INVITED ARTICLE

Dressings for chronic woundsJennifer Gloeckner Powers*, Laurel M. Morton† &Tania J. Phillips†*Division of Dermatology, Vanderbilt University, Nashville, Tennessee and†Department of Dermatology, Boston University, Boston, Massachusetts

ABSTRACT: Covering wounds, acute and chronic, is one of the most fundamental activities of anymedical practitioner. Although wound dressings primarily serve to contain the “good” and keep out the“bad,” research has characterized more specifically the sophisticated interaction between the humanwound bed and its dressing counterpart. Wound dressings for today’s chronic wounds come in manyflavors, ranging from the classic types of moisture-retentive dressings to silver-coated varieties tobiologic dressings serving as skin substitutes. Moisture-retentive dressing types include foams, films,hydrogels, hydrocolloids, and alginates. Appropriate use of these dressings can help to keep the woundbed moist, which allows for epithelial migration, angiogenesis, retention of growth factors, autolyticdebridement, and maintenance of electrical gradients.

KEYWORDS: chronic wounds, moisture-retentive dressings, wound dressings

Introduction

Before having ever treated a patient, most of us havebeen inculcated with the mantra “If it’s dry, wet it; ifit’s wet, make it dry.” Yet, as soon we begin treatingin the field, we find that the variations on this themerequire a more in-depth knowledge of wound dress-ing types, how to apply them to clinical scenarios,and how to make use of advanced wound dressingsthat draw on the latest scientific advancements. Inthis article, we will present the historical context forwound dressings, explain the five basic types ofmoisture-retentive dressing types, present infor-mation about the latest advanced dressing types,and identify dressing strategies for specific chronicwound types. In contrast to acute wounds, chronicwounds, as addressed in this article, are persistentwounds, which remain in an inflammatory state ofdisordered healing (1).

Dressings through the ages

A dressing is defined as a wound covering. Throughthe ages, there have been wound dressings of allshapes, sizes, colors, and origins. In 2100 BC, the“three healing gestures” of the Sumerian societywere as follows: washing a wound with beer andhot water, making plasters (mixture of herbs, oint-ments, and oils), and bandaging the wound.Ancient Egyptians documented the application ofa paste of honey, grease, and lint to open woundsback in 1400 BC. During the Middle Ages, woundswere left to “rot a bit” in order to develop “laudablepus,” which meant the patient would actuallysurvive (2). In the battlefield during the 19thcentury, gunshot wounds were often treated with“boiling oil,” thought to cure the patient of thealleged poison contained in gunpowder. When theboiling oil supply dwindled, an astute clinicianAmbrose Paré used an ancient Roman remedy con-taining turpentine, egg yolks, and oil of roses totreat firearm wounds, providing antisepsis, painrelief, and wound coverage (3).

By the mid- to late 19th century, a preponder-ance of gangrenous wounds led to the application

Address correspondence and reprint requests to: JenniferGloeckner Powers, MD, Assistant Professor of Medicine,Division of Dermatology, Vanderbilt University, 719Thompson Lane, Suite 26300, Nashville, TN 37204, oremail: jennifer.powers@vanderbilt.edu.

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DERMATOLOGIC THERAPYISSN 1396-0296

of the principles of bacteriology and germ theory,pioneered by Louis Pasteur and Robert Koch (4).When Joseph Lister began employing techniquessuch as sterilization of surgical equipment,wearing gloves, and washing hands, surgicalwound infections began to decrease (5). At thistime, it was believed that wounds healed best whenkept dry. In 1874, Dr. Thomas Curtis reported of“Cotton-Wool Dressings for Wounds”: “AlphonseGuerin, Surgeon of the Paris Hospitals . . . insti-tuted a new dressing for wounds, consisting,mainly, in the use of cotton wool, which is appliedin very large quantities around the wounded limb. . . and left undisturbed for several weeks.” Theauthor went on to report that though this dressingmight appear to create “irremediable mischief,” itactually prevents air from reaching the wound,which would thereby inhibit microbial growth (6).The treatment of wounds with various iterations ofdry gauze continued through the early part of the20th century (2).

