The Efficacy of Negative Pressure Wound Therapy for Split-thickness Skin Grafts for Wounds on the Trunk or the Neck: A Randomized Controlled Trial

Introduction. Because applying a splint for a wound on a patient’s trunk or neck (including areas such as the shoulder, chest, buttock, axilla, and abdomen) is considerably difficult, grafted skin may not firmly affix at the wound site. Objective. A study was conducted to compare negative pressure wound therapy (NPWT) to conventional bolster dressings in facilitating firm split-thickness skin graft (STSG) attachment and allowing relatively easy removal of exudates. Materials and Methods. A randomized controlled trial was conducted among 57 patients with wounds on the trunk or the neck who received STSGs between January 2013 and December 2017. Prospective and retrospective data were used for analysis in this study. Patients who were pregnant, immunocompromised, or had severely infected wounds were excluded from the study. Due to discomfort, splints were not used. Patients were divided into 2 groups. Group 1 was provided a NPWT dressing; NPWT was applied continuously for 6 days between -75 mm Hg and -100 mm Hg with dressing changes at postoperative days 3 and 6. After postoperative day 6, antibiotic cream and a nonadherent foam dressing were used on the wounds. Group 2 was provided a conventional bolster dressing for the same time frame. The Mann-Whitney U test was used to compare the variables and outcomes between the 2 groups. Differences were considered statistically significant for P < .05. Results. Among the 57 patients, 27 received NPWT and 30 received the bolster dressing. The size of the wounds in these patients ranged between 100 cm² and 400 cm². In group 1, the average survival score for the skin graft was more than 80 in all patients after postoperative day 7. In group 2, major graft loss occurred in 5 patients, requiring a second STSG. The average score of STSG survival on postoperative day 7 in group 2 was lower than that of group 1. The differences observed between the 2 groups were overall statistically significant (P < .01) based on the results of the Mann-Whitney U test. Conclusions. Owing to the flexibility and elasticity afforded by the transparent adhesive film that is used in NPWT technique, patients were more mobile and felt little discomfort compared to conventional procedures. The negative pressure dressing increased the percentage of graft survival and may reduce need for a second STSG. 

A split-thickness skin graft (STSG) is commonly used for wound coverage owing to its ease of use, the ability to expand coverage via meshing procedures, and the better quality of scar healing than that obtained via secondary interventions.¹ However, STSGs on the trunk or the neck are associated with high rates of morbidity, which presents a significant problem for the patient and surgeon during the early postoperative period. The rate of STSG failure in total has been reported to be between 0% and 33%.²

The recipient area for the STSG must not be infected or excessively exudative; granulation tissue, if present, must be flat and not produce much exudate; and hemostasis must be ensured. Any collection of exudate or blood under the graft jeopardizes graft survival because it hinders adherence and penetration of newly formed capillaries Negative pressure dressing was applied for 6 days with the first negative pressure dressing being changed on postoperative day 3 and the second dressing on day 6. After postoperative day 6, antibiotic cream and nonadherent foam dressing were used on the wounds. Therefore, immobilization of the STSG is critical for fixation. In cases where STSG recipient areas are on the extremities, splints have been shown to be useful for preventing mechanical detachment³; however, this approach prevents the grafted skin from firmly affixing to the wound. 

Unlike the extremities, splints designed for the neck or the trunk (ie, areas including the shoulder, chest, buttock, axilla, and abdomen) are large and heavy, making them difficult to apply in these locations. Patients using splints on the trunk or the neck feel severe discomfort and, as such, their use is avoided. In these cases, the STSG is covered with a conventional tie-over bolster dressing. However, shearing and/or exudate collection under the graft is not always ensured with a conventional bolster dressing.

Negative pressure wound therapy (NPWT) has been reported to improve wound healing, especially in cases involving wounds located in areas where it is challenging to promote healing due to curvature and movements.⁴ Negative pressure dressing is based on the theory of induced mechanical stress resulting in angiogenesis and tissue growth. It also has been suggested that the application of subatmospheric pressure to edematous chronic wounds results in decreased local tissue turgor by fluid removal, which in turn theoretically decompresses small blood vessels, increases blood flow locally, and removes excess interstitial fluid.^5,6 A reduction in bacterial contamination also has been reported.^5,6 The authors conjectured that a negative pressure dressing could help create and maintain firm fixation of the STSGs to a wound on the trunk or the neck as well as allow for the removal of exudates that may accumulate under the grafts. 

