More than Skin-deep

In the past three decades, newer ingredients have been introduced as dressing materials for burns wound management. Sonal Shukla updates you on them

Going by figures, it is indeed a huge number. Twenty seven million burn cases worldwide each year is definitely something that should make one sit up. And of these, seven million require hospitalisation, while more than a million succumb to the injury and die.

In India, around seven million people suffering from burns undergo treatment each year, and among these three million are admitted in hospitals while around one million succumb.

And it is likely that most of these patients could have been saved if we had followed advanced burn management.

According to the President of the National Academy of Burns India (NABI), Dr Arvind Vartak, "Burns wound management is the care of the burn wound in a manner that aids healing faster and needs to be taken from the moment the patient is admitted till the time of discharge."

However, treatment can only be given depending on the intensity of the burn wound. Dressing would be the obvious choice for partial thickness burns as the skin tissue is still intact, while grafts would be executred for full-thickness. As all properties cannot be found in any one wound cover, except the autologus skin, doctors use a combination matching the quality, availability and affordability. This is especially true in the Indian context, where one has to take care of large number of burn victims from low socio-economic status.

Dressings

Dressings have come a long way from the traditional ones like ordinary gauze that adhere to the skin and cause pain. As all burns initially require dressings, today, majority of burn surgeons in India prefer biological dressings like collagen and amniotic membrane. In second degree burns, early wound coverage is done by aseptic dressings or temporarily covering the wounds (till they heal) with biological dressings.

Biological Dressings

Collagen: For superficial burns, collagen dressings, extracted from bovine intestine, tendo-achillis of sheep and from the dermis are commonly used. Dry collagen sheets are commercially available to be used in managing superficial partial thickness and deep partial thickness wounds. The dressing is affordable as a 4x6'' sheet available for Rs 150- 200. The sheet has low antigens and supports cellular regeneration.

Dr Mary Babu from the Central Leather Institute, Chennai was the brain behind this invention in the late 1990s. Dr Thacharodi from Pondicherry improved on it by developing a collagen-based cream—Sore Treat— and also collagen sheet with antibiotics.

Amniotic membrane: Amnion, without the chorion has low antigencity and thus makes for good burns wound cover. It can be collected in a sterile form from the labour room of the hospital and be used as a biological wound cover. It has proved to be effective in reducing bacterial counts in infected burns wound. Especially in superficial injuries, the dressing need not be changed for 7-10 days, by which time the wound would have healed. The advantage of amnion is that it can be sterilised, dried and stored at room temperature for up to nine months, as the membrane removed from human placenta becomes a good wound cover. However, the preparation is cumbersome, feels Dr BP Sarma, Chief Medical Officer, Guwahati Refinery Hospital, Guwahati. The only issue related to using human tissue is HIV and hepatitis B. The membrane can be preserved in 85 per cent glycerol for 24 hours and then be safely used.

Synthetic and Bio-synthetic dressings

Biosynthetic dressings are two-layered, of which one layer is a biological layer that is mixed with normal human tissues. The other layers are a synthetic layer and can be removed and replaced with autografts. Biosynthetic dressings increase the thickness of the skin.

Integra is a bio-synthetic dermal substitute available on demand, but has to be imported and hence is expensive. According to Dr Sarma, "If the whole face of a patient has to be covered, the use of Integra would cost around Rs two lakh.” Today, a variety of covers are available globally. Still factors like price and non-availability of these products in the Indian market reflects the fact that majority of burn patients are from low socio-economic strata and cannot afford them.

Natural Dressings

Paraffin Tulle Grass: This is one of the most easily available materials used frequently for burn wound. Paraffin tulle grass or Vaseline gauze is applied to the pad to prevent its sticking to the wound. This is also available as a commercial preparation, which is expensive. The greasy and porous surface of the material allows escape of discharge from the wound and hence can be used in discharging wound also. The disadvantage of this dressing is that it sticks to the burn wound and removal is painful. One 10x10 cm piece of impregnated tulle grass dressing is available for Rs 20 in the market today.

Boiled potato peel bandage: An invention made by Mumbai-based Dr MH Keswani in the 80s, this dressing is prepared from dried boiled potato peel. Manufactured by Burn Research Society, Mumbai, it retains moisture in the wound and hence does not stick to the wound. Removal of the dressing is therefore not painful.

