Thoracic duct identification with indocyanine green fluorescence to prevent chyle leaks during minimally invasive esophagectomy.

INTRODUCTION: Chylothorax (CT) is a rare yet serious complication after esophagectomy. Identification of the thoracic duct (TD) during esophagectomy is challenging due to its anatomical variation. Real-time identification of TD may help to prevent its injury. Near infra-red imaging with Indocyanine green (ICG) is a novel technique that recently has been used to overcome this issue. METHODS: Patients who underwent minimally invasive esophagectomy for esophageal cancer were divided into two groups with and without ICG. We injected ICG into bilateral superficial inguinal lymph nodes. Identification of TD and its injuries during the operation was evaluated and compared with the non-ICG group. RESULTS: Eighteen patients received ICG, and 18 patients underwent surgery without ICG. Each group had one (5.5%) TD ligation. In the ICG group injury was detected intraoperative, and ligation was done at the site of injury. In all cases, the entire thoracic course of TD was visualized intraoperatively after a mean time of 81.39 min from ICG injection to visualization. The Mean extra time for ICG injection was 11.94 min. In the ICG group, no patient suffered from CT. One patient in the non-ICG group developed CT after surgery that was managed conservatively. According to Fisher's exact test, there was no significant association between CT development and ICG use, possibly due to the small sample size. CONCLUSIONS: This study confirms that ICG administration into bilateral superficial inguinal lymph nodes can highlight the TD and reduce its damage during esophagectomy. It can be a standard method for the prevention of postoperative CT.

Thoracic Duct Visualization in Esophageal Resection: A Pilot Trial.

INTRODUCTION: Inadvertent thoracic duct injury is common during esophagectomy and may result in postoperative chylothorax. This study's objective was to investigate utility of patent blue injection as a modality for intraoperative thoracic duct visualization. METHODS: A prospective, single-arm, interventional study of patients undergoing minimally invasive esophagectomy was performed. Patients were injected with patent blue dye into both groins prior to thoracic stage of surgery and assessed for duct visualization. Control group was formed by propensity score matching using retrospectively collected data regarding patients who underwent esophagectomy. RESULTS: A total of 25 patients were included in analysis, compared to a control of 50 patients after matching. Thoracic duct was visualized in 60% of patients in the study group (15/25 patients). Significant differences were found between study and control groups (p < 0.05) with regards to median operative time (422 vs. 285 min, respectively), overall complications (16 vs. 34%, respectively), and median postoperative length of stay (13.5 vs. 10 days, respectively). There was a difference in rate of chyle leak between study and control groups; however, this was not significant (0 vs. 12%, respectively, p = 0.17). CONCLUSION: Patent blue injection represents a simple method for thoracic duct visualization during minimally invasive esophagectomy which may improve surgical outcomes.

Treatment Of Post-Operative Chylothorax: The Role Of Intranodal Lymphangiography And Thoracic Duct Disruption.

Thoracic duct embolization has been increasingly adopted as a first-line therapy of chylothorax and this procedure includes lipiodol lymphangiography, thoracic duct access and embolization. Lymphangiography itself has a therapeutic role, with volume-dependent success rates of 37%-97% and even a reported 100% success rate in outputs of < 500 mL/day. We present a clinical case of a 48-years-old man diagnosed with esophageal squamous cell carcinoma, who underwent esophagectomy and presented with post-operative high-output (> 1L/day) chylothorax; thoracic duct embolization was proposed. Even though thoracic duct access and embolization were not achieved due to technical and anatomical factors, lipiodol lymphangiography and possibly thoracic duct maceration (after several punctures/attempts) contributed to the clinical success of the procedure, and this chylothorax with output values superior to those reported in the literature resolved within three days. As such, the therapeutic role of intranodal lymphangiography and thoracic duct disruption should be taken into account.

Thoracic Duct Embolization for Treatment of Chyle Leakage After Thyroidectomy and Neck Dissection.

