Wound Assessment
Wound management requires information about:
- Time and mechanism of injury
- Condition (diseases or disorders)
- Practice (Smoking or drugs)
- Medications (corticosteroids, chemotherapeutic agents)
- Nutritional status
- Arterial or venous insufficiency in wounded area
Wound inspection necessary to check for:
- Active hemorrhage
- Viability of wounded tissue
- Presence of foreign bodies
- Potential damage to structures in vicinity of wound
Back to top
Timing and Methods
The main goals of wound treatment are a) Close the wound and b) Establish wound healing
Closure timing is important in order to meet these main goals. Closure timings are:
1. Primary Closure - Close wound at time of presentation
2. Secondary Closure - Allow would to heal by itself
3. Tertiary Closure - Close wound after a period of secondary healing
Deciding the type of closure depends on whether the
wound will satisfactorily heal on its own and whether hemorrhage, dead tissue and foreign
bodies, and bacterial contamination can be adequately dealt with
Wounds without hemorrhage, necrotic tissue, foreign bodies, or contamination
Primary closure works well in this situation; no
extensive wound care is needed and the wound will
reach a healed state quickly
Wounds with hemorrhage
Hemorrhage can be controlled without difficulty in
most wounds by using pressure, cauterization, or ligation. Wound cannot be
closed if it is still bleeding because the hematomas act
as a barrier to the healing. Hematomas must first be drained before closure can
occur. Small hematomas may allow for secondary closure, whereas larger
hematomas usually require primary
closure
Wounds with foreign bodies and necrotic tissue
Foreign
bodies and necrotic tissue must first be removed before closure. Most
foreign bodies and necrotic tissue can be
removed without difficulty either manually or with high-pressure
saline irrigation.
For more firmly embedded foreign bodies, surgical excision can
be used for removal. For foreign material that was injected, such as
paint or grease injected under pressure, radiographs can help
determine the spread of material in the target
area. Radiopaque materials, such as metals or leaded glass, can also
be detected with a radiograph. For other materials that
cannot be easily visualized, techniques to
use include xeroradiography, magnified radiographs and CT scans.
Side Note:
For burn wounds, it extremely difficult to assess tissue damage because
the injury may
become worse in the few days after the burn. This is the reason why
closure of burn wounds is often
delayed
Wounds with bacterial contamination
A wound with greater than 105 organisms/gram
tissue is considered infected. A visual inspection is not adequate to assess bacterial
counts so cultures need to be performed. The rapid slide technique is effective in that it
provides bacteria counts within an hour. Age of the wound is important in that it correlates
with bacteria counts. The first 6-8 hours after a wound is called the
"golden period" because clinical studies show that there
are less than 105 organisms/gram
tissue within that time and so the wound can be closed
safely. Other important factors to consider are the
location (areas with greater blood supply tend to resist infection)
and immune status (younger people less likely to become
infected).
Topical creams
can reduce the number of bacteria in a wound. A commonly used agent is Silvadene (made from silver sulfadiazine). It has a
broad antibacterial spectrum and does not adversely
affect metabolism like other agents (mafenide, silver nitrate). Silver sulfadiazine is also thought to increase
epithelialization rate, thus leading to faster wound healing.
Once the wound is ready to be closed, the
appropriate type of closure method must be chosen. The major methods of wound closure are:
1. Direct approximation (Suture/Staple)
2. Autograft
3. Flap
Back to top
Pre-closure Steps
Anesthesia
The first step to take before wound closure is
proper anesthesia. The most commonly used anesthetic is lidocaine (0.5% or 1.0%) because
of its fast-acting capability, rare instances of allergic
reactions, and the 1-2 hours of local anesthesia it provides which is usually enough time for most wound closures. Often
combined with lidocaine is epinephrine,
which makes the anesthetic effective for a longer time and helps with hemostasis
Irrigation
Irrigation with a high-pressure spray is necessary
to reduce the number of bacteria that may be present. Commonly used irrigants include 0.9%
saline solution and Pluronic F-68, which has
surfactant properties that improve wound cleaning. Antibiotics can be
added in order to remove more bacteria if necessary
Skin preparation
The surrounding tissue should be prepared with an
antibacterial solution, a common one being
povidone-iodine. Foreign matter and necrotic tissue should be removed
to reduce chances of infection. If
conditions allow, wound edges should be made smooth and level using incisions
Side Note:
Some solutions should not be placed on wounds. These include:
-
Povidone-iodine (will damage tissue)
- Chlorhexidine (impedes wound healing)
- Alcohol (toxic to tissues)
- Sodium hypochlorite (toxic to fibroblasts, slows
epithelial growth)
- Acetic acid (toxic to fibroblasts, slows
epithelial growth)
- Hydrogen peroxide (histologic damage to tissue)
- Standard hand soap (can induce histologic damage)
*Ideal wound closure*
- Support wound until it reaches near-full strength
- No inflammation
- No ischemia
- No penetration of epidermis (potential for
additional scarring)
- No interference with healing process
For wounds, regaining strength takes a long time.
