Early Bird or Night Owl: Insights into Dutch Students' Study Patterns using the Medical Faculty's E-learning Registrations.

Phenomenon: Educational activities for students are typically arranged without consideration of their preferences or peak performance hours. Students might prefer to study at different times based on their chronotype, aiming to optimize their performance. While face-to-face activities during the academic schedule do not offer flexibility and cannot reflect students' natural learning rhythm, asynchronous e-learning facilitates studying at one's preferred time. Given their ubiquitous accessibility, students can use e-learning resources according to their individual needs and preferences. E-learning usage data hence serves as a valuable proxy for certain study behaviors, presenting research opportunities to explore students' study patterns. This retrospective study aims to investigate when and for how long undergraduate students used medical e-learning modules. Approach: We performed a cross-sectional analysis of e-learning usage at one medical faculty in the Netherlands. We used data from 562 undergraduate multimedia e-learning modules for pre-clinical students, covering various medical topics over a span of two academic years (2018/19 and 2019/20). We employed educational data mining approaches to process the data and subsequently identified patterns in access times and durations. Findings: We obtained data from 70,805 e-learning sessions with 116,569 module visits and 1,495,342 page views. On average, students used e-learning for 16.8 min daily and stopped using a module after 10.2 min, but access patterns varied widely. E-learning was used seven days a week with an hourly access pattern during business hours on weekdays. Across all other times, there was a smooth increase or decrease in e-learning usage. During the week, more students started e-learning sessions in the morning (34.5% vs. 19.1%) while fewer students started in the afternoon (42.6% vs. 50.8%) and the evening (19.4% vs. 27.0%). We identified 'early bird' and 'night owl' user groups that show distinct study patterns. Insights: This retrospective educational data mining study reveals new insights into the study patterns of a complete student cohort during and outside lecture hours. These findings underline the value of 24/7 accessible study material. In addition, our findings may serve as a guide for researchers and educationalists seeking to develop more individualized educational programs.

Uterine junctional zone and adenomyosis: comparison of MRI, transvaginal ultrasound and histology.

The uterine junctional zone is the subendometrial area in the myometrium that contributes to peristalsis and aids in spermatozoa and blastocyst transport. Alterations in the appearance of the junctional zone on transvaginal sonography (TVS) or magnetic resonance imaging (MRI) are associated with adenomyosis. The lack of standardization of description of its appearance and ill-defined boundaries on both histology and imaging hamper understanding of the junctional zone and limit its role in the diagnosis of adenomyosis. The objectives of this review were to investigate the accordance in definition of the junctional zone across different diagnostic approaches and to examine how imaging findings can be linked to histological findings in the context of diagnosis of adenomyosis. A comprehensive literature review was conducted of articles describing the appearance on imaging and the histological structure of the uterine junctional zone. Our review suggests that the junctional zone is distinguished from the middle and outer myometrium by gradual changes in smooth-muscle cell density, extracellular space, connective tissue, water content and vascular properties. However, while the signal intensity from the junctional zone to the middle myometrium changes abruptly on MRI, the histopathological changes are gradual and its border may be difficult or impossible to distinguish on two-dimensional TVS. Moreover, the thickness of the junctional zone measured on MRI is larger than that measured on TVS. Thus, these two imaging modalities reflect this zone differently. Although a thickened junctional zone is often used to diagnose adenomyosis on MRI, the presence of adenomyosis can be described more accurately as interruptions of the junctional zone by endometrial tissue, which leads to direct signs on imaging such as subendometrial lines and buds on two- and three-dimensional TVS or bright foci on MRI. The histopathological criteria for diagnosis are based on enlargement of the uterus with severe adenomyosis, and might not reflect its early stages. Clinicians should be aware that findings on MRI cannot be extrapolated readily to ultrasound. An understanding of this is necessary when investigating the uterine junctional zone as a functional unit and the association between visualization of direct features of adenomyosis in the junctional zone and clinical symptoms. © 2022 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Consensus on revised definitions of Morphological Uterus Sonographic Assessment (MUSA) features of adenomyosis: results of modified Delphi procedure.

