Surgical Gentle surgical technique with careful and meticulous control of bleeding helps avoid<unk> s. Liposuction contributes to<unk>  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.<unk> s 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" (fibrin) and wound healing have a chance for a permanent bond. Nonsurgical 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. (In abdominoplasty, sitting upright with the knees bent and hips flexed will cause pressure across the lower abdomen and a tendency to<unk>  formation. The patient is best to stand or at least be semirecumbent). 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 backpressure on those fluid sources. Following breast augmentation or double mastectomy, binding the chest may be recommended for several weeks to minimize the risk of<unk> s.
Seroma
Stoma 
Encephalitis
Brain abscess
Meninges
Cerebritis
Hematoma
Meningitis