Circumferential Leg Ulcers With NPWT

Pyoderma gangrenosum (PG) is a challenging disease process to diagnose and manage. The diagnosis is often missed and even when it is considered in the differential, clinicians often mistakenly trust biopsy results, which are notoriously unreliable. As a result of delays in treatment, the lesions can be huge and even limb threatening by the time that the diagnosis is made.
 
Treatment for PG is almost always systemic—not local! The treatment is usually systemic steroids although many other drugs may be used.
 
Importantly, patients must be started on systemic medication before a treatment like negative pressure wound therapy (NPWT) can be safely applied. Without systemic treatment of the inflammatory process first, PG lesions may worsen in response to NPWT because these patients exhibit “pathergy” (worsening of wounds in response to even minor trauma). Also, without system treatment, the pain of NPWT may be intolerable.
 
This patient’s treatment for PG was delayed because the previous clinical team did not make the diagnosis. We started the patient on high dose steroids but this led to peripheral edema, which contributed to ulcerations of the contralateral (right) lower extremity. He subsequently developed necrotizing fasciitis and required multiple trips to the operating room for serial debridement. Eventually when the both the PG and the infection were controlled, it was time to treat the circumferential wounds with NPWT.
 
Applying a circumferential lower extremity NPWT dressing is challenging. It takes several skilled providers to ensure proper application (two hands are not enough), and sometimes there are anatomic structures that require a wound veil or protective layer. Many practitioners apply strips of adhesive drape to temporarily hold the sponge in place until the drape can be applied over the entire wound to create a seal. However, we found a better way that reduces the time and the number of people required to get the job done.

How I Do It

Here’s the trick: use elastic retention netting.
    1.    The sponge pieces are still cut to fit the contours of the wound bed, then laid out on either side of the leg (Figure 1).
    2.    Then the netting is applied to the foot and ankle and the sponge is tucked into the netting as it is pulled up the lower extremity (Figure 2, Figure 3 and Figure 4).  
    3.    As the netting holds these pieces in place, the contours of the wound can then be adjusted and tugged into place so that it covers the wound more accurately (Figure 5). 
    4.    Then little pieces of sponge can be placed in to fill any gaps (Figure 6).
    5.    Once everything is in place, the drape can be placed over the entire sponge/netting complex and negative pressure applied (Figure 7 and Figure 8).
 
We found that the netting did not get overly wet, and it did not cause maceration to the periwound skin. We also found that when NPWT dressing is removed, the netting actually makes removing a large amount of drape from the skin much easier for the provider and less painful for the patient (Figure 9).
 
Sandra Wainwright, MD, is the Medical Director of the Hyperbaric Medicine and Wound Healing Center at Greenwich Hospital, Yale New Haven Health Services. She is also the Director of the Hyperbaric Service Line.

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