OBJECTIVES: To evaluate whether the Morphological Uterus Sonographic Assessment (MUSA) features of adenomyosis need to be better defined and, if deemed necessary, to reach consensus on the updated definitions. METHODS: A modified Delphi procedure was performed among European gynecologists with expertise in ultrasound diagnosis of adenomyosis. To identify MUSA features that might need revision, 15 two-dimensional (2D) video recordings (four recordings also included three-dimensional (3D) still images) of transvaginal ultrasound (TVS) examinations of the uterus were presented in the first Delphi round (online questionnaire). Experts were asked to confirm or refute the presence of each of the nine MUSA features of adenomyosis (described in the original MUSA consensus statement) in each of the 15 videoclips and to provide comments. In the second Delphi round (online questionnaire), the results of the first round and suggestions for revision of MUSA features were shared with the experts before they were asked to assess a new set of 2D and 3D still images of TVS examinations and to provide feedback on the proposed revisions. A third Delphi round (virtual group meeting) was conducted to discuss and reach final consensus on revised definitions of MUSA features. Consensus was predefined as at least 66.7% agreement between experts. RESULTS: Of 18 invited experts, 16 agreed to participate in the Delphi procedure. Eleven experts completed and four experts partly finished the first round. The experts identified a need for more detailed definitions of some MUSA features. They recommended use of 3D ultrasound to optimize visualization of the junctional zone. Fifteen experts participated in the second round and reached consensus on the presence or absence of ultrasound features of adenomyosis in most of the still images. Consensus was reached for all revised definitions except those for subendometrial lines and buds and interrupted junctional zone. Thirteen experts joined the online meeting, in which they discussed and agreed on final revisions of the MUSA definitions. There was consensus on the need to distinguish between direct features of adenomyosis, i.e. features indicating presence of ectopic endometrial tissue in the myometrium, and indirect features, i.e. features reflecting changes in the myometrium secondary to presence of endometrial tissue in the myometrium. Myometrial cysts, hyperechogenic islands and echogenic subendometrial lines and buds were classified unanimously as direct features of adenomyosis. Globular uterus, asymmetrical myometrial thickening, fan-shaped shadowing, translesional vascularity, irregular junctional zone and interrupted junctional zone were classified as indirect features of adenomyosis. CONCLUSION: Consensus between gynecologists with expertise in ultrasound diagnosis of adenomyosis was achieved regarding revised definitions of the MUSA features of adenomyosis and on the classification of MUSA features as direct or indirect signs of adenomyosis. © 2021 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Definition and sonographic reporting system for Cesarean scar pregnancy in early gestation: modified Delphi method.

OBJECTIVE: To develop a standardized sonographic evaluation and reporting system for Cesarean scar pregnancy (CSP) in the first trimester, for use by both general gynecology and expert clinics. METHODS: A modified Delphi procedure was carried out, in which 28 international experts in obstetric and gynecological ultrasonography were invited to participate. Extensive experience in the use of ultrasound to evaluate Cesarean section (CS) scars in early pregnancy and/or publications concerning CSP or niche evaluation was required to participate. Relevant items for the detection and evaluation of CSP were determined based on the results of a literature search. Consensus was predefined as a level of agreement of at least 70% for each item, and a minimum of three Delphi rounds were planned (two online questionnaires and one group meeting). RESULTS: Sixteen experts participated in the Delphi study and four Delphi rounds were performed. In total, 58 items were determined to be relevant. We differentiated between basic measurements to be performed in general practice and advanced measurements for expert centers or for research purposes. The panel also formulated advice on indications for referral to an expert clinic. Consensus was reached for all 58 items on the definition, terminology, relevant items for evaluation and reporting of CSP. It was recommended that the first CS scar evaluation to determine the location of the pregnancy should be performed at 6-7 weeks' gestation using transvaginal ultrasound. The use of magnetic resonance imaging was not considered to add value in the diagnosis of CSP. A CSP was defined as a pregnancy with implantation in, or in close contact with, the niche. The experts agreed that a CSP can occur only when a niche is present and not in relation to a healed CS scar. Relevant sonographic items to record included gestational sac (GS) size, vascularity, location in relation to the uterine vessels, thickness of the residual myometrium and location of the pregnancy in relation to the uterine cavity and serosa. According to its location, a CSP can be classified as: (1) CSP in which the largest part of the GS protrudes towards the uterine cavity; (2) CSP in which the largest part of the GS is embedded in the myometrium but does not cross the serosal contour; and (3) CSP in which the GS is partially located beyond the outer contour of the cervix or uterus. The type of CSP may change with advancing gestation. Future studies are needed to validate this reporting system and the value of the different CSP types. CONCLUSION: Consensus was achieved among experts regarding the sonographic evaluation and reporting of CSP in the first trimester. © 2021 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Effect of single- versus double-layer uterine closure during caesarean section on postmenstrual spotting (2Close): multicentre, double-blind, randomised controlled superiority trial.