This study aimed to present our experiences with skin graft fixation using a negative pressure dressing instead of the bolster dressing technique for wounds on the trunk or the neck (Figure 1). Further, this study aimed to compare the efficacy of a negative pressure dressing with the conventional bolster dressing technique of securing STSGs to wounds on the trunk or the neck.

The study was conducted on patients receiving STSGs on the trunk or the neck from January 2013 to December 2017. Prospective and retrospective data from medical records were used for analysis. Patients who were pregnant, immunocompromised, or had severely infected wounds were excluded from study. 

Indications for skin graft were classified based on wound characteristics in the following manner: fresh surgically created wound after excision of tissue or elevation of flap, acute wounds for coverage within 24 hours of occurrence, and chronic wounds due to burns, trauma, or infection (old cellulitis, abscess, carbuncle, etc) (Table 1). 

Patients were divided into 2 groups based on the treatment method used. 

Group 1: NPWT

Group 1 included patients requiring STSG of the head or neck who were amenable to using a NPWT dressing. STSG was performed with simultaneous wound debridement. The grafted skin was fixed using a skin stapler and covered with 1 layer of petrolatum gauze. The NPWT dressing then was applied over the gauze and black foam; this was covered by a transparent adhesive film. Negative pressure wound therapy was provided using V.A.C. Therapy (3M + KCI) set at a continuous subatmospheric pressure between -75 mm Hg and -100 mm Hg (Figure 2A-C).

Negative pressure wound therapy was applied for 6 days; the first negative pressure dressing change occurred on postoperative day 3 and the second dressing change on day 6. Device alarms that indicated expansion of the foam alerted clinicians to air leakage. If the negative pressure could not be maintained, dressing leaks were immediately covered with sterile adhesive films. After postoperative day 6, antibiotic cream (Esroban ointment; JW Pharmaceutical Corporation) and a nonadherent foam dressing (Renofoam; T&L Company) were used on the wounds. 

Group 2: bolster dressing

In group 2, patients were managed with the conventional bolster dressing after STSG (Figure 2D-1F). STSG was performed with simultaneous wound debridement. The grafted skin was fixed with a skin stapler, and folded petrolatum gauzes were tied over the grafted skin. Splints on the trunk or the neck are big and heavy, so it was difficult to apply splints on wounds on the trunk or the neck. With even the slightest movement on the part of the patient, the bolster-dressing was at risk of detaching because it was unable to firmly stick to the wound. The bolster dressing was removed on postoperative day 5, and antibiotic cream (Esroban ointment) and a nonadherent foam dressing (Renofoam) were applied on the wound. 

Both groups of patients were followed-up for 2 weeks. Percent of survival of the grafted skin was assessed by INFINITT PACS (INFINITT North America Inc) during gross examination on postoperative day 7. Complete graft survival was scored as 100, 50% graft survival as 50, and total graft loss was scored as 0 (Figure 2). Major graft loss was considered for a survival score less than 40.

Statistical analysis

All statistical analyses were performed using SPSS, version 23 (IBM Corp). The Mann-Whitney U test was used to compare the variables and outcomes in the 2 groups. Differences were considered statistically significant for P < .05. 

Ethical considerations

After obtaining Institutional Review Board (IRB) approval from Hanil General Hospital (Seoul, South Korea), written informed consent regarding the procedure and data were obtained from all patients (IRB: HGH-2018-OTH-015).

A total of 57 patients (28 males and 29 females) underwent STSG for wounds on their trunk or the neck; 27 were managed using NPWT, and 30 were managed using the conventional bolster approach. The patient characteristics data for all patients are summarized in Table 1. The size of wounds for all patients ranged between 100 cm² and 400 cm² (group 1 average, 150 cm²; group 2 average, 130 cm²) (Table 1). The causes and sizes of the grafted wounds were not statistically different. Due to discomfort, as reported in the medical records, splints were not used.

