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Purpose of Review: Benign prostatic hyperplasia (BPH) is a disease of the lower urinary tract which often requires surgical treatment. Recently, there has been a deluge of new treatment options, rarely validated or compared to current treatments on a benchtop model. The purpose of this review is to examine the literature and report which benchtop models are currently being used, which therapies have been tested on them, and what outcomes are being studied on each model. Recent Findings: There are various benchtop models to choose from, each with their unique benefits and drawbacks. Perfused porcine kidney models are used to assess bleeding on the benchtop, ex-vivo human prostate helps to see specific interactions of devices with the prostatic tissue, and all other models have evaluated tissue ablation rates and depth of coagulation. There are currently no synthetic or non-animal tissues being used for this purpose, and surgical techniques such as enucleation, water-jet ablation, prostate stents, and water vapor thermal therapy have no representation in these benchtop tests. Summary: Benchtop testing serves an important role in the evaluation and comparison of surgical treatments for BPH. This testing allows these therapies to be objectively compared to one another, helping novel medical devices in their path to market and urologists make treatment decisions. Future directions may include further validation of the animal models currently being used and development of synthetic models which mimic the prostate on the benchtop. [ABSTRACT FROM AUTHOR]

Introduction: This study aimed to describe the fabrication, implementation and evaluation of 3D‐printed patient‐specific models for unskilled students to enhance learning in immediate implant procedures and provisionalization. Materials and Methods: The individualized simulation models were designed and processed based on CT and digital intraoral scanning of a patient. Thirty students performed simulation implant surgery and provisionalized the implant sites on the models and answered questionnaires to assess their perceptions before and after the training. The scores of the questionnaires were analysed using the Wilcoxon signed‐rank test. Results: Significant differences before and after training were found in the students' responses. Students reported better results in understanding of surgical procedures, knowledge in prosthetically driven implantology, understanding of minimally invasive tooth extraction, confirming the accuracy of surgical template, usage of the guide rings and usage of the surgical cassette after simulation training. The overall expenditure on the simulation training involving 30 students amounted to 342.5 USD. Conclusions: The patient‐specific and cost‐efficient 3D printed models are helpful for students to improve theoretical knowledge and practical skills. Such individualized simulation models have promising application prospects. [ABSTRACT FROM AUTHOR]

Background: Remote teaching of procedural skills has demonstrated equivalence in knowledge acquisition compared to in-person teaching. Variations in terminology for probe and needle movements may serve as a barrier in remote training of ultrasound (US)-guided renal access for percutaneous nephrolithotomy (PCNL). This pilot study investigated the utility of standardized terminology in remote training of US-guided renal access for PCNL. Hypothesis: Standardization of verbal terminology to describe US probe and needle movement instruction improves remote teaching of US-guided renal access. Methods: Fifteen urology residents (PGY1-6) were stratified by year and randomized into two groups. We provided participants with images illustrating US probe and needle movements labeled with predetermined standardized terminology for the intervention group and images without labels for the control group. Both groups were asked to perform US-guided renal access on a training mannequin with a remote faculty educator with (intervention) or without (control) use of standardized movement instructions. Quantitative outcomes included number of attempts and time to achieve access. All trainees completed pre- and post-session surveys and participated in focus groups; authors conducted thematic analysis of focus group transcripts. Results: Differences in primary outcomes between groups, including number of attempts and time to achieve access of the renal pole, were not statistically significant. Analysis of focus group interviews revealed that the use of standardized terminology in the setting of remote training can reduce trainee confusion by clarifying ambiguity in educator feedback. Discussion: Use of standardized terminology during remote surgical skills training allows for more effective feedback to trainees.

Heart failure (HF) is a serious health and economic burden worldwide, and its prevalence is continuously increasing. Current medications effectively moderate the progression of symptoms, and there is a need for novel preventative and reparative treatments. The development of novel HF treatments requires the testing of potential therapeutic procedures in appropriate animal models of HF. During the past decades, murine models have been extensively used in fundamental and translational research studies to better understand the pathophysiological mechanisms of HF and develop more effective methods to prevent and control congestive HF. Proper surgical approaches and anesthetic protocols are the first steps in creating these models, and each successful approach requires a proper anesthetic protocol that maintains good recovery and high survival rates after surgery. However, each protocol may have shortcomings that limit the study's outcomes. In addition, the ethical regulations of animal welfare in certain countries prohibit the use of specific anesthetic agents, which are widely used to establish animal models. This review summarizes the most common and recent surgical models of HF and the anesthetic protocols used in rat models. We will highlight the surgical approach of each model, the use of anesthesia, and the limitations of the model in the study of the pathophysiology and therapeutic basis of common cardiovascular diseases.

