To identify effects of surgeon experience and age, in the context of cumulative institutional experience, on risk-adjusted hospital mortality after cardiac reoperations.
From 1951–2020, 36 surgeons ...performed 160,338 cardiac operations, including 32,871 reoperations. Hospital death was modeled using a novel tree-bagged, generalized varying-coefficient method with 6 variables reflecting cumulative surgeon and institutional experience up to each cardiac operation: 1) number of total and 2) reoperative cardiac operations performed by a surgeon, 3) cumulative institutional number of total and 4) reoperative cardiac operations, 5) year of surgery, and 6) surgeon age at each operation. These were adjusted for 46 patient characteristics and surgical components.
1,470 hospital deaths occurred after cardiac reoperations (4.5%). At the institutional level, hospital death fell exponentially and became less variable, leveling at 1.2% after approximately 14,000 cardiac reoperations. For all surgeons as a group, hospital death decreased rapidly over the first 750 reoperations, then gradually decreased with increasing experience to below 1% after about 4,000 reoperations. Surgeon age up to 75 was associated with ever-decreasing hospital death.
Surgeon age and experience have been implicated in adverse surgical outcomes, particularly after complex cardiac operations, with young surgeons being novices and older surgeons having declining ability. However, at Cleveland Clinic, outcome of cardiac reoperations improved with increasing primary surgeon experience, without any suggestion to mid-70s of an age cut-off. Patients were protected by the cumulative background of institutional experience that created a culture of safety and teamwork that mitigated adverse events after cardiac surgery.
Robot-assisted pancreaticoduodenectomy (RPD) has been reported to be safe and feasible. As a new technique, RPD has a learning curve similar to that of other types of minimally invasive pancreatic ...surgery such as laparoscopic pancreaticoduodenectomy. To our knowledge, no reports exist on the outcomes of open pancreaticoduodenectomy (OPD) and RPD after the learning curve.
To analyze and evaluate the actual advantages of RPD.
Between May 2010 and December 2018, 450 patients underwent RPD in the Shanghai Ruijin Hospital affiliated with Shanghai Jiaotong University in Shanghai, China, a high-volume pancreatic disease center. According to our previous study, an important flexion point in the learning curve is 250 cases. Data on the last 200 RPD cases were collected from January 2017 to December 2018. During that period, 634 patients underwent OPD. These patients were divided into 2 groups, and propensity score matching was used to minimize bias. The demographic data and operative outcomes were collected and analyzed. Analysis began May 2019.
Robot-assisted pancreaticoduodenectomy and OPD.
The short-term operative outcomes of RPD and OPD.
After 1:1 matching, 187 cases of RPD and OPD were recorded. In the RPD group, 78 patients (41.7%) were women, and the mean (SD) age was 60.9 (11.4) years. In the OPD group, 80 patients (42.8%) were women, and the mean (SD) age was 60.1 (10.8) years. Robot-assisted pancreaticoduodenectomy had advantages in operative time (mean SD, 279.7 76.3 minutes vs 298.2 78.3 minutes; P = .02), estimated blood loss (mean SD, 297.3 246.8 mL vs 415.2 497.9 mL; P = .002), and postoperative length of hospital stay (mean SD, 22.4 16.7 days vs 26.1 16.3 days; P = .03). However, there was no significant difference in the R0 resection rate and incidence rate of postoperative complications, such as postoperative pancreatic fistula, bile leak, and delayed gastric emptying. The incidence rates of postoperative bleeding and reoperation in the RPD group were similar to those in the OPD group, with no statistically significant difference.
After passing the learning curve, RPD had advantages in operative time and blood loss compared with OPD. There were no differences in postoperative complications such as postoperative pancreatic fistula, bile leak, and delayed gastric emptying. However, patients recovered more quickly after RPD than after OPD. A prospective randomized clinical trial is needed in the future to verify these results.