OBJECTIVE: To evaluate whether double-layer uterine closure after a first caesarean section (CS) is superior compared with single-layer uterine closure in terms of postmenstrual spotting and niche development in the uterine caesarean scar. DESIGN: Multicentre, double-blind, randomised controlled superiority trial. SETTING: Thirty-two hospitals in the Netherlands. POPULATION: A total of 2292 women aged ≥18 years undergoing a first CS were randomly assigned to each procedure (1:1): 1144 women were assigned to single-layer uterine closure and 1148 women were assigned to double-layer uterine closure. METHODS: Single-layer unlocked closure and double-layer unlocked closure, with the second layer imbricating the first. MAIN OUTCOME MEASURES: Number of days with postmenstrual spotting during one menstrual cycle 9 months after CS. SECONDARY OUTCOMES: perioperative and menstrual characteristics; transvaginal ultrasound measurements. RESULTS: A total of 774 (67.7%) women from the single-layer group and 770 (67.1%) women from the double-layer group were evaluable for the primary outcome, as a result of drop-out and amenorrhoea. The mean number of postmenstrual spotting days was 1.33 (bootstrapped 95% CI 1.12-1.54) after single-layer closure and 1.26 (bootstrapped 95% CI 1.07-1.45) after double-layer closure (adjusted mean difference -0.07, 95% CI -0.37 to 0.22, P = 0.810). The operative time was 3.9 minutes longer (95% CI 3.0-4.9 minutes, P < 0.001) and niche prevalence was 4.7% higher (95% CI 0.7-8.7%, P = 0.022) after double-layer closure. CONCLUSIONS: The superiority of double-layer closure compared with single-layer closure in terms of postmenstrual spotting after a first CS was not shown. Long-term obstetric follow-up of our trial is needed to assess whether uterine caesarean closure guidelines should be adapted. TWEETABLE ABSTRACT: Double-layer uterine closure is not superior for postmenstrual spotting after a first caesarean; single-layer closure performs slightly better on other outcomes.

Sonographic examination of uterine niche in non-pregnant women: a modified Delphi procedure.

OBJECTIVE: To generate guidance for detailed uterine niche evaluation by ultrasonography in the non-pregnant woman, using a modified Delphi procedure amongst European experts. METHODS: Twenty gynecological experts were approached through their membership of the European Niche Taskforce. All experts were physicians with extensive experience in niche evaluation in clinical practice and/or authors of niche publications. By means of a modified Delphi procedure, relevant items for niche measurement were determined based on the results of a literature search and recommendations of a focus group of six Dutch experts. It was predetermined that at least three Delphi rounds would be performed (two online questionnaires completed by the expert panel and one group meeting). For it to be declared that consensus had been reached, a consensus rate for each item of at least 70% was predefined. RESULTS: Fifteen experts participated in the Delphi procedure. Consensus was reached for all 42 items on niche evaluation, including definitions, relevance, method of measurement and tips for visualization of the niche. A niche was defined as an indentation at the site of a Cesarean section with a depth of at least 2 mm. Basic measurements, including niche length and depth, residual and adjacent myometrial thickness in the sagittal plane, and niche width in the transverse plane, were considered to be essential. If present, branches should be reported and additional measurements should be made. The use of gel or saline contrast sonography was preferred over standard transvaginal sonography but was not considered mandatory if intrauterine fluid was present. Variation in pressure generated by the transvaginal probe can facilitate imaging, and Doppler imaging can be used to differentiate between a niche and other uterine abnormalities, but neither was considered mandatory. CONCLUSION: Consensus between niche experts was achieved regarding ultrasonographic niche evaluation. © 2018 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of the International Society of Ultrasound in Obstetrics and Gynecology.

Single- versus double-layer closure of the caesarean (uterine) scar in the prevention of gynaecological symptoms in relation to niche development - the 2Close study: a multicentre randomised controlled trial.