Robust and predictive pre‐clinical models of recalcitrant diabetic wounds are critical for advancing research efforts toward improving healing. Murine models have logistic and genetic benefits versus larger animals; however, native murine healing inadequately represents clinically recalcitrant wounds in humans. Furthermore, current humanization techniques employing devices, deleterious mutations or chemical agents each carry model‐specific limitations. To better replicate human wounds in a mouse, we developed a novel wound‐edge inversion (WEI) technique that mimics the architecture of epibole and mitigates contracture, epithelialization, and consequently wound closure. In this study, we evaluated the reliability and durability of the WEI model in wild‐type and obese diabetic mice and compared to healing after (i) punch biopsy, (ii) mechanical/silicone stenting or (iii) exogenous oxidative stressors. In wild‐type mice, WEI demonstrated favourable closure characteristics compared to both control and stented wounds, however, wounds progressed to closure by 4 weeks. In contrast, diabetic WEI wounds persisted for 6–10 weeks with reduced contracture and epithelialization. In both diabetic and wild‐type mice, WEI sites demonstrated persistence of inflammatory populations, absence of epithelialization, and histologic presence of alpha‐SMA positive granulation tissue when compared to controls. We conclude that the WEI technique is particularly valuable for modelling recalcitrant diabetic wounds with sustained inflammation and dysfunctional healing. [ABSTRACT FROM AUTHOR]

Chronic heart failure (CHF) has attracted the attention of researchers and doctors for a long time, because, unfortunately, the number of patients with this pathology grows every year. The study of the etiology, pathogenesis, treatment methods, and possible consequences of CHF is important for effective therapy and prevention. Cardiac pathology is characterized by the appearance of shortness of breath, development of chronic fatigue, edema, decreased physical activity due to disruption of normal perfusion of organs and tissues, and the development of chronic hypoxia. In this regard, modeling of heart failure in animals seems to be very relevant and promising, as it makes it possible to study the etiopathogenetic features of the development of CHF and its complications in detail. The preclinical stage of the study of drugs on animals allows evaluation of the mechanism of action of the drug, choose the right dosage, and describe side effects. The use of small rodents in the creation of CHF models is less time-consuming and economically more feasible than conducting research on large animals. This article provides an analysis of the effectiveness and reproducibility of biological models of CHF. We describe the most common modern surgical and pharmacological models, experimental methods, crucial hemodynamic and histomorphological changes observed during the development of CHF in animals, and the disadvantages and advantages of different types of modeling. [ABSTRACT FROM AUTHOR]

Objective: To systematically review the published literature describing remote alternative educational modalities for plastic surgery residents. Design: Systematic review. Setting: Independent investigators performed searches in the PubMed and Cochrane Library databases using a variety of MeSH terms and search term combinations. These studies were evaluated for inclusion based on PRISMA criteria. Participants: Literature searches were performed from June to December 2020, and articles were collected if they met the inclusion criteria. Studies were also qualitatively assessed to determine whether the described education modality demonstrated high fidelity (anatomic accuracy and similarity to true surgery) and efficacy (improved trainee performance in a standardized skills evaluation). Results: Initial database searches resulted in 2,849 total articles. Of these, 451 articles were deemed relevant for screening, and after applying additional exclusion criteria, 202 articles were assessed for eligibility. Of these, 66 articles met the inclusion criteria and were included in the qualitative synthesis. Articles were organized into three broad categories: physical models (n = 42, 63.7%), virtual simulators (n = 16, 24.2%), and online resources (n = 8, 12.1%). Among the physical models, we identified 15 high fidelity, 20 high efficacy, 5 high fidelity and high efficacy, and 2 high efficacy but low fidelity models. Among the virtual simulators, 6 demonstrated high fidelity, 8 high efficacy, and 2 demonstrated both values. Among the online resources, 3 showed high fidelity and 3 showed high efficacy. Conclusions: A variety of remote training modalities have been published, including articles describing virtual surgical simulators, virtual and physical anatomic models, and online resources with video modules. Further investigation is needed to evaluate how effectively training received through remote means translates to practice in live clinical scenarios in the operating room. ACGME competency addressed: Practice-based Learning and Improvement.

