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A Pilot Study to Compare the Efficacy of Negative Pressure Wound Therapy over Split-Thickness Skin Graft and the Conventional Method of Fixation of Grafts on Wound Healing
*Corresponding author: Kshitij Jyoti, Department of General Surgery, Armed Forces Medical College, Wanowrie, Pune, Maharastra, India. kjyoti@icloud.com
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Received: ,
Accepted: ,
How to cite this article: Uppaluri D, Singh A, Jyoti K, Babu P, Gupta A. A Pilot Study to Compare the Efficacy of Negative Pressure Wound Therapy over Split-Thickness Skin Graft and the Conventional Method of Fixation of Grafts on Wound Healing. Int J Recent Surg Med Sci. 2026:12(e003) doi: 10.25259/IJRSMS_85_2025
Abstract
Objectives:
The standard method of resurfacing wounds that fail to heal secondarily is skin grafting. Prerequisites for successful graft take are a healthy wound bed and adequate adherence. In multiple previous studies, none of the several split-thickness skin graft (STSG) fixation methods were proven to be superior to conventional fixation. In our study, we compare the outcomes of STSG using negative pressure wound therapy (NPWT) fixation vs. conventional fixation concerning the percentage of graft taken, soakage and number of dressings during the first two weeks, time of healing, complications, length of hospital stay and aesthetic results.
Material and Methods:
A randomized controlled pilot study was conducted at a tertiary care hospital on patients requiring STSG cover from 2019-21. A total of 60 patients were randomly allocated to two groups. After STSG, one group received NPWT dressings and the other conventional dressings. Post-procedure wound inspections were carried out, and outcome characteristics were noted. Special emphasis was paid to the number of dressing changes required in the conventional group and the aesthetic outcomes were compared using hypertrophy and pigmentation. The data was analyzed using Statistical Package for Social Sciences (SPSS) Software version 27.0
Results:
Soakage of the first dressing was observed in 11 cases (40.74%) in the STSG group (Group S) compared to 4 cases (12.12%) in the STSG + NPWT group (Group N). The Group S participants required a total of 80 dressings (68.96%) in the first two weeks compared to 36 dressings in Group N (31.03%). Graft take in Group N was 96.96% compared to 80.76% in Group S. Good aesthetic results were seen in 24 patients (77.41%) in Group N compared to 13 participants of Group S (61.90%)
Conclusion:
Compared to Group S, the STSG + NPWT group (Group N) showed increased take of the graft, fewer number of dressings and lesser graft loss. All these factors also significantly decreased the average length of the hospital stay and need for repeat surgery.
Keywords
Graft take
Hospitalization
Negative-pressure wound therapy
Skin graft
Wound healing
INTRODUCTION
Among the various problems that are seen in the surgical field, wounds are one of the most common. Whenever there is an extensive loss of tissue that fails to heal naturally, the commonly used secondary cover is a skin graft. These not only enhance the process of wound healing but also reduce the overall recovery time. This helps in reducing the morbidity of the patient in terms of wound complications and facilitates early discharge from the hospital.
One of the most important post-operative requirements for successful skin grafting is that the wound does not get disturbed for at least one week. It is necessary to prevent shearing forces at the recipient area and reduce/prevent collections between the graft and the recipient bed. To achieve this, several graft-securing techniques (applying bolster dressings, use of staplers, and post-operative immobilization, with splinting joints above and below the operative site) are used. The other commonly used methods are ties and stay sutures, placing rubber bands, industrial foam, rubber foam, fibrin glue, and Cyanoacrylate glue.[1-7] Given so many methods available and the variables of wound healing involved, there is no standard technique described with acceptable and reproducible results.
