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The Chicken Thigh Model For Head and Neck Microvascular Training

Audrey B. Erman, M.D. and Daniel G. Deschler, M.D.

Department of Otolaryngology, Massachusetts Eye & Ear Infirmary, Harvard Medical School, Boston, MA.

Educational Objective

: At the conclusion of this presentation, the participant should be able to design and execute a learning model for microvascular training using the chicken thigh, and compare the vessel caliber of this model to flaps most often used in head and neck microvascular reconstruction.

Objectives

: To describe the relevant vascular anatomy of the chicken thigh, evaluate the anatomical variants of the ischiatic artery and femoral vein, and highlight the utility of this model in training head and neck microvascular surgeons.

Study Design

: Chicken thighs from a local grocer were dissected using loupe magnification. Vessel characteristics including diameter and anatomical variants were assessed.

Results were compared with reported sizes of the vessels in the common free flaps used in head and neck reconstruction: the radial forearm, the fibula, and the anterolateral thigh free flap.

Results

: The anatomy of the chicken ischiatic artery and femoral vein was easily dissectible and constant among specimens. Chicken thigh vessel caliber was comparable to those reported for the radial forearm, the fibula, and the anterolateral thigh free flaps.

Conclusions

: The chicken thigh model is an innovative model for microvascular surgical training, with vascular anatomy comparable to vessels in commonly used flaps for head and neck reconstruction. We offer this technique as a complimentary model (to the standard rat femoral vessel model) with the specific advantages of: ready accessibility, low cost, vivisection avoidance and a vascular pedicle highly similar to the common free flaps in head and neck reconstruction.

• Microvascular free tissue transfer has become a mainstay in the treatment of head and neck cancer.

• Many training programs offer rat vivisection of the femoral artery and vein for introductory microvascular practice.

• The chicken thigh is an easily attainable, low-cost alternative to formal laboratory training.

• We examined the anatomical variations in the chicken thigh vessels and compared their relative size to those found in the most common flaps used in the head and neck.

• 20 whole, raw, fresh chicken quarters obtained from grocer

• Skin and fat cleaned (Fig 1)

• Iliotibial and iliofibularis muscles reflected, and ischiatic artery, femoral vein identified (Fig 2)

• Artery and vein divided at mid femur and diameter measured

• Anastomosis with 9-0 or 8-0 nylon suture under loupe magnification (Fig 3)

Figure 1.

Chicken thigh, after skin and fat removal.

a

Iliotibial m.

a v n

Iliofibularis m.

Figure 2.

Reflection of the iliotibial and iliofibularis muscles reveals the the femoral vein (v), the ischiatic artery (a) and the ischiatic nerve (n)

Figure 3.

The ischiatic artery (a) divided in preparation for microvascular anastamosis.

All 20 chicken specimens had identical vessel anatomy, without variation.

Average diameter of the ischiatic artery 2.1 mm (1.9 - 2.2 mm)

Average diameter of the femoral vein 2.2 mm (1.7 - 2.3 mm)

Donor Site Donor Artery

Radial Forearm

Anterolateral

Thigh

Fibula

Chicken Thigh

Radial

Descending branch lateral femoral circumflex

Peroneal

Ischiatic

Vessel

Diameter

2.5 mm

> 2 mm

1.8 - 2.5 mm

2.1 mm

Table 1.

Comparison of chicken thigh vessels to those most commonly used in head and neck microvascular reconstruction.

• Obtaining a “chicken quarter” rather than whole “chicken leg” ensured an intact vascular bundle from the ischial foramen, and helped maintain vessels on stretch during microvascular anastomosis.

• Chicken thigh supplied by ischiatic artery and femoral vein, easily dissected from surrounding muscles.

• Represents an easily reproducible, low-cost method for microvascular anastomosis training.

• The chicken ischiatic artery has a comparable diameter to the human radial, peroneal, and descending branch of the lateral femoral circumflex arteries.

• The vascular anatomy of the chicken thigh is constant and reproducible.

• The chicken ischiatic artery has a comparable diameter to the human radial, peroneal, and lateral branch of the descending circumflex arteries.

• The chicken thigh is a low-cost, readily accessible alternative to other microvascular training models.

1. Sucur D, Konstantinovic P, Potparic Z: Fresh chicken leg: an experimental model for the microsurgical beginner. Br J Plast Surg 34:488-

9, 1981

2. Baumel JJ, Nuttall Ornithological Club., World Association of Veterinary

Anatomists. International Committee on Avian Nomenclature.: Handbook of avian anatomy : nomina anatomica avium (ed 2nd). Cambridge, Mass.,

[Nuttall Ornithological Club], 1993

3. Song YG, Chen GZ, Song YL: The free thigh flap: a new free flap concept based on the septocutaneous artery. Br J Plast Surg 37:149-59, 1984

4. Muhlbauer W, Herndl E, Stock W: The forearm flap. Plast Reconstr Surg

70:336-44, 1982

5. Song R, Gao Y, Song Y, et al: The forearm flap. Clin Plast Surg 9:21-6,

1982

6. Taylor GI, Miller GD, Ham FJ: The free vascularized bone graft. A clinical extension of microvascular techniques. Plast Reconstr Surg 55:533-44,

1975

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