Acute liver failure is marked by the rapid deterioration of liver function in a previously well patient over period of days to weeks. Though relatively rare, it is associated with high morbidity and mortality. This makes it a challenging disease to study clinically, necessitating reliance on preclinical models as means to explore pathophysiology and novel therapies. Preclinical models of acute liver failure are artificial by nature, and generally fall into one of three categories: surgical, pharmacologic or immunogenic. This article reviews preclinical models of acute liver failure and considers their relevance in modeling clinical disease. [ABSTRACT FROM AUTHOR]

Acute liver failure is marked by the rapid deterioration of liver function in a previously well patient over period of days to weeks. Though relatively rare, it is associated with high morbidity and mortality. This makes it a challenging disease to study clinically, necessitating reliance on preclinical models as means to explore pathophysiology and novel therapies. Preclinical models of acute liver failure are artificial by nature, and generally fall into one of three categories: surgical, pharmacologic or immunogenic. This article reviews preclinical models of acute liver failure and considers their relevance in modeling clinical disease.

Neonates and pediatric populations are vulnerable subjects in terms of health. Proper screening and early optimal treatment would reduce infant and child mortality, improving the quality of life. Researchers and clinicians all over the world are in pursuit of innovations to improve the medical care delivery system. Infant morphometrics changes drastically due to the rapid somatic growth in infancy and childhood, demanding for patient-specific customization of treatment intervention accordingly. 3D printing is a radical technology that allows the generation of physical 3D products from digital images and addresses the patient-specific requirement. The combination of cost-effective and on-demand customization offers a boundless opportunity for the enhancement of neonates and pediatric health. Conclusion: The advanced technology of 3D printing proposes a pioneering breakthrough in bringing physiologically and anatomically appropriate treatment strategies addressing the unmet needs of child health problems. What is Known: • The potential application of 3D printing is observed across a multitude of fields within medicine and surgery. • The unprecedented effect of this technology on pediatric healthcare is still very much a work in progress. What is New: • The recent clinical applications of 3D printing provide better treatment modalities to infants and children. • The review provides an overview of the comparison between conventional treatment methods and 3DP regarding specific applications [ABSTRACT FROM AUTHOR]

Pain is a complex constellation of cognitive, unpleasant sensory, and emotional experiences that primarily serves as a survival mechanism. Pain arises in the peripheral nervous system and pain signals synapse with nerve tracts extending into the central nervous system. Several different schemes are used to classify pain, including the underlying mechanism, tissues primarily affected, and time-course. Numerous animal models of pain, which should be employed with appropriate Institutional Animal Care and Use approvals, have been developed to elucidate pathophysiology mechanisms and aid in identification of novel therapeutic targets. The variety of available models underscores the observations that pain phenotypes are driven by several distinct mechanisms. Pain outcome measurement encompasses both reflexive (responses to heat, cold, mechanical and electrical stimuli) and nonreflexive (spontaneous pain responses to stimuli) behaviors. However, the question of translatability to human pain conditions and potential treatment outcomes remains a topic of continued scrutiny. In this review we discuss the different types of pain and their mechanisms and pathways, available rodent pain models with an emphasis on type of pain stimulations and pain outcome measures and discuss the role of pathologists in assessing and validating pain models. [ABSTRACT FROM AUTHOR]

