Luc Téot - Skin Necrosis

Evidence-based medicine

When analysing the literature from an evidence-based point of view, the Cochrane review considers that debridement has not yet demonstrated its efficacy. Nevertheless, most of the practitioners and paramedics involved in wound healing recognise the beneficial effect of debridement.

Skin necrosis is not infected for the first few days, but becomes heavily colonised when the edges are dissociated from the healthy skin. The time effect depends on a number of factors, grouped under the name of comorbidity markers. These markers may define the capacity of the patient to heal. Some of them, such as ankle brachial pressure index, albuminaemia, glycated haemoglobin and blood pressure measurement are easily collected. Others, such as inflammatory markers or evolution with time of the wound healing process (surrogate end point) should be accurately determined.

Indications and contra-indications of debridement

Debridement is indicated when the limb is vascularised enough to prevent renecrosis on the edges of the wound. During the post operative period, when the skin flap becomes necrotic, a surgical revision removing the necrotic areas is required. However, lower limbs presenting an ABPI (ankle brachial pressure index) lower than 0.5 should not be debrided. When the ABPI is over 0.5, the debridement should follow an algorithm depending on multiple factors such as accessibility to surgery, availability of expertise in the use of advanced dressings such as hydrogels, hydrobalance or new debriders. Wet to dry techniques are not recommended any more.

In the presence of spreading extended necrotic areas, an adapted debridement should be quickly proposed. In necrotising fasciitis, extravasation injuries, haematomas or Fournier gangrene, a large and extensive surgical debridement, including the edges of undermined cavities, is needed and should be considered as an emergency. The immediate post-debridement period should consider the need for repetitive debridement procedures when infection is still present. New debriders such as Versajet or Coblation WoundWand are useful in destroying local germs and preventing biofilm formation.

In the case of necrotising angiodermatitis, pain and skin necrosis may need surgical debridement and rapid skin grafting using pinch grafts to stop pain.

Pressure ulcers are common causes of necrosis, particularly in the perineal area and over the heel. On the perineal area, undermining is frequently observed, as a consequence of the shearing forces exerted on the skin. The skin is more mechanically resistant than the underlying structure, a relatively small opening covering a large undermined area being frequently observed. In this situation, all hidden cavities need to be opened to expose living edges. The granulation tissue and retraction is more rapidly obtained. Excision of the cover (decap surgery) by surgical means is an option, but simple incisions along the undermined area are more easily realised by non-surgeons (Figs. ). On the heel, a vascular assessment is mandatory (pedal pulse absence is the first sign, and should indicate ABPI and Doppler ultrasound, and in case of arteriopathy a vascular surgery consultation is needed) before any mechanical debridement to prevent renecrosis of the edges. An ABPI below 0.5 is a contraindication to debride. Poor vascularisation, end of life and palliative situations are contraindications to surgical debridement.