Over the last three decades, negative pressure wound therapy (NPWT), when applied to wounds, both acute and chronic, has shown very promising results. The use of NPWT reduces the accumulation of blood/exudate under the graft at the site of application using continuous drainage, thus reducing the undesired collection. It offers inherent splinting and promotes adherence of the graft to an uneven wound bed. Other advantages of this method are that it reduces the need for daily dressing changes, reduces bacterial proliferation, and thus promotes wound healing. It is also postulated that NPWT can improve the regional blood flow at the wound site.[8]
Recently, this novel method has been tried successfully, both pre-grafting to promote granulation tissue and angiogenesis at the recipient site and post-grafting to reduce the collection beneath the graft, with promising results.[9,10]
Given this, we conducted the present study on admitted patients in a tertiary care center in Karnataka, India, whose wounds were planned for split thickness skin graft (STSG), to evaluate the utility of NPWT on the recipient site post-grafting.
Aim and the objectives of the study
To compare the outcomes of STSG using negative pressure wound therapy fixation vs. conventional fixation concerning
a) Soakage and number of dressings during the first two weeks
b) Graft take
c) Complications
d) Aesthetic results
e) Length of hospital stay
MATERIAL AND METHODS
This is a randomized controlled pilot study conducted on 60 patients attending the general surgery and plastic surgery departments of a tertiary care hospital, between 2019 and 2021. All patients necessitating STSG fitting the inclusion criteria and who consented to the study were included.
Inclusion criteria
Age 15-80 years, males and females
Wounds greater than 5cm in diameter
Etiology- post-infective, Post-Traumatic, Diabetic wounds, Venous ulcers after correction of reflux, and arterial ulcers post-revascularization
Exclusion criteria
Malignant ulcers
Facial, hand, and perineal wounds
Bleeding disorders
Complex wounds with underlying bone/tendon exposure
Uncontrolled diabetes (HBA1C >10%)
Patients underwent a thorough clinical examination to look for vascular insufficiency and other co-morbid conditions. Informed consent was taken from all patients following the guidelines defined by the institutional ethical committee. Post-infective, post-traumatic, diabetic wounds and wounds of vascular etiology were given graft cover when they did not heal spontaneously. The wounds were inspected for their location, size, depth, tendon or bone exposure, and healthy granulation. The patients were taken up for grafting after ascertaining the bacteriological fitness of the graft bed by swab culture. The wounds were covered with STSG in both groups of patients. Intermediate thickness (0.3mm - 0.45mm) STSGs were attempted in all cases using a dermatome. Conventional dressing with stapler fixation, paraffin gauze, and Gamgee roll [Figure 1] was done on subjects allocated to Group S by randomization compared to NPWT dressing with polyurethane foam and self-adhesive plastic wrap [Figure 2] in Group N. A negative pressure of 50mm Hg in continuous mode using an NPWT device (Triage Meditech) was utilized on subjects of Group N. The graft donor sites were covered by a conventional paraffin dressing. The first wound inspection was done on the 5th post-op day unless the patient showed any evidence of complications. A conventional second dressing was applied to all patients after this wound inspection. Subsequently, wounds were inspected on Post Op days 10, 21, 28, 8 weeks, and 12 weeks. After the wound inspection on post-op op day-10, no further dressing was applied.
- Conventional dressing
- NPWT dressing components. NPWT: negative pressure wound therapy
The following features were specifically noted during every wound inspection:
Graft appearance (pink, dusky, or dark- reflecting survivability of graft) and take in percentage
Soakage and number of dressings during the first two weeks post-op (over and above 2 dressings)
Complications like Graft failure (Graft take less than 60%), Hematoma formation, and Infections during the first 2 weeks post-op
Aesthetic results in the form of hypertrophy and pigmentation
Length of hospital stay calculated from the day of grafting to when the participant was deemed fit for discharge, irrespective of hospitalization for other co-morbidities.
RESULTS
Quantitative variables were compared after calculating the mean values and standard deviation. Qualitative variables were correlated using the Chi-Square test/Fisher’s exact test. A p-value of <0.05 was considered statistically significant. The data were entered in an MS EXCEL spreadsheet, and analysis was done using Statistical Package for Social Sciences (SPSS) version 27.0.