The power of occlusion

In the mid-20th century, some exciting experi-ments began to unveil the importance of maintain-ing a moist healing environment. In 1958, Odlandobserved that a blister healed faster if left unbroken(7). In 1962, Winter discovered that wounds in pigsre-epithelialized 30% better under occlusion (8).One year later, Hinman and Maibach confirmedthat in humans, re-epithelialization is faster ifwounds are occluded (9). These experiments pavedthe way for the modern classes of moisture-retentive dressings. Moisture-retentive dressingsretain moisture or have a low enough moisturevapor transmission rate (MVTR) to permit optimalhealing rates for a given wound. Moisture-retentivedressings maintaining MVTRs of less than 35 g/m2/hour in partial thickness wounds permit moistwound healing (10).

At a very basic level, a moist healing environ-ment is tangibly beneficial. Keratinocyte migrationoccurring either in a train-like fashion or “leapfrogging” method will be promoted by the pres-ence of a good provisional matrix formed by fibrin,fibronectin, and type V collagen. Such migrationcannot happen within an eschar but is facilitated ina moisture-rich environment. Since keratinocytesare migrating at the surface of a wound bed, theyare in close contact with any wound dressing (11).In addition, the direction of keratinocyte migrationis modulated by electric field gradients throughPI3K (phosphoinositol 3-kinase) and PTEN (phos-phatase and tensin homolog) signaling; a dry

wound will be less able to maintain such electricfield gradients (12,13).

At the clinical trial level, the case for moisture-retentive dressings becomes more complex.Although there is clear evidence that moist woundhealing promotes rapid re-epithelialization inacute wounds (14), the data for chronic wounds isless robust. A systematic review of dressings forvarious types of acute and chronic wounds lookingat 99 studies demonstrated that evidence for clini-cal benefit of modern dressings over sterile gauze islacking except for hydrocolloid dressings (15).However, a study on occluded versus non-occluded venous ulcers showed healing to be morerapid in the occlusive dressing group even thoughhealing at 12 weeks was equivalent (16). In addi-tion, when looking at the overall cost for chronicleg ulcer patients using compression but random-ized to hydrocolloid dressings versus sterile gauze,a study by Ohlson et al. showed a significantlylower cost per percent change in wound size for thehydrocolloid group when all factors including costsfor materials, nursing time, and kilometers drivenwere considered (17). For many chronic woundpatients, moisture-retentive dressings offer theadvantage of pain relief, painless wound debride-ment, improved containment of messy exudates,and, therefore, improved quality of life (18).

Discussion

Choosing a dressing can be one of the most chal-lenging aspects of wound care, in part, becausethere is no single dressing that is perfect for allwounds and because rigorous clinical trial data isoften limited. Moreover, each care facility typicallycarries different brands of dressings within each ofthe standard categories below. However, oncepractitioners familiarize themselves with the basicdressing categories and begin to learn the practicallimitations of each type, the decisions about dress-ing selection become very rewarding as patientcomfort improves and drainage is better con-trolled. Dressings should rarely be changed morefrequently than daily (and often less frequently) soas not to disturb the wound healing environment,which can also be very cost-effective.

Common dressings

Before technological developments paved the wayfor a variety of moisture-retentive dressings, dress-ings with natural fenestrations were popular, suchas gauze and Vaseline gauze. Gauze bandages,comprised of cotton, are typically available in 2 ¥ 2

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inch and 4 ¥ 4 inch square dressings or rolled gauze(Kerlix™, Covidien, Mansfield, MA, USA). Gauze iseasy to use, often readily accessible in most clinicsand surgical centers, and is inexpensive. However,once it becomes saturated with exudate, gauzeloses its efficacy (19). Gauze may be made moremoisture retentive through impregnation withthick hydrophobic coatings such as petroleumjelly, wax, or other ointments; examples includeVaseline gauze (The Kendall Co., Mansfield, MA,USA), Xeroform (The Kendall Co.), and Telfa (TheKendall Co.). When more hydrophilic coatings areused on the gauze, they are able to facilitate drain-age of fluids more easily but are less moistureretentive; examples include Xeroflo (The KendallCo.), Mepitel (Molnlycke Health Care, Gotenberg,Sweden), Adaptic (Johnson & Johnson Medical,Arlington, TX, USA), and N-Terface (Winfield Labo-ratories, Dallas, TX, USA).

