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Dressing: Indications
https://t.me/medicina_free
onApplications
GianmarcoTurriziani, FedericoLoTorto,
andDiegoRibuo
9
9.1 Introduction
Wound healing is an intricate and complex process with a multitude of interdependent components. While there are several classications that
have been proposed for wounds, wound healing
in its most rudimentary form consists of four
phases, which work in a cascade hemostasis,
inammation, proliferation, and remodeling [1].
Every wound undergoes these phases with
variable lengths depending on the wound type
and acuity. Faulty signals that lead to prolonged
time in the inammatory stage delay the wound
healing process and are one reason for the development of chronic wounds. A wound is classied
as chronic when wound healing is delayed by
more than 3 weeks or when the wound fails to
return to a functional state.
Various pathological conditions can lead to
the formation of an ulcer, such as vascular insufciency (arterial and/or venous), infections,
poorly controlled diabetes mellitus, and prolonged pressure injuries.
There are extrinsic and intrinsic factors that
can perpetuate the inammatory phase and consequently the chronicity of an ulcer. Extrinsic
factors include malnutrition, microbial infection,
hypoxic conditions, smoking, cancer, radiation,
G. Turriziani · F. LoTorto · D. Ribuffo (*)
Department of Plastic Reconstructive and Aesthetic
Surgery, Sapienza Università di Roma, Rome, Italy
e-mail: diego.ribuffo@uniroma1.it
and medications; among the intrinsic factors,
there are patient general status, age, immunodeciency, hereditary disorders of wound healing,
and other chronic diseases. Supercial or deep
wound infection should always be excluded [2].
There are general principles that allow to optimize the wound condition, ensuring adequate
blood ow, correct local hydration, and the reduction in bacterial load: treat the patient’s basic
pathologies, stop smoking, and the wound bed
debridement.
Goals for dressing management of chronic
wounds include maintaining a moist environment, preventing infections, and preventing skin
irritation and friction.
It is now widely accepted that moist wounds
heal faster than dry wounds. In a dry environment, eschar formation prevents the migration of
cells to the wound bed and, consequently, tissue
regeneration. The occlusion of the wound helps
to maintain this microenvironment; in addition,
an occlusive dressing leads to a state of local
hypoxia, associated with a greater production of
cytokines stimulating the extracellular matrix,
the stimulation of angiogenesis, and the reduction in pain by inhibiting the production of arachidonic acid metabolites by macrophages [3].
After identifying and characterizing a lesion
and correcting the modiable intrinsic and extrinsic variables, the wound bed must be adequately
prepared, removing the necrotic tissue and managing any infection, optimizing the wound mois-
© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023
M. Maruccia et al. (eds.), Pearls and Pitfalls in Skin Ulcer Management,
https://doi.org/10.1007/978-3-031-45453-0_9
89
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ture, and ensuring health of the surrounding
tissue.
As mentioned, necrotic tissue prevents the formation of granulation tissue and therefore must
be excised. Debridement is a process that occurs
naturally, but if this does not happen within 72h,
another form of debridement must be taken into
consideration. These options include surgical,
mechanical, enzymatic, and biological methods.
The presence of a suspected infection must
always be excluded as it contributes to chronic
inammation and failure of wound healing. The
infection can be supercial or deep: The rst is
generally treated in a more conservative way (disinfection with antiseptics, application of topical
antimicrobials, or dressings impregnated with
antimicrobials), while the second is generally
managed through more thorough debridement and
possibly with the administration of systemic antibiotics. It follows that the choice of an appropriate
dressing is facilitated if the pathophysiological
mechanisms underlying the ulcer and the properties of the various dressings available on the market are known. The correct indication for the use of
a dressing or another is often not unique but almost
always challenging, and usually, the clinician’s
experience is decisive in the choice. The clinician
should choose the best dressing that ts the clinical scenario and that is acceptable in terms of
patient comfort and costs, bearing in mind that
there is a lack of scientic evidence for the use of
many wound care products [4] (Table9.1).
The optimal dressing may be selected based
on the conditions of the wound; it is also important to be aware of the changing wound environment and to be able to provide the most optimal
dressing as the conditions of the wound change.
Dry or desiccated wounds require hydration;
wounds producing excess exudates need an
absorbent dressing; infected wounds require
appropriate antimicrobial agents; and wounds
with necrotic tissue necessitate debridement.
