Lymphaticovenous anastomosis of the caudal thoracic duct to the azygous vein: A feline cadaver study

OBJECTIVE

The aim of this study was to describe a technique for anastomosis of the thoracic duct (TD) to the azygos vein (AV) using a microvascular anastomotic coupler (MAC) device in feline cadavers. Our hypothesis was that a TD-AV lymphaticovenous anastomosis would be feasible in feline cadavers.

STUDY DESIGN

Cadaveric study.

ANIMALS

Eight domestic shorthair feline cadavers.

METHODS

A left paracostal laparotomy and 9th or 10th intercostal thoracotomy was performed. Contrast media was injected into a mesenteric lymph node and lymphography was used to identify the TD and its branches. The TD and AV were isolated, ligated, and divided with the aid of a surgical microscope. The TD and AV were anastomosed end-to-end using a 1.5 or 2.0 mm MAC. Intraoperative patency was assessed by manipulation of chyle and venous blood across the anastomosis. Mesenteric lymphography was repeated to confirm postoperative anastomotic patency.

RESULTS

The TD was identified via lymphography in seven of eight cats. The anastomosis was successful and patency was confirmed via intraoperative assessment and postoperative lymphography in all cats. The median (range) duration for the dissection and anastomosis portions of the procedure was 122 (80-150) min.

CONCLUSION

End-to-end anastomosis of the TD to the AV using a MAC was feasible in the feline cadaver without major intraoperative technical challenges.

CLINICAL SIGNIFICANCE

Anastomosis of the TD and AV may have application as an alternative treatment for idiopathic chylothorax in cats. By directly connecting the abdominal lymphatics to the central venous system, the stimulus for collateral vessel development around the site of TD ligation may be minimized, which may prevent leakage of chyle through the more cranial lymphatics.

Preliminary report of a thoracic duct-to-pulmonary vein lymphovenous anastomosis in swine: A novel technique and potential treatment for lymphatic failure

OBJECTIVE

The thoracic duct is the largest lymphatic vessel in the body, and carries fluid and nutrients absorbed in abdominal organs to the central venous circulation. Thoracic duct obstruction can cause significant failure of the lymphatic circulation (i.e., protein-losing enteropathy, plastic bronchitis, etc.). Surgical anastomosis between the thoracic duct and central venous circulation has been used to treat thoracic duct obstruction but cannot provide lymphatic decompression in patients with superior vena cava obstruction or chronically elevated central venous pressures (e.g., right heart failure, single ventricle physiology, etc.). Therefore, this preclinical feasibility study sought to develop a novel and optimal surgical technique for creating a thoracic duct-to-pulmonary vein lymphovenous anastomosis (LVA) in swine that could remain patent and preserve unidirectional lymphatic fluid flow into the systemic venous circulation to provide therapeutic decompression of the lymphatic circulation even at high central venous pressures.

METHODS

A thoracic duct-to-pulmonary vein LVA was attempted in 10 piglets (median age 80 [IQR 80-83] days; weight 22.5 [IQR 21.4-26.8] kg). After a right thoracotomy, the thoracic duct was mobilized, transected, and anastomosed to the right inferior pulmonary vein. Animals were systemically anticoagulated on post-operative day 1. Lymphangiography was used to evaluate LVA patency up to post-operative day 7.

RESULTS

A thoracic duct-to-pulmonary vein LVA was successfully completed in 8/10 (80.0%) piglets, of which 6/8 (75.0%) survived to the intended study endpoint without any complication (median 6 [IQR 4-7] days). Initially, 2/10 (20.0%) LVAs were aborted intraoperatively, and 2/10 (20.0%) animals were euthanized early due to post-operative complications. However, using an optimized surgical technique, the success rate for creating a thoracic duct-to-pulmonary vein LVA in six animals was 100%, all of which survived to their intended study endpoint without any complications (median 6 [IQR 4-7] days). LVAs remained patent for up to seven days.

CONCLUSION

A thoracic duct-to-pulmonary vein LVA can be completed safely and remain patent for at least one week with systemic anticoagulation, which provides an important proof-of-concept that this novel intervention could effectively offload the lymphatic circulation in patients with lymphatic failure and elevated central venous pressures.

Lymphatic failure and lymphatic interventions: Knowledge gaps and future directions for a new frontier in congenital heart disease

Lymphatic failure is a broad term that describes the lymphatic circulation's inability to adequately transport fluid and solutes out of the interstitium and into the systemic venous circulation, which can result in dysfunction and dysregulation of immune responses, dietary fat absorption, and fluid balance maintenance. Several investigations have recently elucidated the nexus between lymphatic failure and congenital heart disease, and the associated morbidity and mortality is now well-recognized. However, the precise pathophysiology and pathogenesis of lymphatic failure remains poorly understood and relatively understudied, and there are no targeted therapeutics or interventions to reliably prevent its development and progression. Thus, there is growing enthusiasm towards the development and application of novel percutaneous and surgical lymphatic interventions. Moreover, there is consensus that further investigations are needed to delineate the underlying mechanisms of lymphatic failure, which could help identify novel therapeutic targets and develop innovative procedures to improve the overall quality of life and survival of these patients. With these considerations, this review aims to provide an overview of the lymphatic circulation and its vasculature as it relates to current understandings into the pathophysiology and pathogenesis of lymphatic failure in patients with congenital heart disease, while also summarizing strategies for evaluating and managing lymphatic complications, as well as specific areas of interest for future translational and clinical research efforts.

Gender Differences in Pharmacokinetics: A Perspective on Contrast Agents

Gender is an important risk factor for adverse drug reactions. Women report significantly more adverse drug reactions than men. There is a growing consensus that gender differences in drug PK is a main contributor to higher drug toxicity in women. These differences stem from physiological differences (body composition, plasma protein concentrations, and liver and kidney function), drug interactions, and comorbidities. Contrast agents are widely used to enhance diagnostic performance in computed tomography and magnetic resonance imaging. Despite their broad use, these contrast agents can lead to important adverse reactions including hypersensitivity reactions, nephropathy, and hyperthyroidism. Importantly, female gender is one of the main risk factors for contrast agent toxicity. As these adverse reactions may be related to gender differences in PK, this perspective aims to describe distribution and elimination pathways of commonly used contrast agents and to critically discuss gender differences in these processes.

Post-traumatic pleural effusion: Don't forget the chylothorax!

In this case we describe a 58-year-old male with bilateral pleural effusion after a blunt trauma to the back. A pleural puncture revealed a chylothorax. An additional computed tomography scan showed a vertebral fracture at level D8 with rupture of the nearby thoracic duct. Our patient could be treated with a conservative approach. This case highlights the importance of ruling out a chylothorax in any post-traumatic pleural effusion. Despite the low prevalence, we consider it a don't-miss diagnosis given the specific treatment requirements.