Group 1: NPWT

The average age of the patients was 55 years. The NPWT dressing was well tolerated by all patients. Air leakage from the NPWT dressing was noted in 4 patients and was corrected immediately. No serious adverse effects were observed. No major graft loss occurred. After postoperative day 7, the average survival score for the skin graft was more than 80 in all patients. Because the NPWT dressing was firmly affixed to the wound, the patients were slightly more mobile than group 2.

Group 2: bolster dressing

The average age of the patients was 60 years. Major graft loss occurred in 5 patients, requiring a second STSG. The average score of STSG survival on postoperative day 7 in group 2 was lower than that of group 1; in particular, the scores associated with grafts applied on wounds on the neck, shoulder, buttock, and axilla were lower in comparison to those of group 1 (Table 2). The differences observed between the 2 groups were overall statistically significant (P < .01) based on the results of the Mann-Whitney U test.

The STSG is a technique whose usefulness in plastic surgery cannot be overemphasized. However, a STSG does not provide satisfactory results when the grafting conditions are less than ideal. Common causes of STSG failure include formation of a hematoma or seroma under the skin graft, imprecise apposition of the graft to the bed, and shearing between the graft and the bed. Several approaches have been used to prevent of shearing and/or collection under the STSG, including staplers and plastic syringes,⁷ rubber bands,^8,9 industrial foam and foam rubber,¹⁰ and fibrin glue.¹¹ However, no method provided consistently satisfactory results across different wound areas and locations.

Fleishmann¹² suggested use of a NPWT dressing as a viable alternative to conventional graft dressings. Although known by different terms (vacuum therapy, vacuum-assisted closure, vacuum sealing, or topical negative pressure therapy), the concept is the same—that is, subjecting the wound to negative pressure in a closed environment.¹²

In addition to the benefits of NPWT as described by Morykwas and Argenta,^5,6 applying a NPWT pressure dressing also provides a means for graft immobilization and apposition to the wound bed.^13-16 Noncomparative studies^11,12,17-22 have reported that a NPWT dressing is effective in treating large, difficult, and traumatic wounds; hence, this dressing should be considered, particularly when graft, graft bed, or grafting conditions are less than ideal.

If the wound is near a joint, the STSG must be adequately dressed and immobilized to prevent mechanical detachment. Because applying a splint to wounds on the trunk or the neck has proven difficult, the grafted skin does not affix firmly to the wound. A NPWT dressing can be used to ensure that the graft remains firmly attached with the additional help of the transparent adhesive film. Owing to the flexibility and elasticity of the supplied transparent adhesive film, patients are more mobile and feel little discomfort. It is postulated that the removal of exudate and bacteria also may help improve the STSG success rate, which can be more easily achieved using a NPWT dressing.

The current study showed that use of a NPWT dressing on STSGs significantly improved the success rate of the procedure. However, this study was limited to wounds on the trunk or the neck. Also, the data showed that the STSGs receiving NPWT dressings were qualitatively better than those receiving bolster dressing on the neck, shoulder, buttock, and axilla. 

A retrospective review of patient data (N = 57) showed that use of a NPWT dressing to secure a meshed STSG seemed to achieve graft fixation in patients with defects of various origins in challenging locations with a better survival rate than using a conventional bolster dressing. Owing to the flexibility and elasticity of the transparent adhesive film that is utilized during this procedure, patients can be more mobile and feel less discomfort. This method increases the percentage of graft survival and apparently reduces the requirement for second STSG operations, subsequently offering the potential to shorten the length of hospitalization. 

Authors: Hong Sil Joo, PhD, MD¹; Seung Je Lee, MD¹; Sang-Yeul Lee, PhD, MD²; and Kun Yong Sung, PhD, MD²

Affiliations: ¹Department of Plastic and Reconstructive Surgery, Hanil General Hospital, Seoul, South Korea; and ²Kangwon National University, Chuncheon, South Korea

Correspondence: Kun Yong Sung, PhD, MD, Kangwon National University, Medicine, 1 kangwondaehak-gil, chuncheon-si, kangwondo 24341, South Korea; ps@kangwon.ac.kr 

Disclosure: The authors disclose no financial or other conflicts of interest.