Validation of Novel Microsurgical Vessel Anastomosis Techniques: A Systematic Review.

INTRODUCTION: Thorough validation of novel microsurgical techniques is deemed essential before their integration into clinical practice. To achieve proper validation, the design of randomized controlled trials (RCTs) should be undertaken, accompanied by the execution of comprehensive statistical analyses, including confounder adjustment and power analysis. This systematic review aims to provide an encompassing overview of the validation methodologies employed in microsurgical studies, with a specific focus on innovative vessel anastomosis techniques. METHODS: A literature search was conducted in PubMed for articles describing the validation of novel microsurgical vessel anastomosis techniques in animal or human subjects. RESULTS: The literature search yielded 6,658 articles. A total of 6,564 articles were excluded based on title and abstract. Ninety-four articles were assessed for full-text eligibility. Forty-eight articles were included in this systematic review. Out of 30 comparative studies, 9 studies validated novel modified interrupted suture techniques, 6 studies modified continuous techniques, 6 studies modified sleeve anastomosis techniques, 1 study a modified vesselotomy technique, 7 studies sutureless techniques, and 1 study a modified lymphaticovenular anastomosis technique. Twenty-eight studies contained animals (n = 1,998). Fifteen animal studies were RCTs. Two studies contained human/cadaveric subjects (n = 29). Statistical power analysis and confounder adjustment were performed in one animal study. Out of 18 noncomparative studies, 5 studies validated novel modified interrupted suture techniques, 1 study a modified continuous technique, 2 studies modified sleeve anastomosis techniques, 4 studies modified vesselotomy techniques, 4 studies sutureless techniques, and 2 studies modified lymphaticovenular anastomosis techniques. Ten studies contained animal subjects (n = 320), with two RCTs. Eight studies contained human subjects (n = 173). Statistical power analysis and confounder adjustment were performed in none of the animal or human studies. CONCLUSION: The current methods of microsurgical technique validation should be reconsidered due to poor study design. Statistical analysis including confounder adjustment and power analysis should be performed as a standard method of novel technique validation.

Most Promising Approaches to Improve Brain AVM Management: ARISE I Consensus Recommendations.

Brain arteriovenous malformations (bAVMs) are complex, and rare arteriovenous shunts that present with a wide range of signs and symptoms, with intracerebral hemorrhage being the most severe. Despite prior societal position statements, there is no consensus on the management of these lesions. ARISE (Aneurysm/bAVM/cSDH Roundtable Discussion With Industry and Stroke Experts) was convened to discuss evidence-based approaches and enhance our understanding of these complex lesions. ARISE identified the need to develop scales to predict the risk of rupture of bAVMs, and the use of common data elements to perform prospective registries and clinical studies. Additionally, the group underscored the need for comprehensive patient management with specialized centers with expertise in cranial and spinal microsurgery, neurological endovascular surgery, and stereotactic radiosurgery. The collection of prospective multicenter data and gross specimens was deemed essential for improving bAVM characterization, genetic evaluation, and phenotyping. Finally, bAVMs should be managed within a multidisciplinary framework, with clinical studies and research conducted collaboratively across multiple centers, harnessing the collective expertise and centralization of resources.

Limb-shaking transient ischemic attacks in patients with carotid occlusion or stenosis: a systematic review and individual patient data meta-analysis.

