A New Synthetic Model for Microvascular Anastomosis Training? A Randomized Comparative Study Between Silicone and Polyvinyl Alcohol Gelatin Tubes

Evaluation of a 3D printed training model with realistic spatial-anatomical conditions for head and neck microsurgery

OBJECTIVES

Although existing microsurgical models provide a high degree of realism in tissue properties, they often neglect the complex and constrained spatial-anatomical conditions typical of head and neck surgery. This study aims to evaluate the effectiveness of the Head and Neck Realistic Anatomical Condition Experience (RACE) model in enhancing microsurgical education.

METHODS

Using a microsurgical competency assessment tool and self-assessment questionnaires, the head and neck RACE model was evaluated through application in two student courses (10 participants) and one resident course (5 participants). In both groups, first the conventional chicken thigh model and then the RACE model were applied. Data were analyzed using a two-way repeated measures ANOVA with Welch's statistics to assess differences between the groups.

RESULTS

In pregraduate courses, the transition from the conventional chicken thigh model to the RACE model initially led to a decline across all eight microsurgical performance parameters (Q1.1-Q4.2). However, after an additional day of training with the RACE model, all parameters-except tissue-preserving technique (Q1.2) - returned to or significantly exceeded baseline levels (Q1.2 p = 0.373, Q1.3 p = 0.003, Q2.1 p < 0.001, Q2.2 p = 0.022, Q2.3 p = 0.008, Q3.1 = 0.014, Q4.1 p = 0.036, Q4.2 p = 0.002). Conversely, residents showed immediate improvement in all parameters, except for suture distance to the vessel's margin, upon switching to the RACE model.

CONCLUSIONS

Head and neck RACE models provide a challenging and practical addition to microsurgery teaching.

CLINICAL RELEVANCE

The positive impact on learning outcomes in this area supports the development of RACE models in other areas of microsurgical and general medical training, and therefore the education of students and clinical practitioners.

Face and construct validity of a novel simulator for microsurgical education: Microsurgery Arena

Simulation in microsurgery is essential for skill acquisition and maintenance. This study evaluated the construct and face validity of the Microsurgery Arena, a low-fidelity simulator designed to improve hand and wrist movements under the microscope, enhance instrument handling and knot-tying skills, and consistently assess user performance. Twenty-one surgical trainees participated in 3-day introductory microsurgical skills courses. Participants performed 2 predefined coordination exercises, "slalom" and "tie-the-knot," before and after the course. The time required to complete the exercises was recorded. The videos of the exercises were anonymized, randomized, and evaluated by 3 independent raters-a senior experimental microsurgeon, a senior clinical microsurgeon, and a junior resident-using the Stanford Microsurgery Residents Training Scale. Participants also completed demographic and face validity questionnaires at the end of the course. Quantitative analysis of pre-course scores vs post-course scores showed a statistically significant improvement in all examined skills. Moreover, the face validity assessment revealed highly positive feedback from the participants. The vast majority of candidates found the device extremely or very useful as an initial training model in microsurgery. Moreover, the model demonstrated its ability to discriminate between skill levels before and after training, supporting its construct validity. As a low-cost and accessible model, it provides a standardized approach for developing essential microsurgical skills. This simulator has the potential to serve as an effective assessment and training tool for students, residents, and microsurgical novices, contributing to improved skill acquisition in microsurgical training programs.

Neurosurgical Microvascular Anastomosis: Systematic Review of the Existing Simulators and Proposal of a New Training Classification System

BACKGROUND

The literature lacks a combined analysis of neurosurgical microvascular anastomosis training models. We performed a systematic literature search to provide an overview of the existing models and proposed a classification system based on the level of simulation and reproducibility of the microvascular anastomosis.

METHODS

The systematic literature search followed the PRISMA guidelines. We consulted MEDLINE, Web of Knowledge, and EMBASE independently for papers about bypass training models. Every training model was analyzed according to six tasks supposed to esteem their fidelity to the real operative setting by using a scoring system from zero to two. Finally, authors classified the models into five classes, from A to E, by summing the individual scores.

RESULTS

This study included 109 papers for analysis. Training models were grouped into synthetic tubes, ex vivo models (animal vessels, fresh human cadavers, human placentas) and in vivo simulators (live animals-rats, rabbits, pigs). By applying the proposed classification system, live animals and placentas obtained the highest scores, falling into class A (excellent simulators). Human cadavers and animal vessels (ex vivo) were categorized in class B (good simulators), followed by synthetic tubes (class C, reasonable simulators).

CONCLUSIONS

The proposed classification system helps the neurosurgeon to analyze the available training models for microvascular anastomosis critically, and to choose the most appropriate one according to the skills they need to improve.