Dosimetric Effect of Thymus and Thoracic Duct on Radiation-Induced Lymphopenia in Patients With Primary Lung Cancer Who Received Thoracic Radiation

Purpose

Radiation-induced lymphopenia is a well-recognized factor for tumor control and survival in patients with cancer. This study aimed to determine the role of radiation dose to the thymus and thoracic duct on radiation-induced lymphopenia.

Methods and Materials

Patients with primary lung cancer treated with thoracic radiation therapy between May 2015 and February 2020 with whole blood count data were eligible. Clinical characteristics, including age, gender, histology, stage, chemotherapy regimen, radiation dosimetry, and absolute lymphocyte count (ALC) were collected. The thymus and thoracic duct were contoured by one investigator for consistency and checked by one senior physician. The primary endpoint was radiation-induced decrease in lymphocytes, defined as the difference in ALC (DALC) before and after radiation therapy.

Results

The data of a total of 116 consecutive patients were retrospectively retrieved. Significant correlations were found between DALC and several clinical factors. These factors include stage, chemotherapy or concurrent chemoradiation, biologically effective dose (BED), mean lung dose, mean body dose, effective dose to immune cells (EDIC), mean thymus dose (MTD), and mean thoracic duct dose (MTDD) (all P < .05). Ridge regression showed that DALC = 0.0063 × BED + 0.0172 × EDIC + 0.0002 × MTD + 0.0147 × MTDD + 0.2510 (overall P = .00025 and F = 5.85). The combination model has the highest area under the curve of 0.77 (P < .001) when fitting the logistic regression model on DALC categorized as binary endpoint. The sensitivity and specificity of the combined model were 89% and 58%, respectively.

Conclusions

This study demonstrated for the first time that radiation doses to the thymus and thoracic duct are strongly associated with radiation-induced lymphopenia patients with lung cancer. Further validation studies are needed to implement thymus and thoracic duct as organs at risk.

Lymphangiography and lymphatic embolisation for the treatment of chyle leaks after neck surgery: assessment of lymphangiography findings and embolisation techniques

OBJECTIVE

To assess lymphangiography findings and outcome of lymphatic embolisation to manage chyle leak after neck surgery.

METHODS

Consecutive cases of lymphangiography performed between April 2018 and May 2022 for management of chyle leaks related to neck surgery were retrospectively reviewed. Lymphangiography findings, techniques, and outcomes were analysed.

RESULTS

Eight patients (mean age: 46.5 years) were included. Six patients had undergone radical neck dissection for thyroid cancer, and two had undergone lymph node excision. Clinical presentations were: chyle drainage through Jackson Pratt catheters in five patients, lymphorrhea through surgical wounds in two, and enlarging lymphocele in one. Lymphangiography techniques included: inguinal lymphangiography in four patients, retrograde lymphangiography in three, and transcervical lymphangiography in one. Lymphangiography revealed leaks in the terminal thoracic duct in two patients, bronchomediastinal trunk in two, jugular trunk in three, and superficial neck channels in one. Embolisation techniques included: non-selective embolisation of terminal thoracic duct (n = 2), selective embolisation of the jugular trunk (n = 3), selective embolisation of the bronchomediastinal trunk (n = 2), and intranodal glue embolisation of superficial neck channels (n = 1). One patient underwent a repeat procedure. Chyle leak resolved in all patients over a mean of 4.6 days. No complication was encountered.

CONCLUSION

Lymphatic embolisation seems to be effective and safe in managing chyle leaks after neck surgery. Lymphangiography allowed for the categorisation of chyle leaks according to their location. Post-embolisation patency of the thoracic duct may be preserved in chyle leaks that do not directly involve the thoracic duct.

ADVANCES IN KNOWLEDGE

Lymphatic embolisation is safe and effective in managing chyle leaks after neck surgery. On lymphangiography, the location of contrast media extravasation may not be consistent. The technique for embolisation should be based on the location of the leak. Post-embolisation patency of the thoracic duct may be preserved in chyle leaks that do not directly involve the thoracic duct.

Cracking the intestinal lymphatic system window utilizing oral delivery vehicles for precise therapy

Oral administration is preferred over other drug delivery methods due to its safety, high patient compliance, ease of ingestion without discomfort, and tolerance of a wide range of medications. However, oral drug delivery is limited by the poor oral bioavailability of many drugs, caused by extreme conditions and absorption challenges in the gastrointestinal tract. This review thoroughly discusses the targeted drug vehicles to the intestinal lymphatic system (ILS). It explores the structure and physiological barriers of the ILS, highlighting its significance in dietary lipid and medication absorption and transport. The review presents various approaches to targeting the ILS using spatially precise vehicles, aiming to enhance bioavailability, achieve targeted delivery, and reduce first-pass metabolism with serve in clinic. Furthermore, the review outlines several methods for leveraging these vehicles to open the ILS window, paving the way for potential clinical applications in cancer treatment and oral vaccine delivery. By focusing on targeted drug vehicles to the ILS, this article emphasizes the critical role of these strategies in improving therapeutic efficacy and patient outcomes. Overall, this article emphasizes the critical role of targeted drug vehicles to the ILS and the potential impact of these strategies on improving therapeutic efficacy and patient outcomes.

Back to the Future II-A Comprehensive Update on the Rapidly Evolving Field of Lymphatic Imaging and Interventions

ABSTRACT

Lymphatic imaging and interventional therapies of disorders affecting the lymphatic vascular system have evolved rapidly in recent years. Although x-ray lymphangiography had been all but replaced by the advent of cross-sectional imaging and the scientific focus shifted to lymph node imaging (eg, for detection of metastatic disease), interest in lymph vessel imaging was rekindled by the introduction of lymphatic interventional treatments in the late 1990s. Although x-ray lymphangiography is still the mainstay imaging technique to guide interventional procedures, several other, often less invasive, techniques have been developed more recently to evaluate the lymphatic vascular system and associated pathologies. Especially the introduction of magnetic resonance, and even more recently computed tomography, lymphangiography with water-soluble iodinated contrast agent has furthered our understanding of complex pathophysiological backgrounds of lymphatic diseases. This has led to an improvement of treatment approaches, especially of nontraumatic disorders caused by lymphatic flow abnormalities including plastic bronchitis, protein-losing enteropathy, and nontraumatic chylolymphatic leakages. The therapeutic armamentarium has also constantly grown and diversified in recent years with the introduction of more complex catheter-based and interstitial embolization techniques, lymph vessel stenting, lymphovenous anastomoses, as well as (targeted) medical treatment options. The aim of this article is to review the relevant spectrum of lymphatic disorders with currently available radiological imaging and interventional techniques, as well as the application of these methods in specific, individual clinical situations.