Moisture-retentive dressings

Modern dressings of the moisture-retentive varietyserve several basic functions. As outlined previ-ously, the moist wound environment can increaseepidermal cell movement and help to maintainthe electrical gradient for directional migra-tion. In addition, the moist wound environmentmore effectively contains growth factors, increasesangiogenesis, and decreases fibrosis. Dressingsalso serve as a barrier from trauma and infection,promote patient functionality with activities ofdaily living, and are also associated with less scarformation (9). From the patient perspective,this translates to reduced pain, less frequent dress-ing changes, and less scar tissue formation.The ideal dressing should not cause irritation orallergy.

The five classic types of moisture-retentivedressings are films, foams, hydrocolloids, alginates,and hydrogels (Table 1).

Films. Films are thin, elastic transparent sheet ofpolyurethane, which are gas permeable and oftenhave acrylic adhesive on one side for adherence.These sheets are effective at keeping bacteria andfluids out but allowing atmospheric gases andwater to pass through. Films have the advantageof permitting easy visualization without disturb-ing the wound. Because they adhere to thewound, they are easy to apply and do not requirea second dressing. However, their lack of absorp-tive capacity leads to fluid collections in anywound with significant exudate (19). In addition,the skin around the wound must be intact for a

good seal with the adhesive backing. The adhesivebacking may cause irritation in dermatiticskin.

Films are excellent for superficial lacerationsand wounds that are mildly exudative such as thinburn wounds, venous catheter sites, and donorsites for split thickness skin grafts (20). They mayalso serve as secondary dressings over alginates,foams, and hydrogels. Because they may exertshearing forces on skin, they should be not usedin those with thin or fragile skin, such as theelderly. Examples of available films include Tega-derm™ (3M Healthcare, St. Paul, MN, USA),Polyskin™II (Kendall Healthcare), Bioclusive®(Johnson & Johnson Medical), Blisterfilm™ (TheKendall Co.), Omniderm® (Omikron ScientificLtd., Renovot, Israel), Proclude® (ConvaTec, Prin-ceton, NJ, USA), Mefilm® (Molnlycke HealthCare), Carrafilm™ (Carrington Lab, Irving, TX,USA), and Transeal® (DeRoyal, Powell, TN,USA).

Foams. Foams are semi-occlusive, bilaminatedressings comprised of hydrophobic polyurethanefoam sheets, which have hydrophilic surfacecoating materials to prevent leakage and bacterialcontamination. They are typically nonadhesiveand thicker than other dressings, but thesefeatures may vary. If nonadherent, they require asecondary dressing to hold in place. Because oftheir bulk, foams can be used to pack cavitiesand to provide padding over bony prominences(21). Disadvantages for foams are that theymay fail to stay in place if patients are moremobile; in addition, they may dehydrate drywounds and are completely opaque so no visual-ization is possible through the dressing. Adhesivefoams can cause contact dermatitis in somepatients.

Foams are excellent to use over mildly to mod-erately exudative wounds, particularly over bonyareas such as the ankle or sacrum. If used over theankle, a multilayer compression wrap with Kerlix™(Covidien), ACE™ (3M), and Coban™ (3M) mayhelp to hold in place. When removing a dry foamdressing, one may have to soak the dressing withsaline solution first (21). Some commercially avail-able foam dressings are Polymem® (Ferris Corp.,Burr Ridge, IL, USA), Allevyn® (Smith & NephewUnited, Largo, FL, USA), Biopatch® (Johnson &Johnson Medical), Curafoam™ (The Kendall Co.),Flexzan® (Dow B. Hickam, Inc., Sugarland, TX,USA), Hydrasorb® (Tyco Health Care/The KendallCo.), Lyofoam® (ConvaTec), and Mepilex® (Moln-lycke Health Care).

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Table 1. Five classic types of moisture-retentive dressings

Dressing type Advantages Disadvantages Examples

Films (elasticsheets ofpolyurethane)

AdherentTransparentForms a bacterialbarrier but is gaspermeable

Fluid collectionDifficult to remove,which may disturbnew keratinocytes

Tegaderm™ (3M Healthcare)Polyskin™II (Kendall Healthcare)Bioclusive® (Johnson & JohnsonMedical)Blisterfilm™ (The Kendall Co.)Omniderm® (Omikron Scientific Ltd.)Proclude® (ConvaTec)Mefilm® (Molnlycke Health Care)Carrafilm™ (Carrington Lab)Transeal® (DeRoyal)

