Negative Pressure Wound Therapy
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Negative Pressure Wound Therapy (NPWT) is the use of sub-atmospheric pressure to promote or assist wound healing, or to remove fluids from a wound site.
[edit] History
Negative Pressure Wound Therapy in its present form was developed by Dr. Louis Argenta and Dr. Michael Morykwas from Wake Forest University School of Medicine. Their early animal research studied the effect of sub-atmospheric pressure on blood flow to the wound area, removal of bacteria from the wound site, and rates of granulation tissue formation. They published three landmark articles regarding these studies in 1997, in which they describe a system of sub-atmospheric pressure delivery to the wound site utilizing a sealed polyurethane foam dressing attached by a tube to a vacuum pump.
The recognition of this origin is challenged by some in the medical industry, who cite Russian studies (The Kremlin Papers) done in 1986 and 1987, in which a vacuum was used to clean wound beds, and an intermittent vacuum therapy was applied with a chamber device to the wound. These studies are subject to interpretation, and whether or not they describe Negative Pressure Wound Therapy is unclear.
[edit] Current use
Currently there are two primary suppliers of NPWT systems in the medical industry. Kinetic Concepts (KCI) uses the patented V.A.C. (vacuum assisted closure) system described by Morykwas and Argenta, and Blue Sky utilizes the Chariker-Jeter system, which the company says is derived from “The Kremlin Papers”. KCI sued Blue Sky in federal court for patent infringement soon after Blue Sky's product won FDA approval.
On August 3rd, 2006 a Texas jury found that Blue Sky Medical had not infringed upon any previous patents by way of what the system purports to do and how that differs from the KCI system. Blue Sky, for example, does not improve wound healing but has been approved to relieve intrabdominal fluid in patients for whom abdominal closure is unsafe. The difference is significant and the 40% dip seen in KCI stock the day after the judgement has largely been made up.
