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"de Laar, Arnold van"
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Under the knife : a history of surgery in 28 remarkable operations
\"Surgeon Arnold Van de Laar uses his own experience and expertise to tell this engrossing history of surgery through 28 famous operations - from Louis XIV to JFK, and from Einstein to Houdini. From the story of the desperate man from seventeenth-century Amsterdam who grimly cut a stone out of his own bladder to Bob Marley's deadly toe, Under the Knife offers all kinds of fascinating and unforgettable insights into medicine and history via the operating theater. What happens during an operation? How does the human body respond to being attacked by a knife, a bacterium, a cancer cell or a bullet? And, as medical advances continuously push the boundaries of what medicine can cure, what are the limits of surgery? From the dark centuries of bloodletting and of amputations without anaesthetic to today's sterile, high-tech operating theatres, Under the Knife is both a rich cultural history, and a modern anatomy class for us all\"-- Provided by publisher.
Book
Sensitivity and Specificity of 50% Excess Weight Loss (50%EWL) and Twelve Other Bariatric Criteria for Weight Loss Success
BackgroundCriteria for bariatric weight loss success are numerous. Most of them are arbitrary. None of them is evidence-based. Our objective was to determine their sensitivity and specificity.MethodsThirteen common bariatric weight loss criteria were compared to a benchmark reflecting the gold standard in bariatric surgery. We used an elaborate baseline BMI-independent weight loss percentile chart, based on retrospective data after laparoscopic Roux-en-Y gastric bypass (LRYGB), performed between 2007 and 2017. Percentile curves p31.6 (patients’ expectation), p25 (interquartile range), p15.9 (1 standard deviation (SD) below median), and p10.9 (surgeons’ goal) were used as possible cutoff for success to determine true or false positive and negative results beyond 1 year.ResultsWe operated 4497 primary LRYGB patients, with mean follow-up 22 (± 1 SD 19; range 0–109) months, 3031 patients with last result ≥ 1 year, 518 ≥ 5 years. For all four cutoff percentile curves for success, specificities were low (2–72%) for criteria < 35 body mass index (BMI), ≥ 25percentage excess BMI loss (%EBMIL), ≥ 50%EBMIL, ≥ 15 percentage total weight loss (%TWL), ≥ 20%TWL, ≥ 25 percentage excess weight loss (%EWL), and high (83–96%) for < 30 BMI. No criterion had > 80% specificity and sensitivity for a cutoff above p15.9. For p15.9, they were both > 80% for criteria ≥ 10 BMI reduction and ≥ 50%EWL, both > 90% for ≥ 25%TWL and ≥ 35 percentage alterable weight loss (%AWL). All criteria had high sensitivities for all cutoff percentile curves (87–100%), except < 30 BMI (65–78%).ConclusionsFor the first time, common bariatric criteria for weight loss success were systematically validated. Most criteria recognized success very well (high sensitivities), but ≥ 15%TWL, ≥ 20%TWL, < 35BMI, ≥ 25%EWL, ≥ 25%EBMIL, and ≥ 50%EBMIL left too many poor responders unnoticed (low specificities). Bariatric weight loss success is best assessed by comparing results to percentile curve 1 SD below median (p15.9) in a bariatric baseline BMI-independent weight loss percentile chart. Criteria ≥ 35%AWL and ≥ 25%TWL came close to that curve, both with > 90% sensitivity and specificity. Among others, criterion ≥ 50%EBMIL did not.
Journal Article
Ursodeoxycholic Acid Use After Bariatric Surgery: Effects on Metabolic and Inflammatory Blood Markers
Background
In addition to the reduction of symptomatic gallstone disease, ursodeoxycholic acid (UDCA) might also have beneficial metabolic effects after bariatric surgery. We examined the impact of UDCA on liver enzymes, hemoglobin A1c (HbA1c), lipids, and inflammation markers.
Methods
Patients in the UPGRADE trial (placebo-controlled, double-blind) were randomized between UDCA 900 mg daily or placebo pills for 6 months after bariatric surgery. Patients without blood measurements pre- or 6 months postoperatively were excluded. The change in liver enzymes, Hba1c, lipids, and inflammation markers after surgery were compared between the UDCA and placebo group, followed by a postoperative cross-sectional comparison.
