The use of Thiel embalmed human cadavers for retrograde injection and visualization of the lymphatic system

Abstract

In order to provide an alternative for fresh frozen specimens to map the lymphatic system, the possibility of using Thiel embalmed specimens for this purpose was explored. The thoracic duct was used to investigate if retrograde injection of contrast agent was possible in Thiel embalmed specimens and to verify up to which diameter lymphatic vessels could be reconstructed and rendered in 3D, after CT scanning. 3D renderings were used for digital diameter measurement, to determine the smallest lymphatic diameter that could still be visualized on CT. Finally, the contrast agent concentration was adapted based on the findings during image reconstruction and 3D rendering. All Thiel embalmed specimens proved suitable for retrograde injection of contrast agent into the thoracic duct and all 3D renderings perfectly overlapped with the dissection pictures. The smallest diameter of contrast filled lymphatics that could be reconstructed and rendered in 3D was 0.23 mm. Increasing the concentration of barium sulfate from 10 to 50% reduced the postprocessing time needed to render a “clean” 3D structure, following automatic segmentation based on grey values, by 95%. The authors would recommend the use of Thiel embalmed specimens for mapping the lymphatic system, as these specimens do not show the rapid putrefaction that occurs in fresh frozen specimens, thus greatly facilitating experimental planning.

The Lymphatic System in Breast Cancer: Anatomical and Molecular Approaches

“…This study also provided evidence that embalmed specimens can be used for lymphatic injections. The 0.23 mm diameter of the lymphatics that could be visualised after retrograde injection is in the size range of the subclavian lymphatic trunk, thus indirectly proving that it should be a possibility to retrogradely inject the subclavian lymphatic trunk as well [72]. A final finding of this study was that the manual injection approach was too crude in relation to the delicate lymphatic walls, so a more sophisticated injection method seemed warranted.…”

“…Based on previous experiments, a proof of concept for retrograde lymphatic filling was provided [72,77]. However, many variables play a role in this process and a combination of adaptations to the current experimental approaches is still required to optimise the retrograde filling methodology.…”

“…During the thoracic duct injection experiments it was found that different solvents caused different amounts of lymphangions to retrogradely fill with contrast agent [72], identifying the contrast agent composition as an important variable in the experimental set up. Experimenting with different contrast agents and different solvents could further optimise the experimental procedure.…”

“…The thoracic duct injection methodology is ideally suited to test the above-described experimental approaches in a standardised setting [72]. A good length of thoracic duct is available in this set up that can be ligated at several intervals to form standardised test units within the same specimen.…”

Current and potential use of fresh frozen cadaver in surgical training and anatomical education

“…Thiel's method is also one of the major methods of embalming with various advantages such as the suitability for biomechanical testing and less odor compared with formalin‐fixed models. In addition, with injected materials, Thiel‐fixed cadavers can have enhanced reality for vascular purposes (Stouthandel et al, 2020). However, FFCs are considered to have an easier and simpler embalming process with most of the advantages of the Thiel's method (Hayashi et al, 2016).…”