Rodent surgical animal models of heart failure (HF) are critically important for understanding the proof of principle of the cellular alterations underlying the development of the disease as well as evaluating therapeutics. Robust, reproducible rodent models are a prerequisite to the development of pharmacological and molecular strategies for the treatment of HF in patients. Due to the absence of standardized guidelines regarding surgical technique and clear criteria for HF progression in rats, objectivity is compromised. Scientific publications in rats rarely fully disclose the actual surgical details, and technical and physiological challenges. This lack of reporting is one of the main reasons that the outcomes specified in similar studies are highly variable and associated with unnecessary loss of animals, compromising scientific assessment. This review details rat circulatory and coronary arteries anatomy, the surgical details of rat models that recreate the HF phenotype of myocardial infarction, ischemia/reperfusion, left and right ventricular pressure, and volume overload states, and summarizes the technical and physiological challenges of creating HF. The purpose of this article is to help investigators understand the underlying issues of current HF models in order to reduce variable results and ensure successful, reproducible models of HF. [ABSTRACT FROM AUTHOR]

Background: Remote teaching of procedural skills has demonstrated equivalence in knowledge acquisition compared to in-person teaching. Variations in terminology for probe and needle movements may serve as a barrier in remote training of ultrasound (US)-guided renal access for percutaneous nephrolithotomy (PCNL). This pilot study investigated the utility of standardized terminology in remote training of US-guided renal access for PCNL., Hypothesis: Standardization of verbal terminology to describe US probe and needle movement instruction improves remote teaching of US-guided renal access., Methods: Fifteen urology residents (PGY1-6) were stratified by year and randomized into two groups. We provided participants with images illustrating US probe and needle movements labeled with predetermined standardized terminology for the intervention group and images without labels for the control group. Both groups were asked to perform US-guided renal access on a training mannequin with a remote faculty educator with (intervention) or without (control) use of standardized movement instructions. Quantitative outcomes included number of attempts and time to achieve access. All trainees completed pre- and post-session surveys and participated in focus groups; authors conducted thematic analysis of focus group transcripts., Results: Differences in primary outcomes between groups, including number of attempts and time to achieve access of the renal pole, were not statistically significant. Analysis of focus group interviews revealed that the use of standardized terminology in the setting of remote training can reduce trainee confusion by clarifying ambiguity in educator feedback., Discussion: Use of standardized terminology during remote surgical skills training allows for more effective feedback to trainees., Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:David Bayne reports financial support was provided by National Institute of Diabetes and Digestive and Kidney Disorders., (© 2023 The Authors.)

Abstract: Introduction: The aim of this study was to evaluate whether inexpensive 3D models can be suitable to train surgical skills to dental students or oral and maxillofacial surgery residents. Furthermore, we wanted to know which of the most common filament materials, acrylonitrile butadiene styrene (ABS) or polylactic acid (PLA), can better simulate human bone according to surgeons' subjective perceptions. Materials and Methods: Upper and lower jaw models were produced with common 3D desktop printers, ABS and PLA filament and silicon rubber for soft tissue simulation. Those models were given to 10 blinded, experienced maxillofacial surgeons to perform sinus lift and wisdom teeth extraction. Evaluation was made using a questionnaire. Results: Because of slightly different density and filament prices, each silicon‐covered model costs between 1.40‐1.60 USD (ABS) and 1.80‐2.00 USD (PLA) based on 2017 material costs. Ten experienced raters took part in the study. All raters deemed the models suitable for surgical education. No significant differences between ABS and PLA were found, with both having distinct advantages. Conclusion: The study demonstrated that 3D printing with inexpensive printing filaments is a promising method for training oral and maxillofacial surgery residents or dental students in selected surgical procedures. With a simple and cost‐efficient manufacturing process, models of actual patient cases can be produced on a small scale, simulating many kinds of surgical procedures. [ABSTRACT FROM AUTHOR]

Objectives:To validate the ovine model of profound oropharyngeal dysphagia and compare swallowing outcomes of laryngotracheal separation with those of total laryngectomy.Methods:Under real-time fluoroscopy, swallowing trials were conducted using the head and neck of two Dorper cross ewes and one human cadaver, secured in lateral fluoroscopic orientation. Barium trials were administered at baseline, pre- and post-laryngohyoid suspension, following laryngotracheal separation, and following laryngectomy in the ovine model.Results:Mean pre-intervention Penetration Aspiration Scale and National Institutes of Health Swallow Safety Scale scores were 8 ± 0 and 6 ± 0 respectively in sheep and human cadavers, with 100 per cent intra- and inter-species reproducibility. These scores improved to 1 ± 0 and 2 ± 0 post-laryngohyoid suspension (p < 0.01). Aerodigestive tract residue was 18.6 ± 2.4 ml at baseline, 15.4 ± 3.8 ml after laryngotracheal separation and 3.0 ± 0.7 ml after total laryngectomy (p < 0.001).Conclusion:The ovine model displayed perfect intra- and inter- species reliability for the Penetration Aspiration Scale and Swallow Safety Scale. Less aerodigestive tract residue after narrow-field laryngectomy suggests that swallowing outcomes after total laryngectomy are superior to those after laryngotracheal separation. [ABSTRACT FROM PUBLISHER]

