Microsurgical training regimen with nonliving chicken 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.

The Role of Simulation in Microsurgical Training

Simulation has been established as an integral part of microsurgical training. The aim of this study was to assess and categorize the various simulation models in relation to the complexity of the microsurgical skill being taught and analyze the assessment methods commonly employed in microsurgical simulation training. Numerous courses have been established using simulation models. These models can be categorized, according to the level of complexity of the skill being taught, into basic, intermediate, and advanced. Microsurgical simulation training should be assessed using validated assessment methods. Assessment methods vary significantly from subjective expert opinions to self-assessment questionnaires and validated global rating scales. The appropriate assessment method should carefully be chosen based on the simulation modality. Simulation models should be validated, and a model with appropriate fidelity should be chosen according to the microsurgical skill being taught. Assessment should move from traditional simple subjective evaluations of trainee performance to validated tools. Future studies should assess the transferability of skills gained during simulation training to the real-life setting.

Comprehensive Analysis of Chicken Vessels as Microvascular Anastomosis Training Model

BACKGROUND

Nonliving chickens are commonly used as a microvascular anastomosis training model. However, previous studies have investigated only a few types of vessel, and no study has compared the characteristics of the various vessels. The present study evaluated the anatomic characteristics of various chicken vessels as a training model.

METHODS

Eight vessels-the brachial artery, basilic vein, radial artery, ulnar artery, ischiatic artery and vein, cranial tibial artery, and common dorsal metatarsal artery-were evaluated in 26 fresh chickens and 30 chicken feet for external diameter (ED) and thicknesses of the tunica adventitia and media. The dissection time from skin incision to application of vessel clamps was also measured.

RESULTS

The EDs of the vessels varied. The ischiatic vein had the largest ED of 2.69±0.33 mm, followed by the basilic vein (1.88±0.36 mm), ischiatic artery (1.68±0.24 mm), common dorsal metatarsal artery (1.23±0.23 mm), cranial tibial artery (1.18±0.19 mm), brachial artery (1.08±0.15 mm), ulnar artery (0.82±0.13 mm), and radial artery (0.56±0.12 mm), and the order of size was consistent across all subjects. Thicknesses of the tunica adventitia and media were also diverse, ranging from 74.09±19.91 µm to 158.66±40.25 µm (adventitia) and from 31.2±7.13 µm to 154.15±46.48 µm (media), respectively. Mean dissection time was <3 minutes for all vessels.

CONCLUSIONS

Our results suggest that nonliving chickens can provide various vessels with different anatomic characteristics, which can allow trainees the choice of an appropriate microvascular anastomosis training model depending on their purpose and skillfulness.

A Novel Perforator Flap Training Model Using a Chicken Leg

INTRODUCTION

Living animal models are frequently used for perforator flap dissection training, but no ex vivo models have been described. The aim of this study is to present a novel nonliving model for perforator flap training based on a constant perforator in the chicken leg.

METHODS

A total of 15 chicken legs were used in this study. Anatomical dissection of the perforator was performed after its identification using ink injection, and in four of these specimens a perforator-based flap was raised.

RESULTS

The anatomical dissection revealed a constant intramuscular perforator with a median length of 5.7 cm. Median proximal and distal vessel diameters were 0.93 and 0.4 mm, respectively. The median dissection time was 77.5 minutes.

CONCLUSION

This study introduces a novel, affordable, and reproducible model for the intramuscular dissection of a perforator-based flap using an ex vivo animal model. Its consistent perforator and appropriate-sized vessels make it useful for training.

Microsurgical Simulation Exercise for Surgical Training

OBJECTIVE

Initial training for orthopedic surgical residents (postgraduate years 1-5) in microsurgery using the turkey wing model and evaluation of their proficiency.

DESIGN

Residents were given a questionnaire on their comfort level with microsurgery and microsurgical knowledge, followed by a lecture on the subject. They watched a surgical dissection and repair of the turkey wing's neurovasculature. Residents performed the dissection and repairs of the artery, vein, and nerve. A postquestionnaire was administered following the simulation exercise. Their performances on repairs were graded and results compared by academic year.

SETTING AND PARTICIPANTS

A total of 21 orthopedic surgery residents were recruited from Stony Brook University Medical Center, Stony Brook, NK.

RESULTS

This training activity resulted in significant improvements in both microsurgical knowledge (41%) and comfort (37%). Senior residents scored significantly higher than juniors on 6 microsurgical parameters. The largest effect was in nerve repair showing 4 parameters that differed significantly between groups.

CONCLUSION

Microsurgical techniques require extensive training to master. The turkey wing model for repair of the artery, vein, and nerve represents a realistic simulation of a human hand artery, vein, and nerve. It provides an inexpensive method for residents to practice on real tissue for improving microsurgical technique.

Step by step: microsurgical training method combining two nonliving animal models

The learning of microsurgical techniques and the maintenance of microsurgical skills have been traditionally based on the use of living animals, mainly laboratory rats. This method although extremely valuable can be economically demanding both for the surgeon and the sponsoring institution; it also requires special training facilities that may not always be available or accessible. Furthermore ethical concerns can limit the use of living animals for training purposes. Alternative training methods, such as inert tubes and gloves have not gained popularity among surgeons since they do not offer an experience similar to that of a clinical situation. Non-living animal models include the use of chicken thighs and wings; they offer a practice experience that resembles a clinical situation to a considerable extent. This type of training is relatively cheap and easily available. The microscope and instruments required can be acquired over the internet, and the chicken pieces can be bought at the local supermarket. This approach allows a motivated trainee to rehearse different types of surgical techniques several times at a reasonable expense, helping to develop or maintain his surgical expertise if more complex facilities are not available. On the current manuscript we describe how to setup a small practice station, how to dissect the specimens, and how to practice both with the chicken thighs and with the chicken wings in a progressive fashion. This approach takes advantage on the versatility of the chicken thigh model and the small size of the chicken wing Brachial artery.