The ideal wound dressing has some general
properties (easy to apply and maintain, cost permissive, easily stored, non-allergenic, and
esthetically pleasing), facilitates healing (moist
environment support, optimal temperature and
pH, reduced trauma or maceration to wound
edges, retention of heat, and gas exchange), and
minimizes risk of infection (necrotic tissue
debridement, exudate absorption, and reduced
external contamination).
Table 9.1 Evidence-based dressing selection
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9.2 Types ofWound Dressings
Wound dressings can be classied based on several factors. A classication divides them into
three groups, based on intrinsic properties: (1)
dressings that facilitate autolytic debridement, in
which the patient’s own phagocytic cells and
autolytic enzymes remove nonviable tissue; (2)
dressings that regulate the moisture of the wound;
and (3) dressings that inhibit bacterial growth [5].
Another classication divides dressings into
(1) moisture-retentive (i.e., lm, hydrogel, hydrocolloid, foam, alginate, and hydrober), (2)
impregnated/antimicrobial (i.e., silver, iodine,
and honey), and (3) tissue-engineered (epidermal, dermal, and composite grafts). Some
dressings are more absorbent, and others are
more moisturizing: In the rst group there are
foam, cotton, and acrylic ber dressing, hydrocolloid, alginate, hydrober, and ceramic dressing; in the second group, there are glycerin
magnesium sulfate, hydrogels, silver-based
dressing, foam, and some hydrocolloid and alginate. The main dressings with their most typical
indications are listed in Table9.2.
9.2.1 Gauze
Gauze is a sterile dressing composed of cotton
yarn and thread, used since the end of the nineteenth century, and available in both woven and
nonwoven forms. Gauze quickly became the
most commonly used surgical dressing, as it is
inexpensive, reliable, and highly absorbent, and
nowadays, it is the standard to which other wound
care products are compared [6]. It is a versatile
dressing, and it can be used in both infected and
non-infected wounds, wounds of various sizes
and shapes, and to remove exudates and prevent
premature wound closure. On the other hand,
woven gauze may potentially lead to wound
trauma and mechanical debridement, as it
requires force to remove. It follows that removal
of the dried gauze may reinjure the wound, cause
pain and discomfort to the patient, and delay
wound healing. Furthermore, evaporation of the
Table 9.2 Wound dressing and typical clinical
indications
Dressing Main indications
Film Minor split-thickness skin graft
donor sites
Minor abrasions
Intravenous access sites
Occlusion for topical medication
to improve absorption
Secondary dressings for
hydrogels, foams, alginates
First-degree burns
Stage 1 pressure ulcer
Hydrogel Dry vascular ulcers
Coumadin-related skin necrosis
Painful and non-exudative wounds
Hydrocolloid Vascular ulcers
Pressure ulcers
Diabetic ulcers
Mild-moderate burns
Skin abrasions and supercial
acute wounds
Foam Wounds over bony prominences
Mildly exudative wounds
Alginate Deep and exudative pressure
ulcers
Pyoderma gangrenosum
Diabetic wounds
Bleeding wounds
Hydrober Deep and exudative pressure
ulcers
Pyoderma gangrenosum
Diabetic wounds
Traumatic wounds
Mild-moderate burns
Silver Supercial infections
Mild burns
Iodine Supercial infections
Tissue-
engineered
• Epidermal
grafts
• Dermal grafts
Xenogenic
Allogenic
• Composite
grafts
Extensive burns
Partial- and full-thickness wounds
Vascular ulcers
Pressure ulcers
Surgical wounds
Severe burns and burn scars
Diabetic ulcers
Dystrophic epidermolysis bullosa
Venous ulcers
Diabetic foot ulcers
wet dressing leads to cooling of the tissues,
resulting in reexive vasoconstriction, hypoxia,
and impaired leukocyte activity, all contributing
to impaired wound healing [7].
In addition, invitro studies have demonstrated
that bacteria readily pass through up to 64 layers
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of gauze and that infection rates are signicantly
higher in wounds using gauze compared to transparent lms or hydrocolloids [8].
Despite these serious critiques of gauze as a
wound dressing, there is tremendous controversy
over its supposed benets, and there is no signicant scientic data that critically compare its efcacy against other dressings [9].
High-quality RCTs are necessary to accurately assess the clinical benets and drawbacks
of gauze.
