Certain types of surgery can increase the risk of blood clots forming in the veins. This is because patients don't move much during and, usually, after some surgeries.

Venous thrombosis is a condition in which the blood clot (thrombus) forms in a vein. This clot can limit blood flow, causing swelling, redness and pain. Most commonly, clots occur in the legs, thighs, or pelvis.

If a part or all of the clot breaks off from where it was formed, it can travel through the veins. The part that breaks off is called an embolus. If the embolus lodges in the lung, it is called a pulmonary embolism, a serious condition that can cause death.

A number of factors can increase a patient's risk of developing blood clots, but doctors can order preventative treatments called prophylaxis to reduce the risk. Prophylaxis may include blood thinning medications, elastic support stockings, or mechanical air stockings that promote circulation in the legs.