The clear and effective teaching of surgical procedures remains a challenging task for the medical community. Complex surgical procedures are difficult to teach solely in the operating theatre, and a great deal of preparatory work is needed to enable the student or resident to follow and understand the complex procedures effectively. In addition, technical skills are needed to perform the required surgical task. Even today, surgical procedures are often learned through theoretical preparation by reading relevant publications or research articles, followed by step-by-step practical training in the operating theatre [9]. Unfortunately, training in the operating theatre is time consuming [10] and even more so without prior preparation of the trainee. In recent years, numerous factors have significantly influenced surgical teaching and training. These include reduced working hours, economic pressures, and the imperative to optimize the use of operating theaters while ensuring patient safety. However, the most notable impact has been the recent COVID-19 pandemic. The disruptions it has caused have been extensive, affecting didactic sessions, research activities, and surgical training programs, thereby presenting additional challenges [11]. The pandemic’s contact restrictions prompted not only changes in medical teaching methodologies but also the recognition of the various advantages offered by simulation training. Consequently, there is a growing advocacy for a shift in learning and teaching approaches with an increased integration of simulation. Simulation facilitates the training of technical, cognitive, and behavioral skills in an immersive and realistic manner, providing a patient-safe environment for acquiring a wide range of proficiencies [12]. The increasing integration of simulation models has underscored the importance of utilizing diverse tools for assessing relevant skill proficiencies [13]. Over the years, the medical community has attempted to improve the teaching and learning of surgical procedures using various forms of simulation. A study by Villanueva et al.. used a combination of simulators such as full manikins, part-task trainers or tabletop models and virtual reality systems for cardiothoracic surgical education and training. Various procedures could be effectively simulated using the above simulators, and simulation was shown to improve learning and trainee performance [14]. Another form of simulation in surgical education, especially in more specialized training for residents, is the use of animal models. These can be only parts of the deceased animal, as shown for cricothyrotomy trainers [15] with porcine trachea, or the popular use of fresh chicken leg for microvascular anastomosis training [16,17,18,19]. Another option is the use of whole euthanized animals, such as for aortic anastomosis training [20], or live animals, as is often the case with rats, which are commonly used for various microvascular training and flap harvesting techniques [21,22,23]. Furthermore, the use of human cadavers for training is often advocated, as this is the only way to work on regular human anatomy and tissues apart from living patients [24]. All of these models can effectively mimic real-life situations in different ways, in a safe environment without the risk of harm to the patient and without time pressure, where mistakes can be made without the consequences of the clinical situation. In general, animal models can provide a good solution in terms of tissue realism, cost-effectiveness, and availability, but a drawback of models based on live animals is the sacrifice of live animals solely for training purposes, which conflicts with animal welfare ethics. In the field of microvascular free flap surgery, many of the above models exist to illustrate the operative process, but there is still a need for a model that allows training of the entire flap harvesting and microvascular transfer process while being cost-effective, easily accessible, and free of ethical concerns. As no such sufficiently realistic model has been previously described, we developed a porcine free flap surgery training model. We identified porcine head halves as the most suitable in terms of availability, cost, and degree of realism. The model relies solely on meat production waste that would otherwise be discarded as an offal. This makes the model ethically acceptable from an animal welfare perspective, as no additional animals need to be harmed for training and education purposes. The use of split porcine head halves is not new to surgical education. For example, Kersey et al. used porcine head halves to train oculoplastic procedures [25], and Kuwahara et al. used this model to practice cutaneous surgery techniques [26]. We attempted to adapt this well-established surgical model to the field of free flap teaching, but for this purpose, the validation of a suitable vascular anatomy had to be evaluated. The present study, which included the dissection of 51 porcine head halves, revealed a reliable vascular anatomy with the possibility of sufficiently realistic fasciocutaneous flap harvesting [Table 1]. After evaluating the sufficient anatomical requirements, we successfully designed and implemented a surgical protocol for fasciocutaneous free flap training and microvascular anastomosis [Table 2]. The flap harvesting process is divided into 6 key steps that are easy to understand and follow. The surgical procedure is very similar to real surgery, such as radial forearm free flap harvesting. The flap can then be freely transferred to the desired defect site, and microvascular anastomosis can be trained on a variety of local recipient vessels in the cervical region. The quality of the microvascular anastomosis performed during exercise can be assessed through direct surgical incision of the vessel, followed by clinical inspection of the sutures. This inspection should focus on evaluating the depth and even distribution of the sutures, as well as identifying any potential through-stitches. Additionally, vessel patency can be evaluated by perfusing the vessels using various devices, if desired [27, 28]. All the highlighted surgical techniques are feasible through a single-surgeon approach. However, based on our experience, adopting an operator-assistant approach further amplifies the didactic benefits, particularly during microvascular anastomosis training. The model presented could serve as an initial practical step in the process of mastering radial forearm free flaps. The educational process can begin with the conventional study of relevant anatomy from textbooks, augmented by the 3D anatomy provided by the haptic radial forearm flap model. Subsequently, the essential surgical steps of flap harvesting can be systematically reviewed on the presented porcine model, coupled with microvascular training. By mastering these fundamental technical aspects, training can progress to advanced stages, involving practice on live animal models or gradually performing more extensive portions of the operation on actual patients under the close supervision of an experienced surgeon. A major advantage of the model is that it is readily available in large quantities at a low cost, making it suitable for large group hands-on workshops and providing realistic access to free flap techniques for a wider audience. No preparation is needed for the porcine head halves, which can be stored under regular refrigerator conditions. In addition, the only necessary items are standard surgical and microsurgical instruments, suture materials, and a standard microscope or magnifying glasses. The illustrated model can be integrated into the training of residents or advanced medical students and can be combined with other surgical simulators, such as anatomical models or 3D simulations, to further enhance the didactic value. It provides an effective and valuable method of initial preparation at an individual speed and intensity before taking the first steps in the operating theatre, where time for surgical teaching is often limited. The process of flap raising and of the anatomical structures involved can be experienced first, and surgical techniques such as suturing, tissue dissection and microvascular surgery can be trained on real tissue. One limitation of the model is its restriction to harvesting a single free flap per porcine specimen. However, the surplus animal material can be effectively utilized for supplementary suture training or for practicing local flap raising and defect covering exercises. Another limitation of the model lies in its mimicking of a vascular pedicle, which features only one venous vessel. Although comparable in terms of diameter and pedicle length to those of a radial forearm free flap, the typical configuration of an artery with two accompanying veins is not anatomically present in the porcine model. The realism of the presented model is inherently constrained by its status as a nonliving animal model, devoid of functioning vessels with consistent blood flow. Consequently, surgical techniques such as perforator identification, subsequent preservation, and surgical hemostasis cannot be accurately simulated. In addition to microvascular anastomosis, the future integration of diverse perfusion methods could significantly enhance the learning experience and augment the didactic benefits [27, 28]. In our department, the model is nevertheless being incorporated into the routine training of residents in reconstructive surgery. A clear drawback of the present research is the lack of verification of the proposed effectiveness, which will be investigated by further evaluations in the future. In addition, further research is certainly needed into how training with these specific and other analogous models translates into improved performance in the operating theatre.
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