OBJECTIVE: This study aimed to evaluate the safety and efficacy of intranodal lymphangiography and thoracic duct embolization (TDE) for chyle leakage (CL) after thyroid surgery. MATERIALS AND METHODS: Fourteen patients who underwent intranodal lymphangiography and TDE for CL after thyroid surgery were included in this retrospective study. Among the 14 patients, 13 underwent bilateral total thyroidectomy with neck dissection (central compartment neck dissection [CCND], n = 13; left modified radical neck dissection (MRND), n = 11; bilateral MRND, n = 2), and one patient underwent left hemithyroidectomy with CCND. Ten patients (76.9%) had high-output CL (> 500 mL/d). Before the procedure, surgical intervention was attempted in three patients (thoracic duct ligation, n = 1; lymphatic leakage site ligation, n = 2). Lymphangiographic findings, technical and clinical successes, and complications were analyzed. Technical success was defined as the successful embolization of the thoracic duct after access to the lymphatic duct via the transabdominal route. Clinical success was defined as the resolution of CL or surgical drain removal. RESULTS: On lymphangiography, ethiodized oil leakage near the surgical bed was identified in 12 of 14 patients (85.7%). The technical success rate of TDE was 78.6% (11/14). Transabdominal antegrade access was not feasible due to the inability to visualize the identifiable cisterna chyli or a prominent lumbar lymphatic duct. Among patients who underwent a technically successful TDE, the clinical success rate was 90.1% (10/11). The median time from the procedure to drain removal was 3 days (with a range of 1-13 days) for the 13 patients who underwent surgical drainage. No CL recurrence was observed during the follow-up period (ranging from 2-44 months; median, 8 months). There were no complications, except for one case of chylothorax that developed after TDE. CONCLUSION: TDE appears to be a safe and effective minimally invasive treatment option for CL after thyroid surgery, with acceptable technical and clinical success rates.

Thoracic Duct Occlusion Leading to Intermittent Left Supraclavicular Swelling and Pancreatitis.

Intermittent left supraclavicular swelling is an uncommon and elusive condition that can lead to extensive diagnostic workups to determine the etiology and treatment. One potential cause is partial, intermittent, or complete thoracic duct occlusion (TDO). We report on a patient who presented with chronic, intermittent left supraclavicular swelling and abdominal pain that was relieved by thoracic duct angioplasty. Thoracic duct occlusion should be included in the differential diagnosis of left supraclavicular swelling. Lymphatic imaging can facilitate the diagnosis and allows for potential percutaneous treatment. Laryngoscope, 134:1313-1315, 2024.

Coil or Plug-Assisted Ethylene Vinyl Alcohol Copolymer (EVOH) Thoracic Duct Embolization in the Treatment of Postoperative Chylothorax.

Eleven patients (5 men, 6 women) with post-operative thoracic duct injuries and high output chylothorax were treated with thoracic duct embolization (TDE). Six patients underwent intraprocedural thoracic duct ligation at the time of original procedure. In all cases, the pleural fluid demonstrated high triglyceride levels (414 mg/dL; interquartile range [IQR], 345 mg/dL). Median daily (IQR) chest tube outputs before and after TDE were 900 mL (1,200 mL) and 325 mL (630 mL), respectively. Coil- or plug-assisted ethylene vinyl alcohol (EVOH) copolymer was used as embolic agent in all patients. Technical and clinical success rates were 100% and 82%, respectively. Nontarget venous embolization of EVOH copolymer was not identified on subsequent imaging.

Computed tomography and magnetic resonance imaging are potential noninvasive methods for evaluating the cisterna chyli in cats.