A simple, novel technique to create silicone vessels for microsurgical training

Background and objectives

Effective microsurgical training necessitates dedicated practice, prompting the development of simulation models that mitigate the hygiene risks, regulatory challenges, and storage difficulties associated with conventional biological models. This study aims to evaluate the preferences of microsurgeons and medical students regarding self-made silicone simulation vessels, comparing them to standard biological models.

Methods

A three-part jig, comprising of a two-part metal clamp component and a transparent acrylic block with 4x4 channels, was designed. This assembly produced 16 vessels with a 1 ​mm inner diameter. Liquid silicone (Ecoflex 00-30), readily accessible from online distributors, was injected into the channels using a syringe. After tightening the clamp component and inserting 16 1 ​mm k-wires, the vessels were left to set for approximately 24 ​h 20 medical students with no prior microsurgical experience and 10 microsurgery-trained surgeons then evaluated these silicone vessels against a commonly used biological model (chicken brachial artery for surgeons or chicken aorta for students). Participants were then surveyed about their preference for a specific model for frequent practice using a 10-point Likert scale.

Results and conclusion

In assessing ideal microsurgical training models, all participants highlighted the importance of realism. Surgeons' main practical considerations were hygiene, availability, and setup and storage ease, while medical students were primarily concerned with cost-effectiveness. Both surgeons and medical students perceived the biological model as more realistic, yet less hygienic and harder to set up and store. Conversely, the silicone model, though deemed less realistic, offered advantages in hygiene, availability, cost-effectiveness, and setup and storage simplicity. The silicone model emerged as the overall favorite amongst all participants for frequent practice. Silicone vessels may serve as a complementary adjunct to biological models, allowing surgeons-in-training to practice their skills outside of the operating room and lab settings.

Synthetic Simulators for Microsurgery Training: A Systematic Review

Background

Microsurgery has a steep learning curve. Synthetic simulators have proven to be useful training tools for the initial learning stages, as well as being ethically sound, viable, safe, and cost-effective. The objective of this review was to determine the quality, effectiveness, and validity of these simulators as well as to assess their ability to evaluate microsurgical skills.

Methods

A systematic review following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines was performed. We searched databases (Web of Science, Scopus, and PubMed) to identify original articles describing synthetic training models for microsurgery. Three reviewers evaluated articles for inclusion following predefined selection criteria. Data were extracted from full-texts of included articles.

Results

Thirty-nine studies met the inclusion criteria. A total of 38 different devices have been recorded. Microsurgical training devices offer a low-cost, fast, and consistent method to concretely quantify and assess the initial microsurgical skills of trainees using standardized exercises that can be scored by the examiner. According to the authors, the outcomes were satisfactory, with a tangible improvement in microsurgical abilities, despite the lack of a common comparison scale.

Conclusions

Thanks to their availability, cost, and effectiveness, synthetic models are the recommended option to train basic, intermediate and advanced procedures before executing them on in vivo models.

Nonliving versus Living Animal Models for Microvascular Surgery Training: A Randomized Comparative Study

BACKGROUND

Ethical and financial considerations have encouraged the use of nonliving models for simulation-based training in microsurgery, such as commercially available chicken thighs. The purpose of this study was to compare the nonliving chicken thigh model to the one currently considered as the standard-namely, the living rat model-in the setting of an initiation microsurgery course.

METHODS

Applicants to the 3-day basic microsurgery course of the Paris School of Surgery were assigned randomly to either one group that received the regular training of the school (RT group), including four hands-on sessions using only living rat models, or one group that received a modified curriculum in which a nonliving chicken thigh model was used for the first hands-on session (CT group). During the following session, all trainees were evaluated on living rat models, using a global rating scale and two task-specific scales (knot-tying and anastomosis); rates of anastomosis patency, animal survival, and technique completion were recorded.

RESULTS

Ninety-three residents were enrolled. Global rating scale, knot-tying, and anastomosis task-specific scale scores were significantly higher in the CT group ( n = 51) than in the RT group, with mean differences of 2.6 points ( P = 0.0001), 1.3 points ( P < 0.0001), and 1.4 points ( P < 0.0001), respectively. Patency and survival rates were significantly higher in the CT group than in the RT group, with mean differences of 22% ( P = 0.0020) and 27% ( P < 0.0001), respectively; completion rates were not statistically different.

CONCLUSION

Subject to the use of validated models, such as the chicken thigh, nonliving animal models are a suitable alternative to the living rat model in microsurgery initial training.

CLINICAL RELEVANCE STATEMENT

The use of validated non-living models, such as the chicken thigh, is a suitable alternative to the living rat model in microsurgery initial training.