Results
In total, 513 patients were included (age [mean ± SD] 45.6 ± 10.7 years; 79% female). Preoperative blood values did not differ between UDCA (
n
= 266) and placebo (
n
= 247) groups. Increase of alkaline phosphatase (ALP) was greater in the UDCA group (mean difference 3.81 U/l [95%CI 0.50 7.12]). Change in other liver enzymes, HbA1c, lipids, and CRP levels did not differ. Postoperative cross-sectional comparison in 316 adherent patients also revealed a higher total cholesterol (mean difference 0.25 mg/dl [95%CI 0.07–0.42]), lower aspartate aminotransferase (mean difference −3.12 U/l [−5.16 – −1.08]), and lower alanine aminotransferase level (mean difference −5.89 U/l [−9.41 – −2.37]) in the UDCA group.
Conclusion
UDCA treatment leads to a higher, but clinically irrelevant increase in ALP level in patients 6 months after bariatric surgery. No other changes in metabolic or inflammatory markers were observed. Except for the reduction of gallstone formation, UDCA has no effects after bariatric surgery.
Graphical Abstract
Journal Article
Risk Factors for Cholecystectomy After Laparoscopic Roux-En-Y Gastric Bypass
BackgroundPatients who have undergone bariatric surgery are at risk for subsequent cholecystectomy. We aimed to identify risk factors for cholecystectomy after laparoscopic Roux-en-Y gastric bypass (LRYGB).MethodsWe conducted a retrospective case-control study of patients who underwent LRYGB between 2013 and 2015. Cases underwent cholecystectomy because of biliary symptoms after LRYGB. For each case, two controls were selected without subsequent cholecystectomy. Logistic regression analyses were used to identify risk factors.ResultsBetween 2013 and 2015, 1780 primary LRYGBs were performed. We identified 233 (13.1%) cases who had undergone cholecystectomy after a median (IQR) of 12 (8–17) months, and 466 controls. Female gender (OR (95% CI) 1.83 (1.06–3.17)), Caucasian ethnicity (OR (95% CI) 1.82 (1.10–3.02)), higher percent total weight loss (%TWL) at 12 months (OR (95% CI) 1.06 (1.04–1.09)), and preoperative pain syndrome (OR (95% CI) 2.72 (1.43–5.18)) were significantly associated with an increased risk for cholecystectomy. Older age (OR (95% CI) 0.98 (0.96–0.99)) and preoperative statin use were associated with a reduced risk (OR (95% CI) 0.56 (0.31–1.00)). A dose-effect relationship was found between the intensity of preoperative statin and risk for cholecystectomy.ConclusionsIn our study, higher %TWL and preoperative pain syndrome were associated with an increased risk for cholecystectomy besides the traditional risk factors female gender and Caucasian ethnicity. These factors can be used to identify high-risk patients, who might benefit from preventive measures. Whether statins can protect bariatric patients from developing gallstones should be investigated prospectively.
Journal Article
What Is Weight Loss After Bariatric Surgery Expressed in Percentage Total Weight Loss (%TWL)? A Systematic Review
Percentage total weight loss (%TWL) might be better than percentage excess weight loss to express weight loss in bariatric surgery. In this systematic review, performed according to the PRISMA statement, results of laparoscopic sleeve gastrectomy (LSG) and Roux-en-Y gastric bypass (LRYGB) are assessed in %TWL. A total of 13,426 studies were screened and 49 included, reporting data of 24,760 patients. The results show that, despite limiting data, LRYGB is favorable over LSG in terms of weight loss in short-term follow-up. Although recent guidelines recommend to use %TWL when reporting outcome in bariatric surgery, this study shows that there is still insufficient quality data in %TWL, especially on LSG. The use of %TWL as the primary outcome measure in bariatric surgery should be encouraged.
