We have provided here a simple model to impart vascular anastomosis skills to surgical residents using formalin-fixed porcine aortic segments. There are several models used to train vascular anastomosis techniques that have been described in the literature so far [3–17]. However, most of these models address microvascular techniques using an operative microscope, and are thus not suitable to learn large-vessel anastomoses due to the small diameter of the vessels used. However, some of these models may be adopted for a more general usage by changing the size of the particular model. Tubes of different artificial material like silicone, Gore-Tex, latex and PTFE have been used for vascular anastomosis training [3, 5, 7, 11, 13]. However, there may be some expense with vascular tube grafts if unsatisfactory amounts are found as leftovers from the operating room. The handling of these artificial materials differs from that of biological materials due to their stiff nature, making tube grafts not the most favourable model for surgical beginners, even though the suturing technique remains the same. Foodstuffs such as vessels chicken wings and legs, turkey necks or breads, animal limbs and organs, or pig hearts, coronaries or omentum vessels are similar to human vascular texture but only suitable for microsurgical purposes [4]. Moreover, some of these models raise ethical concerns since they use human food resources. The presented porcine aorta model comes very close to the vascular texture of humans and does not require any further preparation besides formalin fixation. The aortic segments can be stored in formalin until eventual use.
The model itself was described initially by Greenhalgh and Flack almost 30 years ago and later was extended to an aneurysm anastomotic model [10, 18]. The Royal College of Surgeons of England, which is often on the cutting edge of advancements in structured surgical education has devoted time to promoting skills training workshops for their trainees, and has used this model since it was proposed [9]. However, to the best of our knowledge, no evaluation of the model or the skills course segment for training vascular anastomosis techniques using porcine aortas has been published since its initial introduction. Moreover, the initial report by Greenhalgh and Flack and the report of the description of the first anastomosis workshop by the royal College of Surgeons of England remain the only two references of this model in the literature [10, 18].
When using the porcine aorta model, it is important to control for the diameter of the segments used. The aortic segments used in this study had a diameter of 2.0-3.0 cm. However, if a smaller-diameter vessel is desired, porcine iliac or subclavian arteries can be used instead. Porcine vessels can be obtained from any urban slaughterhouse without great financial efforts since they are a by-product of slaughtering. Obtaining the material should be only a matter of negotiation. Vascular tissue does not enter the food chain and is therefore not open to ethical concerns. No extra preparation is necessary and the teaching session is therefore easily prepared.
The survey evaluation of the model presented revealed that there is a strong need for vascular anastomosis skills training among young surgical residents within their first two years of training. The model itself was rated overall with high acceptance, and the skills module of only one hour was rated, as being exactly what is needed. However, we acknowledge that a comparison to other models e.g., tube grafts, is warranted in the future to determine rankings among the currently available models. The present manuscript represents to our best knowledge both the first profound description of a teaching course to train surgical residents using porcine aorta and an evaluation of the same by German surgical residents. However, we acknowledge the preliminary character of this evaluation due to its limited group size. We have used the present model to teach basic vascular anastomosis skills for several years. We use individualised verbal feedback during anastomotic suturing and after the anastomosis is performed by discussing every single stitch with the trainee to objectify the grade of anastomosis leakage. However, several other methods to assess the operative performance have been described, such as grading possible anastomotic leakage or the motor handling of the surgical instruments quantitatively [3, 5, 19]. These methods can be used as required. Laboratory-based surgical skills training, including vascular anastomosis training, has been demonstrated to improve surgical performance substantially [20]. In this context, it has been previously stated that verbal feedback from an expert instructor leads to lasting improvements in technical performance when learning new surgical skills [21]. It is well recognised that surgical performance determines the patient outcomes. Thus, it has been previously stated that operative procedures are 75% decision-making skills and 25% dexterity [3].
Keeping the importance of manual surgical skills in mind, young surgical residents at the University of Marburg, Germany currently pass through a surgical skills curriculum while they are on non-operative units. They perform, among other procedures; ten bench-model based vascular anastomoses prior to performing them on patients in the operating room [16, 22]. This exemplary attempt to establish a continuous curriculum for surgical residents is one important step towards improving both quality in surgical education and the satisfaction of the trainees in surgery. The particular model the residents are trained with is not as important as to serve the particular needs of the trainees. The present evaluation showed the need for training in vascular anastomoses according to the young general surgical residents. In recent years, undergraduate medical education in Germany was revised and changed to include more structured curricula, including formal evaluations, due to licensing requirements and the obvious need of reforms. It is now time to transfer these experiences and build nationwide comprehensive structured surgical curricula to accompany surgical residency programs. This need becomes apparent when considering a survey of general surgery residency programs in the United States that revealed that 86% had specific curricula for teaching book knowledge, but only 45% had curricula for single surgical techniques [16, 23]. The most important basic surgical skills needed have been already described and have been compulsory in the graduate training program of the Royal Colleges of Surgery of England, among others, for several years [24]. Thus, residency programs can be enhanced and the contentment among the trainees increased with the deployment of suitable and innovative bench models.