In Brazil, there is a great lack of micro-surgeons due to the fact that the training is long, expensive and requires a lot of dedication. With the outbreak of Committee on Animal Research and Ethics, it becomes increasingly restricted the surgical training of academics using small and medium-sized animals. The objective of this work was to report the training of medical academics of the Pontifical Catholic University of Rio Grande do Sul (PUCRS) in microsurgery in the repair of peripheral nerve lesions by means of the tubulization technique. The 12-week training was carried out in a research laboratory of the PUCRS Hospital-School, using a low-cost commercial experimental model (cooled chicken thigh purchased in the local market of the city of Porto Alegre) and consisted in the execution of incision techniques Medial to the femur, dissection of the adjacent structures and exposure of the sciatic nerve, sciatic nerve section and tubulization by suturing the proximal and distal nerve at the ends of the silicone tube. The training provided an evolution in the skill of the trained technicians aswell as in the time necessary for its accomplishment demonstrating that commercialized chicken pieces are an excellent model for the microsurgical training. [ABSTRACT FROM AUTHOR]

Heart failure (HF) is a serious health and economic burden worldwide, and its prevalence is continuously increasing. Current medications effectively moderate the progression of symptoms, and there is a need for novel preventative and reparative treatments. The development of novel HF treatments requires the testing of potential therapeutic procedures in appropriate animal models of HF. During the past decades, murine models have been extensively used in fundamental and translational research studies to better understand the pathophysiological mechanisms of HF and develop more effective methods to prevent and control congestive HF. Proper surgical approaches and anesthetic protocols are the first steps in creating these models, and each successful approach requires a proper anesthetic protocol that maintains good recovery and high survival rates after surgery. However, each protocol may have shortcomings that limit the study's outcomes. In addition, the ethical regulations of animal welfare in certain countries prohibit the use of specific anesthetic agents, which are widely used to establish animal models. This review summarizes the most common and recent surgical models of HF and the anesthetic protocols used in rat models. We will highlight the surgical approach of each model, the use of anesthesia, and the limitations of the model in the study of the pathophysiology and therapeutic basis of common cardiovascular diseases., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Farag, Mandour, Hendawy, Elhaieg, Elfadadny and Tanaka.)

El fallo hepático fulminante (FHF) es un síndrome clínico muy grave, asociado con alta mortalidad, a pesar de los grandes avances que se han producido en los últimos años en la terapia tanto del manejo de los cuidados intensivos mediante diversos soportes hepáticos bioartificiales como del trasplante hepático. Tanto el conocimiento como el tratamiento del FHF han estado limitados por la falta de modelos animales satisfactorios. Así, han sido muchos los intentos de desarrollar un modelo adecuado, entre los que se incluyen los modelos quirúrgicos, tales como la hepatectomía y desvascularización total y/o parcial, la utilización de sustancias químicas con toxicidad hepática tales como el acetaminofeno, azoximetano, galactosamina, tioacetamida, entre otras. Ahora bien, la mayor parte de estos modelos no reflejan de modo idóneo el patrón de la enfermedad humana de FHF y todos ellos presentan importantes limitaciones. A pesar de que la hepatitis vírica es una de las etiologías más frecuentes de FHF, el uso de agentes víricos para desarrollar modelos animales ha sido escaso y desafortunado. Nuestro grupo ha desarrollado recientemente un modelo animal mediante la inoculación de conejos con el virus de la enfermedad hemorrágica del conejo que presenta características bioquímicas, histológicas y signos clínicos compatibles con el FHF del hombre. En el trabajo se resumen los modelos animales más utilizados asi como las ventajas e inconvenientes más reseñables de cada uno de ellos.Fulminant hepatic failure (FHF) is a very serious clinical síndrome that, in spite of the important therapeutical advances that have taken place in the last years by means of bioartifical hepatic support devices and hepatic transplantation, is still associated to a high mortality. Knowledge and treatment of the FHF have been limited by the lack of satisfactory animal models. Among the attempts to develop a suitable model are surgical models, such as hepatectomy and total and/or partial devascularization, or the use of chemical substances with hepatic toxicity, such as acetaminophen, azoximethane, galactosamine or thioacetamide, among others. However, most of these models do not adequatly reflect the pattern of the human disease and all of them present important limitations. Although viral hepatitis is one of the most frequent causes of FHF, the use of viral agents to develop animal models has been little and unfortunate. Our group has recently developed a viral animal model of FHF by means of the inoculation of rabbits with the virus of the rabbit hemorrhagic disease. This model displays biochemical, and histological characteristics, and clinical signs that ressemble those in human FHF. In the present article, the most widely used animal models of FHF, together with their main advantages and disadvantages, are presented.

