Practical Plastic Surgery

The role of povidone-iodine (Betadine®) in topical wound care is somewhat controversial. Several animal studies demonstrate no adverse affect on wound tensile strength or reepithelialization rates. On the other hand, several human in vitro and in vivo studies have shown that Betadine inhibits fibroblast proliferation, kerotinocyte growth and migration, and hampers the phagocytic effect of monocytes and granulocytes. In addition, any admixture of blood, pus or fat has been proven to diminish the 4 antimicrobial effect of Betadine. Given this data, many plastic surgeons do not use Betadine as a topical antimicrobial, although it is still commonly used in the operat-

ing room as a prepping agent. Other specialties that treat wounds still use Betadine due to the lack of convincing clinical trials and a long history of its use.

Enzymatic Agents

In addition to appropriate antimicrobial therapy, the wound must be properly debrided of any devitalized tissue. Necrotic tissue can serve as a culture medium for further bacterial proliferation, and its presence will impede the healing process. Sharp debridement is the simplest, most effective means of eliminating nonviable tissue. Enzymatic debriding agents are an adjunct to surgical debridement. As with antimicrobial agents, there is a spectrum of enzymatic agents that is commercially available (Table 4.2).

Growth Factors

Perhaps the realm with the greatest therapeutic potential in the pharmacologic treatment of wounds is the use of growth factors. A variety of growth factors and chemotactic agents have been discovered since the 1970s, and many have been probed for possible clinical applications. Platelet-derived growth factor (PDGF) is present in acute surgical wounds, however not in chronic, nonhealing wounds. In several randomized controlled trials, topical application of PDGF increased wound tensile strength and accelerated the healing process overall. Recombinant PDGF is currently the only cytokine approved for use in chronic wounds, specifically in neuropathic diabetic foot ulcers. It is available commercially as beclapermin (Regranex®); however the extremely high cost makes its use prohibitive in many centers.

Pearls and Pitfalls

1.Choosing a topical wound care agent must be done in conjunction with choosing the appropriate dressing.

2.If the wound is complicated by underlying osteomyelitis, topical antibiotics will not suffice in eradicating the infection.

3.Close observation is warranted when instituting a new therapy for the wound since many of these agents have side effects and can even induce an allergic reaction.

4.Enzymatic agents cannot penetrate thick eschar. Necrotic tissue should be sharply debrided before applying a topical enzymatic substance.

5.Some topical wound care agents, such as papain-containing enzymatic agents, are painful when they come in contact with surrounding healthy skin.

Suggested Reading

1.Ladin D. Becaplermin gel (PDGF-BB) as topical wound therapy. Plast Reconstr Surg 2000; 105(3):1230.

2.Mustoe TA. Understanding chronic wounds: A unifying hypothesis on their pathogenesis and implications for therapy. Am J Surg 2004; 187(5A):65S.

3.Steed DL. Debridement. Am J Surg 2004; 187(5A):71S.

Untreated underlying osteomyelitis

Nonenteric or unexplored fistulas

Undebrided necrotic tissue

Untreated active soft tissue infection

Exposed internal organs

Exposed blood vessels or vascular prosthetic grafts

Coagulopathic patients (relative)

Technique

Application of NPWT can be performed by anyone with the appropriate training, provided that the wound is hospitable. Prior to application, the wound should be debrided of any necrotic or fibrinous debris and adequate hemostasis achieved. The surrounding skin is then cleansed and dried. The sponge is cut to be slightly smaller than the volume of the wound. The adhesive dressing is then applied over the sponge such that there is at least a 6 cm overlap on adjacent skin; it is imperative that a hermetic seal be achieved. Once the adhesive dressing has been applied, it is pierced and the adhesive suction tube is applied over this opening. The device is then turned on and continuous suction is applied. When placed properly, the dressing will create a closed suction environment. Depending on the nature of the wound, the NPWT dressing can be changed every 48 to 72 hours. The dressing should be taken down sooner should the patient show signs of infection or if the seal on the dressing becomes compromised.

The VAC® device comes with two types of foam available for use. The original foam is black, and it is made of polyurethane. It is hydrophobic which enhances exudate removal. It has reticulated pores and is considered to be the most effective at stimulating granulation tissue while aiding in wound contraction. The second, newer available foam is white. It is a denser foam with a higher tensile strength. It is hydro-

philic and possesses overall nonadherent properties. The white foam does not require the use of a nonadherent layer. It is generally recommended for situations in which slower growth of granulation tissue into the foam is desired or when the patient cannot tolerate the black foam due to pain. Due to the fact that it has a higher density than the black foam, higher pressures must be utilized in order to provide adequate negative pressure distribution throughout the wound. Newer foams

are constantly emerging, such as silver-impregnated foams.

5

Pearls and Pitfalls

•Though the NPWT dressing is applied less frequently than the comparable saline dressings, some patients find it painful and require appropriate premedication with analgesics.

