Severe Pedal Necrosis: When Bandage Management Goes Wrong

This case with Surgeon Ashley Magee, DVM, DACVS, demonstrates the drastic consequences that can occur if a distal extremity bandage is not managed properly, as well as the wound management techniques used to salvage the limb.

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Bandages are commonly used in the management of injuries to the distal extremity in veterinary patients. Bandages offer many benefits for healing of wounds and other injuries to the limb; they provide support, decrease edema, maintain warmth, prevent contamination and hold medications in place. Management of an injury under a bandage also has some inherent risks – one of the main risks involves compromise of the circulation to the extremity by an improperly placed or maintained bandage. Clients must be well educated in bandage management and their potential complications and counseled to seek veterinary attention immediately should warning signs indicating a potential problem with the device occur. The case presented below demonstrates the drastic consequences that can occur if a distal extremity bandage is not managed properly, as well as the wound management techniques used to salvage the limb.

A young adult, large-breed dog was being managed in a splint and bandage post-orthopedic repair for a ruptured tendon. The patient had recovered well from the surgery and was fully weight bearing on the limb. Approximately four weeks post-operatively, the patient was left with a secondary caregiver while the client was out of town. During this time, the patient began chewing at the bottom of the splint and bandage. Previously the dog had left the splint and bandage alone. The caregiver called the hospital and was counseled to bring the patient in for an exam and bandage change immediately. Due to a hectic schedule, the caregiver elected to postpone evaluation until after the weekend. When presented to the hospital 48 hours later, the patient was febrile and non-weight bearing lame on the left hind. The foot with the splint and bandage was covered with a layer of plastic bag encased in electrical tape. A fetid odor was present. Upon removal of this outer covering, the end of the splint and bandage were found to be tattered and wet. The foot was markedly edematous, pale and cold (Figure 1) from the metatarsophalangeal joints distally, consistent with strangulation of the foot by the electrical tape. Evaluation of the foot showed necrosis of the second digit and much of the skin surrounding the metatarsal pad and fourth digit, extending to deep tissue on the plantar surface (Figure 2). Dorsal pedal and plantar pulses were not visible and several thrombosed plantar veins were appreciated. The patient was initially managed with debridement of all devitalized tissue including the second digit and an osmotic bandage in hope that circulation would improve and allow salvage of the foot. Empiric antibiotic therapy was instituted while awaiting culture results. Application of vacuum assisted wound therapy (VAC) was recommended to improve circulation, remove excess edema, facilitate autolytic debridement, and speed the early phases of wound healing.

Figure 1a. Foot at initial presentation. Note sharp line of demarcation in the bandage at the level where to tape was placed.

Figure 1b. Tape and plastic that were placed around the bandage.

Figure 2a-c. Plantar, medial and lateral views of the foot at presentation. Note multiple areas of tissue sloughing, including all of digit 2.

The next day the patient was reevaluated and, while still markedly edematous, no further major necrosis of the foot was appreciated. After a second sharp debridement, a VAC therapy device and bandage was placed on the foot with the patient under heavy sedation (Figure 3). The patient was hospitalized for 72 hours while the device was in place, running a vacuum at -125 mm hg. At bandage removal, the wound was markedly improved, with removal of remaining deep devitalized tissue, improved circulation, and the start of a healthy granulation tissue bed (Figure 4). At recheck three days later, wound condition continued to improve, with granulation tissue covering exposed tendon in the wound (Figure 5). Ten days later, the wounds were granulating and contracting nicely (Figure 6). By eight weeks post injury, the foot was healed and functional. Some loss of flexor control to the third digit was noted but not clinically significant (Figure 7).

Figure 3a: VAC therapy system applied to foot

Figure 3b: Suction canister collecting wound exudate

Figure 4: Day 1 post VAC removal

Figure 5: Day 4 post VAC removal

Figure 6a: Day 11 post VAC removal

Figure 7: Day 58 post VAC removal

This case graphically illustrates the devastating consequences of bandage mismanagement. It also exemplifies the effectiveness of VAC therapy as a method to facilitate the healing of severe injuries.

In the case above, some form of irritation likely developed at the level of the digits, resulting in the patient chewing at the foot of the bandage. When the caregiver added inelastic tape and an impermeable barrier (plastic bag), moisture and swelling developed. As this progressed, the tape acted as a tourniquet and effectively prevented vascular flow to and from the foot, resulting in edema followed by venous outflow obstruction and eventual necrosis. Bacterial colonization of necrotic tissue was facilitated by the moist environment created by the plastic bag.

As illustrated in this case, bandage and splint complications can result in injuries more devastating than the condition from which they are recovering. Detailed discharge instructions, both verbally and reinforced in written form are extremely important and cannot be overemphasized for any patient wearing an extremity bandage. The need for an immediate reevaluation if any change is noted with the bandage or the patient’s comfort level is paramount. Unfortunately, even the most well-educated and well-meaning clients can make a mistake.

Vacuum assisted therapy was chosen as a treatment modality due to documented improvement in blood flow to wounds, decreased edema, increased rate of granulation tissue formation, and decreased reduction in the numbers of pathogenic bacteria within a wound. VAC therapy also improved adherence of avulsed skin from subcutaneous tissue beds. VAC therapy uses an open cell foam dressing applied over wounds and covered with an impermeable plastic film. A suction device and tubing is placed over the foam and connected to a specialized vacuum and reservoir. Continuous suction at -125 mm Hg is used for 48 to 72 hours to draw exudates and edema from the wound while encouraging blood flow and oxygenation to the tissues. When the device is removed, delayed primary closure of the wounds can be performed if applicable, either with or without a second round of VAC therapy to support the wound closure. For this pedal injury, which included vascular compromise, infection and minimal available tissue available for later reconstruction, we were able to effectively salvage the foot using a combination of surgical debridement, digit amputation and open wound management with VAC therapy.

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