To determine the point of entrance of the thoracic duct in the venous system, as well as to evaluate some biometric measurements concerning its terminal portion, we conducted an anatomic study on 25 non-preserved cadavers. The termination of the thoracic duct occurred on the confluence between the left internal jugular vein and the left subclavian vein in 60 % of the individuals. The average results for the biometric measurements were: distance between the end of left internal jugular vein and omohyoid muscle 31.2 ± 2.7 mm; distance between the end of thoracic duct and the left internal jugular vein 0.0 ± 0.0 mm; distance between the end of thoracic duct and the left subclavian vein 3.6 ± 1.0 mm; distance between the end of thoracic duct and the left brachiocephalic vein 10.7 ± 3.1 mm. Moreover, it was identified that the left internal jugular vein length in level IV, measured between its entrance in the left subclavian vein and the omohyoid muscle, was able to predict the termination of the thoracic duct on the junction between the left internal jugular vein and the left subclavian vein (OR = 2.99) with high accuracy (79.3 %). In addition, the left internal jugular vein length at level IV was able to predict the localization of thoracic duct termination. Thus, this finding has practical value in minimizing the risk for a potential chyle leak during or after a left-sided neck dissection.

. Medidas biométricas envolvendo a porção terminal do ducto torácico no nível cervical IV à esquerda: um estudo anatômico / Biometric measurements involving the terminal portion of the thoracic duct on left level IV: an anatomic study. Rev Med (São Paulo). 2015 jan.-mar.;94(1):1-5. RESUMO: INTRODUÇÃO:No esvaziamento cervical do nível IV à esquerda, a porção final do ducto torácico (DT) pode ser lesada, aumentando significativamente a morbimortalidade pós-operatória. O melhor tratamento é a prevenção. Contudo, não há disponível na literatura medidas biométricas que auxiliem a identificação da desembocadura do DT. MATERIAIS E MÉTODOS: a desembocadura do DT foi identificada e distâncias úteis foram medidas em 25 cadáveres não-formolizados. Análise estatística foi realizada para verificar associações. RESULTADOS: a desembocadura do DT ocorreu na confluência jugulo-subclávia (CJS -60%), na veia jugular interna esquerda (VJIE -36%) e na veia braquiocefálica esquerda (4%). Uma associação estatisticamente significante foi encontrada entre a desembocadura na confluência jugulo-subclávia e a distância entre a VJIE e o músculo omo-hioide (Medida #1). Indivíduos cujo DT desemboca na CJS apresentaram a Medida #1 com mediana de 34.5±12.0mm, já os com desembocadura na VJIE apresentaram mediana de 22.3±8.7mm (p=0.015 -Student´s t-test). A regressão logística demonstrou que para cada aumento de 10mm na Medida #1 há uma chance de 1.12x de encontrar a desembocadura do DT na CJS (OR=1.12; CI95%:1,01-1,25; p=0.032). Para essa Medida #1 estabeleceu-se um cut-off de 19mm como teste diagnóstico para prever a desembocadura do DT na CJS, com sensibilidade de 86.7% (CI95%:59.5-98.3%), especificidade de 55.6% (CI95%:21.2-86.3%), PPV de 76.5% (CI95%:50.1-93.2%), NPV de 71.4% (CI95%:25.8-97.2%) e ROC AUC de 79.3% (CI95%: 58.0-92.9%). CONCLUSÃO: este estudo anatômico demonstrou que o local de desembocadura do DT mais frequente é a CJS e que a Medida #1 é capaz de prever o local de desembocadura do DT. ABSTRACT: BACKGROUND: During a neck dissection involving the left IV level, the final segment of the thoracic duct (TD) may be injured, significantly increasing postoperative morbi-mortality. The best treatment is its prevention. However, there is a lack of helpful biometric measurements focusing on the TD termination in the literature. MATERIALS AND METHODS: The TD termination was identified and some helpful biometric measurements were obtained on 25 non-preserved cadavers. DESCRITORES:Statistical analysis was performed to analyze correlations. RESULTS: TD termination was found on the jugulo-subclavian junction (JSJ -60%), on the left internal jugular vein (LIJV -36%), and on the left brachiocephalic vein in 4%. A statistically significant association was found between TD termination on the JSJ and the distance between LIJV and omohyoid muscle (Measurement #1). Individuals with TD termination on the JSJ had median Measurement #1 of 34.5±12.0mm, compared with median Measurement #1 of 22.3±8.7mm among individuals with TD termination on LIJV (p=0....