BACKGROUND: Limb-shaking transient ischemic attack (LSTIA) is a rare neurological condition which presents with involuntary jerky movements of the arm or leg, often because of carotid stenosis or occlusion. Due to the rarity of the condition, the epidemiology of LSTIA is poorly understood and the disease is frequently misdiagnosed. There is no standard treatment to date. The purpose of this study is to provide an overview of the epidemiology of LSTIA and its current treatment options. METHODS: Embase, MEDLINE, Web of Science, Cochrane Central Register of Controlled Trials for randomized controlled trials and Google Scholar were searched from database inception to 30th of December 2023 for articles containing information on the epidemiology and treatment of LSTIA. An individual patient data meta-analysis (IPD-MA) was performed using data extracted from the included articles. Inclusion criteria were description of both the epidemiology and treatment of LSTIA in patients over the age of eighteen with carotid stenosis/occlusion, confirmed by radiographic imaging. Exclusion criteria were studies focusing on pediatrics, no epidemiological data, internal carotid artery (ICA) stenosis/occlusion not radiologically confirmed, full-text unavailable, full-text not in English or Dutch, and non-original articles. RESULTS: Of the 8855 articles screened, 55 articles containing 251 patients were included. 50 articles harboring 81 patients were included in the IPD-MA and 7 articles harboring 187 patients were included in the cohort analysis. The results of the IPD-MA showed that LSTIA was caused by unilateral ICA stenosis/occlusion in 29 patients (36%) and most often from bilateral ICA stenosis/occlusion in 52 patients (64%). Limb-shaking was unilateral in 66 patients (83%) and was accompanied by weakness in 27 patients (33%). The intervention with the highest success rate was endovascular intervention (carotid stenting or balloon angioplasty), as all 10 patients remained asymptomatic after treatment. The cohort analysis showed that LSTIA can be caused by both unilateral and bilateral carotid stenosis or occlusion. The prevalence within cohorts of TIA patients of LSTIA varied considerably from 3.5% to 29%. CONCLUSION: A large international clinical registry is warranted to gain a better understanding of the epidemiology of LSTIA. There is insufficient evidence available to suggest a standard treatment.

ARISE I Consensus Review on the Management of Intracranial Aneurysms.

BACKGROUND: Intracranial aneurysms (IAs) remain a challenging neurological diagnosis associated with significant morbidity and mortality. There is a plethora of microsurgical and endovascular techniques for the treatment of both ruptured and unruptured aneurysms. There is no definitive consensus as to the best treatment option for this cerebrovascular pathology. The Aneurysm, Arteriovenous Malformation, and Chronic Subdural Hematoma Roundtable Discussion With Industry and Stroke Experts discussed best practices and the most promising approaches to improve the management of brain aneurysms. METHODS: A group of experts from academia, industry, and federal regulators convened to discuss updated clinical trials, scientific research on preclinical system models, management options, screening and monitoring, and promising novel device technologies, aiming to improve the outcomes of patients with IA. RESULTS: Aneurysm, Arteriovenous Malformation, and Chronic Subdural Hematoma Roundtable Discussion With Industry and Stroke Experts suggested the incorporation of artificial intelligence to capture sequential aneurysm growth, identify predictors of rupture, and predict the risk of rupture to guide treatment options. The consensus strongly recommended nationwide systemic data collection of unruptured IA radiographic images for the analysis and development of machine learning algorithms for rupture risk. The consensus supported centers of excellence for preclinical multicenter trials in areas such as genetics, cellular composition, and radiogenomics. Optical coherence tomography and magnetic resonance imaging contrast-enhanced 3T vessel wall imaging are promising technologies; however, more data are needed to define their role in IA management. Ruptured aneurysms are best managed at large volume centers, which should include comprehensive patient management with expertise in microsurgery, endovascular surgery, neurology, and neurocritical care. CONCLUSIONS: Clinical and preclinical studies and scientific research on IA should engage high-volume centers and be conducted in multicenter collaborative efforts. The future of IA diagnosis and monitoring could be enhanced by the incorporation of artificial intelligence and national radiographic and biologic registries. A collaborative effort between academic centers, government regulators, and the device industry is paramount for the adequate management of IA and the advancement of the field.

Association Between Early External Ventricular Drain Insertion and Functional Outcomes 6 Months Following Moderate-to-Severe Traumatic Brain Injury.