OBJECTIVE: There is limited information on the normal appearance of the cisterna chyli (CC) in cats on CT and MRI. The aim of this retrospective study was to describe the CT and MRI characteristics of the CC in a group of cats without lymphatic system pathology. SAMPLE: A total of 31 CT and 63 MRI images were obtained of client-owned cats between January 2017 and March 2022. METHODS: The presence, location, shape, maximum width, MRI-signal intensity, mean attenuation, and contrast enhancement of the CC were recorded from CT and MRI scans. RESULTS: The CC was identified in all the CT scans and in 60 MRI studies. The CC was located level with the cranial mesenteric artery in 56 of 91 cases. It was crescent shaped in 34 of 54 cases. On precontrast CT images, the mean attenuation of the CC was 17 HU, and the mean postcontrast attenuation was 28 HU. On T2-weighted sequences, the CC was isointense to CSF and hyperintense to the muscles, while on T1-weighted images, it was isointense to the muscles. Contrast enhancement was variable in both techniques. CLINICAL RELEVANCE: CT and MRI have the potential for noninvasive evaluation of CC in cats.

Efficacy and safety of near-infrared fluorescence identification of the thoracic duct during left lateral neck dissection.

BACKGROUND: Thoracic duct leaks occur in up to 5% of left lateral neck dissections. No one imaging modality is routinely used to identify the thoracic duct intraoperatively. The goal of our study was to evaluate the efficacy and safety of indocyanine green lymphangiography for intraoperative identification of the thoracic duct compared to traditional methods using ambient and evaluate the optimal timing of indocyanine green administration. METHODS: We enrolled all patients who underwent left lateral neck dissection at our institution from 2018 to 2022 in this prospective clinical trial. After indocyanine green injection into the dorsum of the foot, we performed intraoperative imaging was performed with a near-infrared fluorescence camera. We reported the data using descriptive statistics. RESULTS: Of the 42 patients we enrolled, 14 had prior neck surgery, and 3 had prior external beam radiation. We visualized the thoracic duct with ambient light in 48% of patients and with near-infrared fluorescence visualization in 64%. In 17% of patients, we could identify the thoracic duct only using near-infrared fluorescence visualization, which occurred within 3 minutes of injection, and were required to re-dose 5 patients. We visualized the thoracic duct with near-infrared fluorescence in all patients with prior neck radiation and 77% of patients with prior neck surgery. One adverse reaction occurred (hypotension), and 5 intraoperative thoracic duct injuries occurred that were ligated. There with no chylous fistulas postoperatively. CONCLUSION: This trial demonstrates that near-infrared fluorescence identification of the thoracic duct is feasible and safe with indocyanine green lymphangiography, even in patients with prior neck surgery or radiation.

Dynamic Contrast-enhanced CT Lymphangiography to Quantify Thoracic Duct Lymphatic Flow.

Background CT lymphangiography has been used to image the lymphatic anatomy and assess lymphatic abnormalities. There is, however, a need to develop a method for quantification of lymphatic flow rate in the thoracic duct (TD). Purpose To develop and validate a TD lymphatic flow measurement technique using dynamic contrast-enhanced CT lymphangiography. Materials and Methods Lymphatic flow rate was measured with two techniques: a first-pass analysis technique based on a single compartment model and a thresholding technique distinguishing between opacified and nonopacified voxels within the TD. The measurements were validated in a swine animal model between November 2021 and September 2022. CT images were acquired at 100 kV and 200 mA using a fast-pitched helical scan mode covering the entire TD following contrast material injection into the bilateral inguinal lymph nodes. Two helical CT scans, acquired at the base and peak contrast enhancement of the TD, were used to measure lymphatic flow rate. A US flow probe surgically placed around the TD provided the reference standard measurement. CT lymphatic flow measurements were compared with the reference US flow probe measurements using regression and Bland-Altman analysis. Repeatability was determined using repeated flow measurements within approximately 10 minutes of each other. Results Eleven swine (10 male; mean weight, 43.6 kg ± 2.6 [SD]) were evaluated with 71 dynamic CT acquisitions. The lymphatic flow rates measured using the first-pass analysis and thresholding techniques were highly correlated with the reference US flow probe measurements (r = 0.99 and 0.91, respectively) and showed good agreement with the reference standard, with Bland-Altman analysis showing small mean differences of 0.04 and 0.05 mL/min, respectively. The first-pass analysis and thresholding techniques also showed good agreement for repeated flow measurements (r = 0.94 and 0.90, respectively), with small mean differences of 0.09 and 0.03 mL/min, respectively. Conclusion The first-pass analysis and thresholding techniques could be used to accurately and noninvasively quantify TD lymphatic flow using dynamic contrast-enhanced CT lymphangiography. © RSNA, 2023 See also the editorial by Choyke in this issue.

