Under Your Skin Cartoon

Lymphedema and Surgical Treatment Options – The Train Analogy

I’d like to thank Dr. Dhruv Singhal, Director of Lymphatic Surgery at Beth Israel Deaconess Medical Center here in Boston, for sharing his brilliant “train” analogy for lymphedema and for his collaboration in making this latest cartoon happen.

Imagine your heart as the biggest train station in the world. There are red tracks with red trains running away from the heart and dedicated to areas all throughout  your body. This represents your arterial system.

Let’s focus on one location in this analogy: the upper left extremity. Picture a workday, and at 9:00 in the morning, a big red train leaves the heart station, bound for the left arm and hand, and all the passengers get on board.

It makes its way down the left arm to the left hand, and the passengers get off at their various stops along the way and get to work. When the train gets to the end of the line, all of the passengers have gotten off.

At 5:00, it’s the end of the workday, and there are two sets of trains that will take the passengers home (to the heart) again: a blue train (the venous system) and the yellow train (the lymphatic system).

If everything is working well, the trains are on time and there are no problems, all the passengers get on their trains and get a seat, and they all get home on time.

But what if one day, something goes wrong, and the yellow train gets derailed and the passengers get stranded? We’ve all missed a plane or train or bus sometimes, and usually we don’t make a big deal of it, so you might not even know you have any stranded passengers at all for a bit. They might be okay for a little while, waiting around for the next train to come and pick them up.

But what if someone told them “There is no other train coming,” and now they’re stranded for a long time, unable to get home, and just….stuck. They might get a little ticked off. And then they might start getting angry. And they might start to riot.

Those rioting passengers represent the symptoms of lymphedema that might be felt in the body – whether that’s fullness or heaviness or tingling or visible swelling.

So, what can be done when faced with this kind of scenario?

Lymphedema therapists who are doing decongestive therapy (which includes tools like manual lymphatic drainage and compression) can try to help push that yellow train up the track and get it back home. It’s the gold standard in lymphedema treatment, but it can take time and can be resource-heavy.

Excisional surgery procedures (such as debulking and liposuction), which remove excess mass, are like hosing down the rioters, eliminating those stranded passengers altogether.

This can be a great way to reduce the size of the extremity; however, it doesn’t fix the underlying problem. The train is still derailed, other trains are still running and getting stuck behind it, and those other passengers on later trains will end up stranded, too. Without lifelong, 24/7 compression after this kind of surgical procedure, the size reduction won’t be able to be maintained.

Microsurgery treatment options can work with the trains and tracks themselves to try to fix the fundamental problem with the goal of a better physiological outcome.

If the yellow train is trying to return to the heart station and the track is damaged, Lymphovenous Bypass (LVB) surgical procedures can connect the yellow track to a set of blue tracks and trick the yellow train into taking those blue tracks back home. The surgeon can connect the lymphatics to a nearby venous structure to create a new drainage pathway.

But there are times when a train might be beyond repair, and a whole new train and new set of tracks might be needed.

The surgeon might take a train (a lymph node) and some of the train tracks (the node’s afferent and efferent vessels) from a healthy, unaffected part of the body (a donor site) and implant it into the extremity that’s affected. They might take a train from the abdomen and place it in the forearm to help with upper-extremity lymphedema, and when that train gets into its new home, it starts to build its own new train tracks. This is known as Vascularized Lymph Node Transfer (VLNT).

And the exciting and hope-giving future of preventative surgery for lymphedema is that now, with the help of fluorescence imaging, a surgeon might be able to assess potential damage to the yellow train tracks down the line, and then re-route the yellow train onto its neighboring blue tracks BEFORE the yellow train has a chance to hit any trouble.

Whichever treatment option looks like the best fit, the overarching goal is to get that yellow train and its passengers back home and keep them as happy as possible.

Under Your Skin Cartoon

Sentinel Node Biopsies and Lymphedema

The question: “But I only had one lymph node removed when they did my sentinel node biopsy. How could I possibly develop lymphedema if just one little node is gone?”

The answer: Well, let’s take a quick-and-dirty look at how those nodes are distributed and how they work.

We’ve got lymph nodes spread around our bodies, but there are certain larger groupings of nodes in places like your neck (cervical nodes), your armpits (axillary nodes), and your  groin (inguinal nodes). For this example, we’ll focus on the nodes in the axillary region (“axilla” being the proper-albeit-less-humorous name for “armpit”). Think of all these regions as office departments in the corporation that is you.

These little superheroes have multiple tasks – including filtering out harmful stuff like dirt and pathogens, and producing white blood cells called lymphocytes – but for the purposes of this illustration, we’ll talk about their role in fluid balance.

So here in the “right axilla department,” we can see the nodes hard at work. They’re reabsorbing a lot of the water content from the lymphatic fluid, which reduces the amount of lymph that goes back into the venous system.

And let’s say just one of these axillary lymph nodes (along with parts of the transport vessels that run to and from that node) gets taken out of the equation because of a sentinel node biopsy or for some other reason. We’ll call that node “Lenny.”

Many times, that department can totally keep on truckin’, the other neighboring nodes can make up for Lenny’s workload, they re-route the fluid through other nearby lymphatic vessels, and they never even miss the guy. This can happen for a while, or even indefinitely.

But other times, that department really feels Lenny’s absence, and the amount of fluid that needs to get processed out of the tissues of that quadrant and get back into the cardiovascular system can get overwhelming.

This feeling of being “understaffed” can happen right after a node or nodes are removed, or it can happen as much as years down the road if the lymphatic load increases to a point where the department just can’t handle it as efficiently anymore. 

When the lymphatic system gets backed up in a particular region, this can sometimes cause the tissues in that quadrant to swell with protein-rich lymphatic fluid, called lymphedema, and the result can be swelling that you can feel and often see.

So even with only one lymph node removed, the risk for lymphedema still technically exists, though it’s thought to be less compared to multiple lymph nodes having been taken out (imagine Lenny and six or seven of his co-workers disappearing). The risk is low, but it is real.

And plenty of people will never develop lymphedema at all. The hope is that future research in this field will focus on better predicting which people might develop lymphedema. This would mean targeted prevention and intervention strategies, and individualized plans for risk-reducing behaviors. In the meantime, the National Lymphedema Network has some general “healthy habits” that people who might be at risk for lymphedema can follow to help reduce that chance of developing swelling. Check it out here.

Stay tuned for more episodes of “Under Your Skin” on lymphedema and manual lymphatic drainage! There are many more nerdy stories to tell!