9.2.2 Impregnated Gauze
Impregnated gauze was created in order to make
gauze nonadherent and moderately occlusive. It is
linked with various substances such as petroleum,
iodine, bismuth, and zinc Impregnated gauze dressings allow for increased retention of moisture in the
wound bed and decreased desiccation or trauma
during dressing changes. It is a versatile dressing
that can be used both as nonadherent primary dressings and as a contact layer on granulating wound
beds when used with secondary gauze dressings.
They are often used both on the donor and
recipient skin graft sites and on burns, as their
removal is without pain. Even impregnated gauze
has negative sides. Bismuth-containing dressings
are cytotoxic and may cause an exaggerated
inammatory response, so they are not indicated
for venous insufciency ulcers. Iodineimpregnated dressings are also cytotoxic: They
are indicated for secreting deep and tunneling
wounds, but must be frequently changed, as the
cytotoxicity of iodine may cause tissue damage.
Additionally, as impregnated gauzes have no
absorbent properties, they are not recommended
for wounds with heavy drainage.
Comparative studies between gauze and
impregnated gauze did not show signicant differences in terms of reduced wound healing times
or costs [10].
9.2.3 Film
Transparent lm dressings are thin and exible
self-adhesive sheets, most often composed of
polyurethane or co-polyester. They are gas and
water vapor permeable, but impermeable to uid
and bacteria.
By not permitting water loss, they provide a
moist environment for wound healing and promote autolytic debridement. Transparency allows
to monitor wound healing, without frequent
removal of the dressing.
Transparent lm dressings have non- absorbent
properties, and this may lead to excess exudate
accumulation and maceration of wound edges.
Furthermore, they should not be used for
infected or secreting ulcers, as the moist, and nondraining environment is ideal for bacterial growth.
Most often, transparent lm dressings are
used in the setting of surgical incisions, supercial wounds without exudates, intravenous catheter sites, and friction areas.
Despite their lack of absorptive properties,
lm dressings are commonly used over skin graft
donor sites. If exudates are seen to accumulate
under the dressing, the uid can be released and
subsequent patch coverage with another transparent lm. Film dressings are also used on surgical
wounds following primary closure left to heal by
secondary intention. Currently, physicians tend
to use lm dressings less frequently for chronic
cutaneous ulcers, preferring the more advanced
modern dressings. However, they may be used as
a secondary dressing applied over other dressings
or topical preparations.
9.2.4 Hydrogel
Hydrogels are complex hydrophilic organic
cross-linked polymers, composed of 80–90%
water.
Hydrogels are classied according to their
physical structure and chemical composition:
1. Amorphous (non-crystalline).
2. Semi-crystalline (a complex mixture of amor-
phous and crystalline phases).
3. Crystalline.
Hydrogels are packed in tubes, spray bottles,
or foil packets, and they are also available as
sheet or impregnated gauze.
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Hydrogels have the ability to absorb a minimal amount of uid by swelling, but they may
also provide moisture to a dry wound, promoting
autolytic debridement.
Hydrogels promote granulation and epithelialization of the wound bed while cooling skin
temperature by up to 5 °C [11]. Compared to
occlusive dressings, they are more permeable to
gas and water, but they are a poorer bacterial barrier. Hydrogels are typically used to hydrate
wound beds and facilitate debridement.
The skin adjacent to the wound needs to be
protected from excessive hydration, as maceration may occur.
Hydrogels are often indicated for pressure
ulcers, partial- and full-thickness wounds, painful ulcer, thermal injuries, and vascular ulcers or
may be considered for softening dry necrotic
material. They can be used in conjunction with
other topical preparations.
Hydrogels can be left in place for up to 3days
and often require secondary dressings.
9.2.5 Hydrocolloid
Hydrocolloids are unique two-layer dressings.
The inner layer is self-adhesive and composed of
hydrophilic particles such as gelatin, pectin, carboxymethylcellulose (CMC), or another elastomer. The outer layer is composed of polyurethane
and seals the wound from bacteria, foreign debris,
and shearing forces. Hydrocolloid dressings are
sold in a multitude of sizes, and shapes and are
available in a paste, powder, or granule form.
When the inner layer meets uid, such as exudate, the material swells into a gel over the
wound. The gel covering creates a moist and
thermally insulated environment for wound healing. Note that when hydrocolloid dressings are
used, a characteristic gelatinous mass is formed
on the ulcer surface. It is not purulent material.