BACKGROUND: Double-layer compared to single-layer closure of the uterus after a caesarean section (CS) leads to a thicker myometrial layer at the site of the CS scar, also called residual myometrium thickness (RMT). It possibly decreases the development of a niche, which is an interruption of the myometrium at the site of the uterine scar. Thin RMT and a niche are associated with gynaecological symptoms, obstetric complications in a subsequent pregnancy and delivery and possibly with subfertility. METHODS: Women undergoing a first CS regardless of the gestational age will be asked to participate in this multicentre, double blinded randomised controlled trial (RCT). They will be randomised to single-layer closure or double-layer closure of the uterine incision. Single-layer closure (control group) is performed with a continuous running, unlocked suture, with or without endometrial saving technique. Double-layer closure (intervention group) is performed with the first layer in a continuous unlocked suture including the endometrial layer and the second layer is also continuous unlocked and imbricates the first. The primary outcome is the reported number of days with postmenstrual spotting during one menstrual cycle nine months after CS. Secondary outcomes include surgical data, ultrasound evaluation at three months, menstrual pattern, dysmenorrhea, quality of life, and sexual function at nine months. Structured transvaginal ultrasound (TVUS) evaluation is performed to assess the uterine scar and if necessary saline infusion sonohysterography (SIS) or gel instillation sonohysterography (GIS) will be added to the examination. Women and ultrasound examiners will be blinded for allocation. Reproductive outcomes at three years follow-up including fertility, mode of delivery and complications in subsequent deliveries will be studied as well. Analyses will be performed by intention to treat. 2290 women have to be randomised to show a reduction of 15% in the mean number of spotting days. Additionally, a cost-effectiveness analysis will be performed from a societal perspective. DISCUSSION: This RCT will provide insight in the outcomes of single- compared to double-layer closure technique after CS, including postmenstrual spotting and subfertility in relation to niche development measured by ultrasound. TRIAL REGISTRATION: Dutch Trial Register ( NTR5480 ). Registered 29 October 2015.

Quality specifications in postgraduate medical e-learning: an integrative literature review leading to a postgraduate medical e-learning model.

BACKGROUND: E-learning is driving major shifts in medical education. Prioritizing learning theories and quality models improves the success of e-learning programs. Although many e-learning quality standards are available, few are focused on postgraduate medical education. METHODS: We conducted an integrative review of the current postgraduate medical e-learning literature to identify quality specifications. The literature was thematically organized into a working model. RESULTS: Unique quality specifications (n = 72) were consolidated and re-organized into a six-domain model that we called the Postgraduate Medical E-learning Model (Postgraduate ME Model). This model was partially based on the ISO-19796 standard, and drew on cognitive load multimedia principles. The domains of the model are preparation, software design and system specifications, communication, content, assessment, and maintenance. CONCLUSION: This review clarified the current state of postgraduate medical e-learning standards and specifications. It also synthesized these specifications into a single working model. To validate our findings, the next-steps include testing the Postgraduate ME Model in controlled e-learning settings.

Visualisation of microvascular flow in benign uterine disorders: a pilot study of a new diagnostic technique.

Background: Uterine disorders have clear overlapping symptoms and ultrasound discrimination is not always easy. Accurately measuring vascularity is of diagnostic and prognostic value. Power Doppler is limited to imaging only the larger vessels. Assessment of the microvasculature requires advanced machine settings. Objectives: In this pilot study, we aimed to test the feasibility of microvascular flow imaging of benign uterine disorders. Material and Methods: Two experienced gynaecologists (JH, RL) randomly applied power Doppler and MV-flowTM mode during a single day, in ten patients each visiting the outpatient clinic. Images of eight patients were labelled with a diagnosis by the attending physicians and collected as coded data. Main outcome measures: Microvascular flow images of normal uterine architecture including the fallopian tube, and of benign disorders such as fibroids, adenomyosis, endometriosis and uterine niches were collected. For both Doppler techniques, qualitative descriptive evaluation of the vascular architecture and a quantitative vascular index of fibroids were provided. Finally, we evaluated the effect of the cardiac cycle. Results: All microvascular flow images showed more distinctive vascular structures than visible on power Doppler. Calculating a vascular index for fibroids on 2D MV-flowTM images was easily performed on-site. During the cardiac cycle a higher vascular index (VI 75.2) is obtained in systole as compared with diastole (VI 44.0). Conclusion: Microvascular flow imaging allowed detailed visualisation of the uterine vascular architecture and is easy to use. What is new?: Microvascular flow imaging may be of added value for diagnosing uterine disorders, as well as for pre- and post-operative assessment of suited surgical techniques. Yet, validation with histology and clinical outcomes is required.