In our study in Group S, we had 27 patients, including 14 males (51.9%) and 13 females (48.1%), compared to Group N, which had 33 patients, including 19 males (57.6%) and 14 females (42.4%). The patients were randomly allocated to both groups after matching for Age, gender, and comorbidities using a standard randomization tool. Table 1 summarizes the demographic profile of all participants. In the present study, in Group S, we had to change the first dressing due to soakage in 11 cases (40.74%) compared to Group N, where we had only 4 cases (12.12%). The difference between the two groups was statistically significant with a p-value of 0.0058 [Table 2]. In Group S, all 27 patients (100%) needed at least one dressing over and above the first two dressings in the first two weeks post-procedure, compared to 29 patients (87.87%) in Group N. However, on calculation for all the patients combined, Group S participants required a total of 80 dressings (68.96%) in the first two weeks compared to only 36 dressings (31.03%) in Group N ( p<0.0001) [Table 2]. By day 5, in Group S, we had 25 cases (92.59%) compared to 32 cases (96.96%) in Group N, where the graft color was pink.
| Variable | STSG (n = 27) | STSG+NPWT (n = 33) | p-value |
|---|---|---|---|
| Age (years) Mean ± Standard deviation | 52.5 ± 21.1 (16–78) Median: 56 |
48.2 ± 18.1 (18–80) Median: 47 |
0.414 |
| Sex | Male: 14 (51.9%) Female: 13 (48.1%) |
Male: 19 (57.6%) Female: 14 (42.4%) |
0.795 |
| Diabetes mellitus | Yes: 5 (18.5%) No: 22 (81.5%) |
Yes: 13 (39.4%) No: 20 (60.6%) |
0.096 |
| PLHIV | Normal: 25 (92.5%) Compromised: 2 (7.5%) |
Normal: 32 (96.9%) Compromised: 1 (3.1%) |
0.58 |
| Tobacco consumption and smoking | Yes: 11 (40.7%) No: 16 (59.3%) |
Yes: 16 (48.5%) No: 17 (51.5%) |
0.609 |
| Peripheral arterial disease | Yes: 5 (18.5%) No: 22 (81.5%) |
Yes: 3 (9.1%) No: 30 (90.9%) |
0.448 |
| Venous insufficiency | Yes: 5 (18.5%) No: 22 (81.5%) |
Yes: 7 (21.2%) No: 26 (78.8%) |
1.000 |
| Ulcer size (cm2) Mean ± Standard deviation | 10.25 ± 2.85 (2.6–15.6) Median: 10.5 |
9.81 ± 3.12 (4.3–15.6) Median: 10.1 |
0.57 |
STSG: Split-thickness skin graft, NPWT: negative pressure wound therapy, PLHIV: People living with Human Immunodeficiency Virus, Significance level: p value <0.05
| Parameter / Outcome | Group S (n=27) | Group N (n=33) | p-value |
|---|---|---|---|
| Demographics | |||
| Male | 14 (51.9%) | 19 (57.6%) | 0.65 |
| Female | 13 (48.1%) | 14 (42.4%) | |
| Age and comorbidities | Matched | Matched | NS |
| Dressing requirements | |||
| First dressing change due to soakage | 11 (40.74%) | 4 (12.12%) | 0.0058* |
| ≥1 extra dressing in the first 2 weeks (over and above the 2 initial dressings) | 27 (100%) | 29 (87.87%) | 0.93 |
| Total dressings in 2 weeks | 80 (68.96%) | 36 (31.03%) | <0.0001* |
| Graft appearance | |||
| Day 5 – Pink graft | 25 (92.59%) | 32 (96.96%) | 0.48 |
| Day 10 – Pink graft | 22 (81.48%) | 32 (96.96%) | 0.0104* |
| Day 10 – Dusky/dark graft | 5 (18.51%) | 1 (3.03%) | |
| Day 21 – Normal grafts | 21 (100%) | 31 (100%) | NS |
| Day 28 – Normal grafts | 16 (76.19%) | 23 (74.19%) | 0.85 |
| Day 28 – Hyperpigmentation | 5 (23.81%) | 8 (25.81%) | |
| Week 8–12 – Normal pigmentation | 14 (66.66%) | 23 (74.19%) | 0.52 |
| Week 8–12 – Hyperpigmentation | 7 (33.33%) | 8 (25.81%) | |
| Graft take and complications | |||
| Graft take (Day 5) | 92.59% | 96.96% | 0.48 |
| Graft take (Day 10) | 81.48% | 96.96% | 0.0104* |