•The skin surrounding the wound should be completely dry prior to placement of the adhesive. Shaving of hair and application of BenzoinTM may facilitate adhesion.

•The foam should be cut down to the proper size so that it fits within the borders of the wound, otherwise it will compress the surrounding healthy skin.

•After placing the dressing and applying the vacuum, ensure an adequate seal by clamping the tubing leading to the dressing and then disconnecting the tubing from the machine. If the seal is adequate, the sponge should slowly return to its original shape.

•If poor hemostasis is presumed or if the wound is particularly “weepy”, close monitoring of the patient’s hemodynamic and fluid status is warranted.

•The foam should not encroach on normal surrounding skin. However, two separate wounds can be hooked up to a single suction tubing by bridging the two sponges with a thin piece of foam that traverses the normal interfering skin.

•A useful trick for dressing change analgesia is to clamp the tubing and inject 1% lidocaine with epinephrine (10-30 ml) into the tubing distal to the clamp. The vacuum will suck the local anesthetic into the wound.

Suggested Reading

1.Argenta LC, Morykwas MJ. Vacuum-assisted closure: A new method for wound control and treatment: Clinical experience. Ann Plast Surg 1997; 38:563.

2.Morykwas MJ, Faler BJ, Pearce DJ, Argenta LC. Effects of varying levels of subatmospheric pressure on the rate of granulation tissue formation in experimental wounds in swine. Ann Plast Surg 2001; 47(5):547-51.

3.Evans DL, Land LL. Topical negative pressure for treating chronic wounds: A systematic review. Br J Plast Surg 2001; 54:238.

4.Leeches will usually attach immediately. If not, prick the skin with a needle before reapplying the leech.

5.Leeches will typically remain in the same place until they are completely distended, at which point they will fall off. This usually takes 30-45 minutes. Instruct the patient’s nurse to check on the patient often so that leeches are not lost after detachment.

6.Wounds can be encouraged to bleed after detachment by occasionally scraping

the eschar off.

67. Used leeches can be discarded by anesthetizing and then euthanizing them in 8% and 70% alcohol, respectively. They should be considered biohazardous and

disposed of as such.

If several leeches are used concurrently, it may be necessary to check the patient’s hemoglobin/hematocrit at regular intervals. All patients should be started on an oral antibiotic while on leech therapy. Suggested antibiotics include a fluoroquinolone or amoxicillin/clavulanic acid. Patients with HIV or taking immunosuppressive medications should not undergo leech therapy because of the risk of bacterial sepsis.

Pearls and Pitfalls

Leeches should be used as a treatment of last resort when all other means of venous outflow establishment are exhausted. It is imperative to relieve a mechanical or iatrogenic cause of venous compromise.

It is critical to rule out arterial insufficiency as the cause of flap necrosis or pallor, since leeches will not work in this situation.

Flaps demonstrate significantly decreased survival after 3 hours if venous congestion is not relieved. As opposed to arterial ischemia, venous stasis tends to cause irreversible damage. Since leeches must be flown in, it is wise to anticipate their need as early as possible. We have ordered them intraoperatively in some cases.

Although leeches can be reused on the same patient, they tend not to work as well. Used leeches should not be stored with unused ones to prevent cross-contamination. Used leeches should never be applied to another patient.

The importance of an appropriate bedside manner in ensuring acceptance of and compliance with this regimen cannot be understated. Most patients are willing to accept treatment when it is explained in a thorough and confident manner. It is also critical to include nursing and ancillary staff in the discussion of leeches, as many will not have seen them used before. We have found that by observing the first application of a leech, most nurses are willing to apply subsequent leeches without supervision.

Leech Suppliers

Carolina Biological Supply Co.—(800) 262-2922

Leeches U.S.A.—(800) 645-3569, after hours: (800) 488-4400 Ext. #2475

Suggested Reading

1.de Chalain TM. Exploring the use of the medicinal leech: A clinical risk-benefit analysis. J Reconstr Microsurg 1996; 12(3):165-172.

2.Haycox C, Odland PB, Coltrera MD et al. Indications and complications of medicinal leech therapy. J Am Acad Dermatol 1995; 33(6):1053-1055.

3.Utley DS, Koch RJ, Goode RL. The failing flap in facial plastic and reconstructive surgery: Role of the medicinal leech. Laryngoscope 1998; 108(8 Pt 1):1129-1135.

4.Whitaker IS, Izadi D, Oliver DW et al. Hirudo medicinalis and the plastic surgeon. Br J Plast Surg 2004; 57(4):348-53.