Purpose
The application of robotics in the operating theatre for total knee arthroplasty (TKA) remains controversial. As with all new technology, the introduction of new systems is associated with a ...learning curve and potentially associated with extra complications. Therefore, the aim of this study is to identify and predict the learning curve of robot-assisted (RA) TKA.
Methods
A RA TKA system (MAKO) was introduced in April 2018 in our service. A retrospective analysis was performed of all patients receiving a TKA with this system by six surgeons. Operative times, implant and limb alignment, intraoperative joint balance and robot-related complications were evaluated. Cumulative summation (CUSUM) analyses were used to assess learning curves for operative time, implant alignment and joint balance in RA TKA. Linear regression was performed to predict the learning curve of each surgeon.
Results
RA TKA was associated with a learning curve of 11–43 cases for operative time (
p
< 0.001). This learning curve was significantly affected by the surgical profile (high vs. medium vs. low volume). A complete normalisation of operative times was seen in four out of five surgeons. The precision of implant positioning and gap balancing showed no learning curve. An average deviation of 0.2° (SD 1.4), 0.7° (SD 1.1), 1.2 (SD 2.1), 0.2° (SD 2.9) and 0.3 (SD 2.4) for the mLDFA, MPTA, HKA, PDFA and PPTA from the preoperative plan was observed. Limb alignment showed a mean deviation of 1.2° (SD 2.1) towards valgus postoperatively compared to the intraoperative plan. One tibial stress fracture was seen as a complication due to suboptimal positioning of the registration pins.
Conclusion
RA TKA is associated with a learning curve for surgical time, which might be longer than reported in current literature and dependent on the profile of the surgeon. There is no learning curve for component alignment, limb alignment and gap balancing.
Level of evidence
IV.
Transcatheter mitral valve repair (TMVr) for the treatment of mitral regurgitation (MR) is a complex procedure that requires development of a unique skillset.
The purpose of this study was to examine ...the relationship between operator experience and procedural results of TMVr.
TMVr device procedures from the Society of Thoracic Surgeons/American College of Cardiology Transcatheter Valve Therapy registry were analyzed with operator case number as a continuous and categorical (1 to 25, 26 to 50, and >50) variable. Outcomes of procedural success, procedural time, and in-hospital procedural complications were examined. The learning curve for the procedure was evaluated using generalized linear mixed models adjusting for baseline clinical variables.
All TMVr device procedures (n = 14,923) performed by 562 operators at 290 sites between November 2013 and March 2018 were analyzed. Optimal procedural success (≤1+ residual MR without death or cardiac surgery) increased across categories of operator experience (63.9%, 68.4%, and 75.1%; p < 0.001), while procedural time and procedural complications decreased. Acceptable procedural success (≤2+ residual MR without death or cardiac surgery) also increased with operator experience, but the differences were smaller (91.4%, 92.4%, and 93.8%; p < 0.001). These associations remained significant in adjusted, continuous variable analyses. Visual inflection points in the learning curves for procedural time, procedural success, and procedural complications were evident after approximately 50 cases, with continued improvements observed out to 200 cases.
For TMVr device procedures, operator experience was associated with improvements in procedural success, procedure time, and procedural complications. The effect of operator experience was greater when considering the goal of achieving 1+ residual MR.
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Complex endovascular abdominal aortic aneurysm (AAA) repair techniques have evolved over the last decade, yet patterns of physician and hospital system adoption of fenestrated endovascular aneurysm ...repair (FEVAR) remain poorly defined. We investigated clinical outcomes, use trends, and surgeon and hospital experience for FEVAR in a large community hospital system.
We conducted a retrospective cohort study of all FEVAR procedures within our 5-state hospital system between April 2012 and June 2021. AAA repair volumes (open, EVAR, and FEVAR) were captured at the hospital and surgeon levels using Current Procedural Terminology and International Classification of Diseases codes. Clinical and outcomes data were collected for FEVAR patients. To consider if surgeon or hospital experience influenced outcomes, sequential case number was used to divide patients into surgeon experience and hospital experience groups. Inverse probability weighted and generalized linear mixed models, adjusted for demographics and comorbidities, were built to examine risk-adjusted outcomes for surgeon and hospital experience groups.
