A seroma is a pocket of clear serous fluid that sometimes develops in the body after surgery. This fluid is composed ofblood plasma that has seeped out of ruptured small blood vessels and the inflammatory fluid produced by injured and dying cells. Seromas are different from hematomas, which contain red blood cells, and abscesses, which contain pus and result from an infection. Serous fluid is also different from lymph. Early or improper removal of sutures can sometimes lead to formation of seroma or discharge of serous fluid from operative areas. Seromas can also sometimes be caused by injury, such as when the initial swelling from a blow or fall does not fully subside. The remaining serous fluid causes a seroma that the body usually absorbs gradually over time ; however, a knot of calcified tissue sometimes remains. Seromas are particularly common after breast surgery, abdominal surgeries, and reconstructive surgery. They are a treatment target in partial-breast radiation therapy. The larger the surgical intervention, the more likely it is that seromas appear. Larger seromas take longer to resolve than small ones, and they are more likely to undergo secondary infection. A seroma may persist for several months or even years as the surrounding tissue hardens. On CT scans, seromas have a radiodensity of 0–20 Hounsfield units, generally in the lower part of this range, consistent with clear fluid.
Treatment
Seromas may be difficult to manage at times. Research suggests that the procedure of quilting after mastectomy significantly reduces seroma formation. The removal of seromas by fine-needle aspiration is controversial: it is recommended by some for the reason that seromas can be a culture medium for bacteria, whereas others advise it only for collection of excessive amounts of fluid, because even an aspiration carried out under aseptic conditions carries a certain risk of infection. Depending on the volume and duration of leakage, control of a leak may take up to a few weeks to resolve with aspiration of serums and the application of pressure dressings. Manual lymphatic drainage conducted by a trained professional can also assist in managing and treating seromas. If a serum or leak does not resolve, it may be necessary to take the patient back to the operating room in order to place some form of closed-suction drain into the wound. This usually is not necessary and conservative management prevails. In case of lumpectomy, the formation of a seroma at the lumpectomy site has been cited in medical literature as being beneficial, with claims that it can contribute to preserve the contour of the breast. In some cases a seroma may need to be drained prior to a course of radiotherapy adjuvant to surgery.
Prevention
Surgical
Gentle surgical technique with careful and meticulous control of bleeding helps avoid seromas. Liposuction contributes to seroma formation when it is done in conjunction with creating a "flap" and potential space is confluent with the treated area. Controversy exists in tummy tuck surgery as to whether electrosurgical dissection either contributes to serum formation or prevents it. Drains are traditionally used but their use has been challenged by various authors who believe quilting sutures alone may be sufficient to reach results as good as or better than when using drains. Seromas accumulate in what is known as "dead space" where a potential place for the fluid exists. Efforts are directed at reducing or eliminating the dead space. Quilting sutures reduce the risk of the skin–fat layer's separating from the deeper muscle layer, and having the separation fill up with fluid, by physically holding those layers together. Drains suck the two layers together so the body's natural "glue" and wound healing have a chance for a permanent bond.
Non-surgical
Prevention of movement between the layers allows the tentative initial bond of fibrin to be reinforced by wound healing with a thin, strong, layer of scar. Avoiding certain positions for certain surgeries may have an effect.. External pressure may help in immobilization but also is thought to reduce the tendency of the fluid to leak out of vessels by increasing the back-pressure on those fluid sources. Following breast augmentation or double mastectomy, binding the chest may be recommended for several weeks to minimize the risk of seromas.
