Variability of stereomorphotopometric characteristics of structures and sections of the laryngeal cavity in various neck variants in adults and their role in planning surgical access in laryngeal paralysis

The topographic and anatomical variability of laryngeal structures in adults necessitates the development of individualized options for reconstructive laryngoplasty in laryngeal paralysis considering the general, individual and local constitution of the subject.

The aim of the study was to identify interrelationships of individual variability of stereomorphotopometric characteristics of structures and sections of the laryngeal cavity in adult men and women with different neck variants with anthropometric parameters and to develop personalized regression models for the design of surgical techniques for laryngeal paralysis.

Material and methods. The material of the study was larynx preparations taken from the corpses of people 18 60 years old, representing an ethnically homogeneous group of residents of the Middle and Lower Volga region and examined within 12–24 hours after death. Body length, biacromial diameter, chest circumference, anterior neck length and neck circumference were measured, and hyoid bone (PC) and larynx dissection were performed to identify the body type and individual morphologic constitution of the neck. The method of laryngostereotopometry was applied: after fixation of the larynx preparation vertically in a special tripod, the Cartesian coordinates of anatomical points in three coordinate planes were measured. Two indices were used in variation statistical processing and data analysis: thorax height (normal thoracic – T) and length circumference (cervical – C): correlation analysis of relationships between chest and cervical indices was carried out.

Results. A total of 100 adult laryngeal preparations were studied stereomorphotopometrically regarding neck type and anthropometry. The total degree of correlation squares of the cervical index with the HB and anthropometry parameters statistically significantly exceeded the value for the thoracic index, which was the reason for choosing the cervical index as a criterion for dividing the whole sample into 3 groups: I – subjects with short neck, II – subjects with average neck length, III – subjects with long neck. Correlations between the parameters of the structures and sections of the laryngeal cavity and the anthropometry data, thoracic height and cervical coefficients in subjects with different neck variants were determined. The range of significantly deviating values (pre disease) for the larynx and neck parameters important for the selection of optimal surgical access to the laryngeal structures was determined. Regression equations were developed to determine the dimensional parameters of the laryngeal cavity structures and sections with 95% probability, considering sexual dimorphism and anthropometric data. The obtained patterns of constitutional morphology of the larynx were used as a basis for the development of medial and lateral vocal fold fixation techniques in laryngeal paralysis.

Conclusion. Using constitutional approach and regression analysis of data for characterization of morphological structures, the possibility of preoperative determination of the larynx dimensions using anthropometric data of the subject was proved, and the developed algorithm was used to calculate the autograft dimensions for laryngoplasty (p<0.05). Planning of the technique and volume of intervention in patients with laryngeal paralysis with consideration of the individual and typological variability of laryngeal structures in different neck and body constitution variants makes it possible to preserve the vocal function and to obtain adequate breathing through natural ways. Key words: anthropometry, neck type, laryngeal paralysis, stereotopometry. regression equations, lateral fixation, medial fixation of the vocal fold

Conflicts of interest. The authors have no conflicts of interest to declare.
Funding. There was no funding for this study