Traumatic brain injury (TBI) is a leading global cause of morbidity and mortality. Intracranial hypertension following moderate-to-severe TBI (m-sTBI) is a potentially modifiable secondary cerebral insult and one of the central therapeutic targets of contemporary neurocritical care. External ventricular drain (EVD) insertion is a common therapeutic intervention used to control intracranial hypertension and attenuate secondary brain injury. However, the optimal timing of EVD insertion in the setting of m-sTBI is uncertain and practice variation is widespread. Therefore, we aimed to assess if there is an association between timing of EVD placement and functional neurological outcome at 6 months post m-sTBI. We pooled individual patient data for all relevant harmonizable variables from the Erythropoietin in Traumatic Brain Injury (EPO-TBI) and Prophylactic Hypothermia Trial to Lessen Traumatic Brain Injury (POLAR) randomized control trials, and the Collaborative European NeuroTrauma Effectiveness Research in TBI (CENTER-TBI) Core Study version 3.0 and Australia-Europe NeuroTrauma Effectiveness Research in TBI (Oz-ENTER) prospective observational studies to create a combined dataset. The Glasgow Coma Scale (GCS) score was used to define TBI severity and we included all patients admitted to an intensive care unit with a GCS ≤12, who were 15 years or older and underwent EVD placement within 7 days of injury. We used hierarchical multi-variable logistic regression models to study the association between EVD insertion within 24 h of injury (early) compared with EVD insertion more than 24 h after injury (late) and 6-month functional neurological outcome measured using the Glasgow Outcome Score Extended (GOSE). In total, 2536 patients were assessed. Of these, 502 (20%) underwent early EVD insertion and 145 (6%) underwent late EVD insertion. Following adjustment for the IMPACT (International Mission for Prognosis and Analysis of Clinical Trials in TBI) score extended (Core + CT), sex, injury severity score, study and treatment site, patients receiving a late EVD had higher odds of death or severe disability (GOSE 1-4) at 6 months follow-up than those receiving an early EVD adjusted odds ratio; 95% confidence interval, 2.14; 1.22-3.76; p = 0.008. Our study suggests that in patients with m-sTBI where an EVD is needed, early (≤ 24 h post-injury) insertion may result in better long-term functional outcomes. This finding supports future prospective investigation in this area.

Causal inference and observational data.

Observational studies using causal inference frameworks can provide a feasible alternative to randomized controlled trials. Advances in statistics, machine learning, and access to big data facilitate unraveling complex causal relationships from observational data across healthcare, social sciences, and other fields. However, challenges like evaluating models and bias amplification remain.

Early surgery versus conservative treatment in patients with traumatic intracerebral hematoma: a CENTER-TBI study.

PURPOSE: Evidence regarding the effect of surgery in traumatic intracerebral hematoma (t-ICH) is limited and relies on the STITCH(Trauma) trial. This study is aimed at comparing the effectiveness of early surgery to conservative treatment in patients with a t-ICH. METHODS: In a prospective cohort, we included patients with a large t-ICH (< 48 h of injury). Primary outcome was the Glasgow Outcome Scale Extended (GOSE) at 6 months, analyzed with multivariable proportional odds logistic regression. Subgroups included injury severity and isolated vs. non-isolated t-ICH. RESULTS: A total of 367 patients with a large t-ICH were included, of whom 160 received early surgery and 207 received conservative treatment. Patients receiving early surgery were younger (median age 54 vs. 58 years) and more severely injured (median Glasgow Coma Scale 7 vs. 10) compared to those treated conservatively. In the overall cohort, early surgery was not associated with better functional outcome (adjusted odds ratio (AOR) 1.1, (95% CI, 0.6-1.7)) compared to conservative treatment. Early surgery was associated with better outcome for patients with moderate TBI and isolated t-ICH (AOR 1.5 (95% CI, 1.1-2.0); P value for interaction 0.71, and AOR 1.8 (95% CI, 1.3-2.5); P value for interaction 0.004). Conversely, in mild TBI and those with a smaller t-ICH (< 33 cc), conservative treatment was associated with better outcome (AOR 0.6 (95% CI, 0.4-0.9); P value for interaction 0.71, and AOR 0.8 (95% CI, 0.5-1.0); P value for interaction 0.32). CONCLUSIONS: Early surgery in t-ICH might benefit those with moderate TBI and isolated t-ICH, comparable with results of the STITCH(Trauma) trial.