Foams(bilaminatesheetscontainingpolyurethaneand oftensilicone)

AbsorbentMoist healingenvironmentConforms tobody contours

May requiresecondary dressingto placeCan adhere towound if exudatedries

Polymem® (Ferris Corp.)Allevyn® (Smith & Nephew United)Biopatch® (Johnson & JohnsonMedical)Curafoam™ (The Kendall Co.)Flexzan® (Dow B. Hickam, Inc.)Hydrasorb® (Tyco/Kendall Co.)Lyofoam® (ConvaTec)Mepilex® (Molnlycke Health Care)

Hydrogels (96%water,cross-linkedhydrophilicpolymer)

ComfortableAbsorbentPromotes autolyticdebridement

NonadherentMaceration of skinaround wound

Vigilon® (CR Bard)Nu-gel® (Johnson & JohnsonMedical)Tegagel™ (3M)FlexiGel™ (Smith & Nephew)Curagel™ (The Kendall Co.)Clearsite® (Conmed Corp.)Curafil™ (The Kendall Co.)Curasol® (The Kendall Co.)Carrasyn® (Carrington Laboratories)Elasto-Gel™ (SW Technologies)Hypergel® (Scott Health Care)Normgel® (SCA Hygiene Products)2nd Skin® (Spenco Medical, Ltd.)Transigel™ (Smith & Nephew)

Hydrocolloids(carboxymethylcellulosein adhesivebase)

Improved healingEasy to useWaterproofPromotegranulation tissue

Unpleasant odorYellow brown,gel-like fluiddrainageMay overstimulategranulationDifficulty to use incavities

Duoderm® (ConvaTec)NuDerm® (Johnson & JohnsonMedical)Comfeel® (Coloplast Sween, Inc.)Hydrocol® (Dow Hickman)Cutinova® (Smith & Nephew)Replicare® (Smith & Nephew United)Tegasorb™ (3M)

Alginates (naturalpolysaccharidesfrom kelp andalgae)

AbsorbentUseful in sinusesHemostaticproperties

Not useful for drywoundsMay require frequentdressing change iflots of exudate

Algiderm (Bard)Algisite™ (Smith & Nephew)

Algisorb™ (Calgon-Vestal)Algosteril® (Johnson & JohnsonMedical)Kaltostat® (ConvaTec)Curasorb™ (The Kendall Co.)Sorbsan® (Dow B. Hickam)Melgisorb® (Molnlycke Health Care)SeaSorb® (Coloplast)Kalginate® (DeRoyal).

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Hydrocolloids. Hydrocolloids are typically gels orfoams impregnated into self-adhesive polyure-thane films resulting in dressing sheets with theability to conform to different surface shapes. Theyare often comprised of materials such as gelatin,pectin, and carboxymethylcellulose and have anopaque, shiny, and smooth appearance. Because oftheir colloidal nature, these dressings trap any exu-dates on the underside, turning them into gels,which promotes autolytic debridement and detersleakage. Hydrocolloids are impermeable to water,oxygen, and carbon dioxide, conferring a “water-proof” status to these popular dressings. Disadvan-tages of hydrocolloids include the presence of amalodorous gel on the dressing underside, the riskof overgranulation, the potential for macerationaround the edges of the wound (22), and the poten-tial for contact dermatitis since these dressingstend to be left in place for longer than a day (23).

Some randomized controlled trials with hydro-colloids have not proven their benefit, particularlyin pressure ulcers and leg ulcers (15). However, asystematic review demonstrated that hydrocolloiddressings benefit chronic wounds, which is consis-tent with our clinical experience (15). According tothree meta-analyses, treatment with hydrocolloiddressings compared to sterile gauze showed statis-tically significant improvement (odds ratio, 2.57(95% confidence interval, 1.58–4.18) (24); oddsratio 2.45 (95% confidence interval, 1.18–5.12), p =0.02 (25); number needed to treat, 7 (95% confi-dence interval, 4–16) (26). Hydrocolloids are excel-lent for abrasions, postoperative wounds, smallerand more superficial pressure ulcers, venousulcers, burns wounds, and donor sites. Especially,if leg wounds are small and not excessively exuda-tive, the waterproof dressing gives patients the cov-erage they want with the ease of carrying outbathing and other activities freely.