An in silico approach to understanding the interaction between cardiovascular and pulmonary lymphatic dysfunction

The lung is extremely sensitive to interstitial fluid balance, yet the role of pulmonary lymphatics in lung fluid homeostasis and its interaction with cardiovascular pressures is poorly understood. In health, there is a fine balance between fluid extravasated from the pulmonary capillaries into the interstitium and the return of fluid to the circulation via the lymphatic vessels. This balance is maintained by an extremely interdependent system governed by pressures in the fluids (air and blood) and tissue (interstitium), lung motion during breathing, and the permeability of the tissues. Chronic elevation in left atrial pressure (LAP) due to left heart disease increases the capillary blood pressure. The consequent fluid accumulation in the delicate lung tissue increases its weight, decreases its compliance, and impairs gas exchange. This interdependent system is difficult, if not impossible, to study experimentally. Computational modeling provides a unique perspective to analyze fluid movement in the cardiopulmonary vasculature in health and disease. We have developed an initial in silico model of pulmonary lymphatic function using an anatomically structured model to represent ventilation and perfusion and underlying biophysical laws governing fluid transfer at the interstitium. This novel model was tested against increased LAP and noncardiogenic effects (increased permeability). The model returned physiologically reasonable values for all applications, predicting pulmonary edema when LAP reached 25 mmHg and with increased permeability.NEW & NOTEWORTHY This model presents a novel approach to understanding the interaction between cardiac dysfunction and pulmonary lymphatic function, using anatomically structured models and biophysical equations to estimate regional variation in fluid transport from blood to interstitial and lymphatic flux. This fluid transport model brings together advanced models of ventilation, perfusion, and lung mechanics to produce a detailed model of fluid transport in health and various altered pathological conditions.

Current diagnostic and therapeutic strategies for the management of lymphatic insufficiency in patients with hypoplastic left heart syndrome

Children with hypoplastic left heart syndrome share unique hemodynamic features that alter lymphatic integrity at all stages of palliation. Lymphatic congestion is almost universal in this patient group to some extent. It may lead to reversal of lymphatic flow, the development of abnormal lymphatic channels and ultimately decompression and loss of protein rich lymphatic fluid into extra lymphatic compartments in prone individuals. Some of the most devastating complications that are associated with single ventricle physiology, notably plastic bronchitis and protein losing enteropathy, have now been proven to be lymphatic in origin. Based on the new pathophysiologic concept new diagnostic and therapeutic strategies have recently been developed. Dynamic contrast magnetic resonance lymphangiography is now mainstay in diagnosis of lymphatic insufficiency and allows a thorough assessment of anatomy and function of the main lymphatic compartments through intranodal, intrahepatic and intramesenteric lymphatic imaging. Contrast enhanced ultrasound can evaluate thoracic duct patency and conventional fluoroscopic lymphangiography has been refined for evaluation of patients where magnetic resonance imaging cannot be performed. Novel lymphatic interventional techniques, such as thoracic duct embolization, selective lymphatic duct embolization and liver lymphatic embolization allow to seal abnormal lymphatic networks minimally invasive and have shown to resolve symptoms. Innominate vein turn-down procedures, whether surgical or interventional, have been designed to reduce lymphatic afterload and increase systemic preload effectively in the failing Fontan circulation. Outflow obstruction can now be managed with new microsurgical techniques that create lympho-venous anastomosis. Short term results for all of these new approaches are overall promising but evidence is sparse and long-term outcome still has to be defined. This review article aims to summarize current concepts of lymphatic flow disorders in single ventricle patients, discuss new emerging diagnostic and therapeutic strategies and point out lacks in evidence and needs for further research on this rapidly growing topic.

Sonography for assessment of thoracic duct anatomy and physiology before and after meals

The interest in clinical anatomy of the thoracic duct (TD) has recently grown, owing to discoveries linking its morphology to pathologies such as heart failure or liver cirrhosis. In the light of this knowledge, a cost-efficient and reliable in-vivo imaging method of TD should be devised. Ultrasonography satisfies these criteria and hence is a promising tool for assessment of TD's anatomy and function. Thirty-one healthy volunteers attended the examination after 6 h of fasting and 2 h without drink. Ultrasound of the left supraclavicular fossa was performed in search of TD's orifice into the venous angle. In each case, the largest diameter, number of orifices, presence of valves, tributaries, and motility of the TD were examined. We performed examinations in three sessions: after fasting, after standardized meal and 1 h after the meal. The statistical significance has varied among the three sessions. The strongest connection was shown in the third examination. The TD was visualized in 31 cases, 35 orifices were found, most of which drained into the venous angle. Multiple orifices were seen in four cases and valves in 15 cases. Tributaries were present in 17 cases. Mean widest and orifice diameter measured 3.23 and 2.0 mm, respectively. Spontaneous peristaltic-like movements of the TD were observed in 25 cases. We demonstrated that ultrasound is useful for assessment of TD's anatomy, allowing to visualize and quantify its key features. Moreover, our study is presumably the first to capture and describe TD's motility in vivo.

Role of Octreotide in Conservative Management of Chyle Leak Post Neck Dissection in Cases of Head Neck Cancer: A Retrospective Analysis

Chyle leak is a dreadful complication in patients undergoing neck dissections. Octreotide has been used in the management of chyle leak post neck dissections in head and neck cancer patients. Currently there is no consensus and practice guidelines on the same. (1) To study the role of octreotide in early cessation of post neck dissection chyle leak. (2) To study incidence of intra-operative and post-operative CL, its relation to the extent of nodal disease and neck dissection, prior radiotherapy. Retrospective analysis of 16 patients out of 529 neck dissection over a period of 03 years between Jan 2016 and Dec 2019 who developed post-operative chyle leak. All patients who had post-operative chyle leak were administered octreotide. Time taken for chyle leak to stop was primary outcome. Secondary outcomes were duration of hospitalization post-operatively, incidence of intra-operative and post-operative chyle leak, its relation to the extent of nodal disease, prior radiotherapy and type of neck dissection. 59 of 529 neck dissections (11.15%) were noted to have intra-operative chyle leak. 16 of 529 neck dissections (3.02%) developed post-operative chyle leak. On applying chi square test, prior multimodality and N plus neck were found to be significant risk factors in developing postoperative chyle leak. Considering only RT versus no RT in prior multimodality treated group, the difference was insignificant. Onset of chyle leak varied from 1 to 5 post-op day (mean 2.68 days). 15 (93.75%) patients responded to octreotide. Chyle leak resolved between 3 and 10 days (mean 5.18 days) and octreotide was given for 5-12 days (mean-7.18 days). Overall duration of hospitalization ranged from 09 to 18 days (mean 12.18 days). 01 patient (6.25%) had to be re-explored due to high volume leak despite using octreotide. Adverse effects of octreotide were minimal and tolerable. Octreotide is effective in reducing the duration of chyle leak, hospital stay and need for surgical intervention. It may be considered as suitable adjunct to conservative measures in the management for post-operative chyle leak.

Lymph drainage and cervical fascia anatomy-oriented differential nodal CTV delineation at the supraclavicular region for esophageal cancer and nasopharyngeal cancer

PURPOSE

To determine the differences in supraclavicular lymph node metastasis between esophageal cancer (EC) and nasopharyngeal cancer (NPC) and explore the feasibility of differential supraclavicular clinical target volume (CTV) contouring between these two diseases based on the involvement of different fascial spaces.

