Bioengineered Skin & Skin Substitutes in Wound Care

Bioengineered skin was developed because of the need to cover extensive burn injuries in patients who no longer had enough skin for grafting. Not so long ago, a patient with third degree burns over 50% of his body surface usually died from his injuries. That is no longer the case. Today, even someone with 90% TBSA has a good chance of surviving. With the array of bioengineered skin and skin substitutes available today, such products are also finding use for chronic wounds, in order to prevent infection, speed healing and provide improved cosmetic results.

apligraf
Apligraf, Organogenesis

Skin used in wound care may be autograft (from the patient’s own body, as is often the case with burn patients), allograft (cadaver skin), xenogeneic (from animals such as pigs or cows), or a combination of these. Bioengineered skin substitutes are synthetic, although they, too, may be combined with other products. It consists of an outer epidermal layer and (depending on the product) a dermal layer, which are embedded into an acellular support matrix. This product may be autogenic, or from other sources. Currently most commercial bioengineered skin is sheets of cells derived from neonatal allogenic foreskin. This source is chosen for several reasons: because the cells come from healthy newborns undergoing circumcision, and therefore the tissue would have been discarded anyway; foreskin tissue is high in epidermal keratinocyte stem cells, which grow vigorously; and because allergic reactions to this tissue is uncommon.

Selected Bioengineered Skin & Skin Substitutes

bio-skin

Source: Exhibit 3-16 in MedMarket Diligence, LLC, Report #S251. To get excerpts, Click Here

Advanced wound care technologies target high costs, according to new MedMarket Diligence report

September 21, 2009 (For Immediate Release)

While the huge $5 billion global market for wound management technologies may not suggest it, many of its products are designed to target the high cost of wound healing. Chronic wounds and non-healing wounds. See the 2009 MedMarket Diligence report.

FOOTHILL RANCH, CA — Advanced wound management technologies — those used in the clinical management of wounds (not OTC) — represent a $5 billion global market that will triple in the next ten years.  These technologies have continued to evolve beyond simple dressings and bandages to be able to accelerate wound healing, improve clinical outcomes and, in particular, attempt to reduce the cost of managing wound types like arterial, venous, diabetic and stasis ulcers.

The distribution of the advanced wound care market across these different wound care types has continued to shift, especially with the development and application of more expensive wound care technologies, which have been incentivized by the high cost of chronic wounds.  Physical therapies, which include negative pressure devices, positive pressure devices, mechanically assisted wound closure, hydrotherapy, electrical stimulation, ultraviolet therapy and others, are demonstrating the largest relative growth.

The MedMarket Diligence report, "Worldwide Wound Management, 2009:  Established and Emerging Products, Technologies and Markets in the U.S., Europe, Japan and Rest of World," published September 2009, details the complete range of products and technologies used in wound management and wound care, from dressings, bandages, hydrogels, tissue engineered products, physical treatments and others. The report details current clinical and technology developments in this huge worldwide market with high growth sectors, with data on products in development and on the market; market size and forecast; competitor market shares; competitor profiles; and market opportunity. The report provides full year (actual) 2008 market size and share data, with forecast market data to 2017, for the U.S., Europe, Asia/Pacific and Rest of World.

"The intense focus of healthcare reform on the cost of medical technologies might examine wound management as a cost driver, but the reality of products and development in this area is that the high cost of chronic or non-healing wounds is the prime target of the wound management industry’s efforts," says Patrick Driscoll of MedMarket Diligence, publisher of the 2009 Worldwide Wound Management Market report.  According to Driscoll, the high direct and indirect costs of chronic wounds have created an economic opportunity that sustains advanced technology development.  This does not make wound care exempt from the focus of healthcare reform, but does weaken the argument against the "high costs" of advanced technology development.

The report is described in detail at http://mediligence.com/rpt/rpt-s247.htm. It may be purchased online at http://mediligence.com/store/page31.html or it may be ordered via fax order form http://mediligence.com/order_forms/s247_order.pdf.

Tags: woundcare, wound management

 

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Purchase for download: "Wound Management 2009 (PDF)" — $3,250.00
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Management of burn wounds in clinical practice

Major burns can present a substantial physical assault to the body, affecting multiple organ systems. Burn patients may require resuscitation, hemodynamic stabilization, oxygen support, nutritional support, protection against infection, and extensive wound care. The attentions of a dedicated burn team may be necessary to provide the services and support required to manage the physiological, social, and psychological needs of a seriously burned individual.

This is an excerpt from MedMarket Diligence report #S245, "Worldwide Wound Management, 2007-2016: Established and Emerging Products, Technologies and Markets in the U.S., Europe, Japan and Rest of World."

The average hospital stay for patients admitted for burns is 24 days, although the most severely burned patients may require several months of hospital intervention. Survivors of extensive burns will require rehabilitation periods up to seven times the length of their hospitalization. Over the last ten years, improvements in burn wound care and the pressures of DRG systems in various European countries have resulted in reductions in the average hospital stays for burn patients.