Impact of fluorescent thoracic duct lymphography via intranodal approach in minimal access esophageal cancer surgery.

PURPOSE: Chyle leak resulting from thoracic duct (TD) injury poses significant morbidity and mortality challenges. We assessed the feasibility of using near-infrared (NIR) indocyanine green (ICG) imaging for intraoperative fluorescence TD lymphography during minimal access esophagectomy (MAE) in a semiprone position with inguinal nodal injection of ICG dye. METHODS: Ninety-nine patients with esophageal or gastroesophageal junctional cancer undergoing MAE received inguinal node injections of 2.5 mg ICG dye (total 5 mg) under sonographic guidance during anesthesia induction. Stryker's 1688 AIM HD system was used in 76 cases, Karl Storz OPAL 1 S in 20, and in three cases the Karl Storz Rubina. RESULTS: In 93 patients (94%), the TD was clearly delineated along its entire length; it was not visualized in 6 patients (6%). Fluorescence guidance facilitated TD ligation in 16 cases, while 3 cases required clipping of duct tributaries for oncological considerations. Twenty-eight patients exhibited minor duct variations. Fluorescence was sustained throughout surgery (median observation time 60 min post-injection; range 30-330). No patient experienced any chyle leak within 30 days post-surgery and no adverse reactions to ICG was evident. CONCLUSIONS: Intraoperative fluorescence TD lymphography using ICG during MAE in a semiprone position with inguinal nodal injection proved safe, feasible, and effective, allowing clear visualization of the TD in almost all cases. This approach aids safe ligation and reduces chyle leak risk. It offers real-time imaging of TD anatomy and variations, providing valuable feedback to surgeons for managing TD injuries during MAE procedures and represents an excellent educational tool.

Simultaneous Visualization of the Thoracic Duct and Blood Vessels Using MRI: A Comparison Between Balanced Turbo-field-echo and Spin-echo.

OBJECTIVE: Magnetic resonance thoracic ductography (MRTD), concomitant with blood vessel imaging, provides useful anatomical information. The purpose of this study was to assess the visibility of the thoracic duct and blood vessels simultaneously by MRTD using balanced turbo-field-echo (bTFE) and turbo spin-echo (TSE). METHODS: MRTDs concomitant with blood vessel imaging on bTFE and TSE were obtained for 10 healthy volunteers with a 1.5T-magnetic resonance unit. Visibility of the thoracic duct, blood vessels in the thoracic region; motion artifacts; and overall image quality were scored by two radiologists using three-to-five-point scales; those were compared between bTFE and TSE. RESULTS: The thoracic duct was generally well-visualized on MRTD sequences. The upper part of the thoracic duct was better visualized on TSE than on bTFE (p < 0.05). The blood vessels were well visualized on bTFE and TSE; the bilateral subclavian arteries and the right subclavian veins were better visualized on TSE than on bTFE (all p < 0.05). Motion artifacts and overall image quality were better on TSE than on bTFE (p = 0.0039 and 0.0020, respectively). CONCLUSION: MRTD concomitant with blood vessel imaging on TSE has better visibility of the thoracic duct and blood vessels than bTFE.

Lymphatic drainage dysfunction via narrowing of the lumen of cisterna chyli and thoracic duct after luminal dilation.

