Normal form for the onset of collapse: The prototypical example of the nonlinear Schrödinger equation.

The study of nonlinear waves that collapse in finite time is a theme of universal interest, e.g., within optical, atomic, plasma physics, and nonlinear dynamics. Here we revisit the quintessential example of the nonlinear Schrödinger equation and systematically derive a normal form for the emergence of radially symmetric blowup solutions from stationary ones. While this is an extensively studied problem, such a normal form, based on the methodology of asymptotics beyond all algebraic orders, applies to both the dimension-dependent and power-law-dependent bifurcations previously studied. It yields excellent agreement with numerics in both leading and higher-order effects, it is applicable to both infinite and finite domains, and it is valid in both critical and supercritical regimes.

Transparency in surgical randomized clinical trials: cross-sectional observational study.

BACKGROUND: RCTs provide the scientific basis upon which treatment decisions are made. To facilitate critical review, it is important that methods and results are reported transparently. The aim of this study was to explore transparency in surgical RCTs with respect to trial registration, disclosure of funding sources, declarations of investigator conflicts and data-sharing. METHODS: This was a cross-sectional review of published surgical RCTs. Ten high-impact journals were searched systematically for RCTs published in years 2009, 2012, 2015 and 2018. Four domains of transparency were explored: trial registration, disclosure of funding, disclosure of investigator conflicts, and a statement relating to data-sharing. RESULTS: Of 611 RCTs, 475 were eligible for analysis. Some 397 RCTs (83.6 per cent) were registered on a trial database, of which 190 (47·9 per cent) had been registered prospectively. Prospective registration increased over time (26 per cent in 2009, 33·0 per cent in 2012, 54 per cent in 2015, and 72·7 per cent in 2018). Funding disclosure was present in 55·0, 65·0, 69·4 and 75·4 per cent of manuscripts respectively. Conflict of interest disclosure was present in 49·5, 89·1, 94·6 and 98·3 per cent of manuscripts across the same time periods. Data-sharing statements were present in only 15 RCTs (3·2 per cent), 11 of which were published in 2018. CONCLUSION: Trial registration, disclosure of funding and disclosure of investigator conflicts in surgical RCTs have improved markedly over the past 10 years. Disclosure of data-sharing plans is exceptionally low. This may contribute to research waste and represents a target for improvement.

ANTECEDENTES: Los ensayos clínicos aleatorizados y controlados (randomized controlled trials, RCT) proporcionan la base científica para la toma de decisiones terapéuticas. Es importante que los métodos y los resultados se presenten de forma transparente para facilitar la revisión crítica. El objetivo de este estudio fue investigar la transparencia en los RCTs del ámbito quirúrgico según su registro, declaraciones de las fuentes de financiación del estudio y conflicto de interés de los investigadores, así como información referente a compartir los datos. MÉTODOS: Revisión transversal de RCTs quirúrgicos publicados. Se realizó una búsqueda sistemática de los RCTs publicados en 10 revistas de alto impacto en los años 2009, 2012, 2015 y 2018. Se exploraron cuatro dominios de transparencia: el registro de los ensayos, la declaración de los fondos utilizados, la declaración de los conflictos de los investigadores y la información referente a la forma de compartir los datos. RESULTADOS: De 611 RCTs, se incluyeron en el análisis 475. Un total de 397 (83,6%) estudios se registraron en una base de datos de ensayos clínicos, de forma prospectiva en 190 (47,9%). El registro prospectivo aumentó a lo largo del tiempo (26,0% en 2009, 33,0% en 2012, 53,5% en 2015 y 72,7% en 2018). Se mencionaban las fuentes de financiación en el 55%, 65%, 69,4% y 75,4% de los manuscritos, respectivamente. La declaración de conflictos de interés estuvo presente en el 49,5%, 89,1%, 94,6% y 98,3% de los manuscritos en esos mismos períodos de tiempo. Las declaraciones relativas a compartir los datos de la investigación constaban en solo 15 (3,2%) RCTs, 11 de los cuales fueron publicados en el 2018. CONCLUSIÓN: En los últimos 10 años ha mejorado de forma notable el registro de los ensayos y las declaraciones de las fuentes de financiación y conflicto de interés en los RCTs quirúrgicos. La declaración referente a compartir los datos es excepcionalmente baja, lo que puede contribuir al desperdicio de la investigación y constituye un objetivo de mejora.

Patient education about recovery after colorectal surgery: systematic scoping review.

