Learning Curve of Laparoscopic Gastrectomy: A Multicenter Study.

OBJECTIVE: To evaluate the learning curve of laparoscopic gastrectomy (LG) after an implementation program. BACKGROUND: Although LG is increasingly being performed worldwide, little is known about the learning curve. METHODS: Consecutive patients who underwent elective LG for gastric adenocarcinoma with curative intent in each of the 5 highest-volume centers in the Netherlands were enrolled. Generalized additive models and a 2-piece model with a break point were used to determine the learning curve length. Analyses were corrected for casemix and were performed for LG and for the subgroups distal gastrectomy (LDG) and total gastrectomy (LTG). The learning curve effect was assessed for (1) anastomotic leakage; and (2) the occurrence of postoperative complications, conversions to open surgery, and short-term oncological parameters. RESULTS: In total 540 patients were included for analysis, 108 patients from each center; 268 patients underwent LDG and 272 underwent LTG. First, for LG, no learning effect regarding anastomotic leakage could be identified: the rate of anastomotic leakage initially increased, then reached a plateau after 36 cases at 10% anastomotic leakage. Second, the level of overall complications reached a plateau after 20 cases, at 38% overall complications, and at 5% conversions. For both LDG and LTG, each considered separately, fluctuations in secondary outcomes and anastomotic leakage followed fluctuations in casemix. CONCLUSION: On the basis of our study of the first 108 procedures of LG in 5 high-volume centers with well-trained surgeons, no learning curve effect could be identified regarding anastomotic leakage. A learning curve effect was found with respect to overall complications and conversion rate.

Trends in Distal Esophageal and Gastroesophageal Junction Cancer Care: The Dutch Nationwide Ivory Study.

OBJECTIVE: This study evaluated the nationwide trends in care and accompanied postoperative outcomes for patients with distal esophageal and gastro-esophageal junction cancer. SUMMARY OF BACKGROUND DATA: The introduction of transthoracic esophagectomy, minimally invasive surgery, and neo-adjuvant chemo(radio)therapy changed care for patients with esophageal cancer. METHODS: Patients after elective transthoracic and transhiatal esophagectomy for distal esophageal or gastroesophageal junction carcinoma in the Netherlands between 2007-2016 were included. The primary aim was to evaluate trends in both care and postoperative outcomes for the included patients. Additionally, postoperative outcomes after transthoracic and tran-shiatal esophagectomy were compared, stratified by time periods. RESULTS: Among 4712 patients included, 74% had distal esophageal tumors and 87% had adenocarcinomas. Between 2007 and 2016, the proportion of transthoracic esophagectomy increased from 41% to 81%, and neo-adjuvant treatment and minimally invasive esophagectomy increased from 31% to 96%, and from 7% to 80%, respectively. Over this 10-year period, postoperative outcomes improved: postoperative morbidity decreased from 66.6% to 61.8% ( P = 0.001), R0 resection rate increased from 90.0% to 96.5% (P <0.001), median lymph node harvest increased from 15 to 19 ( P <0.001), and median survival increased from 35 to 41 months ( P = 0.027). CONCLUSION: In this nationwide cohort, a transition towards more neo-adju-vant treatment, transthoracic esophagectomy and minimally invasive surgery was observed over a 10-year period, accompanied by decreased postoperative morbidity, improved surgical radicality and lymph node harvest, and improved survival.

Learning Curves of Ivor Lewis Totally Minimally Invasive Esophagectomy by Hospital and Surgeon Characteristics: A Retrospective Multinational Cohort Study.

