Negative pressure wound therapy: an adjuvant to surgical reconstruction of large or difficult skin and soft tissue defects

Abstract

Wide and deep wound defects are a challenge to surgeons, particularly when aggressive or more radical operations are unavailable. This article introduces refined techniques, indications and the clinical experience of the application of negative pressure wound therapy (NPWT) as an easy ancillary wound dressing method for the reconstruction of large or difficult skin and soft tissue defects. The authors used NPWT on 88 patients as an adjuvant therapy before reconstructive surgery since 2006. NPWT was applied for two different treatment strategies: as an adjuvant therapy to facilitate the formation of a healthy wound bed and to reduce the size and depth of a defect. NPWT was used as an alternative dressing method for skin grafting for infants or mobile skin surfaces such as the neck, penis, dorsum of the hand, knee joint, abdomen, etc. There were no typical wound complications. NPWT application, if used appropriately, produces successful surgical reconstructions for large, deep skin and soft tissue defects without extensive or radical flap surgery or loss of skin graft.

INTRODUCTION

Large skin and soft tissue defects can sometimes be created after an elective tumour excision, infection or burn. Consequently, complicated, extensive or radical flap surgery may be required according to the size of the defect. Wide and deep wound defects, however, are a challenge to the surgeons, particularly if aggressive or more radical procedures are unsuitable because patients are either too old or too young or the patients have poor general health or are uncooperative to radical surgery. Although the effectiveness of negative pressure wound therapy (NPWT) is controversial 1, 2, 3, the authors had a successful experience of using NPWT. Therefore, this article introduces the refined techniques, indications and clinical experience of NPWT as an easy ancillary wound dressing method for the reconstruction of large or difficult skin and soft tissue defects.

PATIENTS AND METHODS

Since 2006, NPWT was administered to 88 patients as an adjuvant therapy for surgery. Vacuum‐assisted closure (V.A.C.®, Kinetic Concepts, Inc., San Antonio, TX) was used according to the manufacturer's user guides (http://www.kci1.com/KCI1/vacusermanuals) and the guidelines of the US Food and Drug Administration (FDA) (http://www.fda.gov/Safety/MedWatch/SafetyInformation/SafetyAlertsforHumanMedicalProducts/ucm190704.htm). This treatment was applied under two conditions: one condition is a situation when acute or chronic complicated wounds are presented as wide and deep skin and soft tissue defects but an immediate reconstruction or aggressive or more radical operations are not feasible because the wounds are unsuitable for an early reconstruction, the patients are either too old or too young, have poor general health or are uncooperative (30 patients). The other condition was to improve the result of skin grafting. It was a good adjuvant dressing method for skin grafting, particularly for infants or mobile skin surfaces, such as the neck, penis, dorsum of the hand, joint surface and abdomen (58 patients).

RESULTS

The authors used NPWT as an adjuvant or dressing method before reconstructing the soft tissue defect. There was no typical wound complication during the procedures and most patients were satisfied with the final outcomes. NPWT was applied to 30 patients with a wide, deep, irregular wound defect combined with a minor infection (Figure 1). Among them, there were two immunocompromised patients, who had undergone systemic steroid treatment or chemotherapy. Thirteen wide pressure ulcers were reconstructed by full (3 patients) or thick split thickness skin graft (STSG; 10 patients) with a flap (Figure 2). Six chronic diabetic and one venous ulcer could be reconstructed successfully without microsurgery. As NPWT was an adjuvant procedure before final reconstructive surgery, the duration of NPWT treatment varied considerably according to the status of the wound defect size and location. Normally, 4–8 weeks (average 4·7 weeks) application of NPWT was sufficient to produce a good environment for the final surgical procedures. Surgery was performed as soon as possible when a successful reconstruction was feasible. In our cases, after applying NPWT, the average decrease in defect size was 15·2% (range 5–52·4%), but this cannot be attributed purely to the effect of NPWT because the size‐reducing effect of NPWT normally depends on other important factors, such as the patient's age, nutritional status, duration of NPWT application and wound types or locations. An adjuvant dressing method for skin grafts with NPWT was particularly effective and provided a good final result in 58 patients (5 perineal areas, 13 lower extremities, 7 dorsum of hands, 6 necks and shoulders, 2 chests, 12 upper and lower arms, 3 ankles, 3 dorsal feet, 1 thumb and 6 abdomens). Moreover, there were no problems, such as detachment of the dressing, graft failure or pain in any of the patients. It was particularly useful for an infant or a mobile skin surface, such as neck, penis, dorsum of the hand, joint surface and abdomen, because NPWT provided absolute continuous compression power regardless of the area (Figure 3). A Fournier's gangrene was reconstructed successfully by using bilateral anteromedial thigh fasciocutaneous flaps and STSG assisted by NPWT at the same time (Figure 4).

Figure 1.