AIM: Enhanced recovery after surgery (ERAS) protocols aim to optimize recovery through a series of evidence-based recommendations. A key component of ERAS is the provision of patient education. Whilst the recommendation for this is strong, the evidence to inform its format, timing and delivery is unclear. The aim of this review was to describe previous educational interventions used to improve recovery after colorectal surgery and to explore opportunities for future research. METHODS: A systematic scoping review was performed. MEDLINE and Embase databases were searched between 1 January 1990 and 12 February 2020. Studies which described or assessed the effectiveness of a patient education or information resource to improve recovery after colorectal surgery were eligible. Outcomes of interest included the format, timing and delivery of interventions, as well as key features of intervention and study design. A narrative synthesis of data was produced through a process of charting and summarizing key results. RESULTS: A total of 1298 papers were inspected, and 11 were eligible for inclusion. Five papers were reports of randomized controlled trials, and others reported a mix of non-randomized and qualitative studies. The design of educational interventions included audio-visual resources (n = 3), smartphone device applications (n = 3) and approaches to facilitate person-to-person counselling (n = 5). Most of the counselling interventions reported positive outcomes (mainly in length of hospital stay), whereas the other types reported mixed results. Patients and the public were seldom involved as collaborators in the design of interventions. CONCLUSIONS: Patient education is generally advantageous, but there is insufficient evidence to optimize its design and delivery in the setting of colorectal surgery.

The outcome of pregnancy in women with cystic fibrosis: a UK population-based descriptive study.

OBJECTIVE: To estimate the incidence of cystic fibrosis in pregnancy and to explore obstetric and neonatal outcomes. DESIGN: A population-based descriptive study using the methodology of the UK Obstetric Surveillance System (UKOSS). SETTING: All consultant-led maternity units in the UK. POPULATION: All pregnant women with a diagnosis of cystic fibrosis who booked for antenatal care in a UK obstetric unit between March 2015 and February 2017. METHODS: Prospective case collection identified using UKOSS monthly notification. MAIN OUTCOME MEASURES: Incidence, maternal morbidity, maternal mortality, gestation at delivery, neonatal mortality, neonatal morbidity. RESULTS: We report 71 pregnancies over a 2-year period. There was one early miscarriage, four terminations and three sets of twins, resulting in the live birth of 69 infants. There were no maternal deaths. One infant died following spontaneous preterm birth at 29 weeks' gestation. The mean gestation at delivery was 36.2 completed weeks. The mean birthweight centile for gestational age was the 61st centile. We report a positive correlation between both maternal lung function (FEV1 ) and mean gestation at delivery, and between FEV1 and mean birthweight centile for gestational age. CONCLUSIONS: Pregnancy outcomes are generally good in women with cystic fibrosis. Successful pregnancy is possible even in those women with FEV1 <60% predicted, although such women have higher chance of preterm delivery and a smaller baby. TWEETABLE ABSTRACT: Pregnant women with cystic fibrosis who have poorer lung function at the beginning of pregnancy have a higher risk of having a premature or smaller baby.

Establishing core outcome sets for gastrointestinal recovery in studies of postoperative ileus and small bowel obstruction: protocol for a nested methodological study.

INTRODUCTION: Gastrointestinal recovery describes the restoration of normal bowel function in patients with bowel disease. This may be prolonged in two common clinical settings: postoperative ileus and small bowel obstruction. Improving gastrointestinal recovery is a research priority but researchers are limited by variation in outcome reporting across clinical studies. This protocol describes the development of core outcome sets for gastrointestinal recovery in the contexts of postoperative ileus and small bowel obstruction. METHOD: An international Steering Group consisting of patient and clinician representatives has been established. As overlap between clinical contexts is anticipated, both outcome sets will be co-developed and may be combined to form a common output with disease-specific domains. The development process will comprise three phases, including definition of outcomes relevant to postoperative ileus and small bowel obstruction from systematic literature reviews and nominal-group stakeholder discussions; online-facilitated Delphi surveys via international networks; and a consensus meeting to ratify the final output. A nested study will explore if the development of overlapping outcome sets can be rationalized. DISSEMINATION AND IMPLEMENTATION: The final output will be registered with the Core Outcome Measures in Effectiveness Trials initiative. A multi-faceted, quality improvement campaign for the reporting of gastrointestinal recovery in clinical studies will be launched, targeting international professional and patient groups, charitable organizations and editorial committees. Success will be explored via an updated systematic review of outcomes 5 years after registration of the core outcome set.

Randomized controlled trial of plain English and visual abstracts for disseminating surgical research via social media.

