Systemic Veins of the Thorax.
Fred W Wright in Radiology of the Chest and Related Conditions, 2022
The azygos vein lies anterior to or just to the right of the vertebral bodies until it arches anteriorly over the right main bronchus to join the SVC. It is usually well seen on frontal chest radiographs or conventional tomograms in the right tracheo-bronchial angle, where it makes an oval or rounded shadow above the right main bronchus, unless it lies more laterally within the right upper lobe within an azygos fissure (see below). It often produces a slight indentation on the lower right aspect of the trachea, especially when dilated. Its diameter is variable, being smaller in inspiration, the erect position or during the Valsalva manoeuvre. On erect radiographs its diameter is between 0.6 and 1 cm., but it is larger in heart failure with pericardial disease, venous obstruction (SVC or IVC obstruction), portal hypertension, or in pregnancy (up to 1.5 cm.). In the recumbent position it is commonly 1 to 1.5 cm., but larger even up to 2 cm. with the above conditions. Its appearance also varies with the patterns of pleural reflection. Occasionally the azygos vein is aneurysmal.
Development and anatomy of the venous system
Peter Gloviczki, Michael C. Dalsing, Bo Eklöf, Fedor Lurie, Thomas W. Wakefield, Monika L. Gloviczki in Handbook of Venous and Lymphatic Disorders, 2017
The origin of the azygos vein is not constant. It may arise from the back of the inferior vena cava at the level of the renal veins or it may be the continuation of the right ascending lumbar vein (Figure 2.11). The azygos vein ascends on the right side of the body until the fourth thoracic vertebra and then passes anteriorly to join the superior vena cava. Major tributaries of the azygos vein are the right superior intercostal, the hemiazygos, and the accessory hemiazygos veins. The hemiazygos vein courses on the left side of the vertebral column and its origin is similar to that of the azygos vein. At the level of the eighth thoracic vertebra, it crosses the column and joins the azygos vein. Often, the left renal vein communicates with the hemiazygos vein. The accessory hemiazygos vein descends left to the vertebral column and parallel with the azygos vein. Proximally, it anastomoses with the left brachiocephalic vein and ends distally when it joins to the azygos or the hemiazygos veins at the level of the seventh thoracic vertebra. The azygos veins drain the intercostal veins on both sides, receive several visceral tributaries, and freely anastomose with the vertebral venous plexuses. The azygos veins and their tributaries provide important collateral circulation in the face of superior or inferior vena cava obstruction.
Esophageal atresia and tracheo-esophageal fistula
Prem Puri in Newborn Surgery, 2017
The azygos vein is mobilized and controlled with vascular sloops. The author advocates temporary occlusion of the vein before ligation, as venous return to the heart may rarely be critically dependent on the azygos system. Provided this maneuver does not affect cardiac output, the azygos vein may be safely ligated and divided as it enters the superior vena cava. Alternatively, some surgeons elect to preserve the azygos vein.41 Once divided, the site of the TEF communication between the trachea and the distal esophagus is usually apparent. Having confidently identified the distal esophagus, a vascular sloop is carefully passed around it. Traction on the sloop controls the fistula and enables its junction with the trachea to be located precisely. Although it is possible to suture ligate the fistula, the author prefers to divide the fistula in stages and apply interrupted 5-0 or 6-0 monofilament prolene sutures to the tracheal component of the fistula. The distal esophagus is secured with a stay suture. The integrity of the TEF repair is evaluated by instilling saline into the thoracic cavity and requesting the anesthetist to exert positive airway pressure to ensure that no air bubbles leak from the suture line. Rarely difficulty may be encountered in locating the distal esophagus, and it is quite possible to mobilize the descending aorta in the erroneous impression that it is the esophagus. The surgeon should recognize the distal esophagus by following the vagus nerve as it courses distally, and by observing its rhythmic distension in time with ventilation.
