RECENT ADJUNCTS TO WOUND HEALING

Dr.E.Kaushik Kumar

Department of General Surgery

Stanley Medical College Hospital,Chennai

•  என்பி� லதனை�வெயி�ல்போபி�லக் கா�யுபோ� அன்பி� லதனை�அறம்.

• Virtue will burn up the soul which is without love, even as the sun burns up the creature which is without bone

Introduction

• Tried and True treatments

• Updated and improved variations of previous treatments

• Entirely new fields of study

Advances in Wound Healing

• Silver

• Negative Pressure Therapy

• Advanced Dressings

• Skin Substitutes

• Growth Factors and Biologic wound products

• Hyperbaric Oxygen Therapy

Silver

• Time honored in wound care-69 BC

• New forms of delivery aim to increase the efficacy while minimizing side effects

• Favourable broad spectrum coverage- Antibiotic resistant organisms

• Highly reactive charged silver ion (Ag+) negatively charged particles such as proteins, DNA, RNA, and chloride ions.

• Bactericidal material-kills on contact• Inhibiting the respiratory chain at the

cytochrome level

• Interfering with electron transport

• Denaturing nucleic acids

• Inhibiting DNA replication

• Altering cell membrane permeability

• ↓ MMP activity because of its inhibitory effect on zinc activity

• Inhibitory effect on release of proinflammatory cytokines and tumour necrosis factor–alpha

Ideal Delivery System

• Adequate concentration of silver

• Long enough residual activity.

• Gauze

• Hydrocolloids,

• Alginates

• Foams

• Creams

• Gels but each of them differ in the way in which silver ions are released

Silver Sulfadiazine and Nitrate

• Higher rate of resistance

• Impaired reepithelialization

• Pseudoeschar formation

• Bone marrow toxicity from the propylene glycol

• High enough initial concentration (3176 mg/L and 3025 mg/L, resp. but have little to no residual activity

Nanocrystalline Silver Dressings

Nanocrystalline Silver dressings

• Two layers of high-density polyethylene net sandwiching a layer of rayon/polyester gauze

• Outer layer is coated with a nanocrystalline (<20 nm), noncharged form of silver (Ag0), and the inner layer helps maintain a moist environment for wound healing

• Noncharged silver is less reactive with negatively charged particles in the wound, it is deactivated much more slowly and provides an initial large bolus of silver followed by a sustained release into the wound.

• Maintain adequate concentrations (at least 70 mg/L) with good residual activity, keeping levels elevated over longer periods of time.

Spectrum

• Yeast

• Fungi

• Mold

• Methicillin-resistant Staph aureus (MRSA)

• vancomycin-resistant enterococci (VRE)

Resistance

• E. coli

• Enterobacter cloacae

• Klebsiella pneumoniae

• Acinetobacter baumannii

• Salmonella typhimurium

• Pseudomonas stutzeri 

Effectiveness

Sulfa

diaz

ine

Silv

er N

itrat

e

Nan

orys

talli

ne0

2

4

6

Time to Reduce bacterial colony

• Left in place for up to 5-7 days

• Avoids trauma to the new epithelial growth.

Caution

• Negative impact on fibroblasts

• Inhibition of keratinocyte growth

• Delay in reepithelialization

Topical negative pressure therapy (TNP)

• Vacuum assisted closure (VAC)

• Sub-atmospheric pressure dressing (SPD)

• Vacuum sealing technique (VST)

• Sealed surface wound suction (SSS)

• Negative pressure therapy (NPT)

• Bridge to reconstruction

• Promotes active wound healing at the cellular level through negative pressure.

• Wound is compartmentalised by an airtight seal around it and through a dressing interface

• Compartment is connected to an external suction apparatus

• Continuous or intermittent.

• Pressures used range between -100 to -125 mmHg.

• Macro strain (physical response) and micro strain (biological response) and subsequently removes exudates by an electromechanical pump

• Dressings are usually changed every 48-72h

• Increase dermal perfusion

• Stimulate granulation tissue

• Decrease interstitial fluid

• Control wound exudate

• Decrease bacterial load

Clinical indications

• Ulcers

• Burns

• Wound dehiscences

• Fistulae

• Adjunct in tissue salvage in reconstructive surgery, burns and trauma• preserving the vitality of tissues and flaps of

borderline viability

• Trauma patients undergoing damage-control laparotomy and abdominal compartment syndrome patients

• Traumatic orthopedic injuries

Wound Healing Barrier V.A.C. Therapy Mechanism

Inadequate protection against infection

Provides protected wound healing environment

Excess exudate Removes exudate

Excess edema (interstitial fluid)