Hydrocolloid dressing has been reported to
increase epidermal healing by above 40% [12]. It
absorbs exudates by 20 times the weight of the
pad. It facilitates autolytic debridement, pro-
motes granulation tissue and epithelialization,
and even increases collagen synthesis.
It does not require a secondary dressing.
Hydrocolloids can be left on the wound for up to
7 days and removed once drainage is noted
beneath the dressing. These dressings are regularly used for partial- and full-thickness wounds
with low-to-moderate exudates, granular and
necrotic wounds, minor burns, and pressure
ulcers, so they are particularly useful when autolytic debridement is desirable. They are to be
avoided in wounds suspected to be having anaerobic infection.
Because hydrocolloid dressings are selfadhesive, caution should be taken in fragile skin
adjacent to the wound.
9.2.6 Foam
Foam dressings were developed as an alternative
to hydrocolloids in 1970. They are composed of
semipermeable polyurethane that is manufactured to contain air bubbles. Foam dressings are
available in sheet form or as spreadable foams,
generally sold as semi-occlusive dressing. They
are water vapor and gases permeable, still maintaining moist wound environment, but not bacteria permeable.
These dressings have absorptive properties,
making them ideal for wounds with moderate-toheavy exudates. They can be used on granulating
or slough-covered partial- and full-thickness
wounds, donor sites, ostomy sites, minor burns,
and diabetic ulcers. Additionally, they can be
used on infected wounds, but should be changed
daily [13]. On non-infected wounds, they can be
left in place for 4–7days and changed when saturated with exudates. Maceration of the surrounding skin is seen if dressing becomes saturated.
Removal of foam dressings is painless and does
not reinjure the wound.
Foam dressings are not ideal for dry or escharcovered wounds, third-degree burns, sinus tracts,
or arterial ulcers, due to their ability to further dry
the wound.
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9.2.7 Alginate
Alginate dressings are made of polysaccharide
ber, containing alginic acids, derived from various species of seaweed. These dressings were
rst discovered by sailors in 1880. They are
highly absorbent, nonadherent, and biodegradable. When exposed to serum in a wound, the calcium and sodium ions in the dressings form a
hydrophilic gel, so as to create a moist wound
environment, absorb exudate, and prevent microbial contamination. Alginates are more absorbent
than hydrocolloids: In fact, these products are
capable of absorbing up to 20 times their weight,
making them a good choice for highly exudative
and draining wounds, pressure and vascular
ulcers, surgical incisions, wound dehiscence, tunnels, sinus tracts, skin graft donor sites, exposed
tendons, and infected wounds (Fig. 9.1).
Alginates are also useful in bleeding wounds,
because of their hemostatic properties. Alginate
dressings are not indicated for dry wounds, as
they do not provide hydration. They may be left
in place for up to 7 days in a clean wound but
must be changed daily in infected wounds.
Alginates are not painful at dressing change and
can reduce healing time as compared to other
types of dressings. They are produced as sheets,
ribbons, and ropes, which are used for packing
deep wounds and cavities.
Fig. 9.1 Antiblastic extravasation ulcer with tendonmuscle exposition
Despite the prevalent use of alginate dressings, few studies have reported statistically signicant justication of their use in any particular
type of wound. Some randomized trials have
yielded conicting data. However, it has become
increasingly apparent that the secondary dressing
used in conjunction with the primary alginate is
of tremendous importance. For heavily exudative
wounds, an absorbent pad is useful, while a semipermeable lm or foam is preferred for light-tomoderately exudative wounds.
It has been suggested that there are three primary factors when considering the use of alginate
dressings: (1) chemical nature of alginate, (2)
amount of ber implanted, and (3) vascularity of
tissue at site of implantation [14].
9.2.8 Hydrober
Hydrober dressings are composed of nonwoven
sodium carboxymethylcellulose (CMC) bers,
which form a gel on contact with exudates. As the
bers turn into a gel, the dressing provides a
moist environment for wound healing and serves
as a barrier against microbes. These dressings are
a good choice for heavily exudative or infected
wounds. They may be kept in place for up to
7days or until saturated.
Hydrobers are similar to alginates both in
structure and in properties, even if they have 2–3
times greater absorptive capacity than alginates.
Numerous studies have compared hydrobers to
alginate dressings, as both are indicated for similar wounds: Hydrobers are preferred for their
ease of application and removal, greater interval
between dressing changes, and decreased costs
[15].