Teaching of Microsurgery and Supermicrosurgery for Residents

On the basis of our numerous years of experience in teaching residents without microsurgery experience and assisting in the initiation of microsurgery in clinical practice, we herein describe the general procedures and crucial aspects to consider regarding microsurgery and supermicrosurgery training for residents. The description focuses on training methods, surgical skills, and training time and effort. The target audience of the training is residents who have never performed microsurgery. We believe that any person, regardless of operative experience, can acquire the technique for microsurgery and supermicrosurgery by performing 4 to 5 hours of training per day over a total of 30 days within this program setting. Considering individual differences in learning and experience, the training can be completed in a shorter period by performing additional daily training. It is relatively simple for a well-trained microsurgeon to master the uncommon supermicrosurgery techniques. We hope that this report will help as many residents as possible in learning the art of (super)microsurgery.

Training in microvascular anastomosis - A randomized comparative study between chicken thigh specimen and live rat

Training in microsurgical techniques on live rats is the gold standard, but raises ethical issues related to animal welfare and cost. The aim of this study was to compare acquisition of microsurgical techniques with primary training on chicken thigh specimens. Seventy six students were randomly assigned: 23 to exclusive rat training and 53 to primary chicken-leg training. Both groups were then evaluated on aortic suture and jugular aortic bypass surgery in live rats. The primary criterion for successful anastomosis was the patency test. The survival of the rat, the number of severe vascular wounds and the quality of the dissection were also assessed. Aortic anastomoses were of significantly better quality in the chicken group (p = 0.041). There was no significant difference in the number of serious injuries, rat mortality, or quality of dissection (p > 0.05). For jugular aortic bypass surgery, dissection quality (p = 0.02) and patency test (p = 0.05) were better in the chicken-leg group. There was no significant difference in number of severe wounds or rat mortality (p > 0.05). Students who started their microsurgical training on a chicken leg did not perform worse than those with exclusive live rat training. Initial training on chicken thigh specimens seems to be a reliable alternative to training on live models. LEVEL OF EVIDENCE: Level II - Randomized controlled trial.

A novel approach to microsurgical teaching in head and neck surgery leveraging modern 3D technologies

The anatomically complex and often spatially restricted conditions of anastomosis in the head and neck region cannot be adequately reproduced by training exercises on current ex vivo or small animal models. With the development of a Realistic Anatomical Condition Experience (RACE) model, complex spatial-anatomical surgical areas and the associated intraoperative complexities could be transferred into a realistic training situation in head and neck surgery. The RACE model is based on a stereolithography file generated by intraoperative use of a three-dimensional surface scanner after neck dissection and before microvascular anastomosis. Modelling of the acquired STL file using three-dimensional processing software led to the model's final design. As a result, we have successfully created an economical, sustainable and realistic model for microsurgical education and provide a step-by-step workflow that can be used in surgical and general medical education to replicate and establish comparable models. We provide an open source stereolithography file of the head-and-neck RACE model for printing for educational purposes. Once implemented in other fields of surgery and general medicine, RACE models could mark a shift in medical education as a whole, away from traditional teaching principles and towards the use of realistic and individualised simulators.

Conventional versus fibrin-glue-augmented arterial microanastomosis: An experimental study

The purpose of this experimental study was to develop an alternative technique of arterial microanastomosis using only 2 stay-sutures augmented with fibrin glue, and to compare it to the conventional technique in arteries of varying diameters mimicking hand arteries. Eight anastomoses were performed in 7 male rats, including 1 anastomosis each on the 2 femoral, iliac, and carotid arteries, and 2 on the subrenal aorta. The conventional technique was used on one side and on the first aorta anastomosis, while augmented anastomoses were performed on the other side and on the second aorta. Patency was tested 10 min after unclamping; clamping time, blood loss, anastomosis quality score (out of 15 points) and artery diameter were recorded. In arteries of diameter 0.5-2.2 mm, augmented anastomoses were on average 10.7 ± 3.2 min faster to perform (p &lt; 0.0001), with an average of 1.3 ± 0.9 g less blood loss (p &lt; 0.0001) and an average of 2.6 ± 2.5 points higher quality score (p &lt; 0.0001). There were no significant differences between the two techniques in terms of patency rate, regardless of artery size. However, 3 of the 7 augmented anastomoses were non-permeable in the femoral subgroup (i.e., submillimetric arteries). This straightforward technique appears to be time-saving and reliable, provided that the repaired artery is of sufficient size. Subject to clinical validation, this technique might help surgeons treating extensive hand wounds with multiple severed neurovascular bundles.

Capillary pressure mediated long-term dynamics of thin soft films

HYPOTHESIS

The conventional solid-solid contact is well studied in the literature. However, a number of practical applications, such as adhesive patches and biomimetic surfaces, require a much deeper understanding of soft contact where there is a distinct time-dependent adhesion behavior due to the dual-phase structure (solids and liquids). To understand this, currently existing solid-solid contact behavior is extrapolated to soft contact, wherein the size-effect of the gel film and the preload are typically neglected. When introducing the finite-size effect and preload, gels could experience distinctive long-term contact dynamics in contact with another material.