OBJECTIVE: To describe the pooled learning curves of Ivor Lewis totally minimally invasive esophagectomy (TMIE) in hospitals stratified by predefined hospital- and surgeon-related factors. BACKGROUND: Ivor Lewis (TMIE is known to have a long learning curve which is associated with considerable learning associated morbidity. It is unknown whether hospital and surgeon characteristics are associated with more efficient learning. METHODS: A retrospective analysis of prospectively collected data of consecutive Ivor Lewis TMIE patients in 14 European hospitals was performed. Outcome parameters used as proxy for efficient learning were learning curve length, learning associated morbidity, and the plateau level regarding anastomotic leakage and textbook outcome. Pooled incidences were plotted for the factor-based subgroups using generalized additive models and 2-phase models. Casemix predicted outcomes were plotted and compared with observed outcomes. The investigated factors included annual volume, TMIE experience, clinic visits, courses and fellowships followed, and proctor supervision. RESULTS: This study included 2121 patients. The length of the learning curve was shorter for centers with an annual volume >50 compared to centers with an annual volume <50. Analysis with an annual volume cut-off of 30 cases showed similar but less pronounced results. No outcomes suggesting more efficient learning were found for longer experience as consultant, visiting an expert clinic, completing a minimally invasive esophagectomy fellowship or implementation under proctor supervision. CONCLUSIONS: More efficient learning was observed in centers with higher annual volume. Visiting an expert clinic, completing a fellowship, or implementation under a proctor's supervision were not associated with more efficient learning.

Recurrent Disease After Esophageal Cancer Surgery: A Substudy of The Dutch Nationwide Ivory Study.

OBJECTIVE: This study investigated the patterns, predictors, and survival of recurrent disease following esophageal cancer surgery. BACKGROUND: Survival of recurrent esophageal cancer is usually poor, with limited prospects of remission. METHODS: This nationwide cohort study included patients with distal esophageal and gastroesophageal junction adenocarcinoma and squamous cell carcinoma after curatively intended esophagectomy in 2007 to 2016 (follow-up until January 2020). Patients with distant metastases detected during surgery were excluded. Univariable and multivariable logistic regression were used to identify predictors of recurrent disease. Multivariable Cox regression was used to determine the association of recurrence site and treatment intent with postrecurrence survival. RESULTS: Among 4626 patients, 45.1% developed recurrent disease a median of 11 months postoperative, of whom most had solely distant metastases (59.8%). Disease recurrences were most frequently hepatic (26.2%) or pulmonary (25.1%). Factors significantly associated with disease recurrence included young age (≤65 y), male sex, adenocarcinoma, open surgery, transthoracic esophagectomy, nonradical resection, higher T-stage, and tumor positive lymph nodes. Overall, median postrecurrence survival was 4 months [95% confidence interval (95% CI): 3.6-4.4]. After curatively intended recurrence treatment, median survival was 20 months (95% CI: 16.4-23.7). Survival was more favorable after locoregional compared with distant recurrence (hazard ratio: 0.74, 95% CI: 0.65-0.84). CONCLUSIONS: This study provides important prognostic information assisting in the surveillance and counseling of patients after curatively intended esophageal cancer surgery. Nearly half the patients developed recurrent disease, with limited prospects of survival. The risk of recurrence was higher in patients with a higher tumor stage, nonradical resection and positive lymph node harvest.

Evaluation of an external foam column for in situ product removal in aerated surfactin production processes.

In Bacillus fermentation processes, severe foam formation may occur in aerated bioreactor systems caused by surface-active lipopeptides. Although they represent interesting compounds for industrial biotechnology, their property of foaming excessively during aeration may pose challenges for bioproduction. One option to turn this obstacle into an advantage is to apply foam fractionation and thus realize in situ product removal as an initial downstream step. Here we present and evaluate a method for integrated foam fractionation. A special feature of this setup is the external foam column that operates separately in terms of, e.g., aeration rates from the bioreactor system and allows recycling of cells and media. This provides additional control points in contrast to an internal foam column or a foam trap. To demonstrate the applicability of this method, the foam column was exemplarily operated during an aerated batch process using the surfactin-producing Bacillus subtilis strain JABs24. It was also investigated how the presence of lipopeptides and bacterial cells affected functionality. As expected, the major foam formation resulted in fermentation difficulties during aerated processes, partially resulting in reactor overflow. However, an overall robust performance of the foam fractionation could be demonstrated. A maximum surfactin concentration of 7.7 g/L in the foamate and enrichments of up to 4 were achieved. It was further observed that high lipopeptide enrichments were associated with low sampling flow rates of the foamate. This relation could be influenced by changing the operating parameters of the foam column. With the methodology presented here, an enrichment of biosurfactants with simultaneous retention of the production cells was possible. Since both process aeration and foam fractionation can be individually controlled and designed, this method offers the prospect of being transferred beyond aerated batch processes.