MATERIALS AND METHODS

One hundred patients with supraclavicular nodes positive for EC or NPC were enrolled, and their pre-treatment images were reviewed. The distribution patterns of nodes between the two diseases were compared in the context of node levels defined by the 2017 Japanese Esophageal Society and 2013 International Consensus on Cervical Lymph Node Level Classification. Grouping supraclavicular nodes based on sub-compartments formed by the cervical fascia was discussed, and the feasibility of differential CTV contouring based on the differences in the involvement of these sub-compartments between EC and NPC was explored.

RESULTS

The 2013 Consensus on cervical node levels and 2017 Japanese Esophageal Society node station could not practically guide supraclavicular CTV contouring. We divided the supraclavicular space into six sub-compartments: the para-esophageal space (PES), carotid sheath space (CSS), sub-thyroid pre-trachea space (STPTS), pre-vascular space (PVS), and vascular lateral space (VLS) I and II. EC mainly spread to the PES, STPTS, CSS, and VLS I, whereas NPC tended to spread to the CSS, VLS I, and VLS II. These combinations of sub-compartments may help constitute the supraclavicular CTVs for EC and NPC.

CONCLUSIONS

The fascia anatomy-based sub-compartments sufficiently distinguished metastasis to the supraclavicular space between EC and NPC, thus facilitating differential CTV contouring between these two diseases.

Management of Chyle Leak After Head and Neck Surgery; Our Meritorious Experience in 52 Cases and Review of Literature

Iatrogenic chyle leak is commonly seen when dissection happens very low in neck. Management of chyle leak is conservative with compression dressing, fat restricted diet, somatostatin analogues. Surgery is required in extreme cases with failure of conservative treatment. This is a retrospective observational study carried out from a prospectively maintained database. A total of 6482 head and neck surgeries with neck dissections were carried out between January 2015 till July 2020 at our tertiary cancer center. Out of which there were 52 cases of chyle leak reported post neck dissection. All details regarding age, sex, primary tumor location, surgery performed, level of nodal dissection performed, details related to chyle leak from beginning day and its progression and management offered. The median age in the study group was 42 years (24-70 years). Chyle leak was most commonly seen on left side (88.5%). Low output leaks(n = 43) resolved within a median period of 9 days (5-13 days) period of conservative management. High output leak (n = 9) had leak resolution within a median period of 12 days (7-19 days). Patients who had received preoperative radiotherapy and who had extra nodal extension in lymph nodes had significantly higher incidence of high output leaks. Chyle leak is a rare but serious complication in head and neck surgery. Timely identification and management is crucial. Conservative management is mainstay. Surgical management is instituted in cases of failure of conservative management.

The cisterna chyli: a systematic review of definition, prevalence, and anatomy

The cisterna chyli is a lymphatic structure found at the caudal end of the thoracic duct that receives lymph draining from the abdominal and pelvic viscera and lower limbs. In addition to being an important landmark in retroperitoneal surgery, it is the key gateway for interventional radiology procedures targeting the thoracic duct. A detailed understanding of its anatomy is required to facilitate more accurate intervention, but an exhaustive summary is lacking. A systematic review was conducted, and 49 published human studies met the inclusion criteria. Studies included both healthy volunteers and patients and were not restricted by language or date. The detectability of the cisterna chyli is highly variable, ranging from 1.7 to 98%, depending on the study method and criteria used. Its anatomy is variable in terms of location (vertebral level of T10 to L3), size (ranging 2-32 mm in maximum diameter and 13-80 mm in maximum length), morphology, and tributaries. The size of the cisterna chyli increases in some disease states, though its utility as a marker of disease is uncertain. The anatomy of the cisterna chyli is highly variable, and it appears to increase in size in some disease states. The lack of well-defined criteria for the structure and the wide variation in reported detection rates prevent accurate estimation of its natural prevalence in humans.

Interventional Management of Acquired Lymphatic Disorders

The lymphatic system is a complex network of tissues, vessels, and channels found throughout the body that assists in fluid balance and immunologic function. When the lymphatic system is disrupted related to idiopathic, iatrogenic, or traumatic disorders, lymphatic leaks can result in substantial morbidity and/or mortality. The diagnosis and management of these leaks is challenging. Modern advances in lymphatic imaging and interventional techniques have made radiology critical in the multidisciplinary management of these disorders. The authors provide a review of conventional and clinically relevant variant lymphatic anatomy and recent advances in diagnostic techniques such as MR lymphangiography. A detailed summary of technical factors related to percutaneous lymphangiography and lymphatic intervention is presented, including transpedal and transnodal lymphangiography. Traditional transabdominal access and retrograde access to the central lymph nodes and thoracic duct embolization techniques are outlined. Newer techniques including transhepatic lymphangiography and thoracic duct stent placement are also detailed. For both diagnostic and interventional radiologists, an understanding of lymphatic anatomy and modern diagnostic and interventional techniques is vital to the appropriate treatment of patients with acquired lymphatic disorders. ^©RSNA, 2022.

Case report: Balloon compression for cervical chyle leakage post neck dissection

Postoperative chyle leakage (CL) is a rare but severe complication after neck dissection, and most patients with this complication can be treated conservatively. However, in patients with high-flow leakage, efficient and well-tolerated conservative treatment options are still lacking, and the treatments can be complicated. In this study, we report a case with CL of 1100 ml/day after neck dissection that was successfully treated by balloon compression.

An effective method to reduce lymphatic drainage post-lateral cervical lymph node dissection of differentiated thyroid cancer: a retrospective analysis

Background

Lymph or chyle leak (LL/CL) is severe complications after lateral cervical lymph node dissection (LLND), mainly due to iatrogenic injury of the lymphatic duct. Efficient and well-operated methods to reduce postoperative drainage are still lacking. This was a feasibility study to evaluate a new method of preventing LL/CL compared to conventional treatment.

Method

We retrospectively analyzed 20 consecutive patients who used the “pedicled omohyoid flap covering (POFC)” method during LLND from January 2019 to December 2021 in our center as an observation group. Another 20 consecutive patients used the conventional method during LLND in this period as a control group. The clinical and pathological features of the two groups were compared, and the related factors that affected postoperative lymphatic drainage were analyzed with Cox proportional hazards models.

Results

The drainage volume per 24 h and the incidence of LL/CL in the control group were both higher than that in the observation group (all P < 0.05), and the number of lymph nodes dissected in the IV region > 10 and the use of the POFC method were the independent risk factors that significantly affected the incidence of LL/CL post LLND (all P < 0.05).

Conclusions

POFC is a safe and useful method for reducing drainage and preventing LL/CL post-LLND, especially for patients with heavy metastasis of the lymph nodes in the IV region.

Thoracic Duct Embolization for Postoperative Lymphatic Fistula

Lymphatic fistula as a rare entity particularly emerges after head and neck cancer surgery. It may lead to delayed wound healing, electrolyte loss, malnutrition, dehydration, and immune suppression. Therefore, rapid diagnosis and treatment are of the utmost importance. We aimed to present a lymphatic fistula case who was treated successfully by lymphangiography with percutaneous embolization of the thoracic duct. We believe that minimally invasive techniques could be an alternative to the conservative approach as the first-line choice.