EXPERIMENTS

We reconstruct the evolving surface profile of the gel films intercalated between a glass sphere and glass slide using dual wavelength-reflection interference contrast microscopy. The macro-sized glass sphere compresses the gel. The indentation depth is comparable to the gel film thickness, wherein the conventional contact theories are inapplicable.

FINDINGS

The gel surface experiences two deformation stages. The natural preload and elastic force develop the contact area in the early state. In the later state, the viscous free molecules of the gel develop the ridge. We discover that the residual surface stress relaxes over 85 hr. Our findings on the long-term gel deformation provide a new perspective on soft adhesion, from developing soft adhesives to understanding biological tissues.

New, Innovative, Three-Dimensional In Vivo Model for High-Level Microsurgical and Supermicrosurgical Training: A Replacement for Animal Models

SUMMARY

Microsurgery and supermicrosurgery are surgical subdomains necessary for a large variety of surgical disciplines. So far, there is no training model for lymphatic surgery or perforator flap surgery, and the most commonly used microsurgical training models are living animals. However, the ethical principles of replacement, refinement, and reduction (the three Rs) of living animals for training purposes were implemented, highlighting the necessity of an animal-sparing microsurgical training model. Formed during embryogenesis, the chick chorioallantoic membrane resembles a highly vascularized, noninnervated membrane within fertilized chicken eggs. The aim of this study was to utilize the chorioallantoic membrane model as an innovative and versatile training model for supermicrosurgery and microsurgery that can reduce the number of animals used for these purposes. The variety of different sized vessels for the implementation of an anastomosis proved the chorioallantoic membrane model as a well-functioning supermicrosurgical and microsurgical training model. The circulatory system is resilient enough to withstand the mechanical stress applied to the tissue, and the patency of the implemented anastomosis can be tested for the verification of the procedures. In summary, the integration of the chorioallantoic membrane model into a surgical training program can benefit its quality by representing a realistic anatomical and physiological model with a high variety of vascular structures. Moreover, the chorioallantoic membrane model satisfies the principles of replacement, refinement, and reduction as an animal-sparing model, indicating the potential of this model as an innovative microsurgical training model for the improvement of surgical skills.

An Innovative Simulation Model for Microvascular Training

SUMMARY

Preclinical/clinical microsurgical training is essential for clinical practice. Therefore, various training models have been established, such as synthetic and cadaveric models. The most common limitation of these models is the lack of circulation, which limits the simulation of real intraoperative circumstances. Thus, the authors aimed to create a novel model that provides blood circulation with an extracorporeal perfusion device that they attached to rat cadavers for the reestablishment of a circulatory system. Patent blue and heparin were added to the perfusion fluid to visualize circulation and to dissolve thrombosis, and indocyanine green fluorescent imaging was applied to show the perfusion of the entire body. The femoral and brachial vessels were dissected, and an end-to-end anastomosis was performed on the femoral artery. The patency of the operated vessel was visualized with indocyanine green fluorescent imaging. Indocyanine green fluorescent imaging showed appropriate vessel patency and extremity perfusion through the anastomosis. The use of this novel rat model enables a solution for ethical problems encountered when using rats for surgical training courses. By practicing on these animal-sparing models with intact circulation, microsurgical skills can be improved. Future studies on further microsurgical techniques and vascular perfusion of organs or tumors may benefit from our model.

Video-Based Microsurgical Education versus Stationary Basic Microsurgical Course: A Noninferiority Randomized Controlled Study

BACKGROUND

 Repetitive training is essential for microsurgical performance. This study aimed to compare the improvement in basic microsurgical skills using two learning methods: stationary microsurgical course with tutor supervision and self-learning based on digital instructional materials. We hypothesized that video-based training provides noninferior improvement in basic microsurgical skills.

METHODS

 In this prospective study, 80 participants with no prior microsurgical experience were randomly divided into two groups: the control group, trained under the supervision of a microsurgical tutor, and the intervention group, where knowledge was based on commonly available online instructional videos without tutor supervision. Three blinded expert microsurgeons evaluated the improvement in basic microsurgical skills in both groups. The evaluation included an end-to-end anastomosis test using the Ten-Point Microsurgical Anastomosis Rating Scale (MARS10) and a six-stitch test on a latex glove. Statistically significant differences between groups were identified using standard noninferiority analysis, chi-square, and t-tests.

RESULTS

 Seventy-seven participants completed the course. Baseline test scores did not differ significantly between groups. After the 4-day microsurgical course, both groups showed statistically significant improvement in microsurgical skills measured using the MARS10. The performed tests showed that data for self-learning using digital resources provides noninferior data for course with surpervision on the initial stage of microsurgical training (7.84; standard deviation [SD], 1.92; 95% confidence interval [CI], 7.25-8.44) to (7.72; SD, 2.09; 95% CI, 7.07-8.36).

CONCLUSION

 Video-based microsurgical training on its initial step provides noninferior improvement in microsurgical skills to training with a dedicated instructor.

