Practical Plastic Surgery

Due to the likelihood of multifactorial disease, it is important to rule out an arterial contribution to the chronic wound before applying a compression dressing. The patient should also be encouraged to keep their affected extremities out of the dependent position while resting to further encourage forward flow of blood and edema fluid. Keeping vascular wounds moist and clean is extremely important. To this end, saline dressing changes are the most cost effective choice but must be done twice a day to maintain the moist environment. A hydrogel can be used with dressings that will be changed less often. Vacuum-assisted therapy (VAC) is now being used for vascular wounds with greater success, especially in larger wounds. Whirlpool treatment may also be combined with dressing changes. Many patients find the water soothing, especially in painful venous ulcers.

The surgical approach to venous disease has been met with little success and is often limited to debridement of necrotic wounds and skin grafting. There has been little proven benefit to the restoration or replacement of deep veins or their valves and ligation of veins to prevent retrograde flow of blood has been equally unsuccessful. If a healthy wound bed can be established, autologous split-thickness skin grafts are likely to take. Often, in a healthy wound bed, skin grafting followed by tight wrapping is used in the hopes that there is enough oxygen perfusing the surface level to allow the skin graft to take. Allogenic skin grafts such as Apligraf (Novartis, East Hanover, NJ) are eventually rejected, but provide a “biologic dressing” to prevent bacterial growth and help promote cell migration and speed healing rates. Autologous skin equivalents, cultured from a donor sight, are expensive

17and time consuming to grow, but are another option. Should more definitive closure of these wounds be necessary, with adequate arterial blood flow, a host of rotational and free flap surgical techniques are available. These range from rotational skin flaps, to local myocutaneous flaps (gastrocnemius flaps), to free tissue transfers (radial forearm flap).

Pharmacologic options include the use of pentoxifylline, a drug thought to decrease excessive white blood cell activity and to increase oxygen delivery to tissue. Diuretics should be considered to help alleviate edema.

Generally speaking, antibiotics for vascular wounds should be reserved for cases where systemic involvement is suspected. Wound cultures are of little value in that they only sample superficial bacteria which are often simply skin contaminates. The decision to use antibiotics should be guided by culture and sensitivity results from deep tissue biopsies. In the setting of suspected osteomyelitis, a radiographic workup can be pursued with plane films followed by bone scan if necessary. When ruling out osteomyelitis, it is important to remember that X-rays often lag behind disease progression by two weeks. More recently, MRI, and specifically those using gadolinium, have been used in the workup for osteomyelitis. The definitive procedure is a bone biopsy and culture with a six-week course of antibiotics following positive culture results.

Wounds of Arterial Etiology

Contrary to wounds resulting from venous disease, those with an arterial origin are often managed surgically. In addition to debridement of the ulcer, a revascularization bypass procedure should be performed. In cases of more proximal, focal disease in a larger artery of the leg, intravascular approaches such as balloon dilatation (percutaneous transluminal angioplasty) and stenting can be considered. Anticoagulation shows little benefit, but often aspirin with or without an antiplatelet agent is instituted especially in the setting of stent placement. Drugs often used

include pentoxifylline, clopidogrel and cilostazol. Hyperbaric oxygen has proven to be of benefit in chronic ischemic wounds and is often used as a limb salvage technique with arterial disease, or in the setting of osseomyelitis.

In patients with nonhealing wounds and arterial insufficiency that cannot be treated surgically (poor distal target vessels for bypass options, poor surgical candidate, etc.), recent data suggest that pneumatic compression stockings that deliver retrograde sequential pressure at 120 mm Hg can improve popliteal and distal arterial flow and improve blood delivery to distal tissue.

For embolic disease, rapid institution of therapy is essential. The patient should be kept warm and the affected limb made dependent. Full heparin anticoagulation should be started immediately and early consideration for thrombolytic agents or embolectomy is appropriate.