The definition, diagnosis, and symptoms of the uterine niche - A systematic review.

Of all neonates, 21% are delivered by cesarean section (CS). A long-term maternal complication of an SC is a uterine niche. The aim of this review is to provide an overview of the current literature on imaging techniques and niche-related symptomatology. We performed systematic searches on imaging and niche symptoms. For both searches, 87 new studies were included. Niche evaluation by transvaginal sonography (TVS) or contrast sonohysterography (SHG) proved superior over hysteroscopy or magnetic resonance imaging. Studies that used SHG in a random population identified a niche prevalence of 42%-84%. Niche prevalence differed based on niche definition, symptomatology, and imaging technique. Most studies reported an association with gynecological symptoms, poor reproductive outcomes, obstetrical complications, and reduced quality of life. In conclusion, non-invasive TVS and SHG are the superior imaging modalities to diagnose a niche. Niches are prevalent and strongly associated with gynecological symptoms and poor reproductive outcomes.

Aetiology, risk factors and preventive strategies for niche development: A review.

The increase in caesarean sections (CS) has resulted in an increase in women with a uterine niche. The exact aetiology of niche development has yet to be elucidated but is likely multifactorial. This study aimed to give a systematic overview of the available literature on histopathological features, risk factors and results of preventive strategies on niche development to gain more insight into the underlying mechanisms. Based on current published data histopathological findings associated with niche development were necrosis, fibrosis, inflammation, adenomyosis and insufficient approximation. Patient-related risk factors included multiple CS, BMI and smoking. Labour-related factors were CS before onset of labour, extended cervical dilatation, premature rupture of membranes and presenting part of the fetus at CS below the pelvic inlet. Preventive strategies should focus on the optimal level of incision, training of surgeons and full-thickness closure of the myometrium (single or double-layer) using non-locking sutures. Conflicting data exist concerning the effect of endometrial inclusion. Future studies without heterogeneity in population, using standardized performance of the CS after proper training and using standardized niche evaluation with a relevant core outcome set are required to allow meta-analyses and to develop evidence-based preventive strategies. These studies are needed to reduce the prevalence of niches and prevent complications in subsequent pregnancies such as caesarean scar pregnancies.

Stress, anxiety and depression in 1466 pregnant women during and before the COVID-19 pandemic: a Dutch cohort study.

OBJECTIVE: The coronavirus disease (COVID-19) pandemic has negatively affected many people's mental health with increased symptoms of stress, anxiety and depression in the general population. Anxiety and depression can have negative effects on pregnant women and result in poor neonatal outcomes. Therefore, we analyzed stress, anxiety and depression in pregnant women during the COVID-19 pandemic. MATERIALS AND METHODS: Cohort study of pregnant women during COVID-19 compared to pregnant women before COVID-19. Pregnant women were recruited through social media platforms from 21 May 2020 to 22 June 2020. Pregnant women ≥ 18 years of age, who master the Dutch language were included. The Hospital Anxiety and Depression Scale (HADS) and the Perceived Stress Scale (PSS-10) were analyzed. Demographic features were summarized using descriptive statistics. Possible differences in demographic variables between groups were compared using Mann Whitney U test and Chi-squared test. Significant demographic differences between groups were controlled for using logistical regression analysis or an independent one-way analysis of covariance. RESULTS: Thousand hundred and two pregnant women completed the questionnaires during COVID-19, and 364 pregnant women before COVID-19. We found no differences in clinically high levels of anxiety (HADS-A ≥ 8) and depression (HADS-D ≥ 8) in women during COVID-19 (19.5% and 13.2%, respectively) and women before COVID-19 (23.1% and 15.7%, respectively). A question was implemented whether participants related their stress level to COVID-19. Women who related their stress to the COVID-19 pandemic reported significantly higher overall stress levels on the PSS-10 compared to women with stress unrelated to COVID-19 (mean, 15.62; standard deviation [SD], 6.44 vs. mean, 10.28; SD, 5.48; p < 0.001). CONCLUSION: In contrast to previous studies, COVID-19 did not increase anxiety and depression levels in Dutch pregnant women. Women who related their perceived stress to the COVID-19 pandemic experienced higher stress levels than women who did not relate their stress to the COVID-19 pandemic, suggesting that interventions that specifically aim to reduce COVID-19 stress, may help to reduce overall stress levels in pregnant women during the pandemic.

Feasibility study for performing uterus transplantation in the Netherlands.