•Decreases the rate of systemic absorption

•Reduces the risk of systemic side effects

•Prolongs the duration of action of the anesthetic

•Improved hemostasis due to its vasoconstrictive effects

Premixed solutions containing epinephrine are acidified even further than plain

local anesthetics. This increased acidity delays the onset of action and is more painful on injection. There is no utility in using greater than 1:100,000 epinephrine solutions. No additional vasoconstrictive benefit is offered, whereas the risk of toxicity increases in a dose-dependent manner. Adequate hemostasis relies greatly on allowing adequate time for the vasoconstrictive effects to occur. This usually takes 7-10 minutes.

Contraindications to the use of epinephrine-containing solutions include patients with unstable angina, cardiac dysrhythmias, severe uncontrolled hypertension, or pregnant patients with placental insufficiency. Relative contraindications include hyperthyroidism and concurrent use of MAOI or tricyclic antidepressants. When contraindicated, phenylephrine (1:20,000) can be substituted, however it is not as effective as epinephrine.

The Addition of Bicarbonate

Sodium bicarbonate can be added to local anesthetics in order to alkalinize the solution. This neutralization of the low pH creates a solution that is less irritating to the tissues and less painful on administration. The limiting factor in the addition of bicarbonate is the tendency for the lipid soluble agents, such as bupivicaine, to precipitate at the more neutral pH values. Therefore, bicarbonate can be added to lidocaine but should generally not be used with bupivicaine.

Lidocaine

Lidocaine is the most widely used local anesthetic. It is prepared as a 1% (10 mg/ ml) or 2% (20 mg/ml) solution with or without epinephrine. Its duration of action is about 1.5 hours without epinephrine, and this is doubled to 3 hours with the addition of epinephrine to the solution (1:100,000). Lidocaine can also be used as a dilute solution (0.2%–0.5%) for certain procedures such as a rhytidectomy. This solution is adequately anesthetizing and vasoconstrictive. A commonly used dilute solution, the modified Klein solution, can be prepared as follows: 20 ml of 2% lidocaine, 5 ml of sodium bicarbonate, and 1 ml of 1:1,000 epinephrine all mixed in 500 ml of lactated Ringer’s solution. The maximum safe dose for plain lidocaine is reported as 3-4 mg/kg. With the addition of epinephrine, this increases to 7 mg/kg.

Recent literature, however, refutes this figure, providing evidence for a much higher maximal safe dose-up to 35 mg/kg when combined with epinephrine.

Bupivicaine

Bupivicaine is widely used in plastic surgery because of its long duration of action. It is effective for 3-6 hours, significantly longer than lidocaine. The addition of epinephrine can increase this duration to 10 hours. It comes as a 0.25% or 0.5% solution, with or without epinephrine. It is somewhat more painful than lidocaine on administration. It should not be used for large volume infiltration because of its

high toxicity profile. It can, however, be combined with lidocaine for lengthy facial 7 procedures such as a rhytidectomy. This combination has a rapid onset of action due

to the lidocaine, and a long duration of action due to the bupivicaine. The maximum safe dose of bupivicaine is 2.5 mg/kg, and this increases to 3 mg/kg with the addition of epinephrine.

Mepivicaine

Mepivicaine is similar to lidocaine except for its slightly longer duration of action. Its anesthetic effects can last up to 3 hours. It is prepared as a 0.5% or 1% mixture. It is much less commonly used than lidocaine due to its higher cost and lesser availability. It also has a slightly increased risk of toxicity compared to that of lidocaine.

Eutectic Mixture of Local Anesthetics (EMLA)

EMLA is typically a cream composed of 2.5% lidocaine and 2.5% prilocaine. It provides dense topical anesthesia 45-60 min after application. It must be covered with an occlusive dressing for this period in order for the cream to be effective. Within 2 hours, the maximal depth of penetration is reached. EMLA cream is not widely used because of the long latency until onset of action and the need for the occlusive dressing. It is effective in children who will not tolerate a needle stick, as long as it is applied sufficiently in advance.

Cocaine

Cocaine is used primarily as a topical agent for septo-rhinoplasty procedures. It comes in 4% or 10% solutions. As opposed to other local anesthetics, cocaine produces significant local vasoconstriction without the addition of epinephrine. Its onset is extremely rapid (1-2 minutes), but it takes an additional 5 minutes for its vasoconstrictive effects to begin. Its duration of action is up to 3 hours. Cocaine can be highly toxic by sensitizing the heart to circulating catecholamines. This can lead to tachycardia, hypertension, coronary vasospasm and dysrhythmias. Its CNS effects are stimulatory before leading to confusion, dysphoria and seizures. The maximum safe dose is about 3 mg/kg.

Tetracaine

Tetracaine, similar to cocaine, is used as a topical agent in nasal surgery. It can also be combined with EMLA as a topical agent for anesthesia for closed nasal reduction. It comes as a 0.05% to 4% solution. It has a rapid onset and is effective for 1-3 hours. Tetracaine is several times more potent than cocaine. It is extremely toxic due to its slow rate of metabolism, and the maximum safe dose is 1 mg/kg.