Hydrobers were compared to parafn gauze
dressings in the treatment of split-thickness skin
graft donor sites: The use of hydrober is associated with less pain and faster rates of wound healing, with superior cosmetic results at 1year [16].
CMC products can be also used in partialthickness and small burns.
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9.2.9 Silver
John Woodall first described the antimicrobial
properties of silver in 1617. Silver is a broadspectrum antimicrobial agent with activity
against bacteria, fungi, yeast, and viruses. At
higher concentrations, it is also effective
against MRSA and vancomycin-resistant
enterococci (VRE) [17]. Due to silver’s extensive activity, it can be found in a wide variety
of dressings and products. Silver may also aid
in reducing inflammation, which promotes
wound healing.
To determine the optimal dosing of silver to
achieve either bacteriostatic or bactericidal
effects, the local wound environment must be
thoroughly considered. Silver has been proven to
be effective against supercial microbes, but its
efcacy decreases in deeply inltrating bacterial
infections.
While all silver dressings release silver upon
contact with uid, they vary greatly in the rate,
duration, and peak levels of silver released. To
achieve an antibacterial effect, a minimum concentration between 5 and 50 ppm of silver is
needed in the wound.
The antibacterial mechanism of action of silver is multifactorial. Once the silver cations are
released, they are capable of penetrating cell
walls, inactivating bacterial enzymes, and impairing DNA synthesis. Resistance and allergy are
always possible complications.
The majority of the studies comparing silver
dressings to other treats found no signicant difference in the rates of complete healing. Despite
a lack of quality human trial data, silver-based
products are manufactured in combination with
nearly all types of dressings, including alginates,
collagens, creams, foams, lms, hydrobers,
hydrogels, hydrocolloids, and negative pressure
sponges [18].
Silver is available in dressings in different
forms: elemental ions (silver metal and nanocrystalline silver); inorganic compounds (silver
oxide, silver phosphate, silver chloride, silver
sulfate, and silver calcium sodium phosphate);
and organic complex (silver alginate and silver
carboxymethyl cellulose).
Silver is a good dressing material, and it
requires less frequent changes of dressings,
which may be up to 7days. It should be reserved
for infected wounds.
Silver-containing dressings are not to be used
in patients undergoing MRI examination. Silver
sulfadiazine is not to be used in patients with
G6PD deciency. It should not be used in clean
surgical wounds, not to be used in low-risk of
infections like donor site, closed surgical wounds,
chronic wounds, and patient’s sensitivity to
silver.
9.2.10 Iodine
Iodine is an essential micronutrient in human
metabolism, particularly for thyroid hormones
T3 and T4. Since the initial discovery of the antimicrobial properties of iodine in 1882, iodinebased products have played important roles in the
prevention of surgical site infections. Iodophors
are disinfectants containing iodine and a solubilizing agent that release free iodine when in solution. They were developed in the 1950s as an
alternative to using pure iodine, because of side
effects including pain and skin irritation. The
most commonly used iodophors in dressings
include povidone-iodine and cadexomer iodine.
The povidone-iodine preparations were developed in the 1960s and are widely used as an antiseptic in the preparation of preoperative hand
scrubs.
While not yet fully understood, it is believed
that the antimicrobial effects are due to iodine’s
ability to rapidly penetrate the cell wall of
microorganisms.
With respect to the prevention and management of biolms, some studies have reported that
low-dose, slow-release iodine is effective in killing free-oating bacteria, and they suggest iodine
is a good choice of antiseptic dressing [19].
Controversy also exists regarding the cytotoxicity of iodine resulting in delayed wound healing; however, the relatively slow release of low
doses of iodine can improve healing rates.
Slow-release iodine dressings are indicated in
a variety of wounds with either conrmed or sus-
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pected infection such as pressure ulcers, venous
leg ulcers, diabetic foot ulcers, minor burns, and
supercial skin loss injuries. Iodine dressings
should be changed when they lose their color, as
that is an indicator of their antiseptic effect. Due
to iodine’s critical role in metabolism and thyroid
function, it is imperative to carefully supervise
patients with thyroid disease and iodine sensitivity, those who are pregnant or breastfeeding, and
newborns.
9.2.11 Tissue-Engineered Biological
Dressings
Tissue-engineered biologic dressings are created
to simulate natural scaffolding and matrices during wound healing. These products are skin
products composed mainly of cells, extracellular
matrix materials, or a combination of both. They
can contain living cells (living skin substitutes)
or not (non-living skin substitutes). These tissueengineered dressings essentially mimic autologous skin grafts but are advantageous through
bypassing the creation of painful donor sites.