The use of steroids in treating chylothorax following cardiac surgery in children: a unique perspective

BACKGROUND

Chylothorax is the accumulation of chyle fluid in the pleural space. The incidence of chylothorax is quite common post-cardiac surgeries in pediatrics especially in Fontan procedures. Although several treatment lines are known for the management of chylothorax, steroids were scarcely reported as a treatment option. We present a unique case of a 4-year-old child who underwent Fontan procedure and suffered a long-term consequence of chylothorax. The chylothorax only fully resolved after introducing corticosteroids as part of her management.

METHODS

A literature review about management of chylothorax post-cardiac surgery in children using Ovid Medline (19462021), PubMed, and google scholar was performed.

CONCLUSION

Conservative management without additional surgical intervention is adequate in most patients. Additionally, somatostatin can be used with variable success rate. However, a few cases mentioned using steroids in such cases. More research and reporting on the use of steroids in the treatment of chylothorax post-cardiac surgeries in children is needed to prove its effectivity. In this article, we describe a case of chylothorax post-Fontan procedure that supports the use of steroids.

Surgical anatomy of the upper esophagus related to robot-assisted cervical esophagectomy

Robot-assisted cervical esophagectomy (RACE) enables radical surgery for tumors of the middle and upper esophagus, avoiding a transthoracic approach. However, the cervical access, narrow working space, and complex topographic anatomy make this procedure particularly demanding. Our study offers a stepwise description of appropriate dissection planes and anatomical landmarks to facilitate RACE. Macroscopic dissections were performed on formaldehyde-fixed body donors (three females, three males), according to the surgical steps during RACE. The topographic anatomy and surgically relevant structures related to the cervical access route to the esophagus were described and illustrated, along with the complete mobilization of the cervical and upper thoracic segment. The carotid sheath, intercarotid fascia, and visceral fascia were identified as helpful landmarks, used as optimal dissection planes to approach the cervical esophagus and preserve the structures at risk (trachea, recurrent laryngeal nerves, thoracic duct, sympathetic trunk). While ventral dissection involved detachment of the esophagus from the tracheal cartilage and membranous part, the dorsal dissection plane comprised the prevertebral compartment harboring the thoracic duct and right intercosto-bronchial artery. On the left side, the esophagus was attached to the aortic arch by the aorto-esophageal ligament; on the right side, the esophagus was bordered by the azygos vein, right vagus nerve, and cardiac nerves. The stepwise, illustrated topographic anatomy addressed specific surgical demands and perspectives related to the left cervical approach and dissection of the esophagus, providing an anatomical basis to facilitate and safely implement the RACE procedure.

The effect of respiration and body position on terminal thoracic duct diameter and the lymphovenous junction: An exploratory ultrasound study

The thoracic duct (TD) drains most of the body's lymph back to the venous system via its lymphovenous junction (LVJ), playing a pivotal role in fluid homeostasis, fat absorption and the systemic immune response. The respiratory cycle is thought to assist with lymph flow, but the precise mechanism underpinning terminal TD lymph flow into the central veins is not well understood. The aim of this study was to use ultrasonography (US) to explore the relationship between terminal TD lymph flow, the respiratory cycle, and gravity. The left supraclavicular fossa was scanned in healthy non-fasted volunteers using high-resolution (13-5 MHz) US to identify the terminal TD and the presence of a lymphovenous valve (LVV). The TD's internal diameter was measured in relation to respiration (inspiration vs. expiration) and body positioning (supine vs. Trendelenburg). The terminal TD was visualized in 20/33 (61%) healthy volunteers. An LVV was visualized in only 4/20 (20%) cases. The mean terminal TD diameter in the supine position was 1.7 mm (range 0.8-3.1 mm); this increased in full inspiration (mean 1.8 mm, range 0.9-3.2 mm, p < 0.05), and in the Trendelenburg position (mean 1.8 mm, range 1.2-3.1 mm, p < 0.05). The smallest mean terminal TD diameter occurred in full expiration (1.6 mm, range 0.7-3.1 mm, p < 0.05). Respiration and gravity impact the terminal TD diameter. Due to the challenges of visualizing the TD and LVJ, other techniques such as dynamic magnetic resonance imaging will be required to fully understand the factors governing TD lymph flow.

Sampling Thoracic Duct Lymph After Esophagectomy: A Pilot Study Investigating the "Gut-Lymph" Concept

Introduction: Gut-lymph in animal models of acute disease is altered by intestinal ischemia and contributes to the development of systemic inflammation and organ dysfunction. Investigating gut-lymph in humans is hampered difficulty in accessing the thoracic duct (TD) for lymph sampling. The aims of this study were to develop and pilot a technique of intraoperative TD cannulation with delayed embolization to serially measure TD lymph pressure, flow, and composition (including markers of intestinal injury) during the early postoperative period and in response to enteral feeding and vasopressor treatment. Methods: A Seldinger technique was used for percutaneous TD cannulation during an Ivor Lewis esophagogastrectomy. Lymph flow rate and pressure were measured. TD lymph and plasma were sampled at 12 hourly intervals for up to 120 hours after surgery and before TD embolization. Biochemistry, lipids, cytokines, and markers of intestinal injury were measured before and after enteral feeding commenced at 36 hours. Results: Intraoperative TD cannulation was technically feasible in three of four patients. Delayed TD embolization was only successful in one of three patients, with two patients requiring a re-thoracotomy to treat chylothorax. Profound changes in TD composition, but not flow rate, occurred over time and in response to enteral feeding and vasopressors. TD lymph compared with plasma had significantly higher lipase (1.4-17 × ), interleukin-6 (8-108 × ), tumor necrosis factor-α (2.7-17 × ), d-lactate (0.3-23 × ), endotoxin (0.1-41 × ), and intestinal fatty acid binding protein (1.1-853 × ). Conclusions: Although TD cannulation and lymph sampling were successful, TD embolization failed in two of three patients. The composition of sampled TD lymph changed dramatically in response to enteral feeding, indicating intestinal ischemia that could be exacerbated by nonselective vasopressors. The higher concentration of proinflammatory cytokines and gut injury markers in TD lymph, compared with plasma, lends support to the gut-lymph concept.

Bilateral Chylothorax Following Total Thyroidectomy with Neck Dissection for Papillary Thyroid Cancer: Case report

Bilateral chylothorax is a rare condition that occurs after a thyroidectomy and neck dissection, which can lead to severe morbidity and, potentially, death, if not managed properly. We report a rare complication of neck surgery and subsequent bilateral pleural effusion in a 35-year-old female patient who presented at Sultan Qaboos University Hospital in 2018 with shortness of breath and respiratory distress. The bilateral pleural effusion and related symptoms occurred one week after a total thyroidectomy with central and left lateral neck dissection. The patient was managed conservatively and subsequently recovered.