When applying hydrocolloids, one has to be sureto extend the dressing perimeter beyond thewound so as to have good adherence in 360degrees. Using scissors to round the corners willprevent sharp corners from rolling up. Once thebacking has been removed, a warm hand held for 1minute will ensure good adherence and good con-formation to the underlying skin. One may applysmall amounts of wound products such as silverhydrogel under the hydrocolloid centrally (21). Thedressings may be left in place for 2–4 days provid-ing the wound is not infected. Examples of hydro-colloid dressings are Duoderm® (ConvaTec),NuDerm® (Johnson & Johnson Medical), Com-feel® (Coloplast Sween, Inc., Marietta, GA, USA),Hydrocol® (Dow Hickman), Cutinova® (Smith &

Nephew), Replicare® (Smith & Nephew United),and Tegasorb™ (3M).

Alginates. Alginates are comprised of cellulose-likepolysaccharides derived from algae or kelp, whichhave impressive absorptive abilities. Althoughthese dressings are insoluble in water, in thesodium-filled wound environment, they exchangealgae-based calcium ions and for sodium ions toform a sodium salt and hydrophilic gel that canabsorb significant amounts of fluid. They are typi-cally very dry-appearing sheets, but may alsoappear as ribbons, beads, or pads. Alginates alsouniquely exhibit hemostatic properties (27). Algi-nates can be difficult to remove if they are placedon dry wounds, which can lead to significant painat dressing changes unless saline is used tomoisten dressings before. In addition, they typi-cally require a secondary dressing to keep in place,especially if they are place inside deep sinuses.

Alginates are the most powerful absorptivedressings for heavily exudative, deep wounds. In arandomized clinical trial comparing use of alginatefor 4 weeks in chronic pressure ulcers followed by ahydrocolloid for 4 weeks with use of hydrocolloidfor all 8 weeks, the first group had more significantreduction in ulcer area (28). Other studies havealso validated alginates compared to control treat-ments, demonstrating improved mean surface areareduction per week (29). In addition to deep pres-sure ulcers, alginates are helpful for pyodermagangrenosum, deeper diabetic wounds (30), andheavily exudative venous leg ulcers (FIGS 1 and 2).If used on the leg, they are often used underneath amultilayer compression wrap. Many patients alsodo well with alginate dressings until the exudateis under control, at which point, they may beswitched to other dressing types. Examples ofalginates include the following: Algiderm (Bard,Murray Hill, NJ, USA), Algisite™ (Smith &Nephew), Algisorb™ (Calgon-Vestal, St. Louis, MO,USA), Algosteril® (Johnson & Johnson Medical),Kaltostat® (ConvaTec), Curasorb™ (The KendallCo.), Sorbsan® (Dow B. Hickam), Melgisorb®(Molnlycke Health Care), SeaSorb® (Coloplast,Holtedam, Denmark), and Kalginate® (DeRoyal).

Another variety similar to alginates is thehydrofiber dressing type, which is not derived fromalgae or kelp but which has a similar absorbentcapacity. These dressings are made with carboxym-ethyl cellulose fibers, which interact with thewound exudates to form a gel and which can bethree times as absorbent alginates (21). These arefound under the trade name Aquacel® (ConvaTec)and are used in similar clinical scenarios.

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Hydrogels. At the other end of the spectrum,hydrogels are firm sheets or liquid gel dressings,which are comprised of 96% water inside a cross-linked hydrophilic polymer network of polyvinylalcohol, polyacrylamides, polyethylene, and poly-vinyl pyrrolidone. These dressings are comfortable,absorbent dressings that bathe tissues in water-rich gels, promoting autolytic debridement.Because they are cool, they can be very sooth-ing to patients (31). They may macerate surround-ing skin if used in wounds that are alreadyhighly moist, and the gel forms are particularlynonadherent.