Reconstruction of a large defect from resected giant dermatofibroma in the gluteal area. A 16‐year‐old girl presented with multiple brown skin lesion on the left gluteal area, which enlarged gradually and was painful and itchy for a few months. (Left) A general surgeon removed the skin and soft tissue lesion. The largest diameter of the defect was approximately 10 × 12 cm. Histological examination showed conventional dermatofibroma. Although there was a minor infection, copious saline and bethadine irrigation eradicated infection. After confirming there was no bacterial colony from the culture result, NPWT was administered. (Middle) Three weeks later, the cavity size was reduced by half. (Right) The patient subsequently underwent a reconstruction with wide debridement and two semicircular flaps.

Figure 2.

Reconstruction of extensive pressure ulcer. A 58‐year‐old patient presented with a wide sacral pressure ulcer. Necrotising fasciitis was developed but infection was controlled with copious irrigation and debridement. (Left) The patient was referred from the department of general surgery. The wound measured approximately 20 × 30 cm. (Right) After adequate healthy granulation tissues were generated and most soft tissue tunnels were closed using NPWT, the patient underwent a simultaneous gluteal thigh flap, gluteus maximus muscle flap and thick split thickness skin graft (12/1000 in. thickness) reconstruction.

Figure 3.

Reconstruction of penile skin defect after removal of vaselinoma. A 52‐year‐old male patient was referred from the department of urology with circumferential penile and scrotal skin defect. Paraffin was injected into the penile skin 20 years earlier. (Above, Left) Inflammation and scrotal abscess developed. (Above, Right) An urologist removed all foreign materials. (Below, left) A thick split thickness skin graft (12/1000 in. thickness) was applied with a circumferential negative pressure wound therapy (NPWT) dressing. (Below, right) The patient experienced no complications and was discharged 10 days after surgery. Readers must read the refined technique (16) prior to circumferential application of NPWT because total necrosis of penis can develop.

Figure 4.

A case of Fournier's gangrene of scrotum, penis and perianal areas. This case is a 54‐year‐old man who had diabetes and an anal abscess, which resulted in a wide skin and soft tissue defect on perianal area, scrotum, penis and abdomen because of Fournier's gangrene. (Left) Repeated serial debridements were accomplished by urologists and general surgeons for approximately 1 month and the patient was referred to the department of plastic and reconstructive surgery for reconstruction procedure. At the first stage, extensive debridement and closure of abdominal wound were performed. At second stage, wounds of both scrotal, penile and perianal wound were covered with bilateral anteromedial thigh fasciocutaneous flaps and STSG assisted by NPWT all the same time. (Middle) Flaps were easily elevated with cutaneous nerves and applied to wounds and effective reconstructions were performed without orchiectomy. The patient was in the supine and hip abduction position for 5 days. The drains were removed after 72 hours. (Right) There were no serious complications. Minor revisional surgery was required because the margin of the flaps showed small necrosis. Simultaneous early rehabilitation enabled the patient to return to ordinary daily life.

DISCUSSION

NPWT was developed in the 1990s and has been approved by the US FDA and Korea FDA (KFDA) to treat a variety of chronic, acute, traumatic, subacute and dehisced wounds. In general, the system is relatively easy to use and is well tolerated by patients, particularly by pediatric patients (4). There are many interesting applications of NPWT. Hanasona et al. reported that the NPWT device is a useful tool in the fixation of skin grafts to microvascular free flaps and that its use does not compromise the free flap viability (5). Chronic wounds (6), skin graft for Mayer–Rokitansky–Küster syndrome (7) and the orbit of postexenteration can be reconstructed successfully with NPWT (8).

NPWT manufacturers are currently located in the USA and other countries. In South Korea, CuraVac™ (Daewoong Co. Ltd, Seoul, Korea) is also available by the permission of the KFDA. Recently, the cost of foam or sponge materials used in NPWT for wide skin defects is partially supported by the Korean national medical insurance system.

The mechanism of NPWT is based on the principles of physics (9). The application of controlled subatmospheric pressure imposes a mechanical stress to tissues, which induces wound contraction. As a result, mitosis is stimulated and new vessels are formed. Negative pressure therapy in theory reduces the local interstitial tissue oedema, increases microperfusion of the wound, reduces bacterial colonies, stimulates healthy granulation tissue growth in the wound bed and improves wound microenvironment. Negative pressure therapy results in accelerated wound closure. Acute or chronic wounds treated with NPWT show increased local IL‐8 and VEGF concentrations, which may trigger the accumulation of neutrophils and angiogenesis, thereby accelerating neovascularisation (10).

Some argue that NPWT confers no economic advantage compared to conventional dressing. There is a large range of opinions regarding the cost‐effectiveness of NPWT (11). The authors, however, experienced accelerated wound closure, increased wound bed vascularity, abundant growth of granulation tissue and defect size reduction with NPWT, which is consistent with the experience of Campbell (12). NPWT is a safe and effective method for securing skin grafts as Scherer suggested (13). Although the manufacturers and Scherer (14) suggested that intermittent application of pressure was more effective in facilitating formation of granulation tissue than constant pressure application and Borgquist (15) reported that the application of 80 mmHg of pressure has similar blood flow effects as 125 mmHg, the authors experienced optimal outcomes at 120 mmHg of pressure.