In this study, we aimed to verify the accuracy of models created with the help of open-source Slicer 3.6.3 software (Surgical Planning Lab, Harvard Medical School, Harvard University, Boston, MA, USA) and the Mcor Matrix 300 paper-based 3D printer. Our study focused on the accuracy of recreating the walls of the right orbit of a cadaveric skull. Cone beam computed tomography (CBCT) of the skull was performed (0.25-mm pixel size, 0.5-mm slice thickness). Acquired DICOM data were imported into Slicer 3.6.3 software, where segmentation was performed. A virtual model was created and saved as an .STL file and imported into Netfabb Studio professional 4.9.5 software. Three different virtual models were created by cutting the original file along three different planes (coronal, sagittal, and axial). All models were printed with a Selective Deposition Lamination Technology Matrix 300 3D printer using 80 gsm A4 paper. The models were printed so that their cutting plane was parallel to the paper sheets creating the model. Each model (coronal, sagittal, and axial) consisted of three separate parts (∼200 sheets of paper each) that were glued together to form a final model. The skull and created models were scanned with a three-dimensional (3D) optical scanner (Breuckmann smart SCAN) and were saved as .STL files. Comparisons of the orbital walls of the skull, the virtual model, and each of the three paper models were carried out with GOM Inspect 7.5SR1 software. Deviations measured between the models analysed were presented in the form of a colour-labelled map and covered with an evenly distributed network of points automatically generated by the software. An average of 804.43 ± 19.39 points for each measurement was created. Differences measured in each point were exported as a .csv file. The results were statistically analysed using Statistica 10, with statistical significance set at p < 0.05. The average number of points created on models for each measurement was 804.43 ± 19.39; however, deviation in some of the generated points could not be calculated, and those points were excluded from further calculations. From 94% to 99% of the measured absolute deviations were <1 mm. The mean absolute deviation between the skull and virtual model was 0.15 ± 0.11 mm, between the virtual and printed models was 0.15 ± 0.12 mm, and between the skull and printed models was 0.24 ± 0.21 mm. Using the optical scanner and specialized inspection software for measurements of accuracy of the created parts is recommended, as it allows one not only to measure 2-dimensional distances between anatomical points but also to perform more clinically suitable comparisons of whole surfaces. However, it requires specialized software and a very accurate scanner in order to be useful. Threshold-based, manually corrected segmentation of orbital walls performed with 3D Slicer software is accurate enough to be used for creating a virtual model of the orbit. The accuracy of the paper-based Mcor Matrix 300 3D printer is comparable to those of other commonly used 3-dimensional printers and allows one to create precise anatomical models for clinical use. The method of dividing the model into smaller parts and sticking them together seems to be quite accurate, although we recommend it only for creating small, solid models with as few parts as possible to minimize shift associated with gluing. [ABSTRACT FROM AUTHOR]

