In fact, scar tissue can restrict many layers of muscle and connective tissue, which can cause varying degrees of pain or discomfort. Scar tissue is weaker, less elastic and more prone to re-injury than normal, healthy tissue, and can lead to chronic pain if it affects the functioning of other structures--especially nerves and blood vessels.
Negative pressure means the pressure in the pipe/duct/room is less so flow would go into the room. These are all gauge pressures, which can be positive or negative since they are merely measuring a relative pressure compared against some constant pressure, typically atmospheric which is about 14.7 psi.
Application of a vacuum pump using a foam dressing to a wound. Negative-pressure wound therapy (NPWT) is a therapeutic technique using a vacuum dressing to promote healing in acute or chronic wounds and enhance healing of first and second degree burns.eneral technique for NPWT is as follows: a dressing or filler material is fitted to the contours of a wound (which is covered with a non-adherent dressing film) and the overlying foam is then sealed with a transparent film. A drainage tube is connected to the dressing through an opening of the transparent film.