An update on oral drug delivery via intestinal lymphatic transport

Orally administered drug entities have to survive the harsh gastrointestinal environment, penetrate the enteric epithelia and circumvent hepatic metabolism before reaching the systemic circulation. Whereas the gastrointestinal stability can be well maintained by taking proper measures, hepatic metabolism presents as a formidable barrier to drugs suffering from first-pass metabolism. The pharmaceutical academia and industries are seeking alternative pathways for drug transport to circumvent problems associated with the portal pathway. Intestinal lymphatic transport is emerging as a promising pathway to this end. In this review, we intend to provide an updated overview on the rationale, strategies, factors and applications involved in intestinal lymphatic transport. There are mainly two pathways for peroral lymphatic transport-the chylomicron and the microfold cell pathways. The underlying mechanisms are being unraveled gradually and nowadays witness increasing research input and applications.

Surgical Skills and Technological Advancements to Avoid Complications in Lateral Neck Dissection for Differentiated Thyroid Cancer

Neck dissection is a surgical procedure reserved for thyroid cancer cases with clinically evident lymphatic invasion. Although neck dissection is a reliable and safe procedure, it can determine a significant morbidity involving a variety of structures of nervous, vascular and endocrine typology. A careful pre-operative study is therefore essential to better plan surgery. Surgical experience, combined with accurate surgical preparation and merged with adequate and specific techniques, can certainly help reduce the percentage of complications. In recent years, however, technology has also proved to be useful. Its crucial role was already recognized in the safeguard of the integrity of the laryngeal nerve through neuro-monitoring, but new technologies are emerging to help the preservation also of the parathyroid glands and other structures, such as the thoracic duct. These surgical skills combined with the latest technological advancements, that allow us to reduce the incidence of complications after neck dissection for thyroid cancer, will be reported in the present article. This topic is of significant interest for the endocrine and metabolic surgeons' community.

Anatomical study of the thoracic duct and its clinical implications in thoracic and pediatric surgery, a 70 cases cadaveric study

INTRODUCTION

Given the high variability and fragility of the thoracic duct, good knowledge of its anatomy is essential for its repair or to prevent iatrogenic postoperative chylothorax. The objective of this study was to define a site where the thoracic duct is consistently found for its ligation. The second objective was to define an anatomically safe surgical pathway to prevent iatrogenic chylothorax in surgery for aortic arch anomalies with vascular ring, through better knowledge of the anatomical relationships of the thoracic duct.

METHODS

Seventy adult formalin-fixed cadavers were dissected. The anatomical relationships of the thoracic duct were reported at the postero-inferior mediastinum, at levels T3 and T4.

RESULTS

The thoracic duct was consistently situated between the left anterolateral border of the azygos vein and the right border of the aorta between levels T9 and T10, whether it was simple, double, or plexiform. It was located medially, anteromedially, or posteriorly to the left subclavian artery in 51%, 21%, and 28% of the cases, respectively, at the level of T3. At T4, it was posteromedial in 27% of the cases or had no direct relationship with the aortic arch.

CONCLUSION

These results favor mass ligation of the thoracic duct at levels T9-T10 between the right border of the aorta and the azygos vein, eventually including the latter. To prevent iatrogenic postoperative chylothorax in aortic arch anomalies with vascular ring surgery, we recommend remaining strictly lateral to the left subclavian artery at the level of T3 to reach the aortic arch anomalies with vascular ring at T4.

Traumatic chylothorax: a dilemma to surgeons and interventionists

Chylothorax is generally seen due to iatrogenic injury to the thoracic duct during thoracic or neck surgery. It can also be encountered secondary to chest trauma either blunt or penetrating. Percutaneous thoracic duct embolisation is an alternative to surgical treatment and is considered an effective and safe minimally invasive treatment option for chylothorax with a success rate of about 80%. We present a case of blunt trauma to the chest with chylothorax, which was successfully managed with transvenous retrograde thoracic duct embolisation.

Unusual Left Periclavicular Cutaneous Lymphatic Fistula After Port Explantation Without Lymph Vessel Injury: Imaging and Interventional Treatment

Complex oncological treatment can be associated with lymphatic vascular injury that is burdened by considerable morbidity. Lymphatic imaging and interventional techniques offer new minimally invasive treatment options. We report the case of a 59-year-old woman with an unusual lympho-veno-cutaneous fistula, diagnosed by magnetic resonance lymphangiography and treated by minimally invasive embolization therapy and venous recanalization.

Lymphangiography and Lymphatic Interventions

Compared with the traditional pedal lymphangiography, intranodal lymphangiography and MR lymphangiography have made imaging of the lymphatic system less challenging. Improvements in imaging and availability of newer catheters have allowed embolization of lymphatic system much more feasible that previously envisioned. In this article, we briefly review the anatomy, imaging, and current and future of lymphatic interventions.

Acquired chylothorax in association with supraclavicular ultrasound-guided access to the brachiocephalic vein in a neonate

Achieving and maintaining venous access can be challenging in some premature and low birth weight infants. In this population, the supraclavicular ultrasound-guided in-plane approach to the brachiocephalic vein for central venous access has demonstrated great success with a low rate of complications. This case describes the first report of acquired chylothorax in association with this technique, in a previously extremely preterm and low birth weight infant.

Predictors for Postoperative Chyle Leak Following Neck Dissection, a Technique-Based Comparison

OBJECTIVE

Assess the impact of surgical technique used to address level IV on the rate of postoperative chyle leak.

STUDY DESIGN

Retrospective chart review.

SETTING

Academic tertiary care center.

METHODS

An analysis of 436 consecutive neck dissections (NDs) in 368 patients was performed by 3 head and neck surgeons between 2014 and 2017. Variation in technique reflects individual approaches to the management of level IV and included suture ligation (SL), monopolar electrocautery (MC), and harmonic scalpel transection (HS). Data points included patient demographics, surgical technique, intraoperative findings, postoperative chyle leaks, and leak management. Correlation between variables was analyzed through χ² test and Student t test with statistical α set at .05.

RESULTS

Overall, 12 patients (3.2%) developed chyle leaks postoperatively. Nine of 12 and 3 of 12 presented with left- and right-sided leaks, respectively. Five of 12 leaks occurred following bilateral ND, 5 of 12 following left ND, and 2 of 12 following right ND. Univariate analysis showed a statistically significant difference (P = .001) favoring SL (1.0%) and MC (1.2%) techniques over the HS technique (8.6%). A statistically significant increase existed in the rate of leak with endocrine vs nonendocrine pathology (P = .003). Average duration of leak was 13.3 ± 13.5 days. Management included diet modification (n = 11, 91.6%), pressure-dressing placement (n = 7, 58.3%), and octreotide (n = 5, 41.7%). No cases required reoperation, and no mortality or severe malnutrition was observed in this series.

CONCLUSIONS

SL and MC techniques demonstrated superiority over the HS technique in preventative management of chyle leak in level IV, with a significantly higher rate of chyle leak observed in endocrine-related pathology.

