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Page 8 of 11 Suami et al. Plast Aesthet Res 2019;6:33 I http://dx.doi.org/10.20517/2347-9264.2019.46

Gerota’s method, the microinjection technique requires more dextrous skills in manipulating lymphatic
vessels under the microscope.

When a radiocontrast medium is selected as the contrast agent, the prospective radiographic images
are similar to those produced by lymphoangiography in live subjects. Lymphangiography is an invasive
procedure requiring a small surgery consisting of cutting the skin and cannulating a fine needle into a
[1]
lymphatic vessel under local anaesthesia . Usually, only one lymphatic vessel is cannulated. In contrast to
lymphoangiography, the microinjection technique in cadaver specimens has no limitation on the number
of lymphatic vessels that can be identified, so has the advantage of allowing the researcher to obtain
a comprehensive picture of the lymphatics in each specimen. The disadvantage of the microinjection
technique is that the contrast medium stops at the sentinel node, so further cannulation in the efferent
vessel of the node is essential if the proximal areas are to be investigated. However, the invention of
the microinjection technique enabled anatomists to undertake the study of lymphatic anatomy in adult
cadavers and contributed to better lymphatic mapping of the body regions [28-31] .

Indocyanine greenlymphography
[32]
ICG lymphography was initially developed to map the sentinel lymph nodes for breast cancer treatment .
[4-6]
Its application was then expanded to provide imaging for the diagnosis of lymphoedema . ICG is a water-
soluble agent that emits near infrared-rays when it combines with protein in the human body. When ICG is
injected into the skin, it automatically enters the lymphatic vessels. The infrared camera then scans the limb
and captures the emitted signals, causing the vessels to glow green so that they can be identified in real time
to a depth of 2 cm from the surface of the skin.

The authors injected ICG into fresh cadavers and confirmed that it was able to identify the lymphatic
vessels in post-mortem specimens [33,34] . ICG lymphography was found to be consistent in identifying
the lymphatics and the dye was able to travel long distances from the injection site if fresh, non-frozen
cadavers were used. The technique has demonstrated several advantages in anatomical study in a cadaver
model. Firstly, lymphatic vessels can be identified without a skin incision, so ICG injections do not disrupt
the embalming process to follow and the bodies can be reutilised for anatomical dissection after study of
the lymphatics. Secondly, ICG mapping has helped make the microinjection technique more effective, as it
provides a more efficient way of locating the lymphatic vessels than injecting hydrogen peroxide, the most
time-consuming part of the process. Finally, it has enabled fast mapping of the course of lymphatic vessels
[35]
and allowed the capture of imaging data from multiple cadaver specimens .

AUTHOR’S CURRENT METHOD
Finally, this paper briefly introduces the specific method we currently use for anatomical investigation of
the lymphatic system in a cadaver model. Cadaver specimens are obtained from the institutional willed
body program with appropriate approval for their use in scientific investigation. Fresh, non-embalmed
and non-frozen specimens are ideal, but previously frozen and thawed specimens can also be used. ICG
(Verdye 25 mg, Diagnostic Green GmbH, Germany) is mixed with 20 mL of saline. Taking the investigation
in an upper extremity as an example, 0.1 mL doses of ICG solution are injected intradermally into the sides
of fingers and several spots in the anterior wrist. After a few minutes of massage at the injection sites, the
ICG dye starts entering the lymphatic vessels. Inside the lymphatic vessel, the dye is moved from the distal
to proximal by massaging the skin in an axial direction. If the specimen is within a few days post-mortem,
the ICG moves all way to the axillary nodes and the course of the vessels is demonstrated with the infrared
camera (Photodynamic Eye Neo II, Hamamatsu K.K., Japan). A marker pen is used to mark the lymphatic
vessels on the surface of the skin [Figure 5].

If the specimens are needed for further dissection and for use in an anatomical teaching workshop, the
[33]
microinjection technique is then applied . Five per cent hydrogen peroxide with/without dye is injected