Graphical abstract
Journal Article
Weight Loss Percentile Charts of Large Representative Series: a Benchmark Defining Sufficient Weight Loss Challenging Current Criteria for Success of Bariatric Surgery
Background
The frequently used 35 kg/m
2
body mass index (BMI) and 50 % excess weight loss (%EWL) criteria are no longer adequate for defining the success of a bariatric or metabolic surgery. It is not clear whether they are still useful to simply determine the sufficiency of a patient’s postoperative weight loss. An alternative way of defining sufficient weight loss is presented, using weight loss percentile charts of large representative series as a benchmark.
Methods
Gastric bypass weight loss results from the Bariatric Outcomes Longitudinal Database (BOLD) with ≥2 years of follow-up are presented with percentiles in function of postoperative time and their nadir results in function of initial BMI using different outcome metrics. These percentiles are compared with the BMI35 and 50 %EWL criteria.
Results
Of 49,098 patients eligible for ≥2 years of follow-up, 8,945 had reported weight loss at ≥2 years (20.0 % male, mean initial BMI 47.7 kg/m
2
). They reached nadir BMI at a mean of 603 days. Their 50th percentiles surpassed both 50 %EWL and BMI35 after 135 days. More than 95 % achieved 50 %EWL; more than 75 % achieved BMI35. BMI and %EWL results are influenced more by initial BMI than total weight loss (%TWL) results.
Conclusions
BOLD gastric bypass weight loss data are presented with percentile curves. BMI and %EWL are clearly not suited for this purpose. Provided that follow-up data are solid, %TWL-based percentile charts can constitute neutral benchmarks for defining sufficient postoperative weight loss over time. Criteria for overall success, however, should consider clear goals of health improvement, including metabolic aspects. Frequently used criteria 50 %EWL and BMI35 are inadequate for both. Their static weight loss components do not match the found percentiles and their health improvement components do not match known metabolic criteria.
Journal Article
Ursodeoxycholic acid for the prevention of symptomatic gallstone disease after bariatric surgery: study protocol for a randomized controlled trial (UPGRADE trial)
Background
The number of bariatric interventions for morbid obesity is increasing worldwide. Rapid weight loss is a major risk factor for gallstone development. Approximately 11 % of patients who underwent Roux-en-Y gastric bypass develop symptomatic gallstone disease. Gallstone disease can lead to severe complications and often requires hospitalization and surgery. Ursodeoxycholic acid (UDCA) prevents the formation of gallstones after bariatric surgery. However, randomized controlled trials with symptomatic gallstone disease as primary endpoint have not been conducted. Currently, major guidelines make no definite statement about postoperative UDCA prophylaxis and most bariatric centers do not prescribe UDCA.
Methods
A randomized, placebo-controlled, double-blind multicenter trial will be performed for which 980 patients will be included. The study population consists of consecutive patients scheduled to undergo Roux-en-Y gastric bypass or sleeve gastrectomy in three bariatric centers in the Netherlands. Patients will undergo a preoperative ultrasound and randomization will be stratified for pre-existing gallstones and for type of surgery. The intervention group will receive UDCA 900 mg once daily for six months. The placebo group will receive similar-looking placebo tablets. The primary endpoint is symptomatic gallstone disease after 24 months, defined as admission or hospital visit for symptomatic gallstone disease. Secondary endpoints consist of the development of gallstones on ultrasound at 24 months, number of cholecystectomies, side-effects of UDCA and quality of life. Furthermore, cost-effectiveness, cost-utility and budget impact analyses will be performed.
Discussion
The UPGRADE trial will answer the question whether UDCA reduces the incidence of symptomatic gallstone disease after Roux-en-Y gastric bypass or sleeve gastrectomy. Furthermore it will determine if treatment with UDCA is cost-effective.
Trial registration
Netherlands Trial Register (trialregister.nl)
6135
. Date registered: 21-Nov-2016.