Lymphovenous shunts: from development to clinical applications

The lymphatic system is a vast network of vessels that functions to return excess fluid from the interstitial space to the blood stream. Lymphovenous shunts are anastomoses, either natural or surgical, that connect the lymphatic and venous systems. Connections between the thoracic duct and venous system or between the right lymphatic duct and venous system are prime examples of anatomic lymphovenous shunts. Lymphovenous shunts are also present peripherally in tissues such as lymph nodes. Furthermore, pathologic lymphovenous shunts are observed in conditions such as lymphedema, malignancy, and lymphovenous malformations. Surgically, lymphovenous shunts may be constructed as an approach to treat lymphedema. Here, we discuss anatomic and surgical lymphovenous shunts in the context of normal development and disease. This perspective is intended to give an understanding of the role of lymphovenous shunts in health and disease and to show how they can be leveraged to treat disease surgically.

Lymphatic Pathways of the Thorax: Predictable Patterns of Spread

OBJECTIVE. This article reviews thoracic lymphatic pathways and tributaries, discusses lymphatic anatomic variants and their clinical implications, and emphasizes common patterns of thoracic lymphadenopathy from extrapulmonary malignancies. CONCLUSION. Recognition of common patterns and pathways of thoracic lymphatic drainage can help identify the site of tumor origin and allow a more focused examination of disease extent, both of which are important for disease prognosis and management.

The Identity of Human Tissue-Emigrant CD8+ T Cells

Lymphocyte migration is essential for adaptive immune surveillance. However, our current understanding of this process is rudimentary, because most human studies have been restricted to immunological analyses of blood and various tissues. To address this knowledge gap, we used an integrated approach to characterize tissue-emigrant lineages in thoracic duct lymph (TDL). The most prevalent immune cells in human and non-human primate efferent lymph were T cells. Cytolytic CD8⁺ T cell subsets with effector-like epigenetic and transcriptional signatures were clonotypically skewed and selectively confined to the intravascular circulation, whereas non-cytolytic CD8⁺ T cell subsets with stem-like epigenetic and transcriptional signatures predominated in tissues and TDL. Moreover, these anatomically distinct gene expression profiles were recapitulated within individual clonotypes, suggesting parallel differentiation programs independent of the expressed antigen receptor. Our collective dataset provides an atlas of the migratory immune system and defines the nature of tissue-emigrant CD8⁺ T cells that recirculate via TDL.

The Lymphovenous Junction of the Thoracic Duct: A Systematic Review of its Structural and Functional Anatomy

Background: The lymphovenous junction (LVJ) of the thoracic duct (TD) is the principle outlet of the lymphatic system. Interest in this junction is growing as its role in lymphatic outflow obstruction is being realized, and as minimally invasive procedures for accessing the terminal TD become more common. Despite the growing clinical significance of the LVJ, its precise form and function remain unclear. The aim of this article was to systematically review the literature surrounding the structure and function of the LVJ and its associated lymphovenous valve (LVV). Methods and Results: A systematic review of the structure and function of the LVJ and LVV was undertaken using the MEDLINE, Scopus, and Google Scholar databases. Human and animal studies up to November 2019, with no language or past date restriction, were included. Forty-six relevant articles were reviewed. The LVJ shows marked anatomical variation. A valve is frequently absent at the LVJ, but when present it displays numerous distinct morphologies. These include bicuspid semilunar, ostial, and flap-like structure. Other factors, such as functional platelet plugs, or the tangential/intramural course of the terminal TD across the vein wall, may work to prevent blood from entering the lymphatic system. Conclusions: The form and function of the LVJ remain unclear. Dedicated studies of this area in vivo are required to elucidate how this part of the body functions in both health and disease.

Embolization or disruption of thoracic duct and cisterna chyli leaks post oesophageal cancer surgery should be first line management for ECCG-defined type III chyle fistulae

Chyle leakage from the thoracic duct or cisterna chyli is a relatively rare complication of oesophageal cancer surgery. The majority of cases settle with conservative measures, but high volume leaks may be refractory and result in significant morbidity and require intervention with reoperation or embolization. In the experience of this high-volume centre over the last decade, 3 (0.5%) patients required reoperation and ligation of the thoracic duct; for the so-called type III leaks, interventional radiological approaches were not considered. This article is built around two recent cases, where interventional radiology to embolize and disrupt complex fistulae was successfully performed. The lessons from this experience will change practice at this centre to initial lymphangiography with a view to embolization or disruption of thoracic duct and cisterna chyli leaks as first line therapy for type III chyle leaks, with surgery reserved for where this fails.

The influence of thoracic duct ligation on long-term survival of patients with esophageal cancer: a propensity score-matched analysis

Background

Ligation of the thoracic duct (LTD) is known to be a useful way to prevent postoperative chylothorax, but its impact on long-term survival is rare to be assessed.

Methods

Data from 609 patients with esophageal cancer who underwent esophagectomy from September, 2012, to January, 2014, were retrospectively collected. The study cohort was classified into two groups: the thoracic duct ligation group (LG) and the non-ligation group (NLG). Propensity score matching (PSM) was performed to control confounding factors between the two groups. Postoperative complications and length of stay were compared between the two groups. Overall survival was estimated using the Kaplan-Meier method, and compared using the log-rank test. Independent prognostic factors were determined using Cox regression analysis.

Results

After PSM, there were 185 patients in each of the two groups. LTD had no significant impact on chylothorax, anastomotic leak, recurrent nerve palsy, pneumonia and length of stay (P>0.05). The 1-, 3- and 5-year survival rates were 87.0%, 64.1%, and 50.9% in the LG, respectively, compared to 85.4%, 59.9%, and 42.3%, respectively, in the NLG. The differences between the 2 groups were not statistically significant (P=0.156). In the multivariable analysis, LTD was not an independent prognostic factor, neither before nor after PSM.

Conclusions

Our study demonstrated that LTD had no significant impact on postoperative complications or long-term survival in patients with esophageal cancer.

Retrograde transvenous lymphatic embolization for postoperative chylous ascites: A report of three cases and literature review

Percutaneous transabdominal lymphangiography and embolization have been reported as useful approaches for intractable chylothorax or chylous ascites. However, they are often difficult to perform after extensive lymph node dissection because disruption of the antegrade lymphatic flow makes leaks identification difficult. When the leakage point cannot be identified or percutaneous transabdominal lymphangiography and embolization fail, a retrograde transvenous approach to the thoracic duct can be used instead. We report 3 cases of refractory chylous ascites after retroperitoneal operation or extensive lymph node dissection that was addressed by retrograde transvenous lymphatic embolization. In one case, a combination of retrograde transvenous lymphatic embolization, transcatheter sclerotherapy, and transcatheter embolization was used. These findings suggest that retrograde transvenous lymphatic embolization appears to be feasible and efficient for postoperative chylous ascites.