Simulating the IMA Recipient Site for DIEP Flap Surgery: A New Model for Dynamic Microsurgery Simulation with Real-Time Respiration and a Pilot Study

BACKGROUND

 Breast reconstruction (BR) using autologous free flaps has been shown to have numerous psychosocial and quality-of-life benefits. Unfortunately, the microsurgical learning curve is quite steep due to some unique operative challenges. Currently, there is no realistic simulation model that captures real-life respiratory excursion and the depth of internal mammary vessels within the compact recipient site. The purpose of this study was to delineate intraoperative measurements of depth and motion, describe the resulting simulation model, and conduct a pilot study evaluating the simulator as an educational resource.

METHODS

 This is a single-center, ethics-approved study. For the intraoperative measurements, all consecutive patients undergoing free flap BR using internal mammary vessels as recipients were recruited. Patient and intraoperative factors as well as intraoperative measurements were recorded. A dynamic model was developed based on intraoperative parameters. For the pilot study, plastic and reconstructive surgery trainees were recruited to complete a hand-sewn internal mammary artery (IMA) anastomosis using the new simulator and completed objective questionnaires pre- and postsimulation. Subjective feedback was recorded and themes determined.

RESULTS

 Fifteen operative sites were analyzed. Flap pocket was found to be between 4 and 5 cm in depth with vertical excursion of 3.7 ± 1.0mm and a respiratory rate of 9 to 14 breaths/minute. Previous radiation, rib space, body mass index (BMI), blood pressure, heart rate, tidal volume, and respiratory rate showed no correlation to vessel depth/excursion. Laterality, rib space, BMI, radiation, vitals, and tidal volume had no correlation with vessel movement. Twenty-two trainees were included in the pilot. An increase in confidence and mixed results for anxiety was reported.

CONCLUSION

 This study reports a novel microsurgical simulation model that provides a realistic deep inferior epigastric perforator free flap BR IMA anastomosis experience. It replicates movement of vessels in situ with real-time respiratory excursion and similar physical structures of the internal mammary system. This model shows promising results for increased use in microsurgical education.

Simulation in Upper and Lower Limb Trauma Skill Acquisition: A Review

SUMMARY STATEMENT

This review aimed to explore the published evidence with regard to the types and composition of both full- and part-task trainers to teach surgeons extremity exploration procedures in limb trauma management. Studies were included if they reported the development and/or validation of synthetic or virtual task trainers. Studies were evaluated to determine their derivation, usability, and clinical utility.A total of 638 citations were identified and 63 satisfied the inclusion criteria. Twenty-five articles addressed simulator validation and 36 addressed level of learning achieved with simulator engagement. Two studies described a dedicated limb simulator. Simulators were developed to repair limb structures including skin (n = 15), tendon (n = 7), nerve (n = 1), fascia (n = 1), muscle (n = 1), vascular (n = 24), and bone (n = 11). Considerations such as material fidelity, learning outcomes, cost or reusability, validity, and effectiveness are inconsistently reported. Future studies should address design standards for the effective production of synthetic or virtual simulators for limb trauma management.

MicrosimUC: Validation of a Low-Cost, Portable, Do-It-Yourself Microsurgery Training Kit

BACKGROUND

 Microsurgery depends largely on simulated training to acquire skills. Courses offered worldwide are usually short and intensive and depend on a physical laboratory. Our objective was to develop and validate a portable, low-cost microsurgery training kit.

METHODS

 We modified a miniature microscope. Twenty general surgery residents were selected and divided into two groups: (1) home-based training with the portable microscope (MicrosimUC, n = 10) and (2) the traditional validated microsurgery course at our laboratory (MicroLab, n = 10). Before the intervention, they were assessed making an end-to-end anastomosis in a chicken wing artery. Then, each member of the MicrosimUC group took a portable kit for remote skill training and completed an eight-session curriculum. The laboratory group was trained at the laboratory. After completion of training, they were all reassessed. Pre- and posttraining procedures were recorded and rated by two blind experts using time, basic, and specific scales. Wilcoxon's and Mann-Whitney tests were used to compare scores. The model was tested by experts (n = 10) and a survey was applied to evaluate face and content validity.

RESULTS

 MicrosimUC residents significantly improved their median performance scores after completion of training (p < 0.05), with no significant differences compared with the MicroLab group. The model was rated very useful for acquiring skills with 100% of experts considering it for training. Each kit had a cost of U.S. $92, excluding shipping expenses.

CONCLUSION

 We developed a low-cost, portable microsurgical training kit and curriculum with significant acquisition of skills in a group of residents, comparable to a formal microsurgery course.

