Abstract
As the use of negative pressure wound therapy (NPWT) over skin grafts has increased, traditional methods of NPWT system reimbursement and application are increasingly being challenged. A simplified method of accessing and operating NPWT in the outpatient setting is needed, particularly in cases where immediate outpatient use of NPWT is optimal. We evaluated use of a new ultra‐lightweight, off‐the‐shelf, disposable, single‐patient‐use NPWT system (SP‐NPWT; V.A.C.Via™ Therapy, KCI USA, Inc., San Antonio, TX) over dermal regeneration template (DRT) and/or skin grafts. SP‐NPWT was initiated over a DRT and/or skin graft in 33 patients with 41 graft procedures. Endpoints were recorded and compared to a historical control group of 25 patients with 28 grafts bolstered with traditional rental NPWT (V.A.C.® Therapy, KCI USA, Inc.). Average length of inpatient hospital stay was 0·0 days for the SP‐NPWT group and 6·0 days for the control group (P < 0·0001). The average duration of SP‐NPWT post‐DRT or skin graft was 5·6 days for the SP‐NPWT group and 7·0 days for the control (P < 0·0001). Preliminary data suggest that, compared to traditional NPWT, off‐the‐shelf SP‐NPWT may provide a quicker, seamless transition to home, resulting in decreased hospital stay and potential cost savings.
Keywords: Dermal regeneration template, Skin graft, Ultra‐lightweight negative pressure wound therapy
Introduction
Use of negative pressure wound therapy (NPWT) as an active bolster over skin grafts or dermal regeneration template (DRT) has increased over the past decade. In cases where reliable graft fixation may be difficult to achieve, adjunctive NPWT can reduce shearing and seroma/haematoma formation, improve qualitative appearance of split‐thickness skin grafts (STSGs) and improve patient tolerance of the graft 1, 2, 3. The applied force of NPWT has also shown a positive effect on autograft survival, as well as neovascularisation of the DRT 4, 5, 6, 7.
As NPWT usage increases, however, established methods of NPWT system reimbursement and application are being challenged by clinicians, end users and hospital administrators. For short‐term NPWT application, the usual process of obtaining reimbursement coverage for NPWT transition to home is cumbersome and often not successful within the time period NPWT should be applied. As a result, otherwise‐healthy patients frequently remain hospitalised for the single purpose of receiving NPWT over grafts, which may contribute to higher medical costs. In addition, the bulk, noise and complexity of traditionally available NPWT devices can limit patient compliance and their ability to return to normal daily activities.
Because outpatient care is optimal for most patients who receive NPWT over grafts or DRT, an easier method of accessing and operating NPWT in the outpatient setting is needed. The purpose of this clinical study was to evaluate use of a new ultra‐lightweight, nearly silent, off‐the‐shelf, disposable, single‐patient‐use NPWT system (SP‐NPWT; V.A.C.Via™ Therapy System, KCI USA, Inc.) over DRT and/or skin grafts. Time to hospital discharge, duration of SP‐NPWT and graft take rate were collected and compared to a historical control group of patients who received traditional rental NPWT over DRT and/or skin grafts. SP‐NPWT system characteristics and limitations, as well as mechanisms of action, are also discussed.
Methods
Approval for this study was granted by the internal review board at Southwest Washington Medical Center in Vancouver, Washington. Data were collected for consecutive patients who received SP‐NPWT over DRT or skin graft between 9 September 2010 and 20 June 2011.
All wounds were prepared for DRT or skin graft closure in a similar manner. Wounds were thoroughly debrided and, when indicated, treated with adjunctive NPWT (V.A.C.® Therapy, KCI USA, Inc.) until adequately granulated. A 1:1 meshed, unexpanded DRT (8), a full‐thickness skin graft (FTSG), or a meshed STSG was applied to the prepared wound bed. A thin, porous barrier layer (Adaptic® Nonadhering Dressing, Johnson & Johnson, New Brunswick, NJ), slightly larger than the defect, was applied over the skin graft or dermal layer. A small, spiral, reticulated open‐cell foam dressing (ROCF) (V.A.C.® GranuFoam™ Dressing, KCI USA, Inc.) was cut to the size of the defect and applied over the barrier layer. A drape and tubing disc were applied over the foam, and the tubing was connected to a 250 ml canister within the 0·3 kg device (V.A.C.Via™ Therapy System, KCI USA, Inc.). The pressure button was set to −125 mm Hg, and the mode button was set to continuous.
Patients were discharged home but returned to the clinic 4–6 days post‐graft or after DRT placement for SP‐NPWT dressing removal. At this time, SP‐NPWT was discontinued. For the STSG and FTSG patients, the graft was inspected for take rate and quality by a physician. For the DRT patients, a non‐adherent layer was then applied until a second‐stage STSG could be applied over the DRT; SP‐NPWT was resumed over the STSG for 4–5 days and then discontinued. The second‐stage STSG was then inspected for take rate and quality. Time to hospital discharge from SP‐NPWT initiation, duration of SP‐NPWT, graft take rate and complications were recorded for each patient.