Banana leaf bandage: Mumbai's Lokmanya Tilak Municipal General (LTMG) Hospital has been using this dressing since the last decade. Possessing similar qualities as the boiled potato peel, it is easy to apply because of the large surface area of the leaf. Washed and dried banana leaf is rolled and auto-claved (steamed under pressure). To make it easy to handle, the bandage is stuck on the reverse of the leaf. "The dressing can be finished quickly and the patient need not suffer pain. We are yet to find any drawbacks of this dressing," states Dr Madhuri Gore, Professor and Head, Department of Surgery, LTMG Hospital.

Pros and Cons of Wound Covers

Acticoat dressing + Three-layered synthetic dressing containing two layers of nano-crystalline silver coated high-density polyethylene mesh with a rayon/polyester core. + Allows controlled release of silver into the wound thus killing organisms. -Expensive.

Banana leaf dressing + Easy to apply because of the large surface area of the leaf. + Finished quickly and the patient need not suffer pain. Potato peel bandage + Retains moisture in the wound. + Does not stick to the wound.

Fresh porcine grafts +Plentifully available. + Inexpensive (50 per cent of wound cover costs barely Rs 2000). + Safe if properly procured. +This animal transmits no diseases like Aids and Hepatitis. + Minimal immune reactions as pig is closest to human. -Short lived -two to three weeks as compared to four to six weeks for related donor. - Hard work for burn surgeon. - Porcine xenograft is commer cially available internationally, but not yet in India.

Collagen dressing +Affordable as a four 4x6'' sheet available for Rs 150- 200. +The sheet has low antigens and supports cellular regeneration.

Newer modalities

"A topical medication of flaxseed oil and lime distillate used in Ayurveda is a good analgesia and therefore patients find it very useful" - Dr S Chamania Chief of Burn Unit at Choithram Hospital and Research Center, Indore

Some of the best dressings and medications are known among rural and semi-urban areas. One of them is a topical medication of flaxseed oil and lime distillate used in Ayurveda. Here, the wound is not dressed and is kept open. This preparation is available free of cost and is therefore popular. Minor burns are treated through this Ayurvedic preparation available in a jar. "This application is a good analgesia and therefore patients find it very useful," says Dr S Chamania, Surgeon and Chief of Burn Unit, Choithram Hospital and Research Center, Indore.

Acticoat: It is a three-layered synthetic dressing containing two layers of nano-crystalline silver coated, high-density polyethylene mesh with a rayon/polyester core. Although expensive, it is a life-saver as it allows controlled release of silver into the wound, thus killing organisms. ''However, marketers of Acticoat feel they might not find a market in India,'' believes Dr Chamania. Aquacell silver dressing is similar to Acticoat. Hydrogel formulation in it provides the hydration to the cells. The Bhabha Atomic Research Centre's (BARC) chemistry division, through valuable inputs from the burn unit of LTMG Hospital, has developed Hydrogel which is on the verge of being commercially manufactured in India. Due to its cooling effect, this dressing is popular among burn specialists.

Silverlon: It is composed of knitted fabrics that are flexible, minimally adhering and antimicrobial. Composed of pure nylon-based fibres, it is uniformly and circumferentially covered with a thin coat of pure metallic silver. The circumferential plating of the fibre results in a three-dimensional contact with the wound fluids.

Skin grafts: Third degree burns needs to be excised within few days and skin grafted.The basis of surgery in burns is covering the wound with the patient's own skin. If done early, burnt skin need to be removed surgically. If adequate skin is not available, sheets of skin are cultured in a lab from a piece of patients' skin (keratinocyte culture). This is not available in India yet.

In burns wound management, the split thickness skin graft is more commonly used than full thickness graft. "Split skin grafting procedure has been done from time immortal and remains the same even today. Flap reconstructions have been added to this and microsurgical free flap for limited areas of third degree burns has become popular today," says Dr K Mathangi Ramakrishnan, Director, Intensive Paediatric Burns Care Unit and Chief of Plastic Surgery, Kanchi Kamakoti Childs Trust Hospital, Chennai.

"I prefer split thickness graft because it is easy to harvest, and the donor area heals without much scarring" - Dr PK Bilwani Director of Gujarat Burns Hospital & Research Centre, Ahmedabad

Split skin grafting continues to remain the popular method to heal burn wounds. "I prefer split thickness graft because it is easy to harvest, the donor area heals without much scarring, and the procedure is completed in the shortest possible time," says Dr PK Bilwani, Director of Gujarat Burns Hospital & Research Centre.