The traditional classification for burns (first to fourth degree) has been superseded by classification as partial-thickness, full-thickness, and complete burn wounds. Burns classified under the old system as first degree are not included in the current classification system unless they include injury to greater than 30% of the total body surface (TBS). These wounds are fiery red, very painful, not blistered and can be expected to heal uneventfully in three to five days.
Partial-thickness burns, formerly second degree, extend through the epidermis and may penetrate into the dermis. Partial-thickness wounds will heal by regeneration and should regain full function and appearance.

Full-thickness (third degree) burns penetrate the dermis and may involve subcutaneous tissue. Skin appendages such as hair follicles, sebaceous glands, and sweat glands are destroyed and healing will occur through scar formation and re-epithelialization from the wound borders, or grafting if the wound is extensive. In addition to visible effects, scarring leads to permanently compromised performance of the skin and articulation of the surrounding tissue. The scarred skin is inelastic and the underlying metabolism is compromised by the surface changes. Often, badly scarred tissue needs to be resected and re-engineered by transplantation to reverse these adverse effects. This takes time, is costly, and very traumatic to the patient.

A number of types of burns are referred to burn centers, including partial-thickness burns exceeding 20% of body surface area and full-thickness burns exceeding 10% of body surface area in the adult, along with burns involving the face, hands, feet, perianal area, genitalia, or joints; also circumferential burns of an extremity or chest wall, chemical burns, electrical burns, inhalation burns, and burns complicated with another major injury.

Complete burns (fourth degree burns) extend into the subcutaneous tissue to include muscle, fascia or bone. A complete burn may initially resemble a full-thickness burn and caution must be exercised to confirm the burn severity. Complete burns may generate systemic toxic reactions or rapidly lead to infection or sepsis. Between 44 degrees and 51 degrees Celsius, the rate of cellular destruction doubles with each degree increase in temperature. Above 51 degrees C, brief exposure produces rapid tissue destruction; whereas at 70 degrees C and above a one-second exposure causes full-thickness burns. Burns may also be induced by electricshock, radiation, or toxic chemicals.
 

 Old and New Classification Systems for Burns 

Old System
New System
Summary
First degree
Not classified
Fiery red, very painful,  but not blistered
Second degree
Partial-thickness
Extend through the epidermis and may penetrate into the dermis. Healing by regeneration; full function and appearance should be recovered.
Third degree
Full-thickness
Penetrate the dermis and may involve subcutaneous tissue. Hair follicles, sebaceous glands, and sweat glands are destroyed. Healing occurs through scar formation and re-epithelialization
Fourth degree
Complete burns
Extend into the subcutaneous tissue to include muscle, fascia or bone. They may generate systemic toxic reactions or rapidly lead to infection or sepsis.
 
Source: MedMarket Diligence, LLC

The seriousness of a burn is determined not only by its classification according to thickness or depth, but also by the extent that the burn covers the body. Several scoring systems have been developed to help determine if the burn represents minor, moderate, or major insult to the burn victim. The fastest assessment tool for evaluating burn coverage is the rule of nines. Developed for use with adult patients, the rule of nines divides the body into sections and assigns a percentage of total body surface (TBS) to each section. The clinician can quickly assess which segments of the body are burned and add up the predetermined percent areas assigned to each section to reach a reasonable estimate of TBS affected. The rule of nineteen is a similar

scoring system developed for pediatric burn patients. Both rules are useful for initial assessment when speed is critical.Full-thickness burn wounds heal by secondary intention, where the wound bed is filled by granulation tissue consisting of connective tissue and blood vessels, and by epithelialization where a new epidermis grows over granulation tissue to seal the wound. Large full-thickness burns often require the use of skin grafts to hasten closure once a sufficient bed of granulation tissue is available. In major burn victims, there is often not enough of the patient’s own healthy skin to provide sufficient skin for grafting, and this has spurred the development of a number of forms of skin substitutes.

Although burn wounds are generally sterile immediately following the initial burn, the presence of eschar and serum provide an ideal medium for contamination and proliferation by pathogenic micro-organisms. Contamination may be caused by endogenous flora from the patient’s own body or exogenous flora from contact with healthcare workers or the environment. Infection follows a predictable course, progressing from early colonization by gram-positive organisms followed by gram-negative bacteria. Pathological infection is recognized by wound bacterial counts in excess of 105 micro-organisms per gram of tissue. The likelihood of infection, which may progress to sepsis and death, is reduced through aggressive debridement and the use of topical antimicrobials and/or oral antibiotics. In burn patients, topical antimicrobials such as silver sulfadiazine are used in addition to systemic antibiotics to attack any infection at an early stage. This use of antibiotics is unusual in wound care practice in Europe and reflects the high probability that severe burn patients will develop dangerous infections.

Severely burned patients will need to receive systemic nutrients and large quantities of intravenous fluids. The primary concern during the first 24 hours after a patient is severely burned is to maintain body fluids. Intravenous nutrients have also been found to lead to a reduced mortality rate in burn victims.