Thoracic Lymph Duct Catheterization with a Venous Shunt in the Nonhuman Primate
Published in Journal of Investigative Surgery, 2022
Jon Ehrmann, Claudia Generaux, Sharon Ostergaard, Wendy Johnson, Anne Rose, Vince Mendenhall
For lymph to return and drain back to the systemic circulation, a shunt was used to access a venous blood vessel. The initial use of the jugular vein as the vessel for the shunt posed a few complications. First, the ability to access the medial portion of the neck in surgery while maintaining good exposure of the thoracotomy was less than ideal. Additionally, incisions at the neck line were prone to irritation due to collar or jacket use postoperatively and appeared to reduce the duration of patency of the catheter. Due to its proximity (immediately dorsal to the lymphatic duct) the azygous vein was selected as a better option for shunt placement. This refinement merged the procedures into only one incision and allowed both the lymphatic and venous catheters to exit the body at the same site. The azygous vein is a small vessel much like the lymphatic duct, thus the use of surgical loupes was necessary to visually identify the location of these vessels. Additionally, the intercostal collateral vessels drain into the azygous vein and are quite visible during the dissection. These collaterals will cause a significant amount of bleeding once an incision is made into the azygous, filling the cavity with blood quickly and making it almost impossible to visualize the catheterization location. Therefore, to avoid this situation, ligatures are placed in front of each collateral vessel and the catheter was inserted into the small portion of the azygous vein isolated in between them.
Techniques for lung surgery: a review of robotic lobectomy
Published in Expert Review of Respiratory Medicine, 2018
Sophia Chen, Travis C. Geraci, Robert James Cerfolio
Robotic surgery is feasible and safe for mediastinal and hilar lymph node dissection [27]. It is helpful to dissect mediastinal and hilar lymph nodes before lobectomy both to evaluate the lymph nodes and to access the bronchus and arterial and venous branches [7]. Right side: The inferior pulmonary ligament is divided and the lymph nodes at stations 8 and 9 are removed. The most posterior arm, robotic arm 3, is used to retract the lower lobe anteriorly and medially to remove lymph nodes at station 7. It is also used to retract the upper lobe inferiorly during dissection of stations 2R and 4R, which clears the space between the superior vena cava anteriorly, the esophagus posteriorly, and the azygos vein inferiorly.Left side: The inferior pulmonary ligament is divided to remove the station 9 lymph node, and then the station 8 nodes are removed. Station 7 is accessed lateral to the esophagus, between the lower lobe bronchus and the inferior pulmonary vein. During this process, robotic arm 3 is used to retract the lower lobe medially and anteriorly. Absence of the lower lobe helps with dissecting level 7 from the left. Finally, robotic arm 3 is wrapped around the left upper lobe and presses it inferiorly so the surgeon can dissect lymph nodes at stations 5 and 6. While working in the aortopulmonary window, the surgeon should take care to avoid injuring the left recurrent laryngeal nerve. The presence of the aortic arch typically prevents station 2L from being accessed during left-sided mediastinal lymph node dissection, but the 4L lymph node is frequently removed.
Transmural migration of azygous vein Hem-O-lok clip causing food bolus 3 months following uneventful minimally invasive oesophagectomy
Published in Acta Chirurgica Belgica, 2018
Ali Kordzadeh, Alexandros Charalabopoulos, Bruno Lorenzi
A-69-year-old female with past medical history of hypertension and smoking was diagnosed with squamous cell carcinoma of the distal oesophagus. She was subjected to two stage totally minimally invasive oesophagectomy (MIO) with intrathoracic hand-sewn oesophago-gastric anastomosis at the level of the azygous vein. Intraoperatively, the azygous vein was divided between two hem-o-lok clips (Teflon) at each side as a part of routine step (Figure 1). The patient made an uneventful recovery and was discharged on the 7th postoperative day. In our unit, we do not routinely perform postoperative barium swallow. However, we conduct methylene blue test on postoperative day 3 which was negative in this case. We only perform CT oral contrast or barium swallow if inflammatory response is present or any concern regarding anastomotic healing is present. Postoperatively, we keep patient’s nil by mouth for 3 days. This is followed by clear fluids on the same day following a negative methylene blue test and free fluids on 4th postoperative day, soft diet is commenced on day six. All oesophagectomy patients are reviewed in 3 weeks from discharge date in outpatient clinic. During postoperative period patient did not exhibit any inflammatory syndrome or dysphagia. Three months later, patient presented with complain of worsening dysphagia (5 days) with no other signs and symptoms. The patient underwent gastroscopy with clinical suspicion of anastomotic stricture. However, to our surprise, two Hem-o-lok clips with a small remnant of azygos vein were found in the gastric conduit at the level of the anastomosis causing food bolus (Figure 2). Upon successful extraction, patient dysphagia completely resolved and he was discharged with no complains on follow up. Patient did not require any additional intervention apart from extraction of the clips. Due to the above findings, the level of anastomosis has not been altered. However, we have stopped using Hem-o-lok clips and we have replaced them with 30 mm vascular stapler.
Related Knowledge Centers
- Descending Aorta
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- Venae Cavae
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- Thorax
- Atrium
- Vertebral Column
- Ascending Lumbar Vein
- Subcostal Vein