| Graft loss | 5 (18.51%) | 1 (3.03%) | 0.013* |
| Revision surgery required | 5 | 1 | |
| Death (unrelated causes) | 1 | 1 | NS |
| Hospital stay | |||
| Duration (days) | 11.61±3.21days | 18.63±6.02 | .0001* |
By day 10, in Group S, 22 cases (81.48%) were found to have a pink-colored graft compared to 32 cases (96.96%) in Group N. 2 cases (7.40%) had a dusky graft, while 3 cases (11.11%) had dark discoloration of the graft in Group S. In comparison, only one case (3.03%) in Group N had dark discoloration. The differences between the two groups were found to be statistically significant. (p-value=0.0104) [Table 2]. The grafts, which appeared dusky and dark, resulted in graft failure and hence were analyzed separately in complications. Between Day 10 and Day 21, one patient in each group died owing to unrelated complications like aspiration pneumonia and MODS.
By Day 21, both groups had normal appearing grafts, 21 Participants (100%) in the Group S and 31 cases (100%) in the STSG + NPWT group. There was no hyperpigmentation noted in any of the grafts in either group. On day 28, in Group S, we had 16 cases (76.19%), and in Group N, we had 23 cases (74.19%) who had a normal appearance of the graft. A total of 5 cases in Group S and 8 cases in Group N had hyperpigmentation of the graft. The differences were not statistically significant.
Assessment of the grafts at week 8 showed 7 cases in Group S and 8 cases in Group N with a hyperpigmented graft. A total of 14 cases (66.66%) in Group S and 23 cases (74.19%) in Group N had normal pigmentation. The differences between the two groups were not statistically significant. Assessment of the graft at week 12 showed results unchanged from week 8 [Figures 3 and 4].
- STSG patient. STSG: Split-thickness skin graft
- STSG+NPWT patient. STSG: Split-thickness skin graft, NPWT: Negative pressure wound therapy
The graft take was 92.59% in Group S compared to 96.96% in Group N on day 5. However, day 10 inspection showed 81.48% in Group S compared to 96.96% in Group N.
Complications in both groups were mainly related to graft loss. In Group S, a total of 5 cases (18.51%) had a graft loss compared to only one (3.03%) case in Group N. [Figures 5 and 6] One participant in each group had died due to reasons unrelated to the surgery. Overall, the difference in the rate of complications between the two groups was statistically significant. (p-0.013) A total of 6 patients had graft loss, 5 in Group S and 1 in Group N, who required a revision surgery. Skin grafting was done again after debridement and ensuring the fitness of the recipient bed.
- Graft loss STSG. STSG: Split-thickness skin graft
- Graft loss STSG+NPWT. STSG: Split-thickness skin graft, NPWT: Negative pressure wound therapy
Duration of hospital stay from the date of surgery till the time the patient was deemed fit for discharge, irrespective of the comorbidities for which they were undergoing treatment, was calculated. The mean hospitalization period was significantly shorter in Group N at 11.613.21days compared to the mean hospitalization period of Group S, which was 18.636.02 (p < 0.0001).
DISCUSSION
The ideal method of repair of injured tissues is by primary intention. Whenever there is a loss of tissue beyond the body’s ability to effectively repair, resurfacing by STSG is a useful alternative to healing by secondary intention, which may lead to disfigurement and loss of function depending on the area affected.
