significantly shorter in the high-volume group, however postoperative outcomes were equal in both groups. The CUSUM analysis revealed that approximately 30 procedures were necessary to improve surgical skills. In addition, no effect of surgeon's type including consultant surgeons, fellows and residents on postoperative outcomes was found. Conclusions Surgical training in KTX using a standardize protocol can be accomplished with a steep learning curve without compromising perioperative outcomes under the careful selection of surgeons and procedures.

Background Localization of small pulmonary nodules is an inevitable challenge for the thoracic surgeon. This study aimed to investigate the accuracy of three‐dimensional (3D) printing technology for localizing small pulmonary nodules, especially ground‐glass nodules (GGNs). Methods This study enrolled patients with peripheral small pulmonary nodules (≤ 2 cm) who required preoperative localization. In the comparison period, patients underwent both computed tomography‐guided (CT‐G) and 3D‐printing template guided (3D‐G) localization to compare the accuracies of the two methods. In the testing period, the 3D‐printing technique was implemented alone. The 3D‐printing physical navigational template was designed based on data from perioperative CT images. Clinical data, imaging data, surgical data, and evaluation index were collected for further analysis. The learning curve of the 3D‐printing localization technique was assessed using cumulative sum (CUSUM) analysis and multiple linear regression analysis. Results In the comparison period (n = 14), the success rates of CT‐G and 3D‐G were 100% and 92.9% (P = 0.31), respectively; in the testing period (n = 23), the success rate of 3D‐G was 95.6%. The localization times of CT‐G, 3D‐G (comparison), and 3D‐G (testing) were 23.6 ± 5.3, 19.3 ± 6.8, and 9.8 ± 4.6 minutes, respectively. The CUSUM learning curve was modeled using the equation: Y = 0.48X2 − 0.013X − 0.454 (R2 = 0.89). The learning curve was composed of two phases, phase 1 (the initial 20 patients) and phase 2 (the remaining 17 patients). Conclusions 3D printing localization has adequate accuracy and is a feasible and accessible strategy for use in localizing small pulmonary nodules, especially in right upper lobe. The use of this technique could facilitate lung nodule localization prior to surgery., Localization of small pulmonary nodules is an inevitable challenge for the thoracic surgeon. This study demonstrated that the 3D printing localization technique is a feasible and accessible strategy to localize non‐palpable pulmonary nodules.

Laparoscopic inguinal hernia repair, especially the transabdominal preperitoneal (TAPP) approach, is being performed increasingly worldwide. However, more complications are reported due to inadequate skills. Here, we generate a learning curve associated with TAPP performed in one inguinal hernia center. A total of 109 consecutive TAPP cases performed by a single surgeon were collected between 2011 and 2013 at Qilu Hospital of Shandong University, China. The cumulative sum (CUSUM) analysis was introduced to evaluate the completion of the learning curve. Meanwhile, other surgical observational targets and complications before discharge and during follow-up were analyzed to evaluate the impact of the learning curve. The mean operation time was 77.8 ± 33.3 min. CUSUM analysis indicated that the major inflection point of was at case 30, which divided the learning curve into two phases (phase 1 and phase 2). Differences in operation time and the postoperative length of stay between the two phases achieved statistical significance (102.4 ± 46.3 vs 68.5 ± 20.5 min, P

Rapid developments of wind industry arise the issue of heavy monitoring tasks. The residual monitoring based on normal behaviour modelling is a highly recommended method when fault record information is missing. However, it is difficult to achieve efficient normal behaviour modelling and dynamic residual monitoring simultaneously. To this end, a novel adaptive fault detection scheme, which merges random forest (RF) with adaptive cumulative sum (CUSUM), is proposed. The authors exploit RF to explore the non-linear mechanism between features and the target variable robustly, and obtain the residuals quickly. Then, they design the adaptive CUSUM control chart of time-varying shift to sensitively detect the changes of residuals. For illustration, they apply the proposed scheme to the supervisory control and data acquisition data acquired from a wind farm in China. The empirical results demonstrate that the proposed scheme is superior to several competing methods in capturing faults and reducing false alarms. Meanwhile, the authors find it can detect anomaly quickly, automatically and robustly under different signal-to-noise ratios. These provide operators sufficient time to adopt an effective maintenance strategy.

Background. Video-assisted thoracoscopic segmentectomy has been considered to be an effective management in properly selected patients. Given the substantial technical difficulties, uniportal thoracoscopic segmentectomy is a challenging surgical procedure. The purpose of this study was to investigate the learning curve for uniportal thoracoscopic segmentectomy procedures. Methods. Prospectively collected data were retrospectively analyzed for a series of 124 consecutive patients undergoing uniportal thoracoscopic segmentectomy from August 2016 to September 2018. The learning curve for uniportal thoracoscopic segmentectomy was studied using cumulative sum (CUSUM) combined with risk-adjusted cumulative sum (RA-CUSUM) methods. Results. According to the CUSUM combined with the RA-CUSUM analyses, the learning curve for uniportal thoracoscopic segmentectomy was composed of three well-differentiated phases: cases 1 to 24, cases 25 to 57, and cases 58 to 124. With the procedures proceeded orderly, the operation time tends to progressively decrease. Conclusions. The uniportal thoracoscopic segmentectomy is considered to be a feasible and safe surgical procedure that can be taught to surgeons through a proctored learning curve. The data of the present study indicate that the inflection point for completion the learning curve was reached after a considerable number of 57 cases.