PINTA - Prophylactic Incisional Negative Pressure Therapy for Major Amputations (PINTA)

Prophylactic Single-Use Negative Pressure Wound Therapy Devices for Closed Incision Major Amputations

Post-operative wound issues in abdominal surgery have a significant impact on patient outcomes. This study is taking place to investigate if Negative Pressure Wound Therapy (NPWT) dressings reduces Surgical Site Infections, post surgical complications and improves scar appearance compared to standard dressings.

Many factors influence the risk wound complications. Notably, the presence of unreconstructed proximal occlusive arterial disease is a major influence on stump healing. Patient factors such as smoking, diabetes, obesity, malnutrition and chronic kidney disease are non-modifiable, particularly in the short-term setting. However, surgical factors may be altered in an effort to reduce the risk of wound complications. One option amenable to alteration is what dressing is applied to the closed incision upon procedure completion. The type of dressing may influence factors such as bacterial access to the wound, the development of collections of blood or fluid in the wound or fluid oozing from the wound. Collectively, these wound factors increase the risk of wound infection. Therefore, dressings which reduce these factors have the potential to reduce wound breakdown, thereby reducing the burden for patients and healthcare systems. Negative pressure wound therapy (NPWT) removes excess fluid from wounds as well as limiting bacterial access. Negative pressure dressings consistent of an open cell solid foam, placed on top of the incision and then covered with a semipermeable membrane. A sealed tube connects the foam to a pump to create a partial vacuum over the wound. This negative pressure leads to a sealed environment which prevents bacterial migration into the wound while removing blood and serous exudate. Single-use NPWT systems (such as Smith & Nephew's PICOTM and Acelity's PrevenaTM) are now widely available. The systems can be applied and left in place for up to seven days. Prophylactic NPWT in the setting of closed surgical incisions has been widely evaluated. The most recent Cochrane review (2022) analysed data from 62 randomised controlled trials (RCTs) and 6 economic studies (12). Data were reported from 13,340 participants, undergoing a wide range of procedures (gastrointestinal, gynaecological, vascular, orthopaedic and cardiothoracic). The review was concluded with moderate certainty that prophylactic NPWT reduces SSI but not wound dehiscence. There was a possibility that prophylactic NPWT reduces mortality although the confidence intervals include the possibility of harm. Cost effectiveness studies produced differing results in differing settings with no high-grade evidence of cost efficacy. However, studies specifically investigating the impact of NPWT on closed incision major LEAs are scarce. Early results from a pilot study of prospective, multi-centre, two-arm, randomized controlled trial comparing NPWT to standard dressings after above knee amputations (AKA) and below-knee amputations (BKA) reported promising results (13). In this initial review of 43 patients, NPWT reduced the wound complication rates at 30 days, with complications noted in 5 of 21 controls (23.8%) and 1 of 22 (4.5%) in the treatment group (p=0.068). Despite this, the absence of robust cost effectiveness data to support the routine use of NPWT is of concern. NPWT is considerably more expensive than traditional dressings (approximately £120-145 versus £4 for a standard dressing). In addition, the Cochrane reviewers noted that pain and health-related quality of life were not reported by most of their included RCTs (12). Most studies randomised patients at high-risk for wound complications but did not always define high-risk clearly. Finally, the definition of surgical site infection varied amongst included studies. In particular, it remains unclear whether NPWT reduces all wound infections, superficial infections alone or deep infections. Negative-pressure wound dressings rely on a robust seal around the wound to function. This can be difficult to achieve on the relatively irregular shape of a major limb amputation wound. Seal failures often result in dressings changes, substantially increasing associated costs. Prospective evaluation of wound complications in a trial setting utilising standardised criteria will generate a robust baseline rate upon which to generate a sample size calculation for a full trial. We propose to conduct a multicentre randomised controlled trial comparing prophylactic single-use negative pressure wound therapy with standard dressings in patients with in patients with a closed incision following major lower extremity amputation in terms of SSI incidence, wound healing complications and scar appearance, patient quality of life and financial impact on the patient and healthcare system.

Negative Pressure Wound Therapy, Surgical Site Infection, Post-operative Complications, Abdominal Incision, Health Economics

Application of a negative wound pressure therapy dressing to the wound post major lower extremity amputation

Any wound complication of the amputation stump, including wound infection, dehiscence, seroma, haematoma and stump necrosis.

Inclusion Criteria: i) They are aged 18 years or older; ii) Undergoing major lower extremity amputation, including below-knee amputation, through-knee amputation and above-knee amputation, for any indication; iii) With primary closure of the surgical incision using either interrupted or continuous sutures Exclusion Criteria: i) Patients <18 years; ii) Women who are pregnant and/or breast-feeding; iii) Amputations performed without primary skin closure, including guillotine amputations, amputations deliberately left open for drainage purposes and amputations with soft tissues defects at the stump; iv) Amputations with skin glue as the only means of skin closure v) Clinically absent femoral pulse