The success of skin grafting depends on various systemic and local factors, of which the fitness of the recipient site graft bed and adequate fixation of the graft to the bed are the most important and modifiable factors. In our study, we compared the conventional method of fixation of STSG and NPWT fixation of STSG in terms of:
Soakage and number of dressings required
Complications like graft loss
Graft appearance
Aesthetics
Hospital Stay post-grafting
Comparison of dressing and soakage
In the present study, in the Group S, we had 11 cases (40.74%), and in the STSG + NPWT group, we had 4 cases (12.12%) that had soakage of the first dressing. The soakage of the dressing is attributable to the exudative nature of the wounds, specifically when the surface area is large. NPWT successfully decreased the exudate and maintained better contact of the STSG with the graft bed. The 4 cases in the Group N that had soakage were due to non-maintenance of an air-tight seal due to faulty application technique and/ or application across joints or patient movement and/or machine malfunction. The difference between the two groups was statistically significant with a p-value of 0.0058.
The total number of dressings required in the first two weeks, over and above the initial 2 dressings, was drastically lower in the Group N when compared to the Group S (36 (31.03%) vs 80(68.69%). NPWT created a better environment, increased the graft take, and offered better survivability of the graft; hence, the total number of dressings was reduced. It also reduced the overall workload on the surgical team and increased patient satisfaction. The difference between the two groups was statistically significant with a p-value <0.0001.[11] The use of NPWT for wound bed preparation is well established in medical literature. Our study proves that NPWT also decreases the number of dressings when used in conjunction with STSG.
Comparison of graft loss
In the present study, in the Group S, we had 5 cases (18.51%), and in the STSG + NPWT group, we had 1 case (3.03%) that suffered graft loss. The graft loss was attributable to the exudative wounds, especially in Group S. NPWT contributed significantly to managing the exudate, as evidenced by better graft survival. Our study corroborates the findings of other studies.[10-12] The patients with graft failure required repeat surgeries to cover the wounds. Thus, NPWT also decreased the number of procedures required.
Comparisons of initial graft take
In our study, the NPWT group had a graft take of 96.87%, and the Group S had 80.76% graft take. High initial graft take in the NPWT group is because of the combination of all the factors discussed above, and most importantly, better adherence to the graft even in large, uneven, and unfavorable beds, reduction in the exudate/seroma or hematoma between the graft and its bed, and probably better neo-vascularization. Findings are in agreement with previous studies.[12]
Comparison of aesthetics
STSG can have varying aesthetic results due to a multitude of factors, and generally, they are poor compared with other methods of resurfacing and wound cover.[13] We tried determining if NPWT application changed the aesthetic appearance of the grafts, mainly in terms of hyperpigmentation. We found no statistical significance between the groups.
Comparison of hospital stay
Hospital stay for the Group N was significantly shorter owing to better initial graft take, survivability, and fewer repeated procedures. It indirectly had the advantages of increased patient satisfaction and decreased healthcare burden.
Limitations
Ours is a pilot study; it will require a larger RCT to establish non-inferiority to the conventional practice. Comparison of aesthetic results was subjective, and there may have been observer bias. Though NPWT significantly reduced the number of repeat procedures and the length of hospital stay, a cost-effectiveness analysis was not done.
CONCLUSION
Compared to the Group S, the NPWT over STSG offered better survival of the graft, as evidenced by increased take of the graft. We noted the need for more frequent dressing changes in the Group S as compared to the STSG + NPWT group. Also, the total number of dressings required is significantly lower in the NPWT graft fixation group. The graft loss was found to be less in the Group N, obviating the need for repeat surgeries.
The decreased number of dressings, increased graft takes, and reduced complications significantly decreased the hospitalization period in the group that used NPWT with STSG.
Ethical approval:
The research/study approved by the Institutional Review Board at Command Hospital Air Force, Bangalore, # 02/ CHAFB, dated Nov 11, 2019.
Declaration of patient consent:
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patients have given their consent for their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Conflicts of interest:
There are no conflicts of interest.
Use of artificial intelligence (AI)-assisted technology for manuscript preparation:
The authors confirm that there was no use of artificial intelligence (AI)-assisted technology for assisting in the writing or editing of the manuscript and no images were manipulated using AI.
Financial support and sponsorship: Nil
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