Learning Curves of Minimally Invasive Distal Pancreatectomy in Experienced Pancreatic Centers.

Importance: Understanding the learning curve of a new complex surgical technique helps to reduce potential patient harm. Current series on the learning curve of minimally invasive distal pancreatectomy (MIDP) are mostly small, single-center series, thus providing limited data. Objective: To evaluate the length of pooled learning curves of MIDP in experienced centers. Design, Setting, and Participants: This international, multicenter, retrospective cohort study included MIDP procedures performed from January 1, 2006, through June 30, 2019, in 26 European centers from 8 countries that each performed more than 15 distal pancreatectomies annually, with an overall experience exceeding 50 MIDP procedures. Consecutive patients who underwent elective laparoscopic or robotic distal pancreatectomy for all indications were included. Data were analyzed between September 1, 2021, and May 1, 2022. Exposures: The learning curve for MIDP was estimated by pooling data from all centers. Main Outcomes and Measures: The learning curve was assessed for the primary textbook outcome (TBO), which is a composite measure that reflects optimal outcome, and for surgical mastery. Generalized additive models and a 2-piece linear model with a break point were used to estimate the learning curve length of MIDP. Case mix-expected probabilities were plotted and compared with observed outcomes to assess the association of changing case mix with outcomes. The learning curve also was assessed for the secondary outcomes of operation time, intraoperative blood loss, conversion to open rate, and postoperative pancreatic fistula grade B/C. Results: From a total of 2610 MIDP procedures, the learning curve analysis was conducted on 2041 procedures (mean [SD] patient age, 58 [15.3] years; among 2040 with reported sex, 1249 were female [61.2%] and 791 male [38.8%]). The 2-piece model showed an increase and eventually a break point for TBO at 85 procedures (95% CI, 13-157 procedures), with a plateau TBO rate at 70%. The learning-associated loss of TBO rate was estimated at 3.3%. For conversion, a break point was estimated at 40 procedures (95% CI, 11-68 procedures); for operation time, at 56 procedures (95% CI, 35-77 procedures); and for intraoperative blood loss, at 71 procedures (95% CI, 28-114 procedures). For postoperative pancreatic fistula, no break point could be estimated. Conclusion and Relevance: In experienced international centers, the learning curve length of MIDP for TBO was considerable with 85 procedures. These findings suggest that although learning curves for conversion, operation time, and intraoperative blood loss are completed earlier, extensive experience may be needed to master the learning curve of MIDP.

Age and Charlson Comorbidity Index score are not independent risk factors for severe complications after curative esophagectomy for esophageal cancer: a Dutch population-based cohort study.

BACKGROUND: The number of older patients undergoing curative esophagectomy for esophageal cancer is increasing, and minimally invasive techniques are being increasingly used. The aim of this study is to compare postoperative outcomes after curative esophagectomy between older and younger patients. METHODS: Data was retrieved from the Dutch Upper Gastrointestinal Cancer Audit (DUCA), a national surgical outcome registry. The primary outcome was severe complications, defined as complications graded Clavien-Dindo ≥ 3. The secondary outcomes were postoperative complications, reintervention rates, length of hospital stays, and mortality. Outcomes were compared between patients aged ≥75 and < 75 years. We performed additional subgroup analyses between these age groups after totally minimally invasive esophagectomy (TMIE) and in patients with severe complications. We adjusted for the following parameters: gender, BMI, Charlson Comorbidity Index score (CCI), ASA score, histology, type of neoadjuvant therapy, and surgical technique. RESULTS: Of all 3775 included patients, 455 (12.1%) were aged ≥75 years and 3302 (87.9%) were aged <75 years. Overall, severe complications occurred in 184 (40.4%) older and in 1140 (34.5%) younger patients (CI = 1.009-1.080). After TMIE, severe complications occurred in 150 (42.1%) older and in 891 (35.8%) younger patients (CI = 1.007-1.088). In patients with severe complications, rates of complications, reinterventions, mortality, and ICU stays were comparable between older and younger patients. After adjustment for casemix, age and CCI score were not independent risk factors for (severe) complications and mortality. CONCLUSIONS: Age and Charlson Comorbidity Index are not adequate predictors of postoperative morbidity and mortality after curative esophagectomy for esophageal cancer.