BACKGROUND: The chronological pattern of extrahepatic lymphatic vessel progression in the course of chronic liver disease has not been clarified. This study aimed to clarify the chronological changes in lymphatic vessels with liver disease progression. METHODS: This was a prospective cross-sectional study that enrolled a total of 199 patients. The maximum diameter of the cisterna chyli (CC) or terminal thoracic duct (tTD) was measured using computed tomography or ultrasonography, respectively. Changes in the maximum diameters of the CC and tTD were evaluated with patients with chronic liver disease as the pilot set (n = 138). Subsequently, we examined whether CC/tTD could be used to re-allocate unclassified patients by the Baveno-VII criteria to appropriately diagnose clinically significant portal hypertension (CSPH) in the pilot and validation sets. RESULTS: In the pilot set, a scatter-plot showed that both CC and tTD were narrowed as terminal features in chronic liver disease after dilation. Because there was a significant correlation between the CC diameter and hepatic venous pressure gradient (r = 0.724) in unclassified patients, the diagnostic value of CC and tTD for CSPH was good (AUC: 0.961 and 0.913, respectively). After re-allocation, 68 and 27 unclassified patients were reduced to 4 and 5 in the pilot and validation sets, respectively. CONCLUSION: Both the CC and tTD narrow in the course of liver disease after dilation. Moreover, the maximum diameter of the CC and tTD can be used to re-allocate patients who are unclassified according to the Baveno-VII criteria. CLINICAL TRIAL NUMBER: UMIN trial no. 000044857.

Magnetic resonance three-dimensional steady-state free precession imaging of the thoracic duct in patients with Fontan circulation and its relationship to outcomes.

BACKGROUND: Lymphatic complications are common in patients with Fontan circulation. Three-dimensional balanced steady-state free precession (3D bSSFP) angiography by cardiovascular magnetic resonance (CMR) is widely used for cardiovascular anatomical assessment. We sought to determine the frequency of thoracic duct (TD) visualization using 3D bSSFP images and assess whether TD characteristics are associated with clinical outcomes. METHODS: This was a retrospective, single-center study of patients with Fontan circulation who underwent CMR. Frequency matching of age at CMR was used to construct a comparison group of patients with repaired tetralogy of Fallot (rTOF). TD characteristics included maximum diameter and a qualitative assessment of tortuosity. Clinical outcomes included protein-losing enteropathy (PLE), plastic bronchitis, listing for heart transplantation, and death. A composite outcome was defined as presence of any of these events. RESULTS: The study included 189 Fontan patients (median age 16.1 years, IQR 11.0-23.2 years) and 36 rTOF patients (median age 15.7 years, IQR 11.1-23.7 years). The TD diameter was larger (median 2.50 vs. 1.95 mm, p = 0.002) and more often well visualized (65% vs. 22%, p < 0.001) in Fontan patients vs. rTOF patients. TD dimension increased mildly with age in Fontan patients, R = 0.19, p = 0.01. In Fontan patients, the TD diameter was larger in those with PLE vs. without PLE (age-adjusted mean 4.11 vs. 2.72, p = 0.005), and was more tortuous in those with NYHA class ≥ II vs. class I (moderate or greater tortuosity 75% vs. 28.5%, p = 0.02). Larger TD diameter was associated with a lower ventricular ejection fraction that was independent of age (partial correlation = - 0.22, p = 0.02). More tortuous TDs had a higher end-systolic volume (mean 70.0 mL/m2 vs. 57.3 mL/m2, p = 0.03), lower creatinine (mean 0.61 mg/dL vs. 0.70 mg/dL, p = 0.04), and a higher absolute lymphocyte count (mean 1.80 K cells/µL vs. 0.76 K cells/µL, p = 0.003). The composite outcome was present in 6% of Fontan patients and was not associated with TD diameter (p = 0.50) or tortuosity (p = 0.09). CONCLUSIONS: The TD is well visualized in two-thirds of patients with Fontan circulation on 3D-bSSFP images. Larger TD diameter is associated with PLE and increased TD tortuosity is associated with an NYHA class ≥ II.