Outcomes Associated With Intracranial Aneurysm Treatments Reported as Safe, Effective, or Durable: A Systematic Review and Meta-Analysis.

Importance: Testing new medical devices or procedures in terms of safety, effectiveness, and durability should follow the strictest methodological rigor before implementation. Objectives: To review and analyze studies investigating devices and procedures used in intracranial aneurysm (IA) treatment for methods and completeness of reporting and to compare the results of studies with positive, uncertain, and negative conclusions. Data Sources: Embase, MEDLINE, Web of Science, and The Cochrane Central Register of Clinical Trials were searched for studies on IA treatment published between January 1, 1995, and the October 1, 2022. Grey literature was retrieved from Google Scholar. Study Selection: All studies making any kind of claims of safety, effectiveness, or durability in the field of IA treatment were included. Data Extraction and Synthesis: Using a predefined data dictionary and analysis plan, variables ranging from patient and aneurysm characteristics to the results of treatment were extracted, as were details pertaining to study methods and completeness of reporting. Extraction was performed by 10 independent reviewers. A blinded academic neuro-linguist without involvement in IA research evaluated the conclusion of each study as either positive, uncertain, or negative. The study followed Preferring Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Main Outcomes and Measures: The incidence of domain-specific outcomes between studies with positive, uncertain, or negative conclusions regarding safety, effectiveness, or durability were compared. The number of studies that provided a definition of safety, effectiveness, or durability and the incidence of incomplete reporting of domain-specific outcomes were evaluated. Results: Overall, 12 954 studies were screened, and 1356 studies were included, comprising a total of 410 993 treated patients. There was no difference in the proportion of patients with poor outcome or in-hospital mortality between studies claiming a technique was safe, uncertain, or not safe. Similarly, there was no difference in the proportion of IAs completely occluded at last follow-up between studies claiming a technique was effective, uncertain, or noneffective. Less than 2% of studies provided any definition of safety, effectiveness, or durability, and only 1 of the 1356 studies provided a threshold under which the technique would be considered unsafe. Incomplete reporting was found in 546 reports (40%). Conclusions and Relevance: In this systematic review and meta-analysis of IA treatment literature, studies claiming safety, effectiveness, or durability of IA treatment had methodological flaws and incomplete reporting of relevant outcomes supporting these claims.

Comparative effectiveness of decompressive craniectomy versus craniotomy for traumatic acute subdural hematoma (CENTER-TBI): an observational cohort study.

Background: Limited evidence existed on the comparative effectiveness of decompressive craniectomy (DC) versus craniotomy for evacuation of traumatic acute subdural hematoma (ASDH) until the recently published randomised clinical trial RESCUE-ASDH. In this study, that ran concurrently, we aimed to determine current practice patterns and compare outcomes of primary DC versus craniotomy. Methods: We conducted an analysis of centre treatment preference within the prospective, multicentre, observational Collaborative European NeuroTrauma Effectiveness Research in Traumatic Brain Injury (known as CENTER-TBI) and NeuroTraumatology Quality Registry (known as Net-QuRe) studies, which enrolled patients throughout Europe and Israel (2014-2020). We included patients with an ASDH who underwent acute neurosurgical evacuation. Patients with severe pre-existing neurological disorders were excluded. In an instrumental variable analysis, we compared outcomes between centres according to treatment preference, measured by the case-mix adjusted proportion DC per centre. The primary outcome was functional outcome rated by the 6-months Glasgow Outcome Scale Extended, estimated with ordinal regression as a common odds ratio (OR), adjusted for prespecified confounders. Variation in centre preference was quantified with the median odds ratio (MOR). CENTER-TBI is registered with ClinicalTrials.gov, number NCT02210221, and the Resource Identification Portal (Research Resource Identifier SCR_015582). Findings: Between December 19, 2014 and December 17, 2017, 4559 patients with traumatic brain injury were enrolled in CENTER-TBI of whom 336 (7%) underwent acute surgery for ASDH evacuation; 91 (27%) underwent DC and 245 (63%) craniotomy. The proportion primary DC within total acute surgery cases ranged from 6 to 67% with an interquartile range (IQR) of 12-26% among 46 centres; the odds of receiving a DC for prognostically similar patients in one centre versus another randomly selected centre were trebled (adjusted median odds ratio 2.7, p < 0.0001). Higher centre preference for DC over craniotomy was not associated with better functional outcome (adjusted common odds ratio (OR) per 14% [IQR increase] more DC in a centre = 0.9 [95% CI 0.7-1.1], n = 200). Primary DC was associated with more follow-on surgeries and complications [secondary cranial surgery 27% vs. 18%; shunts 11 vs. 5%]; and similar odds of in-hospital mortality (adjusted OR per 14% IQR more primary DC 1.3 [95% CI (1.0-3.4), n = 200]). Interpretation: We found substantial practice variation in the employment of DC over craniotomy for ASDH. This variation in treatment strategy did not result in different functional outcome. These findings suggest that primary DC should be restricted to salvageable patients in whom immediate replacement of the bone flap is not possible due to intraoperative brain swelling. Funding: Hersenstichting Nederland for the Dutch NeuroTraumatology Quality Registry and the European Union Seventh Framework Program.

