Introduction
Pressure ulcers represent a major medical and socio-economic problem. They significantly impair a patient’s quality of life and may even become life-threatening if left untreated or treated inadequately.1 Although a number of innovative conservative and operative treatment options have been developed, definitive coverage of pressure ulcers remains a challenge.2 The most common sites of predilection are the ischium, sacrum, trochanter and heel. Many factors such as medical conditions, psychological situation and social circumstances have to be considered for an adequate treatment of pressure ulcers. The prognosis of the patient with regard to his mobility and recovery is important for decision making.

Figure 1: Infected right hip joint with loss of both parts of the joint and
chronic osteomyelitis beneath a 4th ° ischial pressure ulcer.

Treatment of pressure ulcers includes several conservative and surgical approaches. In many instances, medical care and maintaining patient comfort should be the goals rather than the institution of major invasive procedures. Generally speaking conservative therapy is appropriate for superficial ulcers in transiently immobilized patients, whereas deep ulcers above bony prominences in long-term immobilized patients such as paraplegic patients require surgery with a flap reconstruction to achieve sufficient and durable coverage. Wound healing and prevention of recurrence become the goals following successful closure of a pressure sore. In addition, reconstruction of any pressure ulcer is aimed at improvement of patient hygiene and appearance, prevention or resolution of osteomyelitis and sepsis, reduction of fluid and protein loss through the wound, and prevention of future malignancy (Marjolin ulcer). Surgical debridement is almost always indicated in advanced ulcers with involvement of the deep tissue, and when conservative wound dressings fail to clean the wound, or when deep ulcers contain significant amounts of necrotic tissue. Surgical debridement may also be carried out to accelerate conservative treatment of more superficial ulcers. Longstanding ulcers are bacterially contaminated. In order to prepare the recipient site for successful plastic surgical flap coverage, the wound bed has to be optimized. The vacuum-assisted closure (V.A.C.®, KCI, Europe) technique is widely used to induce and promote wound healing.3 Surgical debridement combined with topical negative pressure therapy using the VAC device represents a promising tool to facilitate definitive surgical closure with grafts and flaps.4,7,8,9

Figure 2:Typical pressure ulcers with the hip joint still affected after three months
of conservative treatment and first aggressive surgical debridement.

Figure 3: Following surgical debridement a V.A.C. device is applied to a pressure ulcer with
continuous negative pressure until proper wound bed preparation has been achieved.

Methods and Techniques
Since pressure ulcers are analogous to an iceberg (small visible surface with a more extensive unknown base), those more advanced ulcers presenting with muscle involvement and exposed bone (stage III and IV) were selected to receive surgical debridement and plastic surgical closure (Figures 1 and 2). The ulcer’s extent was marked with methylene blue prior to excision. The ulcer was then excised en bloc with the surrounding skin, underlying bursa and soft tissue calcifications as well as the underlying infected bone. Affected bony tissue was radically removed. Accurate haemostasis was always ensured since blood loss may be significant during and after debridement. After excision the bone was carefully recontured in order to prevent recurrence of the ulcer. In our trial surgical reconstruction was attempted after radical surgical debridement followed by continuous Vacuum therapy (V.A.C.®, KCI Int., Amsterdam) until the wound bed was ready for flap surgery (Figures 3 and 4). Continuous negative pressure was applied with –125mm Hg and the wound effluent was collected in a canister. Dressing changes were performed every 48 hours during the wound treatment period. Sequential debridement of necrotic tissue took place when considered clinically needed.

Figure 4: Principles of action of the V.A.C. therapy device (with kind permission of KCI Europe).

Reconstruction was only carried out after complete and radical ulcer excision and adequate preparation of the wound. Tension-free closure of the defect and donor site was always achieved. Preferably, scars were avoided in the region of the former ulcer and above bony prominences. Local fasciocutaneous or myocutaneous flaps were raised and placed in the defect. The choice of flaps followed an ‘escalation scheme’ from simple procedures to more complex coverage techniques (so called ‘reconstructive ladder’) to allow for secondary surgery of relapses in the future. Therefore, for many posterior pressure ulcers of the ischial and trochanteric regions an axially vascularized posterior thigh flap was the flap of first choice for many of our patients (Figures 5 and 6). However, a stepwise approach for any specific defect site was chosen according to individual needs. Free flaps remained as an ultimate solution. Closed suction drainage and perioperative antibiotics administration as well as pressure-relieving positioning in air fluidized beds for three weeks followed by three more weeks on an alternating pressure mattress were generally performed.5 Sutures were left in place for 21 days following flap coverage.

Figure 5: To allow for further surgical options in case of relapse a fasciocutaneous axially vascularized flap
(here: posterior thigh flap) is always the method of first choice in our treatment algorithm.

Results
Between 1983 and 2004 a total of 89 patients with single or multiple pressure ulcers were treated with flaps. From 2001 we used the vacuum device in 14 pressure ulcer patients to prepare the wound bed after surgical debridement and prior to transposition of fasciocutaneous or myocutaneous pedicled flaps. In these patients the use of the vacuum sealing technique following irrigation and debridement decreased the dimensions of the initial wound, thus facilitating healing and the eradication of any pre-existing infection. We found that the period of wound bed preparation was significantly shortened after the introduction of VAC pre-treatment. The majority of patients (93%) with stage III and IV ulcers achieved sufficient wound closure within six weeks of debridement and continuous vacuum pretreatment. Secondary healing occurred in 3.5% of the patients, whereas in the historic control group without VAC pre-treatment the rate was 7.9%. One of the patients with partially secondary wound healing was irradiated in the flap area.

Figure 6: After inset of the posterior thigh fasciocutaneous flap the donor site can be primarily closed.
Note that the tip of the flap has been desepithelialized and buried to fill up the cavity of the ulcer.

Discussion
Whereas for chronically- or terminally-ill patients with long-standing or recurrent ulceration a conservative approach is best suited to deal with a pressure ulcer, aggressive surgical treatment remains in the best interest of the patient when the therapeutic aim of treatment is either to resolve an acute infection with septic conditions or to close the wound and reintegrate the patient into social life. Once the decision has been made to treat a pressure ulcer surgically the mainstay of any procedure is a thorough surgical debridement before surgical closure can be achieved. Very few pressure ulcers can or should be closed primarily following debridement due to unacceptably high complication rates. However, this period of wound bed preparation can be tedious and time consuming. Both factors contribute to some of the major socio-economic problems in pressure ulcer treatment. With the advent of negative topical pressure application following surgical debridement a significant enhancement of this wound bed preparation period has been noticed.

Although the exact mechanism is not yet known in detail, it is hypothesized that negative pressure contributes to wound healing by reducing the bacterial load and removing excess interstitial fluid thereby reducing oedema, increasing vascularity of the wound and creating force to draw the edges of the wound closer together.6 Complications of flap reconstruction include haematoma, seroma, wound separation, flap necrosis, flap dehiscence and infection and these have contributed in part to the bacterial load of the ulcers. The technique of vacuum pre-treatment after surgical debridement and before a definitive wound closure with surgical flaps has resulted in a high flap survival rate (93%) and fewer immediate infection complications. Furthermore, in our experience, it has reduced the rate of seroma formation. We have yet to analyze thoroughly the long-term results of our reconstructed complex pressure ulcer wounds, but we expect this analysis to confirm the long-term efficacy of these reconstructions. In conclusion, the vacuum sealing technique represents an effective option in the management of chronic pressure ulcers and allows efficient and safe plastic surgical reconstruction.

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