Reduces edema (interstitial fluid)

Absence of moisture Provides a moist wound environment

Lack of adequate perfusion Promotes perfusion

Lack of granulation tissue formation

Removes barriers to cell migration and proliferation

Excess bacterial burden Removes infectious materials

Disadvantages

• Pain

• Fluid loss especially in large wounds

• Risk of bleeding

Recent dressings

• Hydrocolloids

• Alginates

• Foams

• Hydrogels

• Hydrofibers

Hydrocolloids

Hydrocolloids

• Gelatin, pectin and or carboxymethylcellulose

• Serve as occlusive or semi-occlusive dressings

• Impermeable to water, bacteria and other contaminants but permeable to water vapour

• Absorb wound exudates to form a hydrophilic gel.

• Most important advantage is their long wear time, which decreases the cost, inconvenience and local trauma associated with dressing changes.

• Promote fibrinolysis

• Angiogenesis

• Wound healing

• Without causing softening and breaking down of tissue.

• Not indicated • Arterial/neuropathic ulcers

• Infected or heavily exuding wounds because of risk of periwound maceration.

• Malodorous exudates, which can be mistaken for infection

Foam

Foam

• Highly absorbent polyurethane dressings, available as pads, sheets and cavity dressings

• Moist environment and provide thermal insulation to the wound

• Nonadherent, easy to apply and remove and are meant for highly exuding wounds

• Layered in combination with other materials with overlying compression bandages.

• Fluid absorption capacity varies with foam thickness

• Cushioning effect but they are not a substitute for pressure relieving devices

• Comparable to hydrocolloids according to some studies

• Foams may produce excessive malodorous drainage necessitating frequent dressing change

Alginates

Alginates

• Soft, non-woven fibres, which contain calcium and sodium salts of alginic acid.

• Ion exchange reaction occurs between calcium in the alginate and sodium in the wound fluid producing soluble calcium–sodium alginate -- a gelatinous mass maintains moist environment and facilitates autolytic debridement

• Fillers for undermined and tunnelled wounds

• Highly absorbent-absorbs 20 times its weight

• Periwound maceration-Lateral wicking

• May leave fibrous debris in the wound-biodegraded (reports of them causing long-term foreign body type reactions)

• Inhibitory to keratinocytes

• Accelerate wound healing when compared to control dressing

Collagen

• Important constituent of connective tissue

• Type I is mostly seen in healing tissues

• Chronic wounds -laying down a matrix which favours deposition of new tissue and attracts cells necessary for healing

• Chemotactic for fibroblasts and macrophages and also provide a temporary scaffold to allow in growth of tissue

• Human , porcine or bovine origin and are available as particle or sheet form

• Absorb wound exudates to form a soft biodegradable gel over the wound surface, which maintains wound moisture

Hydrogels

Hydrogel

• Polymers, glycerine or water-based gels, impregnated gauzes or sheet dressings

• High water content does not allow them to absorb large amount of exudates heavy exuding wounds.

• Gentle yet effective debriding and desloughing action• rehydrating necrotic tissue

• removing without damaging healthy tissue

• Rehydrate the wound bed

• Reduce pain because of their cooling effect

• Non-adhesive

• Fill dead spaces

• Easy to apply and remove

• Best suited for dry wounds or those with minimal exudates.

• Require a secondary dressing.

Hydrofibers

Hydrofibers

• Sterile sodium carboxymethyl cellulose fibres

• Conform to the wound surface, highly absorbent and interact with wound exudates to form a gel.

• Maintain a moist environment and allow autolytic debridement

Uses

• Pressure ulcers

• Lower limb ulcers

• Surgical wounds

Skin Substitutes

• Biosynthetic skin substitutes and cultured autologous engineered skin, are available to provide temporary or permanent coverage, with the advantages of availability in large quantities and negligible risk of infection or immunologic issues.

Biobrane

• Temporary dressing composed of knitted nylon mesh bonded to a thin silicone membrane and coated with porcine polypeptides

• Clean superficial and middermal

depth burns or as coverage for

donor sites in split-thickness

skin grafting

Transcyte

•Biosynthetic dressing of a semi-permeable silicone membrane on a nylon mesh coated with porcine collagen and newborn human fibroblast cells

•Superficial burns that do not require skin grafting, or as a temporary cover for excised burns prior to grafting

Dermagraft

• Dermagraft contains neonatal fibroblasts on a bioabsorbable polyglactin mesh

• Dermal collagen, glycosaminoglycans, growth factors, and fibronectin to support wound healing

• Temporary or permanent cover used for excised burn wounds as well as venous ulcers and pressure ulcers

Apligraf

• Apligraf is composed of an epidermal layer of allogeneic neonatal keratinocytes and fibroblasts from neonatal foreskin on bilayered type I bovine collagen

• adjunct covering to autograft, providing accelerated healing times

Integra

• Semibiologic bilayered dressing

composed of a matrix of type I bovine collagen, chondroitin-6-sulfate, a glycosaminoglycan from shark cartilage, under a temporary silicone epidermal sheet

• Pore size (70–200 μm) is designed to allow migration of the patient’s own endothelial cells and fibroblasts.