Collagen fibers are usually growing by the third day
of injury but the skin wound has no tensile strength. Blood vessels
cross the wound by 8 days, as well as epithelial cells and fibrinous
coagulum. The skin gains strength from 8-21 days and continues to gain for 4 months. It is sometimes
difficult to make the balance between maintaining
wound strength and cosmetic appearance. Currently no wound closure
techniques accomplish all the
requirements for ideal wound closure. The requirements always have
to be balanced depending on the
situation
Back to top
Sutures
Sutures are commonly used when the wound is small and clean enough that
the wound edges can be brought
together without deformation. Suture material should be chosen based on:
- Interaction of material with wound and surrounding tissue
- Configuration of tissue
- Biomechanical properties of wound
Pre- and post-suturing
Two general classes of sutures are absorbable
(rapidly degrade and lose tensile strength within 60 days) and nonabsorbable (maintain strength for
more than 60 days). The type must be chosen depending on the type of wound
Nonabsorbable sutures
Silk - Sterile, non-mutagenic made of natural proteinaceous fibers called fibroin
Metallic - Derived from stainless steel
Polyamides
- Nylon, high tensile strength and low reactivity but relatively large
degradation rate in vivo (12.5% per year). Pliable and easy to
handle, favored for interrupted percutaneous sutures
Polyesters
- Dacron, last indefinitely in tissue, coated with lubricant to reduce
large coefficient of friction
Polypropylene
- Very inert in tissue, retain tensile strength for long time, low drag coefficient so good for
continuous techniques. Used in plastic, cardiovascular, general, and orthopedic surgery
Polybutester
- Unique elongation changes compared to other sutures; low forces
result in longer elongation and high
elasticity allows suture to adapt to changing tensions and removing risk
of hypertrophic scars. Coated with absorbable pollymer to reduce drag forces in musculoaponeurotic,
colonic, and vascular tissue
Non-absorbing suture
Absorbable sutures
Made from
collagen or synthetic polymers treated with aldehyde (to resist
enzymatic degradation).
Disadvantages of natural fiber sutures include fraying during knotting
and more variability in tensile strength.
POLYSORB
- Synthesis of copolymers of glycolide (provides tensile strength) and
lactide (controls rate of hydrolysis for
prolonged strength)
CAPROSYN
- Latest development in monofilament absorbable sutures, retains
strength for longer than other absorbable sutures, greater
breaking strength, less rate of infection, and lower drag
forces
Types of suture techniques are dermal and
percutaneous, and each can be continuous or interrupted
Continuous - More rapidly done, accomodates to edema
Interrupted
- Must make knot for each loop (longer surgery time), constricts tissue
more so cannot accomodate for edema, but is more precise for
approximating wounds
Percutaneous - Easier to operate upon, but leaves scars
Dermal - More difficult to suture, but stronger, no visible scars, and does not need removal
Suture knot
Back to top
Staples
Skin
stapling has been shown to be an effective method to close wounds.
Stapes have several advantages over sutures, including much greater
resistance to infection, greater approximation of wound edges,
decreased wound closure time, 6-8 times faster to approximate wound
edges, and more cost effective. The main disadvantage is the strength
starting three weeks after closure, where the sutures were shown to be
significantly stronger. Additionally, approximation is not as precise
as with sutures
Skin staples are made of metal and are applied using
a skin stapler. There are many brands of skin stapler, each with their
own advantages and disadvantages. In general, most brands are effective
and can be used in most applications requiring stapling.