Hydrogels are ideal for very dry necroticwounds such as arterial ulcers, dry venous ulcers,which have been left to “dry out,” rheumatologiculcers, lesions secondary to coumadin necrosis,

calciphylaxis, and other wounds secondary tocoagulopathic processes (FIGS 3 and 4). Theyshould be cut to the size of the wound and theplaced down after removing the protective back. Ifin gel form known as “amorphous gel,” thehydrogel may simply be squeezed into the cavityand covered with a secondary dressing such as afilm, foam, or hydrocolloid. Trade names are Vig-ilon® (CR Bard), Nu-gel® (Johnson & JohnsonMedical), Tegagel™ (3M), FlexiGel™ (Smith &Nephew), Curagel™ (The Kendall Co.), Clearsite®(Conmed Corp., Utica, NY, USA), Curafil™ (TheKendall Co.), Curasol® (The Kendall Co.), Carra-syn® (Carrington Laboratories), Elasto-Gel™ (SWTechnologies, North Kansas City, MO, USA),Hypergel® (Scott Health Care, Philadelphia, PA,USA), Normgel® (SCA Hygiene Products, Eddy

FIG. 1. Chronic leg ulcer with significant exudate before use of alginate dressing.

FIG. 2. Chronic leg ulcer with improved clinical appearanceand reduced exudate after use of alginate dressing.

FIG. 3. Necrotic leg ulcer before use of hydrogel dressing.

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Stone, PA, USA), 2nd Skin® (Spenco Medical,Ltd., Waco, TX, USA), and Transigel™ (Smith &Nephew).

Hydroactive dressings are a spin-off of hydro-gels and combine the properties of hydrogels andfoams, selectively absorbing excess water butleaving growth factors and other proteins behind(32). The appropriate applications for this type arethought to be similar to hydrocolloids.

Silver dressings and antimicrobials

Although silver-containing dressings are a recentphenomenon, the Romans were using silver nitrateand other metal filings on wounds thousands ofyears ago (2). Silver has a long-standing history asan antimicrobial agent in everything from watervessels to silver sulfadiazine cream in burn care(33). Silver is thought to bind to bacterial cell mem-branes, interfere with bacterial electron transport,bind to bacterial DNA, and to bind up key buildingblocks in the cell (34). Clinical efficacy for suchdressings is yet being assessed.

A systematic review and meta-analysis of silvertreatments and silver-impregnated dressings forthe healing of leg wounds found strong evidencefor wound size reduction but no evidence for com-plete wound healing or improved healing rates(35). A Cochrane Review article looking at use ofsilver-containing dressings and topical agents fordiabetic foot ulcers demonstrated that such inter-ventions have not been appropriately validated,but more studies are needed (36). Moreover, thereis no good evidence to demonstrate that silver-containing dressings can prevent wound infection(37). Although individual trials may support theiruse, there is also some poor-quality evidence that

suggests they may even have more infections withsuch interventions. They are also not validated foruse in infected or contaminated wounds (38). Thefuture of silver-based products may entail a nano-particle formulation, which allows for improvedsilver ion release (39,40). At this time, silver-coateddressings may be used when other antimicrobialapproaches appear ineffective or cost is not amajor concern.

In general, one must be judicious with usingtopical antimicrobials that may be toxic to cells andmay interfere with repair processes. Cadexomeriodine (Iodosorb) is bacteriocidal to all gram-positive and gram-negative bacteria and promotesa moist wound environment through a 3D starchlattice formed into spherical microbeads withiodine trapped at 0.9% w/v. There is some evidenceto suggest that this preparation improves healingin chronic wounds and can be used as an adjunc-tive treatment (41,42).

Pinch grafting

Another bedside intervention available for chronicwounds such as venous leg ulcers is pinch grafting.In 1987, a trial of 53 venous leg ulcer patientsshowed that of patients receiving pinch grafts, 64%and 74% were healed by 6 weeks and 12 weeks,respectively, compared to 29% and 46% of patientsreceiving porcine dermis dressings (43). Pinchgrafting can be executed using the following steps:1. Inject local anesthesia (1% lidocaine) into donor

site (usually the anterior thigh).2. Use a bent #25 gauge needle to raise small

pinches of skin in the donor areas, which canthen be shaved off using a #15 blade.

3. Place the grafts on the dermal wound bed,2–3 mm apart.

4. Cover grafted area and donor site with transpar-ent dressing or petroleum gauze.

5. Apply gauze pad to grafted area covered with anelastic wrap.

6. Aspirate any exudate collecting under the graftwith a #18 gauge needle.

Adjuvant topical treatments

Comprised of collagen and oxidized regeneratedcellulose, Promogran® (Johnson& Johnson) is adressing that inactivates wound proteases,believed to be one of the major driving forces inchronic more than acute wounds (44). A random-ized controlled trial showed this dressing to be ofmarginal benefit in diabetic foot ulcers present forless than 6 months compared with moistened

FIG. 4. Improved leg ulcer after use of hydrogel dressing.