Factors Contributing to Successful Transvenous Retrograde Thoracic Duct Cannulation.

PURPOSE: To identify key factors for successful transvenous retrograde cannulation (TVRC) of the thoracic duct. MATERIALS AND METHODS: A total of 47 consecutive patients (62.1 ± 13.2 years; 32 men) who underwent attempted TVRC between July 2016 and July 2021 were included. Reasons for interventions were chylous leakage from the chest (n = 36), abdomen (n = 6), and other sites (n = 5). Patient age, sex, access vein (femoral vs brachial), anatomic classification (presence of dominant channel vs plexiform) of the terminal thoracic duct, and engagement of a diagnostic catheter into the jugulovenous junction were included in the analyses. Anatomic details were evaluated according to catheter-based high-pressure lymphangiography and conventional intranodal lymphangiography. The Firth bias-reduced penalized-likelihood logistic regression model was used to analyze prognostic factors. RESULTS: TVRC was successful in 33 of the 47 patients (70%). In univariate analysis, femoral access, diagnostic catheter engagement, and presence of dominant channel were significant positive prognostic factors (P <.05). In multivariate analysis, diagnostic catheter engagement and presence of dominant channel were significant prognostic factors (P <.05). Diagnostic catheter engagement showed the highest prognostic performance (accuracy = 0.872), followed by presence of a dominant channel. High-pressure catheter-based lymphangiographic findings showed better performance (accuracy, 0.844 vs 0.727) than intranodal lymphangiography to delineate the anatomy of the terminal thoracic duct. CONCLUSIONS: A secure selection of the jugulovenous junction and the presence of a dominant channel in the terminal portion of the thoracic duct were significant prognostic factors for successful TVRC.

Delayed non-selective contrast-enhanced CT can reveal spontaneous contrast enhancement of the lymphatic system in cats.

The authors incidentally observed that, on delayed postcontrast CT studies, feline patients could show increased attenuation of the lymphatic system. The aim of the present study was to evaluate if the lymphatic system of feline patients undergoing intravenous administration of contrast medium might consistently enhance on delayed postcontrast CT studies. Feline patients that underwent CT examination for variable diagnostic purposes were included in this multicentric observational descriptive study. A 10-min delayed postcontrast whole-body CT series was obtained for all cats enrolled and the following anatomic structures were systematically assessed: mesenteric lymphatic vessels, hepatic lymphatic vessels, cisterna chyli, thoracic duct, and anastomosis of the thoracic duct with the systemic venous system. A total of 47 cats were included in the study. The mesenteric lymphatic vessels showed enhancement in the selected series in 39 of 47 (83%) patients and the hepatic lymphatic vessels in 38 of 47 (81%) patients. The cisterna chyli, thoracic duct, and the point of anastomosis of the thoracic duct with the systemic venous circulation were enhanced in 43 (91%), 39 (83%), and 31 of 47 (66%) cats, respectively. This study confirms the initial observation. The mesenteric and hepatic lymphatic system, the cisterna chyli, the thoracic duct, and its anastomosis with the systemic venous circulation of feline patients undergoing intravenous administration of iodinated contrast medium can show spontaneous contrast enhancement in non-selective 10-min delayed contrast-enhanced CT series.

Therapeutic effect of lymphography in the postoperative chylothorax - case reports and literature review.

Postoperative chylothorax is a well-known rare complication of thoracic surgery. It is a serious complication that is fatal in cases of inadequate treatment. The authors present 2 cases of postoperative chylothorax that were successfully treated by performing pedal and/or intranodal lymphography. In one case, the patient underwent lymphography after previous unsuccessful surgical ligation of the thoracic duct. The presented case reports describe therapeutic importance of conventional lymphography as a minimally invasive treatment of the postoperative chylothorax.