Handling missing values in healthcare data: A systematic review of deep learning-based imputation techniques.

OBJECTIVE: The proper handling of missing values is critical to delivering reliable estimates and decisions, especially in high-stakes fields such as clinical research. In response to the increasing diversity and complexity of data, many researchers have developed deep learning (DL)-based imputation techniques. We conducted a systematic review to evaluate the use of these techniques, with a particular focus on the types of data, intending to assist healthcare researchers from various disciplines in dealing with missing data. MATERIALS AND METHODS: We searched five databases (MEDLINE, Web of Science, Embase, CINAHL, and Scopus) for articles published prior to February 8, 2023 that described the use of DL-based models for imputation. We examined selected articles from four perspectives: data types, model backbones (i.e., main architectures), imputation strategies, and comparisons with non-DL-based methods. Based on data types, we created an evidence map to illustrate the adoption of DL models. RESULTS: Out of 1822 articles, a total of 111 were included, of which tabular static data (29%, 32/111) and temporal data (40%, 44/111) were the most frequently investigated. Our findings revealed a discernible pattern in the choice of model backbones and data types, for example, the dominance of autoencoder and recurrent neural networks for tabular temporal data. The discrepancy in imputation strategy usage among data types was also observed. The "integrated" imputation strategy, which solves the imputation task simultaneously with downstream tasks, was most popular for tabular temporal data (52%, 23/44) and multi-modal data (56%, 5/9). Moreover, DL-based imputation methods yielded a higher level of imputation accuracy than non-DL methods in most studies. CONCLUSION: The DL-based imputation models are a family of techniques, with diverse network structures. Their designation in healthcare is usually tailored to data types with different characteristics. Although DL-based imputation models may not be superior to conventional approaches across all datasets, it is highly possible for them to achieve satisfactory results for a particular data type or dataset. There are, however, still issues with regard to portability, interpretability, and fairness associated with current DL-based imputation models.

Sample Size, Replicability, and Pre-Test Likelihoods-Essential, Overlooked, and Critical Components of Statistical Inference: A Journal of Neurotrauma Guide to Statistical Methods and Study Design.