BACKGROUND: Patients are increasingly taking an active role in the design and delivery of surgical research. Public communication of results should also be encouraged, but this is often limited to non-expert commentary. This study assessed the role of plain English abstracts disseminated via social media in engaging patients and clinicians in the communication of surgical research. METHODS: A three-arm randomized controlled trial with crossover of two intervention arms was performed. Manuscripts accepted for publication in BJS were allocated to one of three arms and disseminated via Twitter: plain English abstracts, visual abstracts and standard tweets. The primary outcome was online engagement (a composite of tweets, replies and likes) by members of the public within 14 days. The secondary outcome was online engagement by healthcare professionals. RESULTS: Forty-one manuscripts were randomized to plain English abstracts (14), visual abstracts (14) and standard tweets (13). The number of public engagements was low, with a mean of 1·8 (range 0-8), 2·5 (0-11), and 1·2 (0-4) for plain English abstracts, visual abstracts and standard tweets respectively. The mean number of engagements by healthcare professionals was 29·4 (6-66), 45·3 (6-161) and 28·8 (10-52) respectively. Overall, visual abstracts attracted a significantly greater number of engagements than plain English ones (P < 0·001). CONCLUSION: Online, public engagement with surgical research was low. Overall engagement (predominantly from healthcare professionals) was enhanced by the use of visual abstracts.

ANTECEDENTES: Los pacientes están tomando cada vez más un papel activo en el diseño y en la difusión de la investigación quirúrgica. También se debe fomentar la comunicación pública de los resultados, pero a menudo ésta se limita a comentarios de personas no expertas. Este estudio evaluó el papel de los resúmenes redactados en un inglés sencillo difundidos a través de las redes sociales para involucrar a pacientes y médicos en la comunicación de la investigación quirúrgica. MÉTODOS: Se realizó un ensayo aleatorizado y controlado de tres brazos con un diseño cruzado de los dos brazos de intervención. Los manuscritos aceptados para publicación en BJS se asignaron a tres brazos y se difundieron vía twitter: resúmenes redactados en un inglés sencillo, resúmenes visuales, y tweets estándar. El criterio de valoración principal fue la interacción online (variable compuesta de tweets, respuestas y me gusta) por parte del público durante los primeros 14 días. El criterio de valoración secundario fue la interacción online de los profesionales de la salud. RESULTADOS: Un total de 41 manuscritos se asignaron al azar a resúmenes redactados en un inglés sencillo (n = 14), resúmenes visuales (n = 14) y tweets estándar (n = 13). El número de interacciones por parte del público fue bajo, con una media de 1,8 (rango 0-8), 2,5 (rango 0-11) y 1,2 (rango 0-4) para resúmenes en inglés sencillo, resúmenes visuales y tweets estándar, respectivamente. El número medio de interacciones por profesionales de la salud fue de 29,4 (rango 6-66), 45,3 (6-161) y 28,8 (10-52). En general, los resúmenes visuales atrajeron un número significativamente mayor de interacciones que los de inglés sencillo (P = 0,001). CONCLUSIÓN: La interacción online del público con la investigación quirúrgica fue baja. La participación general (predominantemente de profesionales de la salud) mejoró mediante el uso de resúmenes visuales. Los próximos trabajos podrían considerar si el público desea interaccionar y de qué modo con resúmenes redactados en un inglés sencillo.

Research waste in surgical randomized controlled trials.

BACKGROUND: Research waste is a major challenge for evidence-based medicine. It implicates misused resources and increased risks for research participants. The aim of this study was to quantify constituent components of waste in surgical RCTs and explore targets for improvement. METHODS: ClinicalTrials.gov was searched for RCTs registered between January 2011 and December 2012 using the keyword 'surgery'. The primary outcome was research waste, defined as non-publication, inadequate reporting or presence of an avoidable design limitation. Serial systematic searches of PubMed and Scopus databases were performed to determine publication status. Adequacy of reporting was assessed using the CONSORT checklist. Avoidable design limitations were evaluated according to the presence of bias and/or the absence of a cited systematic review of the literature. RESULTS: Of 5617 registered RCTs, 304 met all eligibility criteria. Overall, 259 of 304 (85·2 per cent) demonstrated at least one feature of waste. Of these, 221 (72·7 per cent) were published in a peer-reviewed journal and 219 were accessible for full-text review. Only 73 of 131 (55·7 per cent) RCTs with a pharmacological intervention and 24 of 88 (27 per cent) with a non-pharmacological intervention were reported adequately, and 159 of 219 (72·6 per cent) demonstrated an avoidable design limitation. Multicentre (odds ratio 0·31, 95 per cent c.i. 0·11 to 0·88) and externally funded (OR 0·35, 0·15 to 0·82) RCTs were less associated with research waste. CONCLUSION: This study identified a considerable burden of research waste in surgical RCTs. Future initiatives should target improvements in single-centre, poorly supported RCTs.