• Silicone sheet removed & a thin autograft is grafted onto the neodermis to complete the wound coverage.

• Indicated for excised deep partial- and full-thickness burn wounds

• Complex traumatic soft tissue reconstruction over exposed tendons, joints, and bone, as well as wounds from vascular and pressure ulcers

Growth Factors and Biologic Wound Products

• Biologic wound products aims to accelerate healing by augmenting or modulating inflammatory mediators

• Prostaglandin E1

• Cytokines-Chemokines , lymphokines, monokines, interleukins, colony-stimulating factors, and interferons.

• Becaplermin(Regranex)rhPDGF & EGF-FDA-approved products in the growth factor family

Top Closure System

• An innovative new technology created for skin stretching and secure wound closure

• Post traumatic

• Surgical

• Acute and chronic skin wounds, which do not respond to conventional wound care.

• Avoiding the need for tissue expanders

• Substitute for tension sutures 

JETFORCE

•Comprehensive innovation for cleansing andDebridement

• Compressed oxygen combined with a minimalamount of saline solution

•fast and virtually painless debridement compared toother mechanical debridement methods.

Other methods

• Stem cell therapy

• Biodebridement- Maggots

• Topical Insulin

• Topical Anti0oxidant

• Hyperbaric oxygen(HBO)

References

• Advances in Wound Healing: A Review of Current Wound Healing Products Patrick Murphy  and Gregory R. D. Evans,Aesthetic and Plastic Surgery Institute, University of California Irvine Medical Center, 200 S. Manchester Avenue, Suite 650, Orange, CA 92868, USA

• M. Trop, M. Novak, S. Rodl, B. Hellbom, W. Kroell, and W. Goessler, “Silver-coated dressing acticoat caused raised liver enzymes and argyria-like symptoms in burn patient,” Journal of Trauma, vol. 60, no. 3, pp. 648–652, 2006. 

• E. K. Mooney, C. Lippitt, and J. Friedman, “Silver dressings [safety and efficacy reports],” Plastic and Reconstructive Surgery, vol. 117, no. 2, pp. 666–669, 2006. 

• W. Stanford, B. W. Rappole, and C. L. Fox, “Clinical experience with silver sulfadiazine, a new topical agent for control of pseudomonas infections in burns,” Journal of Trauma, vol. 9, no. 5, pp. 377–388, 1969.

• R. Warriner and R. Burrell, “Infection and the chronic wound: a focus on silver,” Advances in skin &amp; wound care., vol. 18, pp. 2–12, 2005. 

• B. S. Atiyeh, M. Costagliola, S. N. Hayek, and S. A. Dibo, “Effect of silver on burn wound infection control and healing: review of the literature,” Burns, vol. 33, no. 2, pp. 139–148, 2007. 

• R. Khundkar, C. Malic, and T. Burge, “Use of Acticoat dressings in burns: what is the evidence?” Burns, vol. 36, no. 6, pp. 751–758, 2010.

• Winter GD. Formation of scab and rate of epithelialization of superficial wounds in the skin of the young domestic pig. Nature. 1962;193:293–4. 

• Cho CY, Lo JS. Excision and repair: Dressing the part. DermatolClin. 1998;16:25–47. [PubMed]

• Moon CH, Crabtree TG. New wound dressing techniques to accelerate healing. Curr Treat Options Infect Dis. 2003;5:251–60.

• Varghese MC, Balin AK, Carter DM, Caldwell D. Local environment of chronic wounds under synthetic dressings. Arch Dermatol. 1986;122:52–7.

•  Alvarez OM, Mertz PM, Eaglstein WH. The effect of occlusive dressings on collagen synthesis and re-epithelialization in superficial wounds. J Surg Res. 1983;35:142–8. 

• Rubio PA. Use of semiocclusive, transparent film dressings for surgical wound protection: An experience in 3637 cases. Int Surg. 1991;76:253–4. 

•  Jones AM, San Miguel L. Are modern wound dressings a clinical and cost effective alternative to the use of gauze? J Wound Care. 2006;15:65–9.