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October 13, 2012
8:00:00 AM - 11:00:00 AM
Room Hall C-E-Poster area
External Neck Measurements, Laryngeal Anatomy and Gender/Height Controlled Variability in Adult Patients
Davide Cattano, M.D.,Ph.D., Jacek Wojtczak, M.D., Carmen Seitan, M.A., Sadiya Shamam, M.D., Hassan Aijazi, M.B.,B.S., Henrique Vale, M.D., Alfonso Altamirano, M.D., Carin A. Hagberg, M.D.
University of Texas Health Science Center Houston, Houston, Texas, United States
For an anesthesiologist, the ability to accurately predict the size of a patient’s airway can facilitate clinical choices, such as establishing a plan for managing a patient’s airway,or determining the correct size of a supraglottic airway. However, research regarding the measurement of airway size is limited.1-2 The primary aim of this study is to evaluate measurement of certain neck landmarks in an adult patient cohort as an estimation of laryngeal scaffold size. Using primarily the thyroid and cricoid cartilages as landmarks, we proposed that these structures correlate closely to the size of the internal airway.

After obtaining IRB approval, external neck measurements were collected from 100 male and 100 female patients comprised of non-obese (BMI ≤ 30 kg/m2) adults aged 18-80, ASA I-II, Mallampati I or II, who presented for general surgery requiring general anesthesia. Patient eligibility was determined by height; male patients 165 - 185 cm and female patients 155 - 175 cm were eligible. All measurements were taken in centimeters (cm) using a disposable measuring tape. Primary measurements included thyroid width (TWD), the distance across the lateral borders of the upper thyroid cartilage, and thyroid cricoid distance (TCD), the distance from the thyroid notch to the lower border of the cricoid cartilage. Secondary measurements included the thyromental distance (TMD), the distance from the lower midline border of the mandible with the jaw occluded and neck extended to the thyroid notch, the hyoid cricoid distance (HCD), the distance from the hyoid bone and the upper border of the cricoid cartilage, and the sternomental distance (SMD), the distance between the lower midline border of the mandible with the jaw occluded and neck extended to the sternum. Univariate and multivariate analyses were performed. Patients were then stratified by gender and height.

The patient population included 200 patients (Table 1): 100 females and 100 males. Interestingly, female and male patients that were taller tended to have shorter TCD but larger TWD on average (p< 0.01).Female patients also tended to have longer TMDs compared to male patients -this value however, was not significant (female 155-165cm (n=60), TMD= 8.34±2.00, TCD=5.75±1.68 and TWD=5.04±0.81; 165-175cm (n=33), TMD= 8.60±2.11, TCD=5.51±1.42 and TWD=5.43±0.80; male 165-175cm (n=46), TMD= 8.23±1.74, TCD=5.87±1.87 and TWD=5.61±0.86; 175-185 cm (n=49 p), TMD= 8.41±1.68, TCD=5.59±1.59 and TWD=5.89±0.76.

We offered an assessment of laryngeal anatomy size utilizing accepted parameters such as weight, age, gender, and height, and experimental parameters such as TCD, TWD and TCD. Future research is planned to increase the accuracy of our measurements by using a caliper, ultrasound and remote photography based anatomy analysis. Also, the hyoid bone space appears to be an interesting novel value to explore.3


1. Sakuraba S, Serita R, Kuribayashi J, Kosugi S, Arisaka H, Yoshida K, Takeda J. Comparison of tracheal diameter measured by chest x-ray and by computed tomography. Anesthesiol Res Pract 2010; 2010: 269171.

2. Breatnach E, Abbott G, Fraser R. Dimensions of the normal human trachea. Am J Roentgen 1983; 141: 903-906.

3. Wojtczak JA. Submandibular Sonography. Assessment of Hyomental Distances and Ratio, Tongue Size, and Floor of the Mouth Musculature Using Portable Sonography. J Ultrasound Med 2012; 31:523-528
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