ANTECEDENTES: El despilfarro en investigación es uno de los mayores retos para la medicina basada en la evidencia. Conlleva mala utilización de los recursos y aumento de los riesgos para los participantes en las investigaciones. El objetivo de este trabajo fue cuantificar los componentes que conforman este despilfarro en los ensayos aleatorizados y controlados (randomised controlled trials, RCTs) del ámbito quirúrgico y explorar los aspectos clave de mejora. MÉTODOS: Se realizó una búsqueda de los RCTs registrados en la base de datos ClinicalTrials.gov entre enero de 2011 y diciembre de 2012, utilizando la palabra clave cirugía. La variable primaria fue el despilfarro en investigación, definido como la no publicación, el informe inadecuado o la presencia de debilidades del diseño evitables. Para determinar el estado de las publicaciones, se realizaron búsquedas sistemáticas en las bases de datos PubMed y Scopus. La adecuación del informe se evaluó usando la lista de verificación CONSORT. Las debilidades del diseño evitables se evaluaron de acuerdo con la presencia de sesgo y/o la ausencia de citación en revisiones sistemáticas publicadas en la literatura. RESULTADOS: De los 5.617 RCTs registrados, 304 cumplieron con los criterios de elegibilidad. De ellos, 259/304 (85%) cumplieron al menos una de las características de despilfarro. De estos, 221 (73%) se publicaron en una revista con peer review y 219 eran accesibles a texto completo. Únicamente 73/131 (56%) RCTs con una intervención farmacológica y 24/88 (27%) con una intervención no farmacológica presentaban un informe adecuado, y 159/219 (73%) se demostró una debilidad del diseño evitable. Los RCTs multicéntricos (OR: 0,31; i.c. del 95%: 0,11 a 0,88) y con financiación externa (OR: 0,35; i.c. del 95%: 0,15 a 0,82) se asociaron con menos despilfarro de investigación. CONCLUSIÓN: Este estudio constató una carga considerable de despilfarro en investigación en los RCTs quirúrgicos. Se deberían promover iniciativas de mejora, especialmente dirigidas a los RCTs realizados en un solo centro y con menos financiación.

A simple mechanochemical model for calcium signalling in embryonic epithelial cells.

Calcium signalling is one of the most important mechanisms of information propagation in the body. In embryogenesis the interplay between calcium signalling and mechanical forces is critical to the healthy development of an embryo but poorly understood. Several types of embryonic cells exhibit calcium-induced contractions and many experiments indicate that calcium signals and contractions are coupled via a two-way mechanochemical feedback mechanism. We present a new analysis of experimental data that supports the existence of this coupling during apical constriction. We then propose a simple mechanochemical model, building on early models that couple calcium dynamics to the cell mechanics and we replace the hypothetical bistable calcium release with modern, experimentally validated calcium dynamics. We assume that the cell is a linear, viscoelastic material and we model the calcium-induced contraction stress with a Hill function, i.e. saturating at high calcium levels. We also express, for the first time, the "stretch-activation" calcium flux in the early mechanochemical models as a bottom-up contribution from stretch-sensitive calcium channels on the cell membrane. We reduce the model to three ordinary differential equations and analyse its bifurcation structure semi-analytically as two bifurcation parameters vary-the [Formula: see text] concentration, and the "strength" of stretch activation, [Formula: see text]. The calcium system ([Formula: see text], no mechanics) exhibits relaxation oscillations for a certain range of [Formula: see text] values. As [Formula: see text] is increased the range of [Formula: see text] values decreases and oscillations eventually vanish at a sufficiently high value of [Formula: see text]. This result agrees with experimental evidence in embryonic cells which also links the loss of calcium oscillations to embryo abnormalities. Furthermore, as [Formula: see text] is increased the oscillation amplitude decreases but the frequency increases. Finally, we also identify the parameter range for oscillations as the mechanical responsiveness factor of the cytosol increases. This work addresses a very important and not well studied question regarding the coupling between chemical and mechanical signalling in embryogenesis.

Systematic review of definitions and outcome measures for return of bowel function after gastrointestinal surgery.