Diabetic Wounds

Initial treatment for diabetic wounds should be aimed at eliminating pressure at the wound site. Total contact casting for a diabetic foot ulcer is very effective. This ensures that when the extremity meets a hard surface like the floor, the pressure is distributed across the entire foot. Another option is the orthopedic shoe. It serves a similar purpose but is easily removed for wound care and daily cleaning. Finally, the patient should be encouraged to avoid using the foot as much as possible, preferably relying on the use of crutches, or wheelchair for as brief a time as is necessary to allow wound healing.

Along with foot care, aggressive surgical wound debridement is a vital part of the 17 healing process of diabetic wounds. Devitalized tissue that can act as a site for bacte-

rial growth and as a barrier to the migration of new granulation tissue should be excised. Although they are expensive and little benefit has been shown in clinical trials, enzymatic debridement dressings are often used as part of institutional wound care protocols.

Diabetic wounds hold the distinction of being the first class of wounds shown to benefit from growth factor therapy. Topical recombinant platelet derived growth factor BB (becaplermin) and granulocyte-colony stimulating factor have both been shown to be beneficial in randomized control trials. Synthetic skin substitutes using neonatal dermal fibroblasts and Apligraf (Novartis) are often used and, as is the case in venous wounds, may help promote cellular infiltration. Lastly, strict glucose control is of utmost importance in promoting a more effective healing process.

Pearls and Pitfalls

Definitive reconstructive procedures such as flaps and grafts are doomed to failure as treatments for chronic wounds unless the primary ‘wound diathesis’ has been identified and optimally treated. Flap failure, graft loss or wound recurrence, not cure, are the more likely outcomes if the patient’s arterial, venous or metabolic issues have not been corrected. Most chronic wounds can be addressed in the ambulatory setting, through medical management, optimization of comorbidities, local debridement and proper wound care. Once tissue oxygen delivery has been assured, converting the chronic wound back into an acute wound by serial debridements leads to improved outcomes with less chronic inflammation and improved wound repair.

As is the case with antibiotics, there will likely be no single topically applied growth factor that will promote healing and be truly effective in the absence of satisfactory blood flow and local wound care. The promise of improved angiogenesis with gene therapy-enhanced wound healing agents is also under active investigation.

Suggested Reading

1.Choucair MM, Fivenson DP. Leg ulcer diagnosis and management. Dermatol Clin 2001; 19:659.

2.Lautenschlager S, Eichmann A. Differential diagnosis of leg ulcers. Curr Prob Dermatol 1999; 27:259.

3.Mekkes JR, Loots MAM, Van Der Wal AC et al. Causes, investigation and treatment of leg ulceration. Brit J Dermatol 2003; 148:388.

4.Miller IIIrd OF, Phillips TJ. Leg ulcers. J Am Acad Dermatol 2000; 43:91.

5.Simon DA, Dix FP, McCollum CN. Management of venous leg ulcers. BMJ 2004; 328:1358.

6.Weingarten MS. State-of-the-art treatment of chronic venous disease. Clin Infect Dis 2001; 32:949.

7.Weitz JI, Byrne J, Clagett GP et al. Diagnosis and treatment of chronic arterial insufficiency of the lower extremities: A critical review. Circulation 1996; 94:3026.

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acute injury (<6 months) or chronic injury (>6 months). On a cellular level, the toxic manifestations are multiple. Keratinocytes, being the most superficial and proliferative cell type in the skin, are the most radiosensitive. Erythematous reactions, which signal epidermal damage, are said to be trimodal. The first, often not clinically evident, occurs just 1-24 hours post radiation and is most likely due to activation of proteolytic enzymes and increased local capillary permeability. This is typically followed by a more intense reaction appearing approximately one week after therapy; this phase is caused by injury to the basal layer of the epidermis. Inflammatory and immune response to this injury lead to a third phase of erythema, which may occur 6-7 weeks after radiation. Complete destruction of the epidermal layer results in the characteristic moist desquamation seen in early radiation damage. Owing to the turnover time of the epidermis (59-72 days), the daily rate of epidermal loss in irradiated tissue occurs at 2.6% ± 0.2%. Other epidermal residents are also affected by radiotherapy. Exposure of melanocytes to ionizing radiation results in increased melanin transfer to keratinocytes and thus hyperpigmentation of the skin. This is seen early in treatment, whereas at a later time, melanocyte death leads to patches of hypopigmentation characteristic of chronic cases.

