Chick chorioallantoic membrane as a model for simulating human true vocal folds.

Objectives: Evolving photoangiolytic laser techniques for treating vocal fold lesions motivated the development of a model for research and surgical training. The chick chorioallantoic membrane (CAM), which is composed of a microvasculature suspended within the egg albumen, simulates the vocal fold microcirculation within the superficial lamina propria (SLP). To characterize this model, we compared measurements of vessel diameters to superficial vessels in human vocal folds.
Methods: The diameters of first-, second-, and third-order CAM vessels were measured in fertilized chicken eggs. The superficial blood vessels of the human vocal fold were measured from intraoperative images.
Results: According to the branching pattern, vessel segments were identified as first-, second-, or third-order, with average diameters of 0.035 mm (0.02 to 0.1 mm), 0.18 mm (0.12 to 0.41 mm), and 0.8 mm (0.6 to 0.98 mm), respectively. The total vessels measured included 362 first-order, 119 second-order, and 82 third-order vessels. In 10 adult human vocal folds, an average vessel diameter of 0.04 mm (0.015 to 0.1 mm) was observed in 50 vessels.
Conclusions: The CAM microvasculature suspended in albumen provides a useful surgical model simulating the microcirculation within the SLP of the human vocal fold. Although first-order CAM vessels best approximate the size of normal vocal fold subepithelial vessels seen at surgery, second- and third-order vessels resemble the vascular abnormalities frequently encountered during microsurgery for phonotraumatic lesions.