APPOSE Skin
Stapler
MULTIFIRE Skin Stapler
Back to top
Grafts and Flaps
When
a wound is severe enough that the edges cannot be approximated without
excessive tension or deformation of skin and surrounding tissue, other
methods are needed. Skin grafts and flaps use tissue from another
location of the body to replace the lost tissue at the wound site.
Grafts must be protected from infection, bleeding, and shearing until
it has reached maturity. Once it
has matured, it will regain perspiration and sensiility characteristics
of the recipient site rather than
the donor site.
Skin grafts cannot heal over areas >1.0-1.5 cm2
of denuded bone, nerve, or tendon because those areas have most likely
become avascular and a skin graft will not revascularize. For those situations, a flap can be used because they do
not require complete revascularization since they use the vasculature from their original site. Flaps retain color,
texture, hair, and other activity. Sensibility and perspiration are eventually regained.
Illustration of flap method
Additionally, use of skin substitutes has also been
attempted. Alloderm and Integra contain dermal elements of skin, while
Apligraf contains other components as well, including epithelium. Improvements are still necessary for skin
substitutes, however.
Back to top
Adhesives
Tissue adhesives have primarily been used in repair of traumatic
lacerations in the Emergency Department. Adhesives have an advantage
over sutures in that they rapidly unite wound edges, there is no need
to remove them like for sutures, and they are less painful for
application. Three commonly used adhesives are Histoacryl, Dermabond,
and Indermil. They have been shown to be highly effective in their use.
These adhesives can also be more cost effective for certain
applications, such as pediatric facial lacerations. A downside is that
tissue can adversely react to the compounds
Cyanoacrylate
Adhesive
Adhesives used in glaucona drainage
Back to top
Future
Currently, methods to close severe wounds are generally very effective
when applied to the proper situations. Because different methods exist (suture,
staple, grafts and flaps, and adhesives), different types of wounds can
be handled and treated. There are still many ways to improve wound
repair, however. One improvement would be to decrease the time needed
for suture insertion and tying. If a device were to be constructed that
could be set to automatically insert the sutures and knot them, it
would save a great deal of time and effort for the surgeons.
Each closure method itself can be improved,
but an ideal improvement to wound treatment in general could
include one standard type of treatment for all wounds. This seems very
difficult because the severity and types of wounds is so varied, but a
standard treatment would make things much easier for surgeons. No time
would be lost deciding what closure method is best, and no training
would be needed for several different types of closure.
Another improvement to wound healing could involve
ways to make tissue repair faster. Faster healing would allow the
closure device to be removed sooner and thus would improve the cosmetic
aspect of wound closure. Ways to accomplish this could include growth factors and hormones to instigate growth. The
field of tissue engineering deals with this and could be applied to
create more effective wound closure and repair methods.
In conclusion, methods of wound closure are
currently effective but can still be improved, modified, and combined
with different techniques to create superior techniques to save time,
increase cost efficiency, increase comfort of patients and decrease
effort for surgeons
Back to top
References
Lawrence,
Thomas W; Bevin, Griswold A; Sheldon, George F. "Acute wound care:
approach to acute wound management." ACS Surgery Online, 2002
Lin, Kant Y; Long, William B III. "Revolutionary advances in skin
stapling and tissue adhesives." Dannemiller Memorial Educational
Foundation, 2005
Lin,
Kant Y; Long,
William B III. "Scientific basis for the selection of surgical needles
and sutures." Dannemiller Memorial Educational Foundation, 2005
Lin, Kant Y; Long,
William B III. "Scientific basis for the selection of sutural skin
closure." Dannemiller Memorial Educational Foundation, 2005
Schmidt, Ben. "Advances in medical textiles: novel suture technologies." Jour TATM, 2004
Back to top
This website was
created by Ashish Jani for BME 240, taught by Professors Brian Wong and
Ranjan Gupta. This project is under the name of the University of
California, Irvine and was completed June 2007