Of the cells in the dermis, the fibroblast is the primary target in radiation injury. Fibrotic response to multiple radiation insults (“reactive” fibrosis) has been shown to be mainly due to alterations in the physiology of this cell type. Overexpression of collagen, differentiation of fibroblast progenitors into myofibroblasts and increased production of TGF-β1, a profibrotic cytokine, all appear to contribute to clinically evident fibrosis. Paradoxically, long-term radiation leads to fibroblast depletion and thus the poor wound healing potential and compromised tensile strength inherent

18in chronic wounds. Reconstitution of chronic wounds with nonirradiated fibroblasts or with platelet-derived growth factor-BB (PDGF-BB), which indirectly stimulates fibroblasts via activated macrophages, restores normal wound breaking strength and time to healing.

Clinical Presentation

Clinical manifestations of radiation injury can be divided into acute and chronic. Acute effects include erythema, dry desquamation (which occurs at moderate radiation doses) and moist desquamation (which occurs with ablation of most skin cancers). As the skin cancer is treated, the basal epidermal layer becomes denuded, resulting in serous oozing characteristic of the last condition. It follows that as radiation injury becomes chronic, dermal and adnexal structures are affected. Hypoand hyperpigmentation, thickening of the dermis and loss of sebaceous and sweat gland function result in dessicated, poorly vascularized tissue that is difficult to handle. These changes are irreversible. Finally, necrosis and even cancer can arise from a chronic damage of a radiated target. Considering these changes, any nonhealing ulcer that arises within a radiated field must always be biopsied to rule out neoplasia.

Local Wound Care

Given these characteristics of the chronic radiation wound, its propensity to dessicate and its inability to generate the normal inflammatory response, meticulous local wound care is essential. Maintaining a moist wound bed to prevent bacterial intrusion is important. In early phases of injury, patient education is critical: one must be informed of avoidance of sun exposure, alcohol-based emollients,

cosmetic-based agents and trauma to the radiated area. Gentle cleansing with normal saline or mild soap solutions is recommended. Moist desquamation requires copious irrigation with dilute hydrogen peroxide or normal saline, followed by light application of Silvadene. When dealing with dry desquamation, one must compensate for the loss of moisture secondary to sebaceous/sweat gland destruction. Several hydrophilic preparations (e.g., hydrogels) and antipruritic agents have been used with good effect.

Beyond topical therapy, an irradiated wound must be kept clean at all times. Manual irrigation with pressurized water helps to clean off surface exudates. A helpful suggestion to patients is to use multiple forceful showers for large wounds, or the irrigating pulse of a dental cleaner for small wounds. In wounds where surface cleansing does not suffice, meticulous sharp debridement, with the overall goal of reducing or eliminating bacterial counts by clearance of devascularized tissue, is critical for wound closure. Debridement should not only be aggressive, but frequent; the presence of small amounts of devascularized tissue can result in progressive bacterial overgrowth and subsequent necrosis. The “poorly” vascularized tissues of tendon, bone and cartilage are the most troublesome to treat, due to the difficulty in maintaining a moist environment and the prevention of new tissue dessication.

Surgical Considerations

Radiation Enteric Fistula

The incidence of chronic radiation injury to the intestine, occurring in 2-5% of patients who receive abdominal or pelvic radiation, is on the rise. Its manifestations, including abdominal strictures, hemorrhage, perforation and fistulae result in com- 18 plex abdominal wall defects. Most frequently, small bowel adherent to and fixed by

scar into the pelvis receives an inordinately high local dose of radiation. This happens after treatment for rectal, bladder and gynecologic malignancies. Surgical goals in these cases consist of damage control, return of intestinal continuity and reconstruction of the abdominal wall.