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gauze, though patient satisfaction with the dress-ing was higher (45). There has also been someclinical experience with this dressing for venous legand pressure ulcers but no clinical trials have vali-dated the efficacy in such situations (46,47).

Honey, particularly of the medical variety, hasbecame a hot topic in the wound care field, presentboth as a topical wound salve as well as the basisfor impregnated dressings.

A Cochrane Review of honey to treat a variety ofwounds in 19 trials showed that honey mayimprove healing times in mild to moderate super-ficial and partial thickness burns; however, there isno demonstrable benefit for other types of ulcers(48). There is little data showing that honey isharmful to wounds, but at this point, this remainsmore of an experimental therapeutic for chronicwounds for which data is building.

Santyl® ointment (collagenase from Clo-stridium histiolyticum; Healthpoint, Fort Worth,TX, USA) works at high pH to chemically debridedry ulcers when applied once daily. In animalstudies, the ointment has improved endothelialcell and keratinocyte migration (49). In a random-ized controlled trial, Santyl® appeared to be ofsimilar clinical efficacy to another chemicaldebriding agent (50). This can be a great alternativefor patients in whom surgical debridement is lessideal such as in diabetic foot ulcers where proce-dural interventions may put patients at increasedrisk for infection.

Another alternative for “biologic” debridementincludes Medical Maggots™ (Monarch Labs,Irvine, CA, USA), sterilized green bottle fly larvaeLucilia (Phaenicia) sericata. Basic and clinicalstudies suggest that the larvae are effective at liq-uefying necrotic tissue with their proteolyticenzymes while sparing healthy tissue and provid-ing antimicrobial and wound healing benefits (51–53). However, randomized controlled trials havenot found maggots to effectively reduce time tohealing compared to standardized dressings(54,55). The larvae have to be housed over thewound for 48 to 72 hours and then changed. Theirpopularity seems limited by the negative stigmamany patients and caretakers have for this inter-vention (56). For most wound practices, this alsoremains an experimental therapeutic option,which may be used in particular cases where otherstandard approaches have failed.

Growth factors

Growth factors can stimulate fibroblasts, promoteangiogenesis, and encourage cellular proliferation

of keratinocytes (57). Topical application of thesegrowth factors to human wounds has shown somebenefits in animal models and clinical trials (58).Initial studies performed in the diabetic mousemodel showed statistically significant wound-healing benefits with both platelet-derived growthfactor (PDGF) and fibroblast growth factor (FGF)(58). Clinical trials in humans showed efficacy withPDGF-derived gel, becaplermin, increasing theincidence of complete wound closure by 43%,which allowed for Food and Drug Association(FDA) approval of this gel for diabetic ulcersextending to subcutaneous tissue (59). Of note, ablack box warning has been placed on this productbecause of increased mortality secondary to malig-nancy in patients who use more than three tubes ofthis product, thus this is not advised in patientswith a history of malignancy (58). Although cost-benefit analyses have justified becaplermin’s cost,the clinical experience has not met the high expec-tations and insurance coverage can be difficult toobtain (60). FGF topical agents are not yet com-mercially available or FDA approved in the UnitedStates, but a clinical study in diabetic ulcersshowed significant decrease in surface area com-pared to placebo (61).

Conclusion

This is truly an exciting time to be treating chronicwounds of all varieties. Although our wound dress-ings will never be replacements for good diabeticcontrol or frequent positional changes in bed-bound patients or compression therapy for venousulcers, dressings are an essential component of thetreatment plan. Dressing options have evolved sig-nificantly from dry gauze and boiling oil. The datasupporting the use of moisture-retentive dressingsin chronic wounds is building, particularly forhydrocolloid dressings. Foam and alginate dress-ings remain important options for very exudativewounds, whereas hydrogel dressings can be helpfulwhen wounds are dry or necrotic. Films can permitgood visualization for superficial ulcers. Silver-coated dressings may help to decrease ulcer sizesbut have not yet been proven to be effective athealing ulcers. Biologic dressings, growth factors,and other advanced dressing options can be quitecostly but have also been FDA approved for specificuses because of their demonstrated efficacy.Learning how to apply these wound dressings invarious clinical scenarios is not only essential toachieving healing but also giving patients backtheir quality of life.

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