Closed Incision Negative Pressure Therapy: Review of the Literature

Surgical site infection and other common surgical site complications (dehiscence, hematoma, and seroma formation) can lead to serious and often life-threatening complications. Gauze, adhesive dressings, and skin adhesives have traditionally been utilized for incision management. However, the application of negative pressure wound therapy over clean, closed surgical incisions (closed incision negative pressure therapy, ciNPT), has become a recent option for incision management. A brief review of ciNPT clinical evidence and health economic evidence are presented. A brief literature review was performed using available publication databases (PubMed, Ovid®, Embase®, and QUOSA™) for articles in English reporting on the use of ciNPT between October 1, 2016, to March 31, 2019. The successful application of ciNPT over clean, closed wounds has been reported in a broad spectrum of patients and operative interventions, resulting in favorable clinical results. Four of the five studies that examined health economics following the use of ciNPT reported a potential reduction in the cost of care. The authors’ own experience and published results suggest that patients at high risk for developing a surgical site complication may benefit from the use of ciNPT during the immediate postoperative period. Additional studies are needed across various surgical disciplines to further assess the safety, and cost-effectiveness of ciNPT use in patient populations.


Introduction And Background
Surgical site infections (SSIs) and other common surgical site complications (dehiscence, hematoma, and seroma formation) can lead to serious and often life-threatening complications. Recent reports suggest that there are 8.2 million people at risk for SSIs annually in the United States [1][2][3]. SSIs frequently occur and are now the most common and costly of all healthcare-acquired infections, with a reported incidence ranging from 15-37% [4][5][6][7]; and accounts for 33.7% of the $9.8 billion costs to the US healthcare system per year [1].
Standard of care (SOC) therapy typically consists of dry or moistened gauze, abdominal pads, adhesive dressings, or skin adhesives. However, gauze dressings have been criticized for their inherent nonocclusive nature [8] and associated with a higher infection rate than transparent films or hydrocolloids [9,10]. A more recent option for surgical incision management, especially

Literature Search
A total of 88 articles were identified during the literature search. Once duplicates and articles not meeting the inclusion criteria were removed, 40 articles were identified. Of these included articles, 12 were randomized controlled trials (RCTs), six were prospective cohort studies, 15 were retrospective comparative studies, and seven were case series.

Economic Analysis of Published Clinical Studies
Only two studies identified from the literature search examined the economic impact of ciNPT use in patients at high risk for developing SSIs (Table 3) [14,28]. The Kwon et al. study indicated a cost savings of $6,045 in ciNPT patients; however, Ruhstaller et al. found an increase in patient costs ($10,300) in the ciNPT patient group [14,28]. More economic studies are needed to fully assess the potential economic benefit of ciNPT use.

Author Patient Population Results
Kwon et al. [14] 119 incisions; vascular surgery ciNPT, n=59 Control, n=60 Cost for high-risk ciNPT group care was $6,045 less than the high-risk control group, though not statistically significant (p=0.11).
Ruhstaller et al. [28] 136 patients; Cesarean delivery ciNPT, n=67 Control, n=69 The prevention of one SSI would increase patient costs an average of $10,300 (US). 28 ciNPT would need to be placed to prevent one SSI.

TABLE 3: Economic evidence in the use of closed incision negative pressure therapy
ciNPT -closed incision negative pressure therapy

Patient Selection
The potential clinical value of ciNPT over clean, closed surgical incisions in a variety of patients at risk for developing surgical site complications has been shown in a growing body of literature. A review the RCT literature reports that patients that benefit most from ciNPT use were those at greater risk for infection, seroma, hematoma, and dehiscence [14-16, 18, 19]. These patients were found to have one or more risk factors that negatively affected wound healing and were undergoing high-risk surgical procedures. Stannard and associates have proposed the use of a Patient Grading System, which may be helpful in identifying candidates for ciNPT use ( Table 4) [29]. Known patient risk factors or comorbidities include diabetes, obesity, smoking, hypertension, steroid use, radiation exposure, and other factors affecting wound healing (Table 5) [30,31]. Patients without pre-existing medical conditions may not be candidates for the ciNPT use as their surgical incisions usually heal well on their own [31,32].

Patient Risk Factors Description Grade
Otherwise healthy, no pre-existing medical conditions No risk factors Grade 1 Presence of a known risk factor* Single risk factor Grade 2 Presence of multiple known risk factors Multiple risk factors Grade 3

Discussion
SSIs and other common surgical site complications (dehiscence, hematoma, and seroma formation) can lead to serious and often life-threatening complications. Traditional postoperative incision management has included gauze dressings, adhesive dressings, and skin adhesives; however, ciNPT can offer healthcare providers another incision management option.
A growing body of evidence has reported reduced rates of SSI and other surgical site complications resulting from ciNPT usage. The literature search identified 12 RCTs, a majority of which reported reduced SSI rates, reduced readmission rates, and reduced reoperation rates. Six of the non-RCT, comparative studies identified also reported reduced rates of SSIs, readmissions, and reoperations [20][21][22][23][24][25]. However, these studies examined a wide range of patients, with a variety of comorbidities, undergoing different surgical procedures. Thus, a definitive conclusion on the potential clinical benefit of ciNPT for specific patient groups or surgical procedure cannot be made with this literature search. Future meta-analyses limited to specific patient groups and surgical procedures are necessary.
Health economic data for ciNPT use is limited. While only two studies were identified in the literature search, they provided differing conclusions [14,28]. Additionally, since 2009, only three other studies examining the health economics of ciNPT use have been published [33][34][35]. Chopra et al. [33] report that in their 829 patients undergoing abdominal wall reconstruction, ciNPT use resulted in an estimated cost savings of $1,542.52 and could be a cost-effective option when the estimated SSI rate is above 16% for the patient population. Similarly, Grauhan et al. [34] reported an estimated cost savings of 60,000,000€ to 90,000,000€ per year in Germany for patients undergoing cardiac surgery. Matatov and colleagues [35] noted that for their vascular surgery patients, none required an extended hospital stay or care for SSI, suggesting cost savings with ciNPT use compared to the >$45,000 costs for infection care and extended hospital stay for two control patients with Szilagyi grade III infection. Despite these additional studies, the health economic analysis of ciNPT use requires further research as the current body of literature is too limited to provide a definitive conclusion.

Limitations
This review is not without limitations. The review presented is not a systematic meta-analysis, but a literature review including both RCTs and observational studies and a variety of patient subgroups and surgical types. A number of meta-analyses have been published in recent years with results in favor of ciNPT use; however, they do not list patient use selection recommendations which we believe is beneficial for healthcare providers considering adding ciNPT to their patient treatment plans. As this review included a variety of patients and surgical procedures, additional patient subset or surgical type-specific meta-analyses are necessary to draw conclusions on the clinical effectiveness of ciNPT use. Additionally, health economic data regarding ciNPT use is limited. More research is needed as current data is too limited to provide a definitive conclusion.

Conclusions
The published literature suggests that patients at high risk for developing a surgical site complication may benefit ciNPT during the immediate postoperative period. Additional studies are needed across various surgical disciplines to further assess the safety, and costeffectiveness of ciNPT use in patient populations.