Control data were extracted from randomly selected, complete records of patients who received a full course of traditional NPWT with a rented device over DRT, FTSG or STSG between 4 January 2010 and 14 September 2010. A minimum of 10 and maximum of 30 control patient records were established. Control data were compared with SP‐NPWT group data using chi‐squared test for categorical data and Wilcoxon's rank sum test for continuous variables. All the analyses were performed using Statistical Analysis System (SAS® software; SAS Institute Inc., Cary, NC) version 9.1.3.
Results
A total of 33 patients (16 male and 17 female) with 41 graft procedures treated with SP‐NPWT were analysed and compared to a retrospective control group of 25 patients (14 male and 11 female) with 28 graft procedures treated with traditional NPWT. Mean age was less for the SP‐NPWT group versus the control (53 versus 61 years, respectively; P = 0·049), and there were significantly more patients with peripheral vascular disease (PVD) in the SP‐NPWT group compared with the control (12 versus 0, respectively; P = 0·001). A greater number of acute wounds were present in the SP‐NPWT group versus the control (26 versus 10, respectively; P = 0·029). All other patient demographics and wound characteristics were similar (1, 2).
Table 1.
Comparative patient demographics
| Patients | SP‐NPWT N = 33 | Control N = 25 | P value | |
|---|---|---|---|---|
| Age (years) | N | 33 | 25 | 0·049 |
| Mean (SD) | 52·7 (15·85) | 61·1 (21·38) | ||
| Range | (26·0–79·0) | (19·0–84·0) | ||
| Gender | F | 17 (51·5%) | 11 (44·0%) | 0·606 |
| M | 16 (48·5%) | 14 (56·0%) | ||
| Co‐morbidity | Any | 23 (69·7%) | 21 (84·0%) | 0·235 |
| Diabetes | 15 (45·5%) | 12 (48·0%) | 1·000 | |
| Obesity | 16 (48·5%) | 6 (24·0%) | 0·100 | |
| PVD | 12 (36·4%) | 0 (0·0%) | 0·001 | |
| Smoker | 4 (12·1%) | 9 (36·0%) | 0·054 | |
Table 2.
Comparative graft/wound characteristics
| DRT or skin grafts | SP‐NPWT N = 41 | Control N = 28 | P value | |
|---|---|---|---|---|
| Total area (cm2) | N | 41 | 28 | 0·849 |
| Mean (SD) | 38·0 (23·85) | 38·8 (24·96) | ||
| Range | (12·0–100·0) | (15·0–140·0) | ||
| Etiology | Acute | 26 (63·4%) | 10 (35·7%) | 0·029 |
| Chronic | 15 (36·6%) | 18 (64·3%) | ||
| Graft type | DRT | 10 (24·4%) | 3 (10·7%) | 0·215 |
| FTSG | 8 (19·5%) | 0 (0·0%) | ||
| STSG | 23 (56·1%) | 25 (89·3%) | ||
| Wound location | Buttock | 3 (7·3%) | 0 (0·0%) | 0·020 |
| Head | 5 (12·2%) | 0 (0·0%) | ||
| Lower Extremity | 16 (39·0%) | 20 (71·4%) | ||
| Perineum | 1 (2·4%) | 0 (0·0%) | ||
| Trunk | 11 (26·8%) | 3 (10·7%) | ||
| Upper Extremity | 5 (12·2%) | 5 (17·9%) | ||
The mean duration of NPWT post‐DRT or skin graft was 5·6 days for the SP‐NPWT group and 7·0 days for the control (P < 0·0001). Mean length of inpatient hospital stay was 0·0 days for the SP‐NPWT group and 6·0 days for the control group (P < 0·0001). Mean graft take rate for DRT, FTSG and STSG was 98·9% for the SP‐NPWT group and 98·2% for the control. Among FTSG‐ and STSG‐only patients (no DRT), the mean graft take rate was 98·5% for the SP‐NPWT group and 98·0% for the control. There were no failed grafts, complications or additional surgical procedures required in either group. Mean follow‐up time was 6·4 months for the SP‐NPWT group and 12·7 months for the control group. Table 3 summarises the comparative endpoint outcomes.
Table 3.
