INTERVERTEBRAL VEINS DIRECTLY CONNECTING THE VERTEBRAL VENOUS SYSTEM TO THE AZYGOS VENOUS SYSTEM RATHER THAN THE PROXIMAL END OF THE POSTERIOR INTERCOSTAL VEINS. Venas intervertebrales conectando directamente el sistema venoso vertebral al sistema venoso

Abstract

La estructura de las venas de la cavidad torácica varía significativamente en función de sus conexiones. Treinta cadáveres embalsamados con la técnica de Thiel fueron disecados (18 mujeres, 12 hombres), con edades comprendidas entre 48 y 98 años (media 81.3±12.40). Los pulmones, el corazón, la aorta torácica, el esófago y la pleura parietal fueron cuidadosamente retirados para permitir la visualización de las venas ácigos, hemiácigos y hemiácigos accesoria así como el conducto torácico. En la mayoría de los especímenes (21) se encontró que las venas intervertebrales estaban directamente conectadas con el sistema venoso ácigos en vez de con la parte terminal proximal de las venas intercostales posteriores. Se observó también que dicha distribución es más común en el lado derecho, pero no en todos los niveles vertebrales. Estas conexiones podrían jugar un rol en la regulación del volúmen de sangre entre los sistemas venosos ácigos y vertebral: también podrían actuar como vías metastásicas entre las regiones torácica y abdominal. Dado que su aspecto es bastante similar al de los vasos intercostales posteriores, es importante que los cirujanos sean conscientes de esta variación para evitar lesiones que induzcan hematomas postoperatorios. Veins in the thoracic cavity are highly variable in terms of their communications. Thirty Thiel-embalmed cadavers were dissected (18 females and 12 males), ranging in age from 48 to 98 years old (mean 81.3±12.40). The lungs, heart, thoracic aorta, oesophagus and parietal pleura were removed carefully to expose the azygos, hemiazygos, accessory hemiazygos veins and thoracic duct. In most specimens (21) intervertebral veins were connected directly to the azygos venous systems rather than the proximal end of the posterior intercostal veins. This presentation was observed to be more common on the right side, but not at all vertebral levels. These communications could play a role in regulating blood volume between the azygos and vertebral venous systems; they may also act as metastatic pathways between the thoracic and abdominal regions. As they mimic posterior intercostal vessels, it is important for surgeons to be aware of this variation to avoid injuries leading to postoperative hematomas.

A Case Series Cadaveric Study on Acquired and Congenital Azygos Venous System Variations

“…Type 2 consists of separate AZY, HAZY, and AHAZY. This type was divided further into groups A through E according to the number of retro-aortic communications from one (group A) to five or more (group E) as classified by Dahran and Saomes [6]. Type III, the single column type, consists of a single vein located in the midline, often called a unicolumnar vein [4] that drains both the left and right PIs.…”

“…Because of its origin at the IVC and drainage into the SVC, the AZY can function as a connection between these two great vessels. The AVS becomes essential in cases of obstruction of the IVC as it allows the lower half of the body to drain into the SVC instead [5,6].…”

“…In other instances, communications between the AZY and its leftsided counterparts are variable. The number of these communications, which often lie behind the aorta, determine the subgroup of Type II of the Anson McVay system using the Dahran and Soames system[6]. And lastly, when a single mid-line AZY occurs, it is classified as Type III in the Anson McVay system.In the current study, the distribution of the classifications is comparable to those reported in previous studies, and most of the donors could be classified into the existing classification system subgroups.…”

Paraspinal structures of thermoregulation

“…Основной отток крови из этого сплетения осуществляется через межпозвоночные вены в задние межрёберные вены. N. Dahzan, R. Soames [11] обнаружили, что межпозвоночные вены могут впадать не в проксимальные концы задних межреберных вен, а непосредственно в непарную и полунепарную вены, чаще на правой стороне, но не на всех уровнях. Эти связи могут играть определенную роль в регуляции кровотока между непарными венами, венозным руслом спинного мозга и эпидуральным венозным сплетением.…”