Egg membrane as a training model for microsurgery

Teaching microsurgery is limited by the availability of appropriate training models. In-vivo models, such as rats, remain the gold standard, but ethical and economic limitations restrict their use for initial training. This study investigated the feasibility of using egg membrane as an inert model, an accessible and economical alternative for introduction to microsurgery. The specifications for inert models include ease of access, low cost, high reproducibility and realistic reproduction of relevant characteristics. Fourteen microsurgery students assessed egg membrane as an inert training model on a 10-item questionnaire evaluating the specifications for use in microsurgery teaching. Easy access to the material and the ease with which it could be set up were evaluated positively. Dissection of the membrane added an educational dimension, distinguishing this model from other inert alternatives. On the other hand, the flexibility of the egg membrane and its resistance to the passage of the needle or the tightening of the thread were generally considered to be different from the in-vivo arterial wall. In conclusion, egg membrane as an inert model offers a practical, economical alternative in microsurgery training despite a lack of fidelity in reproducing the most relevant characteristics of the arterial wall. This model is more suited to the initial phase of learning microsurgery: in particular, working under a microscope, eye/hand coordination, tremor management and digital dexterity.

Surgical Anatomy and Exercises Using the Chicken Thigh Sciatic Nerve for Microsurgery Training

Introduction  Vessel repair in a chicken thigh is commonly used in microsurgery training model. The sciatic nerve is closely associated with the vessels and has been used for training nerve coaptation, which has different technical considerations from vessel anastomosis. We describe in detail the relevant surgical anatomy and training exercises that can be used with this model. Methods  With 32 fresh store-bought chicken thighs, 16 were used to analyze the gross and histological features of the sciatic nerve, and 16 were intended to create and perform training models. Results  The average visible length of the nerve in the thigh was 51 mm (standard deviation [SD] 2.57 mm). The average diameter of the nerve was 2 mm (SD 0.33 mm) and was largest at its proximal end (3.21 mm, SD 0.27 mm). The nerve consistently branched into two along the chicken thigh, with more branching subsequently. This simulation model is appropriate not only for the classical end-to-end epineural suture, but also for advanced exercises, in terms of longitudinal fasciculus dissection, mismatched size nerve transfer, injured nerve preparation, and vein conduit technique. Dyeing of nerve fascicles enhanced the visibility of nerve surface quality. Conclusion  The sciatic nerve in the chicken thigh is a suitable and accessible model for microsurgery training. The branching and fascicular patterns of the nerve lends itself well to both novice training and advanced simulation. We have incorporated this model into our training curricula.

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.

Low-fidelity simulation models in urology resident's microsurgery training

PURPOSE

To evaluate the gain of microsurgical skills and competencies by urology residents, using low-fidelity experimental models.

METHODS

The study involved the use of training boards, together with a low-fidelity microsurgery simulator, developed using a 3D printer. The model consists in two silicone tubes, coated with a resin, measuring 10 cm in length and with internal and external diameters of 0.5 and 1.5 mm. The support for the ducts is composed by a small box, developed with polylactic acid. The evaluation of the gain of skills and competencies in microsurgery occurred throughout a training course consisting of five training sessions. The first sessions (S1-S4) took place at weekly intervals and the last session (S5) was performed three months after S4. During sessions, were analyzed: the speed of performing microsurgical sutures in the pre and post-training and the performance of each resident through the Objective Structure Assessment of Technical Skill (OSATS) and Student Satisfaction Self-Confidence tools in Learning (SSSCL).

RESULTS

There was a decrease in the time needed to perform the anastomosis (p=0.0019), as well as a progressive increase in the score in the OSATS over during sessions S1 to S4. At S5, there was a slightly decrease in performance (p<0.0001), however, remaining within the expected plateau for the gain of skills and competences. The SSSCL satisfaction scale showed an overall approval rating of 96.9%, with a Cronback alpha coefficient of 83%.