Tissue-engineered biologic dressings have been
studied and are used in a variety of chronic ulcer
including diabetic foot ulcers, venous ulcers,
burns, surgical wounds, and epidermolysis
bullosa.
9.2.11.1 Non-Living Skin Substitutes
These products originally are derived from living
tissues, but do not contain living cells when
applied to the wound. They fulll the main purposes of an optimal dressing: provision of a moist
environment, prevention of water loss, and protection against external infections or trauma.
Allogeneic cadaver skin may be used as a
biological dressing. Devitalization of the allograft
obviates its antigenic effect. It can also be produced as an acellular dermal matrix by the
removal of the epidermis and the cells in the
dermis.
Xenografts consist of porcine, bovine, or
equine skin. These products are presently irradiated to achieve sterility. The use of xenografts is
well documented for burns, surgical wounds, and
cutaneous ulcers [20].
Collagen-based biological dressings are
divided into “naturally occurring collagen
matrix” and “synthetic collagen-base dressing.”
The rst one consists of sheets of xenografts
(porcine or bovine) that have been processed to
make them suitable for use on denuded skin
areas. The second one is made up of collagen that
has undergone a more complex processing.
A collagen matrix may serve as a skeleton or
scaffolding on which the new tissue gradually
forms [21]. It has been suggested that attachment
of broblasts to the implanted collagen enhances
new collagen synthesis during wound healing
[22]. A collagen matrix protects the ulcer and its
surroundings from mechanical trauma and provides a moist environment.
Some investigators suggest that the acellular
dermis may serve as a template for dermal regeneration. Some of these non-living substitutes are
said to contain cytokines [23], which may render
them more effective than synthetic dressings.
Further studies are needed to obtain a more accurate evaluation of their efcacy; however, the
overall impression is that they do not actively
stimulate or enhance wound healing, as do living
substitutes.
9.2.11.2 Living Skin Substitutes
These substitutes consist of epidermal, dermal, or
composite components. They are living skin
equivalents, created to re-establish the appropriate physiological microenvironment needed for
optimal wound repair.
Keratinocyte grafts are multi-layered stratied skin equivalents that very closely resemble
natural skin. Keratinocyte grafts are divided into
autologous [24] and allogeneic grafts [25]: The
rst requires a biopsy specimen from the patient’s
skin or a sample of his/her hair follicles, and the
second is derived from the foreskins of newborns.
It seems that the graft works as a semi-occlusive
dressing that prevents dehydration and reduces
pain. Keratinocyte grafting does provide some
degree of improvement in most cases, even in
ulcers that do not heal completely. Improvement is
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manifested by granulation tissue formation, epithelialization advancing from the ulcer margin,
and a signicant reduction in the ulcer surface
area. Disadvantages include a long culture time
(several weeks) of the keratinocytes, the fragile
nature of the graft, expense, and a short shelf life.
They can be indicated in patients with deep burns.
Dermal grafts can be xenogeneic or allogeneic. These dressings are typically composed of
collagen and additional extracellular matrix components. Xenogeneic grafts are typically made
from porcine or bovine collagen. Depending on
the characteristics of the matrix, they can be used
in severe burns, vascular or pressure ulcers, and
partial- or full-thickness wounds. Allogeneic
grafts are composed of cadaveric dermis or neonatal foreskin, so they can trigger antigenicity and
rejection of the graft. These grafts undergo biodegradation after a period of 3–4weeks, providing the
wound with time for in-growth of blood vessels,
and broblast and keratinocyte proliferation.
Typical indications are full- thickness diabetic
ulcers and wounds related to dystrophic epidermolysis bullosa.
Composite grafts are bilayer tissueengineered skin equivalents, composed of human
keratinocytes (epidermal layer) and bovine collagen with broblasts (dermal layer). These products increase the rate of healing when compared
with traditional dressings [26]. Venous ulcers and
full-thickness diabetic foot ulcers are the main
indications.
Honey is used as a dressing material for
4000years. It is derived from many oral sources.
Manuka honey and pasture honey are two main
types of honey used for dressing. The effect is
deodorizing and reduces inammation, edema,
and exudates, and it has some antibacterial effects
as well.