Refined techniques are very important when applying NPWT safely or without complications. This article describes the procedures for applying NPWT. It is important to remove devitalised or necrotic tissues and controlling infections or arterial bleeding before applying NPWT. NPWT can be used to facilitate the formation of a healthy wound bed, faster growth of granulation tissue and reduce the size and depth of a defect. After cleaning the wound with copious saline or povidon iodide irrigation, the NPWT foam was cut to fit the shape and size of the wound, including the tunnels and undermined areas. The wound was covered with adhesive drape and a pinched drape, a 2‐cm round hole was cut and the adhesive pad was then placed on the excised site. A tube was connected to a canister of the NPWT machine. Secured sealing and target pressure (120 mmHg) was achieved, and there must be no randomness of the negative pressure or air leakage. During the period of NPWT application, the authors checked for the maintenance of pressure, inflammation or bleeding sign by inspecting the fluid accumulated in the canister daily. The authors usually prefer a continuous mode of pressure (120 mmHg) over an intermittent mode. 5‐cc saline was injected to the foam over the drape every other day and sealed again with transparent tape (Tegaderm™, 3M, St. Paul, MN) for more moisturising wound conditions. When replacing the adhesive foam and pad twice a week, the authors gently lifted, rather than pulled the drape off the skin. Normal saline with 50 cc syringe was normally infused before replacing the foam because it induced spontaneous separation of the sponge from the wound surface without bleeding. Aggressive cleaning and debridement or curettage was repeated at each time during the procedure of replacing NPWT. If there is any sign of infection, the application of NPWT was discontinued, and the dressing method was changed into another. With the application of NPWT repeatedly, an effective decrease in the size of wound defect or healthy granulation tissue on the wound surface could be achieved. Therefore, a simpler operation, such as a regional flap or skin graft, could be performed.

Meanwhile, if NPWT is used as an alternative dressing method for performing a split or full thickness skin graft for infant or mobile skin surface, such as the neck, penis, dorsum of hand, knee joint and abdomen, some techniques were considered. As NPWT provided continuous compression power and a moisturising environment irrespective of the body area, the graft was taken more successfully. Using a no. 11 blade, multiple linear incisions (3–5 mm length) were made on the harvested skin, which enabled NPWT to evacuate the haematoma or seroma through the slit. The harvested skin was then sutured at the recipient site, and vaseline and paraffin gauze (Bactigras®, Smith & Nephew, Hull, UK) were placed over the graft. The NPWT foam was cut slightly 1–2 cm larger than the graft skin and overlaid on the paraffin gauze and fixed to the normal skin around the periphery of the graft skin. Secure and continuous moisturised compression by the NPWT foam was achieved after the skin graft, even for a child or infant, but a small splint may be useful for immobilisation of the joint area. Excellent graft take was achieved irrespective of the wound bed characteristics, for example, wounds are located in mobile areas, such as abdomen or uneven, bulged wound skin surfaces. Three days after the graft, 5–10 cc normal saline was injected directly into the foam of NPWT, which had some advantages because it removed the minor haematoma and cell debris and provided a more moisturised environment. NPWT was removed 5–7 days postoperatively. After injecting sufficient saline solution and waiting for approximately 1–2 minutes, NPWT was removed slowly and classical wet to dry dressing was applied for a further 2–4 days.

The following are normally considered contraindications for NPWT applications: wounds with necrotic tissue, untreated osteomyelitis, fistulas to organs or body cavities, placement directly over exposed veins and arteries, or a malignancy within the wound (4). Our experience suggests that few complications will develop if the surgeons pay particular attention to the following: (i) do not apply NPWT to an infected or necrotic wound, aggressively clean the wound and periwound areas and debride the necrotic tissue completely before applying NPWT, (ii) apply NPWT using an aseptic technique after controlling active bleeding in the wound, (iii) apply normal saline infusion, if necessary, to moisten the wound bed and loosen the sponge before removing the sponge from the wound bed and (iv) if the colour of fluid collected in the tube of the canister is yellowish, turbid or has a foul smell, stop applying NPWT and change the dressing method.

Although NPWT cannot replace surgery and early surgical reconstruction must be performed as soon as possible, as shown in our cases and systemic reviews (15), if NPWT is administered as an alternative dressing method, its application can sometimes result in a successful surgical reconstruction of large and deep skin and soft tissue defects.

CONCLUSION

NPWT is an adjuvant and effective dressing method for the preparation of wound bed in large skin and soft tissue defects. NPWT can also be used effectively to improve the result of skin grafting. Although NPWT per se cannot replace a surgical procedure, using NPWT appropriately, a simpler surgical procedure can be performed rather than an extensive or a radical surgery in selected cases. In particular, it is very useful when aggressive or radical procedures are unavailable, or the wound is unsuitable for an immediate reconstruction, the patients are too old or too young, the general health is poor, or the patient does not want to undergo radical surgery.

ACKNOWLEDGEMENT

None of the authors has a financial interest in any of the products, devices or drugs mentioned in this article.