Can May Thurner Syndrome cause symptoms in BOTH legs?

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Absolutely! Imagine the deep veins in your left leg as a 3 lane highway going all the way up to your belly button. In May Thurner Syndrome (MTS), the left common iliac vein is compressed by the overlying right common iliac artery. At this point of compression, the left common iliac vein goes from a 3 lane highway to a 1 lane highway and a traffic jam of blood develops. The blood says “Oh my goodness, we can’t all fit down that one lane. We need to find a detour!”


There are 3 main detours that blood uses to reroute itself so that it can find its way back to the heart. 

  1. Down the left leg – the blood goes backwards down the left leg which leads to left leg swelling, heaviness, fatigue, and pain
  1. Ascending lumbar vein (ALV) – this is a branch off of the left common iliac vein that is normally very small like a one lane country road. When the iliac vein is compressed, blood coming up the left leg takes a detour thru the ALV which gets engorged and goes from a 1 lane road to a 3 lane road which it was not designed for. This leads to chronic low back pain.


FIG 1: ALV seen as one of the detours used by the body to reroute blood. Note that the left iliac vein is not completely blocked


  1. Pelvic veins – blood detours thru small pelvic veins which again were not designed to handle such a large volume of “detoured” blood. The engorged pelvic veins lead to a host of symptoms known as pelvic congestion syndrome (PCS) or pelvic venous insufficiency.

FIG 2: Dilated pelvic veins leads to chronic pelvic pain.

Since blood cannot drain via the left iliac vein, blood detours thru the pelvic veins and drains into the right iliac vein. Since the right iliac vein is not designed to drain both legs, it gets overwhelmed, leading to heaviness, pain, and swelling in the right leg. 

Generally, swelling in the right leg is not as severe as the left leg. Many physicians are at a complete loss as to why there are symptoms in the right leg and they instead put stents in the right AND left common iliac veins which is incorrect. If a single stent is properly placed in the left iliac vein, then it goes from a one lane highway back to a 3 lane highway. The blood no longer has to take a detour back down the left leg, thru the pelvic veins, or up the ALV. This leads to a significant improvement in low back pain, pelvic congestion symptoms, and right leg symptoms. There are cases where the right common iliac artery compresses both the left and right common iliac veins. In such cases, a stent may be required on both sides but this is more the rarity than it is the norm.  







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