Perhaps one of the most overlooked components of statistical inference is the sample size. While in randomized controlled trials, power analysis is common and sample size justification is an integral component of the core statistical analysis plan, observational and laboratory research studies often rely on convenience samples and/or underpowered analyses. Insufficiently powered studies increase uncertainty associated with the results and limit interpretability. Moreover, they increase the likelihood that the findings might be disproved in future replication studies. A scientific study can be compared with a diagnostic test for the "truth"- i.e., whether a certain effect exists or whether a relationship is actually true. In this diagnostic analogy, the positive predictive value is dependent not only on the statistical power of the study in question, but also on the pre-test likelihood that any true relationship exists at all. The concept of using an estimate of the pre-test likelihood to interpret observed results is another critical and often overlooked component of statistical inference. Even if a statistically significant relationship or an effect is found, however, such finding alone may be insufficient. It often must be replicated, ideally in a more generalizable setting. Further, if the effect size is small, replication often requires sample sizes that are substantially larger than the original study. For most neurotrauma research, thousands of subjects are usually not required, but many studies do require substantially larger sample sizes than are typically presented in published research to increase replicability. In this methodological tutorial, choice of sample size, pre-test probability, and the concept of positive predictive value for scientific findings will be discussed, together with suggestions to improve replicability of neurotrauma research in the future.

A universal AutoScore framework to develop interpretable scoring systems for predicting common types of clinical outcomes.

The AutoScore framework can automatically generate data-driven clinical scores in various clinical applications. Here, we present a protocol for developing clinical scoring systems for binary, survival, and ordinal outcomes using the open-source AutoScore package. We describe steps for package installation, detailed data processing and checking, and variable ranking. We then explain how to iterate through steps for variable selection, score generation, fine-tuning, and evaluation to generate understandable and explainable scoring systems using data-driven evidence and clinical knowledge. For complete details on the use and execution of this protocol, please refer to Xie et al. (2020),1 Xie et al. (2022)2, Saffari et al. (2022)3 and the online tutorial https://nliulab.github.io/AutoScore/.

Impact of an external ventricular shunt (EVD) handling protocol on secondary meningitis rates: a historical cohort study with propensity score matching.

BACKGROUND: External ventricular drainage (EVD) is frequently used in neurosurgical procedures for cerebrospinal fluid (CSF) drainage. It is, however, associated with high infection rates, namely secondary meningitis and ventriculitis. Based on a previous high prevalence of these infections among patients with EVDs, we have proposed and implemented a protocol in an effort to decrease the infection rate. The aim of this study was to measure the effect of hospital-wide implementation of the EVD handling protocol on secondary EVD infections. PATIENTS AND METHODS: We included 409 consecutive patients who received a new EVD for other indications than infectious pathologies from January 2000 until June 2012. Patients above 18 years of age were divided into pre- (n = 228) and post-protocol (n = 181) groups. Patient and disease demographics, as well as EVD data together with confounders for secondary meningitis were recorded in a database. Propensity score matching was then performed to create groups matched for sex, age, reason for drainage, type of shunt, time in situ and duration of surgery to place the EVD. Binomial logistic regression for confounder adjustment and regression discontinuity analyses were then performed on the matched cohort. RESULTS: Infections occurred more frequently in the pre-protocol group (23% vs 9%, p <  0.001). The incidence of infection was 33/1000 drain-days pre-protocol and 9/1000 drain-days post-protocol. Regression analysis in a propensity score-matched cohort (n = 103 in the pre- and n = 178 in the post-protocol groups) showed that the pre-protocol period was independently associated with more infections (OR 2.69; 95%-CI 1.22-5.95, p = 0.01). CONCLUSIONS: The incidence of secondary EVD infections can be reduced significantly by the implementation of a strict hospital-wide EVD handling protocol.

Trapped fourth ventricle: to stent, shunt, or fenestrate-a systematic review and individual patient data meta-analysis.