CONCLUSIONS

The low-fidelity simulation was able to guarantee urology residents a solid gain in skills and competencies in microsurgery.

Fundamentals of Microsurgery: A Novel Simulation Curriculum Based on Validated Laparoscopic Education Approaches

BACKGROUND

 Microsurgical techniques have a steep learning curve. We adapted validated surgical approaches to develop a novel, competency-based microsurgical simulation curriculum called Fundamentals of Microsurgery (FMS). The purpose of this study is to present our experience with FMS and quantify the effect of the curriculum on resident performance in the operating room.

METHODS

 Trainees underwent the FMS curriculum requiring task progression: (1) rubber band transfer, (2) coupler tine grasping, (3) glove laceration repair, (4) synthetic vessel anastomosis, and (5) vessel anastomosis in a deep cavity. Resident anastomoses were also evaluated in the operative room with the Stanford Microsurgery and Resident Training (SMaRT) tool to evaluate technical performance. The National Aeronautics and Space Administration Task Load Index (NASA-TLX) and Short-Form Spielberger State-Trait Anxiety Inventory (STAI-6) quantified learner anxiety and workload.

RESULTS

 A total of 62 anastomoses were performed by residents in the operating room during patient care. Higher FMS task completion showed an increased mean SMaRT score (p = 0.05), and a lower mean STAI-6 score (performance anxiety) (p = 0.03). Regression analysis demonstrated residents with higher SMaRT score had lower NASA-TLX score (mental workload) (p < 0.01) and STAI-6 scores (p < 0.01).

CONCLUSION

 A novel microsurgical simulation program FMS was implemented. We found progression of trainees through the program translated to better technique (higher SMaRT scores) in the operating room and lower performance anxiety on STAI-6 surveys. This suggests that the FMS curriculum improves proficiency in basic microsurgical skills, reduces trainee mental workload, anxiety, and improves intraoperative clinical proficiency.

Low cost and easy acquisition: corn grain in microsurgery training

OBJECTIVES

develop an easily accessible model for training the initial motor practice in microsurgery using corn kernels.

METHODS

ten corn kernels (Zea mays) were used. A 7mm longitudinal cut was made on one side of the corn grain. The training consisted of performing 4 simple knots between the edges of the incision, using 10-0 mononylon thread. The parameters analyzed were 1) cost of the model; 2) assembly time of the model test system; 3) time for performing the knots; 4) distance between the knots.

RESULTS

in all corn kernels tested, it was possible to perform the proposed microsurgical suture training, without any difficulty in the procedure. The average time to perform the 4 knots was 6.51±1.18 minutes. The total cost of the simulator model was R$3.59. The average distance between the knots was 1.7±0.3mm. The model developed from corn grains has an extremely low cost when compared to the use of animals or high-tech simulators. Other advantages are the easy availability of canned corn kernels and the possibility of making more than four knots along the 7mm incision.

CONCLUSION

the training model developed has low cost, is easy to acquire and viable for training basic manual skills in microsurgery.

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.

Baixo custo e fácil aquisição: grãos de milho no treinamento microcirúrgico

RESUMO Objetivo: desenvolver um modelo facilmente acessível para o treinamento da prática motora inicial em microcirurgia a partir da utilização de grãos de milho. Métodos: foram utilizados dez grãos de milho (Zea mays). Realizou-se um corte longitudinal de 7mm em uma das faces do grão de milho. O treinamento consistiu na realização de 4 pontos simples entre as bordas da incisão, utilizando fio de mononáilon 10-0. Os parâmetros analisados foram 1) custo do modelo; 2) tempo de montagem do sistema de teste do modelo; 3) tempo de realização dos nós; 4) distância entre os pontos. Resultados: em todos os grãos testados foi possível realizar o treinamento de sutura microcirúrgica proposto, sem dificuldade ao procedimento. O tempo médio para a realização dos 4 pontos foi de 6,51±1,18 minutos. O custo total do modelo simulatório foi de R$3,59. A distância média entre os pontos foi de 1,7±0,3mm. O modelo desenvolvido a partir de grãos de milhos apresenta custo extremamente baixo quando comparado ao uso de animais ou de simuladores de alta tecnologia. Outras vantagens são fácil disponibilidade de grãos de milho em conserva e possibilidade de serem realizados mais de quatro pontos ao longo da incisão de 7mm. Conclusão: o modelo de treinamento desenvolvido é de baixo custo, de fácil aquisição e viável para o treinamento de habilidades manuais básicas em microcirurgia.

