Clinical Significance of New Magnetic Resonance Thoracic Ductography Before Thoracoscopic Esophagectomy for Esophageal Cancer

Risk Factors and Treatment of Chylothorax After Minimally Invasive Esophagectomy for Esophageal Cancer

Background Postoperative chylothorax is a rare but life-threatening complication of esophagectomy. However, due to its rarity, researching the risk factors and selecting appropriate treatment options has been limited. Methods This study included 727 patients with esophageal cancer who underwent minimally invasive esophagectomy at our hospital. To detect the risk factors for chylothorax, we divided the patients into two groups, with and without postoperative chylothorax. We then compared patient characteristics, tumor-specific variables, and operative details. Subsequently, we analyzed the peri-treatment characteristics and outcomes for the three distinct treatment options we had chosen: surgery, conversion (the group that finally underwent surgery after unsuccessful conservative treatment), and conservative. Results Of the 727 patients, 18 (2.5%) developed a chylothorax. The mean BMI was lower (20.3 vs. 21.9, p=0.057), and more cases of thoracic duct resection were found in the chylothorax group (33.3% vs. 6.2%, p=0.001), with statistical significance. Multivariate analysis identified thoracic duct resection as a risk factor (adjusted odds ratio, 6.83). The drainage volume two days after chylothorax was higher in the surgery group, although the difference was not statistically significant (surgery group, 1,405 ml vs. conversion group, 260 ml vs. conservative group, 310 ml; p=0.073). The surgery group had the shortest median postoperative hospital days among these groups (21.5 as compared to 102 and 25.0 days in the conversion and conservative groups, respectively; p<0.001). None of the patients died during their hospital stays. Conclusion Thoracic duct resection during the initial minimally invasive esophagectomy was an independent risk factor for chylothorax. If drainage volume does not decrease on the second day, early surgery may lead to earlier discharge.

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.

Clinical impacts of magnetic resonance thoracic ductography on preventing postoperative chylothorax after thoracoscopic esophagectomy for esophageal cancer

PURPOSE

The study aimed to determine whether magnetic resonance thoracic ductography (MRTD) is useful for preventing injury to the thoracic duct (TD) during thoracoscopic esophagectomy and for reducing the incidence of postoperative chylothorax.

MATERIALS AND METHOD

A total of 389 patients underwent thoracoscopic esophagectomy between September 2009 and February 2019 in Tokai University Hospital. Of them, we evaluated 228 patients who underwent preoperative MRTD (MRTD group) using Adachi's classification and our novel classification (Tokai classification). Then, the clinicopathological factors of the MRTD group (n = 228) were compared with those of the non-MRTD group (n = 161), and comparative analyses were conducted after propensity score matching (PSM).

RESULTS

The TD could be visualized by MRTD in 228 patients. The MRTD findings were divided into 9 classifications including normal findings and abnormal TD findings (Adachi classification vs Tokai classification; 5.3% vs 16.2%). After PSM, both groups consisted of 128 patients. The rate of postoperative chylothorax after thoracoscopic esophagectomy was significantly lower in the MRTD group (0.8%) than in the non-MRTD group (6.3%) (p = 0.036). In the multivariate analysis for risk factors for chylothorax, the independent prognostic factors were preoperative therapy and the presence of MRTD.

CONCLUSIONS

This study revealed that MRTD was useful for preventing of chylothorax after thoracoscopic esophagectomy for esophageal cancer.

Combining non-contrast enhanced magnetic resonance thoracic ductography with vascular contrast-enhanced computed tomography to identify the canine thoracic duct

Background:

In humans, visualization of the thoracic duct by magnetic resonance imaging (MRI) has been attempted, and recent advances have enabled clinicians to visualize the thoracic duct configuration in a less invasive manner. Moreover, MRI does not require contrast media, and it enables visualization of morphological details of the thoracic structures. In veterinary practice, the thoracic duct has not been visualized three dimensionally in MRI.

Aim:

This study aimed to assess the performance of our magnetic resonance thoracic ductography (MRTD) technique to visualize the thoracic duct and the surrounding 3D anatomical structures by combining MRTD and vascular contrast-enhanced thoracic computed tomography (CT) images in dogs.

Methods:

Five adult male beagle dogs (11.4–12.8 kg) were included in this study. Sagittal and transverse T2-weighted images were scanned in MRI. Scanning in MRTD used a single-shot fast spin echo sequence with a respiratory gate. CT was performed after the intravenous injection of contrast medium. All MRTD and CT images were merged using a workstation.

Results:

The thoracic ducts were identified in MRTD images of all dogs, and the surrounding anatomical structures were located with the aid of contrast-enhanced thoracic CT. In all dogs, the thoracic ducts coursed along the right-dorsal side of the aorta, cranially from the L2 level. Thereafter, these bent to the left side at the aortic arch and curved at the left external jugular vein angle. A comparison of the number of thoracic ducts at each vertebra between transverse T2WI and MRTD did not reveal any significant differences for all vertebrae.

Conclusion:

The results from our study suggest that MRTD using the single-shot fast spin echo sequence could be a useful tool for visualization of the thoracic duct. Furthermore, the image merged from MRTD and vascular-enhanced images provided detailed anatomical annotation of the thorax. The MRTD protocol described in this study is safe and easily adaptable, without the need for contrast medium injection into the lymph system. In addition, the images fused from MRTD and vascular contrast-enhanced CT image of the thorax could provide detailed anatomical annotations for preoperative planning.