Developing microsurgical milestones for psychomotor skills in neurological surgery residents as an adjunct to operative training: the home microsurgery laboratory

OBJECTIVE

A variety of factors contribute to an increasingly challenging environment for neurological surgery residents to develop psychomotor skills in microsurgical technique solely from operative training. While adjunct training modalities such as cadaver dissection and surgical simulation are embraced and practiced at our institution, there are no formal educational milestones defined to help residents develop, measure, and advance their microsurgical psychomotor skills in a stepwise fashion when outside the hospital environment. The objective of this report is to describe an efficient and convenient "home microsurgery lab" (HML) assembled and tested by the authors with the goal of supporting a personalized stepwise advancement of microsurgical psychomotor skills.

METHODS

The authors reviewed the literature on previously published simulation practice models and designed adjunct learning modules utilizing the HML. Five milestones were developed for achieving proficiency with each graduated exercise, referencing the Accreditation Council for Graduate Medical Education (ACGME) guidelines. The HML setup was then piloted with 2 neurosurgical trainees.

RESULTS

The total cost for assembling the HML was approximately $850. Techniques for which training was provided included microinstrument handling, tissue dissection, suturing, and microanastomoses. Five designated competency levels were developed, and training exercises were proposed for each competency level.

CONCLUSIONS

The HML offers a unique, entirely home-based, affordable adjunct to the operative neurosurgical education mandated by the ACGME operative case logs, while respecting resident hospital-based education hours. The HML provides surgical simulation with specific milestones, which may improve confidence and the microsurgical psychomotor skills required to perform microsurgery, regardless of case type.

3D-printed cranial models simulating operative field depth for microvascular training in neurosurgery

BACKGROUND

The skills required for neurosurgical operations using microsurgical techniques in a deep operating field are difficult to master in the operating room without risk to patients. Although there are many microsurgical training models, most do not use a skull model to simulate a deep field. To solve this problem, 3D models were created to provide increased training in the laboratory before the operating room, improving patient safety.

METHODS

A patient's head was scanned using computed tomography. The data were reconstructed and converted into a standard 3D printing file. The skull was printed with several openings to simulate common surgical approaches. These models were then used to create a deep operating field while practicing on a chicken thigh (femoral artery anastomosis) and on a rat (abdominal aortic anastomosis).

RESULTS

The advantages of practicing with the 3D printed models were clearly demonstrated by our trainees, including appropriate hand position on the skull, becoming comfortable with the depth of the anastomosis, and simulating proper skull angle and rigid fixation. One limitation is the absence of intracranial structures, which is being explored in future work.

CONCLUSION

This neurosurgical model can improve microsurgery training by recapitulating the depth of a real operating field. Improved training can lead to increased accuracy and efficiency of surgical procedures, thereby minimizing the risk to patients.

Superiority of living animal models in microsurgical training: beyond technical expertise

Background

Many studies are investigating the role of living and nonliving models to train microsurgeons. There is controversy around which modalities account for the best microsurgical training. In this study, we aim to provide a systematic literature review of the practical modalities in microsurgery training and compare the living and nonliving models, emphasizing the superiority of the former. We introduce the concept of non-technical skill acquisition in microsurgical training with the use of living laboratory animals in the context of a novel proposed curriculum.

Methods

A literature search was conducted on PubMed/Medline and Scopus within the past 11 years based on a combination of the following keywords: “microsurgery,” “training,” “skills,” and “models.” The online screening process was performed by two independent reviewers with the Covidence tool. A total of 101 papers was identified as relevant to our study. The protocol was reported in line with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement.

Results

Living models offer the chance to develop both technical and non-technical competencies (i.e., leadership, situation awareness, decision-making, communication, and teamwork). Prior experience with ex vivo tissues helps residents consolidate basic skills prior to performing more advanced techniques in the living tissues. Trainees reported a higher satisfaction rate with the living models.

Conclusions

The combination of living and nonliving training microsurgical models leads to superior results; however, the gold standard remains the living model. The validity of the hypothesis that living models enhance non-technical skills remains to be confirmed.

Level of evidence: Not ratable.

Thiel-embalmed porcine placenta: A valid and reusable microsurgical practice model

BACKGROUND

Simulation models are increasingly important for skill acquisition during microsurgery training. Prosthetics, living and non-living biological models have been proposed in the literature in the optics of recreating real-life scenarios in a controlled environment. This study aims to validate and prove the reusability of a novel non-living biological model: the porcine placenta.

METHODS

A prospective comparative study was carried out to assess face and content validities of the proposed model, as well as the reusability and quality of the Thiel-embalming method. Participants were asked answer a questionnaire for each anastomosis they performed on porcine placental vessels of ≤2mm (small) and 2-4mm (large). Scores were classified according to different subgroups, either small or large vessels and first or second sessions. Reliability analysis of the questionnaire was carried out using Cronbach's α, to ensure an α>0.7. Median scores for each question were analyzed using boxplots and compared amongst each subgroup using a non-parametric independent Mann-Whitney U test.