Training benchmarks based on validated composite scores for the RobotiX robot-assisted surgery simulator on basic tasks.

The RobotiX robot-assisted virtual reality simulator aims to aid in the training of novice surgeons outside of the operating room. This study aimed to determine the validity evidence on multiple levels of the RobotiX simulator for basic skills. Participants were divided in either the novice, laparoscopic or robotic experienced group based on their minimally invasive surgical experience. Two basic tasks were performed: wristed manipulation (Task 1) and vessel energy dissection (Task 2). The performance scores and a questionnaire regarding the realism, didactic value, and usability were gathered (content). Composite scores (0-100), pass/fail values, and alternative benchmark scores were calculated. Twenty-seven novices, 21 laparoscopic, and 13 robotic experienced participants were recruited. Content validity evidence was scored positively overall. Statistically significant differences between novices and robotic experienced participants (construct) was found for movements left (Task 1 p = 0.009), movements right (Task 1 p = 0.009, Task 2 p = 0.021), path length left (Task 1 p = 0.020), and time (Task 1 p = 0.040, Task 2 p < 0.001). Composite scores were statistically significantly different between robotic experienced and novice participants for Task 1 (85.5 versus 77.1, p = 0.044) and Task 2 (80.6 versus 64.9, p = 0.001). The pass/fail score with false-positive/false-negative percentage resulted in a value of 75/100, 46/9.1% (Task 1) and 71/100, 39/7.0% (Task 2). Calculated benchmark scores resulted in a minority of novices passing multiple parameters. Validity evidence on multiple levels was assessed for two basic robot-assisted surgical simulation tasks. The calculated benchmark scores can be used for future surgical simulation training.

Cold Brew Coffee-Pilot Studies on Definition, Extraction, Consumer Preference, Chemical Characterization and Microbiological Hazards.

Cold brew coffee is a new trend in the coffee industry. This paper presents pilot studies on several aspects of this beverage. Using an online survey, the current practices of cold brew coffee preparation were investigated, identifying a rather large variability with a preference for extraction of medium roasted Arabica coffee using 50-100 g/L at 8 °C for about 1 day. Sensory testing using ranking and triangle tests showed that cold brew may be preferred over iced coffee (cooled down hot extracted coffee). Extraction experiments under different conditions combined with nuclear magnetic resonance (NMR) analysis showed that the usual extraction time may be longer than necessary as most compounds are extracted within only a few hours, while increasing turbulence (e.g., using ultrasonication) and temperature may additionally increase the speed of extraction. NMR analysis also revealed a possible chemical differentiation between cold brew and hot brew using multivariate data analysis. Decreased extraction time and reduced storage times could be beneficial for cold brew product quality as microbiological analysis of commercial samples detected samples with spoilage organisms and contamination with Bacillus cereus.

Learning curve and postoperative outcomes of minimally invasive esophagectomy.

Surgical innovation is necessary to increase surgical effectiveness and to decrease postoperative complications, but can be associated with learning curves. The significance of surgical learning curves is increasing and it is important to take surgical learning curves into account when interpreting outcome data that is acquired during an implementation period. This may especially be the case for a technically challenging procedure like minimally invasive esophagectomy (MIE). This review article provides an overview of the published literature that has described a learning curve for MIE, with particular interest in the relationship between the learning curve and postoperative complications. Twenty two studies reported learning curves of different types of MIE. These studies showed that the length of the learning curve of MIE can be significant, but most studies are single center studies of limited methodological quality. In addition, several learning curve analysis methods are used but a clear recommendation regarding the preferred method is lacking. Most studies use intraoperative parameters (e.g., operative time) to define the length of the learning curve. However, significant learning curve effects have been found for clinically more relevant parameters (e.g., anastomotic leak), especially for Ivor Lewis MIE. These studies suggest that patient safety can be substantially compromised during learning curves. To increase patient safety and shorten the learning curve, evidence based and effective safe implementation programs are necessary.