Journal Article
A novel fully covered double-bump stent for staple line leaks after bariatric surgery: a retrospective analysis
BackgroundStaple line leakage after bariatric surgery can be treated by endoscopic placement of a self-expandable stent. The success rate of stent placement is generally high, but migration is a frequent adverse event that hampers successful treatment. The Niti-S Beta stent is a fully covered double-bump stent that was specifically designed to prevent migration. This study aimed to evaluate the effectiveness and adverse event rate of the Niti-S Beta stent.MethodsA retrospective study was performed in three high-volume bariatric centers. All consecutive patients between 2009 and 2016 who underwent placement of a Beta stent for staple line leakage were included. Primary outcome was resolution of the leakage; secondary outcome was the adverse event rate including migration.ResultsThirty-eight patients were included. Twenty-five (66%) had resolution of the leakage. Success rate was higher in patients who were treated with implantation of a Beta stent as initial treatment (100%) than in patients who were treated with a stent after revisional surgery had failed (55%, p = 0.013). Migration occurred in 12 patients (32%). There were two severe adverse events requiring surgical intervention, including a bleeding from an aorto-esophageal fistula.ConclusionsThe success rate and the migration rate of the Beta stent seem comparable to other stents in this retrospective study. Despite the novel double-bump structure of the stent, the migration rate does not seem to be decreased.
Journal Article
Fixed-Dose Enoxaparin After Bariatric Surgery: The Influence of Body Weight on Peak Anti-Xa Levels
Introduction
There is lack of data on the pharmacodynamics of low-molecular-weight heparins in obese patients.
Background
The aims of this study are to investigate the correlation between anti-factor Xa (anti-Xa) levels and body weight with fixed-dose enoxaparin after bariatric surgery and to investigate the percentage of patients that reach the desired prophylactic range for anti-Xa levels.
Methods
Blood for anti-Xa peak levels measurement was drawn 3–5 h after administration of enoxaparin at the planned visit 8–16 days after surgery. Patients were included in three categories: <110 kg (group 1), 110–150 kg (group 2), and >150 kg (group 3).
Results
Fifty-one patients were included (43.9 ± 9.9 years, 75 % women). Mean anti-Xa level was 0.37 ± 0.14 IU/ml. This level was the highest in group 1 (0.47 ± 0.13 IU/ml) and lowest in group 3 (0.23 ± 0.07). No subprophylactic (<0.2 IU/ml) anti-Xa levels were detected in group 1, whereas this was observed in 38 % in patients in group 3. Supraprophylactic levels (>0.5 IU/ml) were most often present in group 1 (36 %). With multivariable regression analysis, body weight (
β
−0.720 (95 % confidence interval −.717; −.993),
p
< 0.001) was an independent predictor of anti-Xa levels, whereas lean body was not independently associated. This was confirmed in a non-linear mixed effects analysis of the data.
Conclusions
Patients with excessive body weight may not be adequately treated with fixed-dose enoxaparin thromboprophylaxis while patients with lower body weight may have an increased bleeding risk. Body weight is a better predictor of anti-Xa levels compared to lean body weight.
Journal Article
Risk Stratification Models: How Well do They Predict Adverse Outcomes in a Large Dutch Bariatric Cohort?
Background
Risk prediction models are useful tools for informing patients undergoing bariatric surgery about their risk for complications and correcting outcome reports. The aim of this study is to externally validate risk models assessing complications after laparoscopic Roux-en-Y gastric bypass (LRYGB) surgery.
Methods
All 740 patients who underwent a primary LRYGB between December 2007 and July 2012 were included in the validation cohort. PubMed was systematically searched for risk prediction models. Eight risk models were selected for validation. We classified our complications according to the Clavien-Dindo classification. Predefined criteria of a good model were a non-significant Hosmer and Lemeshow test, Nagelkerke
R
2
≥ 0.10, and c-statistic ≥0.7.
Results
There were 85 (7.8 %) grade 1, 54 (7.3 %) grade 2, 5 (0.7 %) grade 3a, 14 (1.9 %) grade 3b, and 14 (1.9 %) grade 4a complications in our validation cohort. Only one model predicted adverse events satisfactorily. This model consisted of one patient-related factor (age) and four surgeon- or center related factors (conversion to open surgery, intraoperative events, the need for additional procedures during LRYGB and the learning curve of the center).
Conclusions
The overall majority of the included risk models are unsuitable for risk prediction. Only one model with an emphasis on surgeon- and center-related factors instead of patient-related factors predicted adverse outcome correctly in our external validation cohort. These findings support the establishment of specialty centers and warn benchmark data institutions not to correct bariatric outcome data by any other patient-related factor than age.
Journal Article