One of the biggest challenges for discovering more efficacious drugs for the control of neuropathic pain has been the diversity of chronic pain states in humans. It is now acceptable that different mechanisms contribute to normal physiologic pain, pain arising from tissue damage and pain arising from injury to the nervous system. To study pain transmission, spot novel pain targets and characterize the potential analgesic profile of new chemical entities, numerous experimental animal pain models have been developed that attempt to simulate the many human pain conditions. Among the neuropathic pain models, surgical models have paramount importance in the induction of pain states. Many surgical animal models exist, like the chronic constriction injury (CCI) to the sciatic nerve, partial sciatic nerve ligation (pSNL), spinal nerve ligation (SNL), spared nerve injury (SNI), brachial plexus avulsion (BPA), sciatic nerve transaction (SNT) and sciatic nerve trisection. Most of these models induce responses similar to those found in causalgia, a syndrome of sustained burning pain often seen in the distal extremity after partial peripheral nerve injury in humans. Researchers most commonly use these surgical models in both rats and mice during drug discovery to screen new chemical entities for efficacy in the area of neuropathic pain. However, there is scant literature that provides a comparative discussion of all these surgical models. Each surgical model has its own benefits and limitations. It is very difficult for a researcher to choose a suitable surgical animal model to suit their experimental set-up. Therefore, particular attention has been given in this review to comparatively provide the pros and cons of each model of surgically induced neuropathic pain. [ABSTRACT FROM AUTHOR]

Our study aimed to determine the accuracy of a low-cost, paper-based 3D printer by comparing a dry human mandible to its corresponding three-dimensional (3D) model using a 3D measuring arm. One dry human mandible and its corresponding printed model were evaluated. The model was produced using DICOM data from cone beam computed tomography. The data were imported into Maxilim software, wherein automatic segmentation was performed, and the STL file was saved. These data were subsequently analysed, repaired, cut and prepared for printing with netfabb software. These prepared data were used to create a paper-based model of a mandible with an MCor Matrix 300 printer. Seventy-six anatomical landmarks were chosen and measured 20 times on the mandible and the model using a MicroScribe G2X 3D measuring arm. The distances between all the selected landmarks were measured and compared. Only landmarks with a point inaccuracy less than 30% were used in further analyses. The mean absolute difference for the selected 2016 measurements was 0.36 ± 0.29 mm. The mean relative difference was 1.87 ± 3.14%; however, the measurement length significantly influenced the relative difference. The accuracy of the 3D model printed using the paper-based, low-cost 3D Matrix 300 printer was acceptable. The average error was no greater than that measured with other types of 3D printers. The mean relative difference should not be considered the best way to compare studies. The point inaccuracy methodology proposed in this study may be helpful in future studies concerned with evaluating the accuracy of 3D rapid prototyping models. [ABSTRACT FROM AUTHOR]

Good science in translational research requires good animal welfare according to the principles of 3Rs. In many countries, determining animal welfare is a mandatory legal requirement, implying a categorization of animal suffering, traditionally dominated by subjective scorings. However, how such methods can be objectified and refined to compare impairments between animals, subgroups, and animal models remained unclear. Therefore, we developed the RELative Severity Assessment (RELSA) procedure to establish an evidence-based method based on quantitative outcome measures such as body weight, burrowing behavior, heart rate, heart rate variability, temperature, and activity to obtain a relative metric for severity comparisons. The RELSA procedure provided the necessary framework to get severity gradings in TM-implanted mice, yielding four distinct RELSA thresholds L1<0.27, L2<0.59, L3<0.79, and L4<3.45. We show further that severity patterns in the contributing variables are time and model-specific and use this information to obtain contextualized between animal-model and subgroup comparisons with the severity of sepsis > surgery > restraint stress > colitis. The bootstrapped 95% confidence intervals reliably show that RELSA estimates are conditionally invariant against missing information but precise in ranking the quantitative severity information to the moderate context of the transmitter-implantation model. In conclusion, we propose the RELSA as a validated tool for an objective, computational approach to comparative and quantitative severity assessment and grading. The RELSA procedure will fundamentally improve animal welfare, data quality, and reproducibility. It is also the first step toward translational risk assessment in biomedical research., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Talbot, Struve, Wassermann, Heider, Weegh, Knape, Hofmann, von Knethen, Jirkof, Häger and Bleich.)