RESULTS

With nine participants, the Cronbach's α for each category of question was 0.867, 0.778, 0.720 and 0.593. Statistical differences were found between responses of small and large vessels on 5/10 questions, where large vessels reported higher validity. No statistical differences were found between scores of the first and second sessions.

CONCLUSION

By evaluating face and content validity, the Thiel-embalmed porcine placenta has proven its suitability as a microsurgery model, especially for vessels of larger caliber. Qualities that distinguish this model is its reliable reusability, its low cost-effectiveness, and its ethical acceptability.

Augmentation of Chicken Thigh Model with Fluorescence Imaging Allows for Real-Time, High Fidelity Assessment in Supermicrosurgery Training

BACKGROUND

 The skills required for supermicrosurgery are hard-earned and difficult to master. The University of Wisconsin "blue-blood" chicken thigh model incorporates perfusion of the thigh vessels with a blue liquid solution, allowing users to visualize flow across their anastomoses. This model has proven to be an excellent source of small vessels (down to 0.3 mm) but assessing the quality of anastomoses at this spatial scale has proven difficult. We evaluated whether fluorescent imaging with indocyanine green (ICG) in this realistic training model would enhance the assessment of supermicrosurgical anastomoses, and therefore improve real-time feedback to trainees.

METHODS

 Anastomoses of vessels ranging from 0.35 to 0.55mm in diameter were performed followed by the capture of white light with and without fluorescence imaging overlay during infusion of "blue-blood" and ICG. Videos were randomized and shown to seven fellowship-trained microsurgeons at the University of Wisconsin-Madison who rated each anastomosis as "patent," "not patent," or "unsure." Surgeon accuracy, uncertainty, and inter-rater agreement were measured for each imaging modality.

RESULTS

 Use of fluorescence significantly increased surgeon accuracy to 91% compared with 47% with white light alone (p = 0.015), decreased surgeon uncertainty to 4% compared with 41% with white light alone (p = 0.011), and improved inter-rater agreement from 53.1% with white light alone to 91.8% (p = 0.016).

CONCLUSION

 Augmentation of the University of Wisconsin "blue-blood" chicken thigh model with ICG fluorescence improves accuracy, decreases uncertainty, and improves inter-rater agreement when assessing supermicrosurgical anastomoses in a training setting. This improved, real-time feedback enhances this model's value as a supermicrosurgical training tool.

Arteriovenous anastomosis learning curve using low cost simulator

Background

In order to reduce difficulties with learning surgical techniques, supplementary tools for training were developed. This paper describes the learning curve followed by student volunteer research subjects who used an alternative model for practicing vascular anastomosis.

Objectives

To evaluate the vascular anastomosis technique learning curve and development of manual skills using a low-cost experimental model.

Methods

Experimental and prospective study using end-to-side vascular anastomosis in latex balloons over five successive phases, initiated after theoretical and practical guidance given by experienced vascular surgeon. The study subjects were six undergraduate medical students from Universidade Federal da Paraíba (UFPB), João Pessoa, PB, Brazil, in their third to fifth years of the course. Cluster analysis was used to interpret the data collected on the quality of anastomoses and the time taken.

Results

The time taken to perform anastomosis reduced for all students, with statistical differences from phase 1 compared to phases 4 and 5. There was also a trend to increasing scores on the quality index as the phases progressed. However, no statistical differences were detected using the Friedman test, which is appropriate for data measured with ordinal levels (quality was assessed on a scale of 1 to 5).

Conclusions

It was found that the training model used was effective for increasing learning of this technique. It is believed that future studies with larger samples or a higher number of phases could demonstrate both reduced time and improved quality of the anastomoses performed with statistical significance.

3D Exoscope-Assisted Microvascular Anastomosis: An Evaluation on Latex Vessel Models

Background. Over the last few years, advances in technologies and digital imaging have led to the introduction of systems that enable a new approach to microsurgery and supermicrosurgery. The exoscope is a new magnification system that provides a 3D image of the surgical field: microsurgical procedures can be performed with the aid of this instrument. Here, we describe our preliminary experience with a high-definition 3D exoscope (VITOM^®, Karl Storz, Tuttlingen, Germany), evaluating the characteristics of the instrument, and also its use as a magnification device for microanastomosis training. Methods. Six microsurgeons with various levels of experience were asked to perform three end-to-end anastomoses and two end-to-side anastomoses on latex vessel models, using, as a magnification system, the VITOM^® 3D 4K exoscope. None of the surgeons involved had previous experience with the exoscope, with robotic surgery, with endoscopic surgery, nor with training simulators. Results. The results of the reported evaluation of the tool’s qualities, (VITOM Quality Assessment Tool) included: a good focusing of the surgical field; high image quality; strong luminance; good magnification; clear stereoscopy; and excellent freedom of movement. The exoscope proved to be user-friendly. A constant reduction in the time needed to perform the microsurgical anastomosis at each exercise was recorded. Among other advantages were the easy switching from the magnified image to the macroscopic view, superior ergonomics allowing a relaxed posture while performing the anastomosis, adequate space, and a convenient setting for the assistants to view the operating field. Conclusions. Our study showed that the exoscope VITOM 3D can be successfully used as a magnification tool for microsurgical anastomosis on synthetic vessels, and that it can also be helpful during training courses in microsurgery.