Hyaluronic acid (HA) is a natural component
of extracellular matrix; it controls water retention
and ionic and molecular diffusion. HA facilitates
the growth and movement of broblast. It is
available as cream, sponge, bers, and threads. It
is also used as a scaffold for broblast and keratinocyte culture.
Collagen dressings are made of collagen
extracted from rat tendon, bovine skin, or pig
intestine. They are available in the form of powder, cream, and sheet or wafers, or in combinations with alginates, metronidazole, mupirocin,
gentamycin, and silver sulfadiazine. Collagen is
thought to work as a scaffold for cells involved in
repair process and for the proteolytic enzymes
present in chronic wounds. The whole process
reduces the chronic inammatory stage of the
wound. Collagen dressing is not a debriding
agent or an antiseptic: It can be used in chronic
and exudating wounds, without infection or
necrotic tissue.
Hydroconductive dressing, charcoal dressing,
polyhexamethylene biguanide dressing, pHmodulating dressing, and hemoglobin spray are
other possible products that can be used for
wound care.
9.2.12 Other Types ofDressings
Silicone dressings can be used for hypertrophic
and keloid scars instead of pressure garments.
Over time, silicone dressings are able to soften
the scar tissue, allowing for a decrease in the
height of the hypertrophic scar [27]. It seems that
the dressing prevents water vapor loss, increasing
hydration of the scar. Silicone dressings have
continued to become more widely used, as it has
a non-traumatic adhesive component, which
makes dressing changes less painful.
9.3 Negative Pressure Wound
Therapy (NPWT)
Negative pressure wound therapy (NPWT), or
topical negative pressure (TNP), has gained
widespread use from the vacuum-assisted closure
technique (VAC™; Kinetic Concepts Inc., San
Antonio, TX) that applies localized negative
pressure to the wound bed through a polyurethane reticulated open-cell foam dressing or a
polyvinyl alcohol foam dressing [28].
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The mechanisms of action are not completely
understood, though the biophysical and biochemical effects are important.
The technique is based on delivering topical
negative pressure through a material that is
applied to a wound.
NPWT is effective because it removes exudates and debrides, increases blood perfusion by
neovascularization, leads to the formation of
granulation tissue, and increases the local circulation of antibiotics into the wound bed [29].
The microdeformations induced by the application of sub-atmospheric (negative) pressure
through the foam dressing are instrumental in
regulating granulation tissue formation.
The reduction in local and interstitial tissue
edema, the increased perfusion of the peri-wound
area, the changed bacterial composition, and the
mechanical stimulation of the wound bed contribute to the clinical success of the NPWT.
The VAC therapy system seems to be a safe
and effective treatment for complex diabetic foot
wounds and could lead to a higher proportion of
healed wounds, faster healing rates, and
potentially fewer re-amputations than standard
care [30].
Most evidence supports the effectiveness of
NPWT on chronic leg ulcers and post-traumatic
ulcers. Moreover, there is a signicant benet of
VAC therapy after skin grafting in chronic leg
ulcer patients [31]. NPWT is recommended in
contaminated or colonized shallow wounds with
no exposed bone or foreign body. It can also be
used either in wounds with low risk of infection
or in infected wounds (Fig.9.2a, b).
The use of NPWT requires careful preparation
of the wound bed, so debridement is an essential
initial step (Fig.9.3a–d).
The usefulness of NPWT in other types of
chronic wounds such as vasculitic ulcers or
malignant wounds has yet not been studied systematically. There is some causal evidence for the
use of NPWT in pyoderma gangraenosum as an
adjunct to immunosuppressive treatment [32].
Continuous NPWT delivered at −125mmHg
has been recommended, despite consistent
research ndings suggesting potential advantages
a
b
Fig. 9.2 (a) Scrotal ulcer in a patient with Fournier’s
gangrene. (b). After treatment with absorbent dressings,
subsequently VAC therapy, and dermal substitute
to the use of lower pressures and intermittent
therapy.
For home treatment with NPWT, a systematic
education of patients and relatives is necessary to
ensure the same level of efcacy and safety as in
the hospital setting.
NPWT has high material costs; however, these
are compensated by the lower number of timeconsuming dressing changes and the shorter duration until the wound is “ready for the surgery.”
NPWT appears to be a safe treatment, and
serious adverse events have been rarely reported.
NPWT adverse effects include discomfort, pain,
and excessive tissue growth into the dressing.
Complications are limited if the device is used
properly.
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