Generally a multidisciplinary approach, involving nutritional, colorectal, oncological, and reconstructive specialists, is mandatory. When perforation or fistulization is present, the first objective is to decrease the amount of fluid flowing across the fistula point. This can be achieved with simple measures such as bowel rest, or require a more aggressive approach, such as proximal diversion.

A second objective is to decrease local inflammation of the soft tissues with adequate drainage of feculent material, gentle surface cleansing and antibiotics. A surgical repair can be contemplated when the wound is less acute and inflamed, when nutrition has been optimized, and when the anatomy is thoroughly understood. Even then, the complication rate can be formidable. Anastomosis of diseased and even normal bowel segments within the irradiated field is fraught with morbidity and potential mortality. Along these lines, studies have demonstrated a leak rate of 36% and mortality as high as 21% in patients who underwent resection and anastomosis in cases of radiation enteritis. The difficulty inherent in such scenarios is pinpointing exactly what segment of bowel is diseased and what is normal. Neither intraoperative frozen section nor Doppler survey of bowel segments have been beneficial in reducing complications. From this experience, it makes the most clinical sense to widely resect the bowel in the area of the fistula and to locate the new anastomosis far away from the radiation field.

At our institution, several principles are employed to guide treatment of the abdominal wall. The debridement of all inflamed tissue is critical, so that in no case should the success of the procedure depend on the healing of fibrotic, scarred tissue without pulsatile blood flow. After debridement, two independent decisions must be made to guide intraoperative planning: first, what is the quality of the abdominal wall, and second, what is the quality of the soft tissue (skin) cover? Integrity of the abdominal wall is obtained using the separation of parts procedure for midline defects. For nonmidline defects, our tissue of choice is a sheet of autogenous fascia lata. There is interest in the use of new biologic agents such as Alloderm® and Surgisys® in these situations as well to avoid the donor site morbidity of fascia lata harvest. These sheets of tissue are sewn to the undersurface of the intact abdominal wall using horizontal mattress sutures with as much overlap to good tissue as possible. When the skin can be mobilized and closed (either in the midline or over the fascia lata laterally), the procedure is finished. In certain instances, myocutaneous TFL and rectus abdominis flaps are used to provide full-thickness vascularized coverage to the abdominal wall reconstruction.

The radiated pelvis is its own subject, as radiated bowel loops often can become adherent and fistulize out the perineum. The abdominal wall reconstruction is usually not as important as keeping bowel out of the pelvis after surgery. After a wide bowel resection and placement of the new anastomosis away from the radiated field, a flap is chosen to separate the intraabdominal contents from the pelvis inflammation which can not be easily debrided. In these cases, a rectus flap with a skin paddle based obliquely from the periumbilical perforators and angled toward the tip of the scapula is raised and dropped into the pelvis. This oblique rectus abdominis

18myocutaneous flap (ORAM) is preferable to the standard VRAM flap, as this technique significantly decreases the amount of muscle harvested, while still adequately filling the pelvic dead space. The subcutaneous fat does not atrophy over time, and so the bowel loops do not have the opportunity to slowly reenter the pelvis.

Summary

Management of the irradiated wound requires a multidisciplinary approach. Knowledge of the pathophysiology of radiation damage will lead to successful care. Aggressive local wound measures, and keeping the wound clean and moist with a low threshold for surgical debridement, are critical steps towards healing. In terms of enteric damage, control of fistula in conjunction with staged bowel repair and definitive abdominal wall reconstruction with autogenous tissue, minimize local wound morbidity and recurrence.

Pearls and Pifalls

•Discard all stiff, nonpliable, inflamed radiated tissue. The best repairs discard the most tissue. En bloc resections of bowel, fistula and skin are preferred.

•Avoid the use of alloplastic materials as much as possible.

•For midline defects, use the separation of parts repair.

•Use fascia lata (or Alloderm) for nonmidline defects with good skin cover.

•Use flaps such as the TFL and/or myocutaneous rectus abdominis flaps for full-thickness abdominal wall defects.

•Use the oblique rectus abdominis myocutaneous flap to obliterate radiated pelvic defects.