Trapped or isolated fourth ventricle (TFV) is a rare but critical neurosurgical condition, mostly occurring in pediatric patients, caused by a blockage of the in- and outlets of the fourth ventricle. The purpose of this study is to review all available data on the treatment options of TFV and to compare their safety, efficacy, and durability. MEDLINE, Embase, and Google Scholar were searched from inception to September 13, 2022, for prospective or retrospective cohorts, case-control studies, case series or case reports, reporting detailing outcomes of TFV patients, treated with an endoscopic-, microsurgical-, shunt placement,- or hybrid approaches to TFV. All authors were contacted to provide individual patient data. Eighty-seven articles (314 patients) were included in the individual patient data meta-analysis (IPD) and 9 (151 patients) in the cohort meta-analysis. The IPD revealed that primary endoscopic (aOR 0.21; [95% CI 0.08-0.57]) and microsurgical interventions (aOR 0.21; [95% CI 0.05-0.82]) were associated with a significantly lower revision rate, compared to shunt placement, when adjusted for confounders. Endoscopy was also associated with a significantly higher rate of clinical improvement (aOR 4.56; [95% CI 1.2-18]). The meta-analysis revealed no significant difference in revision rate between the endoscopic (0.33 [95% CI 0.0-0.52]) and shunt group (0.44 [95% CI 0.0-1.0]). Endoscopy should be considered as the first-line treatment of TFV due to its superior efficacy, durability, and similar safety, compared to shunt placement and its minimally invasive nature. Microsurgery should be considered as a second treatment option, due to its similar clinical outcomes and revision rate as endoscopy, but it is more invasive in nature.

AutoScore-Ordinal: an interpretable machine learning framework for generating scoring models for ordinal outcomes.

BACKGROUND: Risk prediction models are useful tools in clinical decision-making which help with risk stratification and resource allocations and may lead to a better health care for patients. AutoScore is a machine learning-based automatic clinical score generator for binary outcomes. This study aims to expand the AutoScore framework to provide a tool for interpretable risk prediction for ordinal outcomes. METHODS: The AutoScore-Ordinal framework is generated using the same 6 modules of the original AutoScore algorithm including variable ranking, variable transformation, score derivation (from proportional odds models), model selection, score fine-tuning, and model evaluation. To illustrate the AutoScore-Ordinal performance, the method was conducted on electronic health records data from the emergency department at Singapore General Hospital over 2008 to 2017. The model was trained on 70% of the data, validated on 10% and tested on the remaining 20%. RESULTS: This study included 445,989 inpatient cases, where the distribution of the ordinal outcome was 80.7% alive without 30-day readmission, 12.5% alive with 30-day readmission, and 6.8% died inpatient or by day 30 post discharge. Two point-based risk prediction models were developed using two sets of 8 predictor variables identified by the flexible variable selection procedure. The two models indicated reasonably good performance measured by mean area under the receiver operating characteristic curve (0.758 and 0.793) and generalized c-index (0.737 and 0.760), which were comparable to alternative models. CONCLUSION: AutoScore-Ordinal provides an automated and easy-to-use framework for development and validation of risk prediction models for ordinal outcomes, which can systematically identify potential predictors from high-dimensional data.

Reduction of Anastomotic Time Through the Use of Cyanoacrylate in Microvascular Procedures.

Background: Ever since the description of the first microvascular anastomosis, numerous alternative methods have been described to the classical approach. Tissue adhesive has shown promising result in previous studies and can be a fast and efficient alternative which still requires more studies to allow its clinical implementation. Methods: A randomized comparative experimental study was conducted on rats' femoral arteries and an end-to-end anastomosis was performed in order to compare 2 anastomosis techniques. In one group, a simple interrupted suture was utilized, whereas in the second group a combination between fewer sutures and tissue adhesive was used. The anastomotic time, total operative time, blood flow velocity before, immediately after and 48 hours after the procedure, as well as an independent grading of the anastomosis immediately after the procedure were performed. Magnetic resonance imaging (MRI) was performed in order to assess the degree of stenosis. After euthanasia, histology and scanning electron microscopy (SEM) were performed on the vessels in order to assess possible complications. Results: A total of 24 anastomoses were performed, of which 12 with a classic technique and 12 with an adhesive technique. All the anastomoses were patent with a significant reduction of anastomotic and total operative time. The grading of the anastomoses showed better results in the classic suture group. The blood flow velocities were not statistically significant between the 2 groups. On MRI there was one stenotic anastomosis, whereas histology and SEM showed more complications on the adhesive group. Conclusion: Anastomotic times were significantly lower with a non-significant trend toward more thrombotic complications in the adhesive group. Further improvement of the glue properties and refinement of the technique will likely make it a viable alternative to interrupted suturing in the future.