According to him, a change in the management of third degree burns has happened in the last three decades. Earlier, burns were treated with dressings alone and the skin was then grafted. This caused infection. Now, most surgeons excise the burns early and encourage skin grafting, thereby reducing the hospital stay and infection. The introduction of better skin grafting knives and electronic dermatomes has made the procedure simple. Better mesh graft dermatomes are also available. Some manufacturers have now started manufacturing skin grafting knife and mesh graft dermatomes in India.

"Banana leaf dressing can be finished quickly and the patient need not suffer pain. We are yet to find any drawbacks of this technique" - Dr Madhuri Gore Professor and Head of Department of Surgery, LTMG Hospital, Mumbai

Human allografts: Skin from living related and unrelated and cadaveric sources are used across centres as a useful skin substitute. The disadvantage is that the patient has to undergo a painful operation under anaesthesia while obtaining allograft from living donors. Also, the skin that can be harvested from a living donor is limited. Cadaver allografts help avoid the above disadvantages.

According to experts, cadaver skin is the best option considering the other extravagantly costly skin grafts available in the market. In fact, in foreign countries, a wound coverage is done with cryopreserved cadaveric homografts, thanks to the well-developed skin banks there. LTMG Hospital has set up the first ever cadaver skin bank in India. Says Dr Gore, "More number of donors are required. Lack of awareness has restricted availability of cadaver allografts in India." According to Dr Marella Hanumadass, Former Chairman, Division of Burn Surgery and Former Director, Sumner Koch Burn Center, USA, “Even though many engineered materials are available as substitutes in the USA, and many burn surgeons are using them, the ultimate gold standard is the human cadaver skin. There is no substitute.”

According to Dr Anand Kale, In-charge of Burn Unit, Bhopal Charitable Hospital, Bhopal, the live related-homografts (from near relatives) should be promoted in India. "Like a kidney donation, relatives can also donate skin. I practise it in my unit and it has proved beneficial," he says.

Xenografts: One can harvest skin from other animals, like pigs and cows. Although a temporary cover, it can help during a critical stage. Porcine xenograft is commercially available internatio-nally, but not yet in India. "Pig skin graft is safe (HIV and hepatites B safe), affordable and convenient. It is in use for the last 30 years. I personally use fresh porcine grafts which have always given good results," says Dr Ranjit Mirje, Kolhapur Plastic Surgery Clinic, Kolhapur. According to Dr Mirje's study, the reported results of porcine heterografts are varied and even
contradictory. This is because the pig grafts used in different centres are in different forms. A total of 42 cases treated between January 1990 and December 1994 showed that pig grafts is good for shorter duration and causes no delayed hypersensitivity.

Cultured Epidermal Autograft: A new method, cultured epidermal autograft, where a small piece of skin from the patient can be removed and cultured in the laboratory has been developed. Three weeks later, this skin enlarges to cover the whole body. This is useful for extensively burnt patients who do not have enough donor area left for skin grafting. Yet to be made available in India, a new wound cover has been developed in the western countries, called Integra. It contains a deep layer of the skin, in addition to the superficial silicon membrane.

A Look at the Future

Today, the focus of research in burns is on tissue engineering to evolve with best possible permanent skin substitute, stem cells from human umbilical cord blood, better topical antibacterial agents and better temporary skin substitutes.

Dr Burd A, Chief of Plastic Surgery, Department of Surgery, The Chinese University of Hong Cong, Prince of Wales Hospital, Hong Kong, while speaking at the National Academy of Burns (NABI) conference held in Mumbai, said, "When the term tissue engineering was officially coined at a National Science Foundation Workshop in the USA in 1998, it was understood to mean the application of principles and methods of engineering and life sciences toward the fundamental understanding of structure, function relationships in normal and pathological mammalian tissues and the development of biological substitutes to restore, maintain or improve tissue function." This concept has led to some serious misconception that the skin is a tissue like cartilage, and would be relatively simple to address as a tissue engineering challenge.

Tissue engineering skin products are being described as skin substitutes to aid healing and repair by temporary skin replacements but seldom help in regeneration. According to Dr Burd, the potential for using Human Umbilical Cord Blood (HUCB) and human umbilical cord derived stem cells, particularly in the context of emerging economy like India, is tremendous. Humans produce over 10 million litres of HUCB, which is a free and natural resource. Moreover, the potential of systemic infusion of ABO compatible HUCB and/or the topical application of such blood to burns and other wounds has unlocked the possibility of providing cheap and accessible burns and wound care to the world's neediest patients.

However, it now depends on dedication and the willingness of the experts to take burns care management to an advanced level in India too.

sonal.shukla@expressindia.com