Of 3850 patients treated with AAA procedures of any kind between 2012 and 2021, 160 (4.2%) underwent FEVAR. FEVAR procedures were performed by 34 different surgeons at 12 hospitals, with intraoperative complications and unplanned adjunctive procedures occurring in 18.8% (n = 30) and 19.4% (n = 31) of patients, respectively. Among FEVAR patients, in-hospital mortality was 1.3% (n = 2) and postoperative morbidity was 16.9% (n = 27). Renal function decline occurred postoperatively in 5.1% of patients. Early (<30 day) postoperative endoleaks occurred in 15.3% of patients (n = 21). Target vessel patency was 95.6% on initial postoperative imaging. Surgeon and hospital experience had a small positive impact on outcomes after the first one to three cases. Significant decreases in operative time, fluoroscopy time, and estimated blood loss were observed with increased surgeon experience, relative to a surgeon's first case (P < .05). There were lower odds of intraoperative complications after a surgeon's first case (odds ratio OR, 0.16; 95% confidence interval CI, 0.03-0.77, for cases 2-3) or after a hospital's first one to three cases (OR, 0.19; 95% CI, 0.04-0.89, for cases 4-8; OR, 0.12; 95% CI, 0.03-0.55 for cases 9-49).
Clinical outcomes of FEVAR across our hospital system compare favorably with previously published reports. Although system-wide FEVAR adoption increased 3-fold over the last decade, FEVAR continued to be performed by a minority of hospitals in our system. The results from this cohort demonstrate low rates of adverse events, high rates of technical efficiency, and a small impact of surgeon and hospital experience, thereby supporting this advanced endovascular technology as a safe, efficacious, and generalizable treatment alternative to open repair for patients with complex aortic anatomy.
Background
His‐bundle pacing (HBP) provides physiological ventricular activation. Observational studies have demonstrated the techniques’ feasibility; however, data have come from a limited number of ...centers.
Objectives
We set out to explore the contemporary global practice in HBP focusing on the learning curve, procedural characteristics, and outcomes.
Methods
This is a retrospective, multicenter observational study of patients undergoing attempted HBP at seven centers. Pacing indication, fluoroscopy time, HBP thresholds, and lead reintervention and deactivation rates were recorded. Where centers had systematically recorded implant success rates from the outset, these were collated.
Results
A total of 529 patients underwent attempted HBP during the study period (2014‐19) with a mean follow‐up of 217 ± 303 days. Most implants were for bradycardia indications.
In the three centers with the systematic collation of all attempts, the overall implant success rate was 81%, which improved to 87% after completion of 40 cases.
All seven centers reported data on successful implants. The mean fluoroscopy time was 11.7 ± 12.0 minutes, the His‐bundle capture threshold at implant was 1.4 ± 0.9 V at 0.8 ± 0.3 ms, and it was 1.3 ± 1.2 V at 0.9 ± 0.2 ms at last device check.
HBP lead reintervention or deactivation (for lead displacement or rise in threshold) occurred in 7.5% of successful implants.
There was evidence of a learning curve: fluoroscopy time and HBP capture threshold reduced with greater experience, plateauing after approximately 30‐50 cases.
Conclusion
We found that it is feasible to establish a successful HBP program, using the currently available implantation tools. For physicians who are experienced at pacemaker implantation, the steepest part of the learning curve appears to be over the first 30‐50 cases.
Introduction
Laparoscopic sleeve gastrectomy plus duodenojejunal bypass (LSG-DJB) has emerged as an alternative bypass surgery. Despite its potential benefits, the technical challenges of the ...procedure have limited its adoption. This study aims to present the learning curve for LSG-DJB and explore potentially beneficial technical modifications for the standardization of the procedure.
