Thoracic Duct

Cranial lymphatic vessels (LVs) are involved in the transport of fluids, macromolecules and central nervous system (CNS) immune responses. Little information about spinal LVs is available, because these delicate structures are embedded within vertebral tissues and difficult to visualize using traditional histology. Here we show an extended vertebral column LV network using three-dimensional imaging of decalcified iDISCO+-clarified spine segments. Vertebral LVs connect to peripheral sensory and sympathetic ganglia and form metameric vertebral circuits connecting to lymph nodes and the thoracic duct. They drain the epidural space and the dura mater around the spinal cord and associate with leukocytes. Vertebral LVs remodel extensively after spinal cord injury and VEGF-C-induced vertebral lymphangiogenesis exacerbates the inflammatory responses, T cell infiltration and demyelination following focal spinal cord lesion. Therefore, vertebral LVs add to skull meningeal LVs as gatekeepers of CNS immunity and may be potential targets to improve the maintenance and repair of spinal tissues.

BackgroundChyle leaks following oesophagectomy are a frustrating complication of surgery with considerable morbidity. The use of near infra-red (NIR) fluorescence in surgery is an emerging technology and the use of fluorescence to identify the thoracic duct has been demonstrated in animal work and early human case reports. This study evaluated the use mesenteric and enteral administration of indocyanine green (ICG) in humans to identify the thoracic duct during oesophagectomy.MethodsPatients undergoing oesophagectomy were recruited to the study. Administration of ICG via an enteral route or mesenteric injection was evaluated. Fluorescence was assessed using a NIR fluorescence enabled laparoscope system with a visual scoring system and signal to background ratios. Visualisation of the thoracic duct under white light and NIR fluorescence was compared as well as any identification of active chyle leak. Patients were followed up post-operatively for adverse events and chyle leak.Results20 patients received ICG and were included in the study. The enteral route failed to fluoresce the thoracic duct. Mesenteric injection (17 patients) identified the thoracic duct under fluorescence prior to white light in 70% of patients with a mean signal to background ratio of 5.35. In 6 participants, a possible active chyle leak was identified under fluorescence with 4 showing active chyle leak from what was identified as the thoracic duct.ConclusionThis study demonstrates that ICG administration via mesenteric injection can highlight the thoracic duct during oesophagectomy and may be a potential technology to reduce chyle leak following surgery.Clinical trial registrationClinical trials.gov (NCT03292757).

BackgroundThe aim of this study was to investigate the impact of thoracic duct embolization (TDE) on the management of postoperative chyle leakage.MethodsWe retrospectively reviewed the electronic medical record database of 4171 patients who underwent curative resection for lung or esophageal cancer between January 2015 and June 2017. We classified the period before the introduction of TDE as the first period and the period after the introduction of TDE as the second period.ResultsA total of 105 patients who developed chyle leakage after surgery were included. In the first period, 49 patients who underwent lung surgery developed chylothorax. Of those, two patients (4.1%) underwent surgical ligation of the thoracic duct (TD). Of eight patients with chyle leakage after esophagectomy, four patients (50%) underwent TD ligation. In the second period, 30 patients developed postoperative chyle leakage after pulmonary resection. Only one (3.3%) of them required surgical ligation. Of eight patients with chyle leakage after esophagectomy, only two (11.1%) patients underwent TD ligation. Five patients (16.7%) received TDE after lung surgery and five patients (27.7%) after esophageal surgery. Also, in the second period, the hospital stay of patients who underwent lung cancer surgery was shorter than the first period (12.6 ± 4.6 days vs. 16.3 ± 9.7 days; p = 0.026).ConclusionsTDE is an effective method for the management of chyle leakage and might help to avoid invasive surgery.

The thoracic duct (TD) is the largest lymphatic vessel proximal to the venous system. It undergoes morphological changes in response to lymph flow from the periphery, with automatic contraction controlling the dynamics to propel lymph toward the venous system. Recent advancements in ultrasonography have facilitated non-invasive observations of the TD's terminal, including its valve and wall motions. Observations of TD movements allow predictions of lymphatic flow dynamics. However, no studies have yet documented the changes in the TD under exercise-induced lymph flow enhancement in humans. Here, using 18-MHz high-frequency ultrasonography, we demonstrate for the first time that the TD diameter significantly expands under exercise load. This study analyzed 20 participants; the maximum TD diameters at rest and post-exercise were 2.69 ± 1.06 mm and 3.41 ± 1.32 mm, respectively (p = 0.00000056). While various methods exist for observing the TD, our approach-dynamically monitoring the TD diameter using sonography in real time and correlating it with lymphatic flow dynamics-offers a novel contribution.