Background: Ileus is common after gastrointestinal surgery and has been identified as a research priority. Several issues have limited previous research, including a widely accepted definition and agreed outcome measure. This review is the first stage in the development of a core outcome set for the return of bowel function after gastrointestinal surgery. It aims to characterize the extent of variation in current outcome reporting. Methods: A systematic search of MEDLINE, Embase, CINAHL (Cumulative Index to Nursing and Allied Health Literature) and the Cochrane Library was performed for 1990-2017. RCTs of adults undergoing gastrointestinal surgery, including at least one reported measure relating to return of bowel function, were eligible. Trial registries were searched across the same period for ongoing and completed (but not published) RCTs. Definitions of ileus and outcome measures describing the return of bowel function were extracted. Results: Of 5670 manuscripts screened, 215 (reporting 217 RCTs) were eligible. Most RCTs involved patients undergoing colorectal surgery (161 of 217, 74·2 per cent). A total of 784 outcomes were identified across all published RCTs, comprising 73 measures (clinical: 63, 86 per cent; radiological: 6, 8 per cent; physiological: 4, 5 per cent). The most commonly reported outcome measure was 'time to first passage of flatus' (140 of 217, 64·5 per cent). The outcomes 'ileus' and 'prolonged ileus' were defined infrequently and variably. Conclusion: Outcome reporting for the return of bowel function after gastrointestinal surgery is variable and not fit for purpose. An agreed core outcome set will improve the consistency, reliability and clinical value of future studies.

Systematic review of the stage of innovation of biological mesh for complex or contaminated abdominal wall closure.

BACKGROUND: Achieving stable closure of complex or contaminated abdominal wall incisions remains challenging. This study aimed to characterize the stage of innovation for biological mesh devices used during complex abdominal wall reconstruction and to evaluate the quality of current evidence. METHODS: A systematic review was performed of published and ongoing studies between January 2000 and September 2017. Eligible studies were those where a biological mesh was used to support fascial closure, either prophylactically after midline laparotomy, or for reinforcement after repair of incisional hernia with midline incision. The primary outcome measure was the IDEAL framework stage of innovation. The key secondary outcome measure was the GRADE criteria for study quality. RESULTS: Thirty-five studies including 2681 patients were included. Four studies considered mesh prophylaxis, 23 considered hernia repair, and eight reported on both. There was one published randomized trial (IDEAL stage 3), none of which was of high quality; the others were non-randomized studies (IDEAL stage 2a). A detailed description of surgical technique was provided in most studies (27 of 35); however, no study reported outcomes according to the European Hernia Society consensus statement and only two described quality control of surgical technique during the study. From 21 ongoing randomized trials and observational studies, 11 considered repair of incisional hernia and 10 considered prophylaxis (seven in elective settings). CONCLUSION: The evidence base for biological mesh is limited, and better reporting and quality control of surgical techniques are needed. Although results of ongoing trials over the next decade will improve the evidence base, further study is required in the emergency and contaminated settings.

Postoperative ileus following major colorectal surgery.

BACKGROUND: Postoperative ileus (POI) is characterized by delayed gastrointestinal recovery following surgery. Current knowledge of pathophysiology, clinical interventions and methodological challenges was reviewed to inform modern practice and future research. METHODS: A systematic search of MEDLINE and Embase databases was performed using search terms related to ileus and colorectal surgery. All RCTs involving an intervention to prevent or reduce POI published between 1990 and 2016 were identified. Grey literature, non-full-text manuscripts, and reanalyses of previous RCTs were excluded. Eligible articles were assessed using the Cochrane tool for assessing risk of bias. RESULTS: Of 5614 studies screened, 86 eligible articles describing 88 RCTs were identified. Current knowledge of pathophysiology acknowledges neurogenic, inflammatory and pharmacological mechanisms, but much of the evidence arises from animal studies. The most common interventions tested were chewing gum (11 trials) and early enteral feeding (11), which are safe but of unclear benefit for actively reducing POI. Others, including thoracic epidural analgesia (8), systemic lidocaine (8) and peripheral µ antagonists (5), show benefit but require further investigation for safety and cost-effectiveness. CONCLUSION: POI is a common condition with no established definition, aetiology or treatment. According to current literature, minimally invasive surgery, protocol-driven recovery (including early feeding and opioid avoidance strategies) and measures to avoid major inflammatory events (such as anastomotic leak) offer the best chances of reducing POI.