STUDY QUESTION: Is it feasible to perform uterus transplantations (UTx) in a tertiary centre in the Netherlands? SUMMARY ANSWER: Considering all ethical principles, surgical risks and financial aspects, we have concluded that at this time, it is not feasible to establish the UTx procedure at our hospital. WHAT IS KNOWN ALREADY: UTx is a promising treatment for absolute uterine factor infertility. It is currently being investigated within several clinical trials worldwide and has resulted in the live birth of 19 children so far. Most UTx procedures are performed in women with the Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome, a congenital disorder characterized by absence of the uterus. In the Netherlands, the only possible option for these women for having children is adoption or surrogacy. STUDY DESIGN SIZE DURATION: We performed a feasibility study to search for ethical, medical and financial support for performing UTx at the Amsterdam UMC, location VUmc. PARTICIPANTS/MATERIALS SETTING METHODS: For this feasibility study, we created a special interest group, including gynaecologists, transplant surgeons, researchers and a financial advisor. Also, in collaboration with the patients' association for women with MRKH, a questionnaire study was performed to research the decision-making in possible recipients. In this paper, we present an overview of current practices and literature on UTx and discuss the results of our feasibility study. MAIN RESULTS AND THE ROLE OF CHANCE: A high level of interest from the possible recipients became apparent from our questionnaire amongst women with MRKH. The majority (64.8%) positively considered UTx with a live donor, with 69.6% having a potential donor available. However, this 'non-life-saving transplantation' requires careful balancing of risks and benefits. The UTx procedure includes two complex surgeries and unknown consequences for the unborn child. The costs for one UTx are calculated to be around €100 000 and will not be compensated by medical insurance. The Clinical Ethics Committee places great emphasis on the principle of non-maleficence and the 'fair distribution of health services'. LIMITATIONS REASONS FOR CAUTION: In the Netherlands, alternatives for having children are available and future collaboration with experienced foreign clinics that offer the procedure is a possibility not yet investigated. WIDER IMPLICATIONS OF THE FINDINGS: The final assessment of this feasibility study is that that there are not enough grounds to support this procedure at our hospital at this point in time. We will closely follow the developments and will re-evaluate the feasibility in the future. STUDY FUNDING/COMPETING INTERESTS: This feasibility study was funded by the VU Medical Center (Innovation grant 2017). No conflicts of interest have been reported relevant to the subject of all authors. TRIAL REGISTRATION NUMBER: n.a.

A Randomised Controlled Trial of Consent Procedures for the Use of Residual Tissues for Medical Research: Preferences of and Implications for Patients, Research and Clinical Practice.

BACKGROUND: Despite much debate, there is little evidence on consequences of consent procedures for residual tissue use. Here, we investigated these consequences for the availability of residual tissue for medical research, clinical practice, and patient informedness. METHODS: We conducted a randomised clinical trial with three arms in six hospitals. Participants, patients from whom tissue had been removed for diagnosis or treatment, were randomised to one of three arms: informed consent, an opt-out procedure with active information provision (opt-out plus), and an opt-out procedure without active information provision. Participants received a questionnaire six weeks post-intervention; a subsample of respondents was interviewed. Health care providers completed a pre- and post-intervention questionnaire. We assessed percentage of residual tissue samples available for medical research, and patient and health care provider satisfaction and preference. Health care providers and outcome assessors could not be blinded. RESULTS: We randomised 1,319 patients, 440 in the informed consent, 434 in the opt-out plus, and 445 in the opt-out arm; respectively 60.7%, 100%, and 99.8% of patients' tissue samples could be used for medical research. Of the questionnaire respondents (N = 224, 207, and 214 in the informed consent, opt-out plus, and opt-out arms), 71%, 69%, and 31%, respectively, indicated being (very) well informed. By questionnaire, the majority (53%) indicated a preference for informed consent, whereas by interview, most indicated a preference for opt-out plus (37%). Health care providers (N = 35) were more likely to be (very) satisfied with opt-out plus than with informed consent (p = 0.002) or opt-out (p = 0.039); the majority (66%) preferred opt-out plus. CONCLUSION: We conclude that opt-out with information (opt-out plus) is the best choice to balance the consequences for medical research, patients, and clinical practice, and is therefore the most optimal consent procedure for residual tissue use in Dutch hospitals. TRIAL REGISTRATION: Dutch Trial Register NTR2982.