Clinical implications of thoracic duct dilatation in patients with chronic liver disease

This study aimed to investigate the association between the degree of thoracic duct dilatation and the progression of chronic liver disease.In this cross-sectional and retrospective study, 179 patients (mean age, 60.9 years; 114 men) with chronic liver disease who underwent chest CT were enrolled. Dilatation of the left distal thoracic ducts (DTD) was measured and divided into the following 3 grades according to the maximum transverse diameter: grade 0, invisible thoracic duct; grade 1, visible duct with <5-mm diameter; grade 2, diameter of ≥5 mm. Statistical analyses were conducted using the binary logistic regression model.The proportion of grade 2 DTD was notably higher as the chronic liver disease progressed to cirrhosis. Visible DTD on chest CT was significantly related to the presence of cirrhosis (odds ratio [OR], 3.809; P = .027) and significant varix (OR, 3.211; P = .025). Grade 2 DTD was observed more frequently in patients with ascites (OR, 2.788; P = .039). However, 40% of patients with cirrhosis and ascites still exhibited no visible DTD while demonstrating significant amount of ascites, and their ascites were more predominant of recent onset and transient than that observed in other patients (85.7% vs 48.4%, P = .010 and 66.7% vs 29.0%, P = .009, respectively).The degree of thoracic duct dilatation is significantly associated with progression to cirrhosis and advancement of portal hypertension. Further, insufficient lymph drainage to DTD might contribute to the development of ascites.

Prophylactic thoracic duct ligation is associated with poor prognosis and regional lymph node relapse in esophageal squamous cell carcinoma

OBJECTIVES

The ligation of thoracic duct interrupts the normal lymphatic circulation. Whether the ligation of thoracic duct would affect tumor recurrence and patient survival is unclear.

METHODS

The correlations between prophylactic thoracic duct ligation (PLG) and prognosis were examined in patients with esophageal squamous cell carcinoma. Patients who received Ivor Lewis or McKeown esophagectomy with systemic lymph node dissection and R0 resection between 2003 and 2013 in Sun Yat-sen University Cancer Center were included in the study.

RESULTS

A total number of 473 and 462 were included in the PLG group and non-prophylactic thoracic duct ligation (NPLG) group, respectively. The PLG group had a lower 5-year survival rate (48.2% vs 61.6%, P < .001). After a 1:1 propensity score matching, 874 cases (437 pairs) were included and the survival analysis showed that PLG was associated with worse 5-year cumulative survival of 48.6% vs 61.6% in those patients without ligation (P < .001). The multivariate analysis revealed that PLG was an independent factor for poor prognosis after esophagectomy (hazard ratio, HR = 1.56; 95% confidence interval, 95% CI, 1.26-1.93, P < .001). Additionally, PLG was associated with regional lymph node relapse (P = .015).

CONCLUSIONS

PLG should not be performed routinely if no sign of thoracic duct rupture or tumor invasion were identified.

Morphometry and Lymph Dynamics of Swine Thoracic Duct

Background: The goal of this study was to characterize the thoracic duct (TD) both morphologically and hemodynamically. Methods and Results: The lymphatic flow and pressure gradient from the cisterna chyli (CC) to the lymphovenous junction were measured in anesthetized swine (n = 9). After the animals were euthanized, the TD were harvested for histomorphometric analyses in which three samples were perfused with 9% gelatin to obtain the morphometry of the TD valve in both the open and closed configuration. Spectral analyses were performed. An afferent lymphatic vessel of the CC was accessed and cannulated after the animal was euthanized for casting (n = 3) to obtain morphometric data. The in vivo flow rate was 0.7 ± 0.49 mL/minute. Spectral analysis (Fast Fourier Transformation) showed correlation coefficients of 0.858 ± 0.063 and 0.586 ± 0.112 (p < 0.05) for the TD and JVPs, respectively. The average pressure gradient was 8.1 mmHg along the TD. The length of the TD was 35.6 ± 2.2 cm. The maximal width of the CC ranged from 11.4 to 15 mm. The diameter of the TD varied irregularly from 2 to 4.3 mm. The geometry of the TD leaflets was determined to have an area of 1.99 ± 0.53 mm², a leaflet length of 3.26 ± 0.86 mm, a packet depth of 0.66 ± 0.19 mm, and a wall length of 5.46 ± 2.16 mm. The TD media thickness was ∼7 ± 3 μm. The number of valves ranged from 9 to 13 in the full length of the TD. Conclusions: A relatively constant pressure gradient in the swine TD drives lymph flow from the CC to the jugular vein. The TD is a thin-walled vessel with valves that prevent reflux of lymph flow. This study of morphometric and lymphatic dynamics is important for interventionalists to understand the anatomy and physiology of the TD to design new diagnostic, interventional procedures, and devices.

A detailed pathway and termination of thoracic duct in a Japanese female cadaver with situs inversus totalis

Although the thoracic duct (TD) requires special attention during thoracic surgery, to our knowledge, its detailed course in the situs inversus totalis (SIT) case has not been reported. We encountered an 86-year-old Japanese female cadaver with SIT during a student anatomical practice and examine the TD. The TD originated from the cisterna chyli at the level of the 2nd lumbar vertebra, ascended along with the left side of aorta and then passed behind the aortic arch on the right side of the esophagus. The TD turned right at the first thoracic vertebra and finally emptied into the basal portion of the right external jugular vein without branching. The present running pathway of the TD was approximately in the inverted position of the normal, but its connection site to the vein and manner was very rare and has not been reported to date. Therefore, this junctional anomaly may occur during the developmental period in SIT. Further anatomical and embryological studies are required, but this report provides useful morphogenetic information of the TD and lymphovenous junction in SIT.

Anatomical variations in distal portion of the thoracic duct-A systematic review

The objective of this study was to identify and analyze the anatomical variations in the termination of the thoracic duct (TD) in cadavers or patients by anatomical dissections and surgical or radiological procedures for better knowledge of the interindividual variations through a systematic review. The search strategy included PubMed and reference tracking. Studies were identified by searching the electronic Medline databases. The search terms included "TD," "Jugular Vein," "Subclavian Vein," or "Cervical," and the protocol used is reported herein. These search results yielded 20 qualitative review articles out of the 275 articles consulted. We collected all the important data from these 20 articles with 1,352 TD analyzed by varying sources in our search. Regarding the characteristics of the studies and the anatomy of the TD, the results were heterogeneous. The TD most commonly terminates in the internal jugular vein in 54.05% of cases (95% confidence interval [CI]: 54.03; 54.07), in the jugular-venous angle in 25.79% (95% CI: 25.77; 25.81), and in the subclavian vein in 8.16% of cases (95% CI: 8.14;8.18). Other terminations were found in 12% of cases. This systematic review provided an overview of the variations in the distal portion of the TD. This study can be helpful for surgeons in selecting the most appropriate methods to achieve successful surgical results and avoid complications, such as chylothorax; it also offers detailed information on the cervical termination of the TD in new diagnostic and therapeutic methods involving the TD. Clin. Anat. 32:99-107, 2019. © 2019 Wiley Periodicals, Inc.