Ileus Management International (IMAGINE): protocol for a multicentre, observational study of ileus after colorectal surgery.

AIM: The management of postoperative ileus following colorectal surgery remains controversial. It is the commonest complication after elective colorectal resection and is associated with an increased incidence of postoperative adverse events. The prevention and management of postoperative ileus remains unstandardized. This study aims to describe an international profile of gastrointestinal recovery after colorectal surgery and will assess the role of non-steroidal anti-inflammatory drugs, when used as postoperative analgesia, in expediting the return of gastrointestinal function. METHODS: A multicentre, student- and trainee-led, prospective cohort study will be conducted across both Europe and Australasia. Adult patients undergoing elective colorectal resection during 2-week data collection periods between January and April 2018 will be included. A site-specific questionnaire will capture compliance to Enhanced Recovery after Surgery components at participating centres. The primary outcome is time to gastrointestinal recovery, measured using a composite outcome of bowel function and oral tolerance. The impact of non-steroidal anti-inflammatory drugs on gastrointestinal recovery will be evaluated along with safety data with respect to anastomotic leak, acute kidney injury and complications within 30 days of surgery. DISCUSSION: This protocol describes the methodology of an international, observational assessment of gastrointestinal recovery after colorectal surgery. It discusses key challenges and describes how the results will impact on future investigation. The study will be conducted across a large student- and trainee-led collaborative network, with prospective quality assurance and data validation strategies.

#colorectalsurgery.

BACKGROUND: The use of social media platforms among healthcare professionals is increasing. A Twitter social media campaign promoting the hashtag #colorectalsurgery was launched with the aim of providing a specialty-specific forum to collate discussions and science relevant to an engaged, global community of coloproctologists. This article reviews initial experiences of the early adoption, engagement and utilization of this pilot initiative. METHODS: The hashtag #colorectalsurgery was promoted via the online microblogging service Twitter across a 180-day interval. Data on all tweets containing the #colorectalsurgery hashtag were analysed using online analytical tools. Data included total number of tweets, number of views, and user engagement since registration and launch of the campaign. Content of tweet and user demographic analysis was undertaken. RESULTS: The number of tweets using #colorectalsurgery grew rapidly following the launch on 24 April 2016; #colorectalsurgery was used in 15 708 tweets, which resulted in 65 398 696 impressions and involved 1863 individual Twitter accounts. Increased volumes of #colorectalsurgery tweets were noted in association with the timing of three major international colorectal surgical conferences, and geographical trends were noted. Some 88·4 per cent of all posts were by male users. The top 25 users by volume of #colorectalsurgery tweets had considerable influence and posted 8023 tweets (51·1 per cent). CONCLUSION: Online global communities formed via healthcare-related hashtags, such as #colorectalsurgery, unify social media posts, scientists, surgeons and authors who have an interest in coloproctology. Furthermore, they facilitate greater connectivity among geographically separate users.

Cross-sectional observational study of the availability of evidence supporting novel implantable devices used in gastrointestinal surgery.

BACKGROUND: Evidence supporting the implementation of novel surgical devices is unstandardized, despite recommendations for assessing novel innovations. This study aimed to determine the proportion of novel implantable devices used in gastrointestinal surgery that are supported by evidence from RCTs. METHODS: A list of novel implantable devices placed intra-abdominally during gastrointestinal surgery was produced. Systematic searches were performed for all devices via PubMed and clinical trial registries. The primary outcome measure was the availability of at least one published RCT for each device. Published RCTs were appraised using the Cochrane tool for assessing risk of bias. RESULTS: A total of 116 eligible devices were identified (implantable mesh 42, topical haemostatics 22, antiadhesion barriers 10, gastric bands 8, suture and staple-line reinforcement 7, artificial sphincters 5, other 22). One hundred and twenty-eight published RCTs were found for 33 of 116 devices (28·4 per cent). Most were assessed as having a high risk of bias, with only 12 of 116 devices (10·3 per cent) supported by a published RCT considered to be low risk. A further 95 ongoing and 23 unpublished RCTs were identified for 42 of 116 devices (36·2 per cent), but many (64 of 116, 55·2 per cent) had no evidence from published, ongoing or unpublished RCTs. The highest stage of innovation according to the IDEAL Framework was stage 1 for 11 devices, stage 2a for 23 devices, stage 2b for one device and stage 3 for 33 devices. The remaining 48 devices had no relevant clinical evidence. CONCLUSION: Only one in ten novel implantable devices available for use in gastrointestinal surgical practice is supported by high-quality RCT evidence.