Methods
The study retrospectively analyzed 100 patients who underwent LSG-DJB as a primary procedure from July 2014 through September 2021. Baseline characteristics, weight loss outcomes, remission of metabolic diseases, and perioperative complications were assessed. The operative time was analyzed across both time trends and anastomosis type subgroups.
Results
At 1-year follow-up after LSG-DJB, the mean %total weight loss and the mean BMI loss were 25.38 ± 8.58% and 9.38 ± 4.25 kg/m2, respectively. Remission rates for type 2 diabetes, hypertension, and dyslipidemia were 72.0% (67/93), 84.1% (37/44), and 70.3% (52/74), respectively. In the analysis of operative time, the learning curve exhibited a plateau after 25 cases. The mean operative time was 136.00 ± 21.64 min in the stapled anastomosis group, and 150.62 ± 25.42 min in the hand-sewn anastomosis group.
Conclusion
The learning curve for LSG-DJB plateaued after 25 cases. In the LSG-DJB procedure, stapled duodenojejunal anastomosis is feasible and achieves similar outcomes to the hand-sewn method.
Graphical Abstract
Abstract
Seawater reverse osmosis (SWRO) desalination is expected to play a pivotal role in helping to secure future global water supply. While the global reliance on SWRO plants for water security ...increases, there is no consensus on how the capital costs of SWRO plants will vary in the future. The aim of this paper is to analyze the past trends of the SWRO capital expenditures (capex) as the historic global cumulative online SWRO capacity increases, based on the learning curve concept. The SWRO capex learning curve is found based on 4,237 plants that came online from 1977 to 2015. A learning rate of 15% is determined, implying that the SWRO capex reduced by 15% when the cumulative capacity was doubled. Based on SWRO capacity annual growth rates of 10% and 20%, by 2030, the global average capex of SWRO plants is found to fall to 1,580 USD/(m
3
/d) and 1,340 USD/(m
3
/d), respectively. A learning curve for SWRO capital costs has not been presented previously. This research highlights the potential for decrease in SWRO capex with the increase in installation of SWRO plants and the value of the learning curve approach to estimate future SWRO capex.
Plain Language Summary
Seawater desalination is expected to play a pivotal role in helping to secure future global water supply as water demand surges and freshwater resources diminish. While there are various seawater desalination technologies, the dominant desalination technology is expected to be seawater reverse osmosis (SWRO). The aim of this paper is to understand how the capital cost of SWRO plants has changed in the past as more plants were built and operated. This is based on the “learning by doing” concept that illustrates the relationship between cost reduction in industries and the increase in production output. The relevance for SWRO plants is studied by assessing 4,237 plants that were operated from 1977 to 2015. It is found that as the cumulative global capacity of SWRO plants doubled, the average capital cost reduced by 15%. The results suggest that for every future doubling of SWRO capacity, the capital cost will reduce by 15%. This is the first such observation presented for SWRO plants and can be used to project the future capital costs of SWRO plants.
Key Points
First learning curve established for the capital costs of SWRO plants
SWRO capex has decreased by 15% for every doubling of cumulative online SWRO capacity. This implies a learning rate of 15% for SWRO plants
Based on 20% annual growth rate, 2030 SWRO capex is estimated to be 1,340 USD/(m
3
/d)
The signal is the outcome of interest in a study; it may be the value of a variable or it may be the value of a relationship between variables. Signals in research are distorted by statistical noise. ...This statistical noise is generated by extraneous variables that may be adequately measured, inadequately measured, unmeasured, or unknown; the subject-to-subject variation in the signal resulting from the effects of these extraneous variables is captured by the standard deviation. Thus, the standard deviation is a measure of statistical noise. This article, the first in a series, explains all of these concepts with the help of examples.
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