Efficacy of preoperative laryngogram for localization of the ventricle at the anterior commissure

Abstract

The localization of the ventricle exactly above the anterior commissure of the vocal cords is important in performing supraglottic laryngectomy. The lateral projections of pre‐operative laryngograms are examined and the following two dimensions are measured on the film: (1) distance between the bottom of the thyroid notch and the inferior border of the thyroid cartilage and (2) distance between the anterior part of the ventricle and the inferior border. The ratio of these two distances is obtained and is designated as distance ratio (DR). The DR is similarly calculated from the actual measurements of the laryngeal specimens and is compared with the DR based on the laryngograms. Differences between these two DR's are nonsignificant (0.5 <p <0.6). Also, there is a high degree of relationship between these two DR's (P <0.001). Thus, the DR based on the laryngogram is an accurate index to determine the level of the ventricle just above the anterior commissure in performing a transection of the thyroid cartilage. When the thyroid cartilage is exposed completely during surgery a measurement between the bottom of the thyroid notch and the inferior border is made. Actual distance between the inferior border and the anterior part of the ventricle can be calculated by the DR obtained from the preoperative laryngogram. This method ensures that neither anterior commissure nor pre‐epiglottic space is violated when the thyroid cartilage is transected.

Análise tomográfica para o planejamento da tireoplastia tipo I: estudo experimental em laringes humanas excisadas

“…A maioria dos laringologistas assume tal projeção na metade da distância entre a incisura tireoideana e a margem inferior da cartilagem tireóidea, conforme padronizado por Isshiki et al, em 1974. Porém, essa localização não é um consenso em estudos morfométricos (Seiffert, 1943;Gurr, 1948;Minnigerode, 1955;Ogura, 1958;Hiroto e Toyozumi, 1968;Hiramoto (1977); Tokita e Daly, 1978;Koufman e Isaacson, 1991;Tucker, 1993;Koufman e Postma, 1999;.…”