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.

Structured evaluation of a comprehensive microsurgical training program

OBJECTIVES

This study proposed a structured microsurgical training program and evaluated it with the assistance of a large sample of surgeons.

METHODS

The practical course comprised 16 sessions of approximately 4 hours each. This included two sessions for suturing rubber gloves and two sessions for suturing arteries, veins, and nerves in chicken thighs. The other sessions were performed on the femoral vessels of rats: 5 sessions for end-to-end arterial anastomosis, 5 for end-to-end venous anastomosis, 1 for arterial grafting, and 1 for end-to-side anastomosis. We conducted a structured assessment of the microsurgical skills in each training session.

RESULTS

In this study, 89 surgeons were evaluated. The mean scores for the different procedures were as follows: glove suturing, 33.3±0.59; chicken nerve end-to-end anastomosis, 40.3±0.49; chicken artery suturing, 40.9±0.36; chicken vein suturing, 42.3±0.36; graft interposition, 44.8±0.7; and end-to-side anastomosis, 43.7±0.63 (p<0.05 for all). The chicken thigh suturing scores were significantly higher than the rubber gloves suturing scores (p<0.01). There were no differences between scores of the rat artery and chicken thigh suturing procedures (p=0.24). The rat venous anastomosis scores were higher than the rat arterial anastomosis scores (p=0.02), as were graft interposition scores when compared with end-to-end venous anastomosis scores. The end-to-side anastomosis scores did not differ significantly from the grafting scores (p=0.85). The most common errors were inadequate knotting technique and suture rupture due to inadequate technique (both n=88 [98.9%]).

CONCLUSION

We propose a 16-step, progressive microsurgical training program to learn the basic microsurgical techniques comprehensively and reliably. The program was evaluated in a large sample of trainees, and it demonstrated the adequacy of the training sequence and results.

Dye-Perfused Human Placenta for Vascular Microneurosurgery Training: Preparation Protocol and Validation Testing

BACKGROUND

Human placenta is recognized as a valuable vascular microneurosurgery training model because of its abundant availability, ethical acceptance, and analogous vasculature with other vessels of the human body; however, human placenta laboratory preparation techniques are not well described in the literature. This study outlines a detailed and standardized laboratory protocol for preparation of a color-perfused human placenta model. Survey-based validation of the model is also reported herein.

METHODS

The protocol involved cleaning and cannulation of the umbilical vein and arteries, irrigation with heparin, and storage at 3°C or freezing at -18°C. Before use, arteries were perfused with carmine/cochineal, and veins were perfused with methylthioninium chloride. A questionnaire with 5 questions was administered to 40 participants among attending or resident neurosurgeons, otolaryngologists, and maxillofacial surgeons on 4 consecutive microsurgical courses to assess the reliability of the placenta model. Trainees were divided into 3 groups based on their experience. A χ² test was used to identify differences between groups.

RESULTS

Forty-two placentas were considered appropriate for training and were successfully perfused with dyes. Thirty-three participants completed the questionnaire, of which most, especially advanced and intermediate participants, indicated the placenta as a valuable, accurate, and reproducible model. No differences were observed among the groups.

CONCLUSIONS

The human placenta is an excellent tool for vascular microneurosurgery laboratory training. Color perfusion enhances the reliability of this model, which was validated by most surgeons, regardless of their experience.