Suggested Reading

1.Bernstein EF, Sullivan FJ, Mitchell JB et al. Biology of chronic radiation effect on tissues and wound healing. Clin Plast Surg 1993; 20(3):435.

2.Dumanian GA, Llull R, Ramasastry SS et al. Postoperative abdominal wall defects with enterocutaneous fistulae. Am J Surg 1996; 172:332.

3.Hall EJ. Radiobiology for the Radiologist. 3rd ed. Philadelphia: JB Lippincott, 1988:108-136.

4.Hopewell JW. The skin: Its structure and response to ionizing radiation. Int J Radiat Biol 1990; 57:751.

5.Mendelson FA, Divino CM, Reis ED et al. Wound care after radiation therapy. Adv Skin and Wound Care 2002; 15(5):216.

6.Mustoe TA, Porras-Reyes BH. Modulation of wound healing response in chronic irradiated tissues. Clin Plast Surg 1993; 20(3):465.

7.Nussbaum ML, Campana TJ, Weese JL. Radiation-induced intestinal injury. Clin Plast Surg 1993; 20(3):573.

8.Sukkar SM, Dumanian GA, Szcerba SM et al. Challenging abdominal wall defects. Am J Surg 2001; 181(2):115.

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Common Sites of Occurrence

Pressure ulcers can develop over any bony prominence. There are four areas that encompass most of the pressure sores seen by plastic surgeons:

•Ischium—due to prolonged pressure in the sitting position

•Trochanter—due to prolonged pressure in the lateral decubitus position

•Sacrum—due to prolonged pressure in the supine position

•Calcaneus and occiput—due to prolonged pressure in the supine position

Preoperative Considerations

Infection and Antibiotics

The majority of pressure ulcers do not develop invasive, soft tissue infection because they drain freely. They are all, however, colonized with bacteria. It is rare for a pressure sore to be the cause of a fever in a paraplegic patient who presents to the emergency department. For the noninfected pressure sore, antibiotics are not required. It is important, however, to rule out soft tissue infection with a thorough evaluation of the ulcer because a pressure ulcer must be free of infection prior to flap coverage. Any undrained abscess cavity should be incised, drained and packed. Grossly necrotic tissue should be debrided as it serves as a nidus for infection. Tetanus prophylaxis should be administered when necessary.

Underlying osteomyelitis is critical to diagnose prior to coverage. If a flap is placed over infected bone, there is a significantly higher risk of flap failure and other complications such as deep abscess or sinus tract formation. The diagnosis of osteomyelitis is accomplished with the measurement of an ESR level and a core needle biopsy. The combination of an ESR greater than 120 and a positive bone biopsy has

the highest combined sensitivity and specificity. A simple method of biopsy is the 19 Jamshidi core needle bone biopsy. Culturing the specimen is useful for identifying

the specific organism, but since almost all bone will be colonized with bacteria, culture alone is not sufficient to make the diagnosis of osteomyelitis. When the diagnosis of osteomyelitis is made, the patient should receive a 4-6 week course of intravenous antibiotics prior to surgery.

The use of MRI and other imaging modalities is time consuming and not cost effective. Furthermore, with the exception of MRI, most of these tests have a relatively low specificity. In academic centers in which MRI is readily available, it remains an option for diagnosing osteomyelitis.

Patient Compliance

There is a difference between a pressure sore that is appropriate for surgery, and a patient that is a good surgical candidate. Due to the high risk of recurrence and complications, a compliant patient is essential to offer any chance of treatment success. For those patients who will not be compliant with the postoperative instructions, nonsurgical management should be considered. Many individuals with pressure ulcers suffer from depression and often feel socially isolated. This is especially true for paralyzed patients. A psychiatric evaluation can be of benefit in certain cases.

Nutrition Optimization

Most insensate patients are young and can achieve an adequate nutritional status. In contrast, bed-bound, debilitated patients, especially the elderly, are often malnourished. It is critical to optimize nutritional status prior to surgery. Many surgeons use a serum albumin level of 2.0 as their minimum cut-off for surgery.