A novel three-in-one silicone model for basic microsurgery training

Background

Microsurgery simulation is an important aspect of surgical training. Animal models have been widely used in simulation training, but they have some limitations including ethical restrictions, cost and availability. This has led to the use of synthetic models that can reduce reliance on animals in line with the 3R (refinement, reduction and replacement) principles. The aim of this paper was to evaluate the face validity of Surgitate™ three-in-one (artery, vein and nerve) silicone model.

Methods

Fourteen candidates performed one end-to-end anastomosis on artery, vein and nerve. The face validity of the vessel was assessed via questionnaires detailing their previous microsurgical experience and their feedback of using this model using the Likert scale. Data management and analysis were performed using IBM SPSS software (25.0).

Results

Participants tended to value this model in the earlier stages of microsurgical training particularly in the acquisition of basic microsurgical skills. It could be particularly useful in enhancing suturing skills as a replacement or reduction in the use of chicken models. The model has some drawbacks preluding its utilization into more advanced stages of surgical training. Further studies are needed to validate the model using more objective measures.

Conclusion

We present a novel synthetic model that can be potentially introduced to early stages of microsurgery training. The model would be ideal to meet the 3R principles of the use of animal models and as an alternative to the commonly used synthetic models.

Level of evidence: Not ratable.

Nonbiological Microsurgery Simulators in Plastic Surgery Training: A Systematic Review

BACKGROUND

Simulation has gained notable recognition for its role as an effective training and assessment modality in the present era of competency-based medical education. Despite the well-documented efficacy of both live and cadaveric animal models, several ethical, financial, and accessibility issues persist with their use. Lower fidelity nonbiological simulators have gained recognition for their ability to circumvent these challenges. This systematic review reports on all prosthetic and virtual reality simulators in use for microsurgery training, with an emphasis on each model's complexity, characteristics, advantages, disadvantages, and validation measures taken.

METHODS

A systematic search was performed using the National Library of Medicine (PubMed), MEDLINE, and Embase databases. Search terms were those pertaining to prosthetic and virtual reality models with relevance to microsurgical training in plastic surgery. Three independent reviewers evaluated all articles retrieved based on strict inclusion and exclusion criteria.

RESULTS

Fifty-seven articles met the inclusion criteria for review, reporting on 20 basic prosthetic models, 20 intermediate models, 13 advanced models, and six virtual reality simulators.

CONCLUSIONS

A comprehensive summary has been compiled of all nonbiological simulators in use for microsurgery training in plastic surgery, demonstrating efficacy for the acquisition and retention of microsurgical skills. Metrics-based validation efforts, however, were often lacking in the literature. As plastic surgery programs continue to innovate, ensure accountability, and safely meet today's training standards, prosthetic simulators are set to play a larger role in the development of a standardized, ethical, accessible, and objectively measurable microsurgery training curriculum for the modern-day plastic and reconstructive surgery resident.

3D printed coaxial nozzles for the extrusion of hydrogel tubes toward modeling vascular endothelium

Engineered tubular constructs made from soft biomaterials are employed in a myriad of applications in biomedical science. Potential uses of these constructs range from vascular grafts to conduits for enabling perfusion of engineered tissues and organs. The fabrication of standalone tubes or complex perfusable constructs from biofunctional materials, including hydrogels, via rapid and readily accessible routes is desirable. Here we report a methodology in which customized coaxial nozzles are 3D printed using commercially available stereolithography (SLA) 3D printers. These nozzles can be used for the fabrication of hydrogel tubes via coextrusion of two shear-thinning hydrogels: an unmodified Pluronic® F-127 (F127) hydrogel and an F127-bisurethane methacrylate (F127-BUM) hydrogel. We demonstrate that different nozzle geometries can be modeled via computer-aided design and 3D printed in order to generate tubes or coaxial filaments with different cross-sectional geometries. We were able to fabricate tubes with luminal diameters or wall thicknesses as small as ∼150 μm. Finally, we show that these tubes can be functionalized with collagen I to enable cell adhesion, and human umbilical vein endothelial cells can be cultured on the luminal surfaces of these tubes to yield tubular endothelial monolayers. Our approach could enable the rapid fabrication of biofunctional hydrogel conduits which can ultimately be utilized for engineering in vitro models of tubular biological structures.

A simple, inexpensive and non-microscope based model for microsurgical training

In this manuscript we present a simple, inexpensive, non-microscope training model for microsurgery.