Historique: Depuis que la première anastomose microvasculaire a été décrite, de nombreuses méthodes ont été utilisées en plus de la méthode classique. L'adhésif tissulaire a donné des résultats prometteurs dans des études antérieures et peut représenter une solution rapide et efficace qui devra faire l'objet de plus d'études avant d'être adoptée en clinique. Méthodologie: Les chercheurs ont mené une étude expérimentale aléatoire et comparative sur des artères fémorales de rat. Ils ont effectué une anastomose de bout en bout pour comparer deux techniques d'anastomose. Dans un groupe, une seule suture interrompue a été utilisée, et dans le second, une combinaison d'un moins grand nombre de sutures et d'adhésif tissulaire a été privilégiée. La durée de l'anastomose, la durée totale de l'intervention, la vélocité du débit sanguin avant, immédiatement après et 48 heures après l'intervention, de même que le classement indépendant de l'anastomose immédiatement après l'intervention. L'imagerie par résonance magnétique a permis d'évaluer le degré de sténose. Après l'euthanasie, les chercheurs ont effectué l'histologie et la microscopie électronique sur les vaisseaux pour évaluer les complications possibles. Résultats: Au total, 24 anastomoses ont été exécutées, soit 12 avec la technique classique et 12 avec la technique d'adhésion. Toutes les anastomoses étaient perméables et s'associaient à une réduction importante de la durée de l'anastomose et de l'opération totale. Le classement de l'anastomose a révélé de meilleurs résultats dans le groupe de suture classique. La vélocité du débit sanguin n'était pas statistiquement significative entre les deux groupes. On a constaté une anastomose sténosée à l'imagerie par résonance magnétique, tandis que l'histologie et la microscopie électronique ont révélé plus de complications dans le groupe d'adhésion. Conclusion: La durée de l'anastomose était beaucoup plus courte et présentait une tendance non significative vers un plus grand nombre de complications thrombotiques dans le groupe d'adhésion. Des améliorations des propriétés de la coller et le raffinement des techniques en feront probablement une solution viable pour remplacer les sutures.

Reduction of the Number of Live Animals Used for Microsurgical Skill Acquisition: An Experimental Randomized Noninferiority Trial.

BACKGROUND: Live animals have been used for decades as one of the many training models for developing surgical skills. Microsurgery in particular relies on training for skill acquisition and maintenance, using live animal models, especially rats (murine models). Efforts are underway to reduce the number of rats sacrificed to achieve this objective. METHODS: A group of students with minimal microsurgical experience, after having gone through a basic microsurgical course, were randomly split into three equal groups, all three groups following a 24-week standard training program based on low- and medium-fidelity training models with standardized murine training days. In addition to the standard training regimen, each participant performed supplementary training on live rats every 4, 6, or 8 weeks. According to the training program, the procedures have been performed on chicken legs, flower petals, and rats, each procedure being blindly assessed and evaluated using validated models and scales. The primary evaluated outcome was the Stanford Microsurgery and Resident Training (SMaRT) scale result of the final rat anastomosis performed by each group, for which the tested hypothesis was one of noninferiority. The secondary outcomes were represented by the final rat anastomosis time, final chicken leg anastomosis result and time, and the final petal score. RESULTS: After the 24th week, no differences were observed between the three groups regarding their microsurgical skills, as measured by the aforementioned surgical outcomes. All participants improved significantly during the study (mean [standard deviation] 19 ± 4 points on the SMaRT scale), with no significant differences between the groups, p < 0.001 for noninferiority. CONCLUSION: A training regimen based on low- and moderate-fidelity models, with the addition of training on a live rat every 8 weeks was noninferior to a training regimen that used a live rat every 6 weeks and also noninferior to a training regimen that used a live rat every 4 weeks.