1. Department of Surgical Research, Instituto Nacional de Enfermedades Respiratorias Ismael Cosio Villegas, Tlalpan, 14080 Mexico City, DF, Mexico
2. Department of Morphology, Instituto Nacional de Enfermedades Respiratorias Ismael Cosio Villegas, Tlalpan, 14080 Mexico City, DF, Mexico
3. Department of Otolaryngology-Head and Neck Surgery, Instituto Nacional de Enfermedades Respiratorias Ismael Cosio Villegas, Tlalpan, 14080 Mexico City, DF, Mexico
4. Medical Direction, Instituto Nacional de Enfermedades Respiratorias Ismael Cosio Villegas, Tlalpan, 14080 Mexico City, DF, Mexico