Efficacy endpoints comparing SP‐NPWT and control
| SP‐NPWT | Control | P value | ||
|---|---|---|---|---|
| Duration of NPWT (days) | N | 41 | 28 | <0·0001 |
| Mean (SD) | 5·6 (0·90) | 7·0 (1·14) | ||
| Median (Q1, Q3) | 6·0 (5·0, 6·0) | 7·0 (6·0, 8·0) | ||
| Range | (3·0–8·0) | (5·0–9·0) | ||
| Total DRT, FTSG and STSG graft take rate (%) | N | 40 | 28 | 0·085 |
| Mean (SD) | 98·9 (1·46) | 98·2 (3·90) | ||
| Median (Q1, Q3) | 100·0 (98·0, 100·0) | 100·0 (100·0, 100·0) | ||
| Range | (95·0–100·0) | (90·0–100·0) | ||
| FTSG and STSG graft take rate (%) | N | 26 | 25 | 0·046 |
| Mean (SD) | 98·5 (1·50) | 98·0 (4·08) | ||
| Median (Q1, Q3) | 98·5 (98·0, 100·0) | 100·0 (100·0, 100·0) | ||
| Range | (95·0–100·0) | (90·0–100.0) | ||
| Time to hospital discharge (days) | N | 33 | 25 | <0·0001 |
| Mean (SD) | 0·0 | 6·0 (1·19) | ||
| Median (Q1, Q3) | 0·0 (0·0, 0·0) | 6·0 (5·0, 7·0) | ||
| Range | (0·0–0·0) | (4·0–8·0) |
Case studies
Clinical experience with the SP‐NPWT system is reported in the following case studies.
Case study 1
Repair of open tibia‐fibula fracture with STSG and SP‐NPWT.
A 24‐year‐old male patient presented with a 3‐month‐old open tibia‐fibula fracture (Figure 1A). Thorough surgical debridement showed a draining sinus tract with osteomyelitis (Figure 1B), which was treated with antibiotics for 3 weeks. A meshed STSG was applied over the wound (Figure 1C), followed by a non‐adherent layer. SP‐NPWT was initiated over the non‐adherent layer and STSG was applied at −125 mm Hg continuously (Figure 1D), and the patient was discharged home the same day. On postoperative day 5, the patient returned to the outpatient clinic for follow‐up and removal of the SP‐NPWT bolster. Graft take was approximately 100%. Figure 1E shows the wound at 14 days post‐STSG placement and Figure 1F at the 4‐month follow‐up post‐graft.
Figure 1.
Repair of open tibia‐fibula fracture. (A) Open tibia‐fibula fracture; (B) draining sinus tract with osteomyelitis; (C) meshed STSG applied over the wound followed by a non‐adherent layer; (D) SP‐NPWT initiated over the non‐adherent layer and STSG; (E) 14 days post‐STSG placement and (F) 4‐month follow‐up post‐STSG.
Case study 2
Scalp reconstruction with DRT, STSG and SP‐NPWT.
A 71‐year‐old male patient presented for evaluation of scalp reconstruction with diagnosis of melanoma with Breslow thickness of 5·3 mm and with a failed graft. The patient's medical history included PVD, type‐II diabetes and coronary artery disease. Wide local excision with sentinel node biopsy was performed, and DRT was used to cover the defect (Figure 2A–C). A non‐adherent layer, cut slightly larger than the DRT, was applied over the skin substitute. SP‐NPWT was applied on top of the non‐adherent layer, and pressure was initiated at −125 mm Hg continuous (Figure 2D). The patient was discharged home.
Figure 2.
Scalp reconstruction with DRT, STSG and SP‐NPWT. (A and B) Wide local excision with sentinel node biopsy was performed; (C) DRT was applied to cover the defect; (D) application of SP‐NPWT over DRT; (E) application of STSG on postoperative day 24; (F) follow‐up at 6 days post‐second‐stage STSG placement and application of SP‐NPWT and (G) follow‐up at ∼4 months post‐second‐stage STSG.
On postoperative day 5, the patient returned to the outpatient clinic for follow‐up and removal of the spiral SP‐NPWT dressing. The DRT appeared intact and viable. A non‐adherent layer was then applied until a second‐stage STSG could be applied over the DRT. Following availability of final pathology showing clear margins, an STSG was placed on postoperative day 24 (Figure 2E). A non‐adherent layer and an NPWT dressing were then placed over the STSG. SP‐NPWT was discontinued 6 days post‐STSG (Figure 2F) with 100% take of the graft at ∼ 4 months follow‐up (Figure 2G). No delays were encountered for SP‐NPWT system approval.
Discussion
This study evaluated the use of an ultra‐light, disposable, SP‐NPWT system as a bolster over DRT and/or skin grafts. Classic protocol of 4–6 days of NPWT over skin grafts or DRT appears to yield similar graft take results with SP‐NPWT as with traditional NPWT. Our high graft take and 0% graft failure rates are similar to studies reporting on traditional NPWT 6, 9, 10. In a case series of patients treated with standard NPWT over STSG, Scherer et al.(6) reported 1 graft failure in 34 NPWT‐treated patients, and Blume et al.(9) reported a 3·5% graft failure rate in 87 foot and ankle reconstructive surgeries that involved NPWT over STSG. Additionally, our combined FTSG and STSG graft take rate of 98·5% with SP‐NPWT is similar to the 96 ± 6% STSG take rate reported by Scherer et al.(6) and the 96 ± 9% graft take rate reported by Blume et al.(9). Our mean FTSG or STSG take rate over DRT (98·5%) was higher than the 91·5% reported by Park et al.(10), but our sample size was too small for accurate comparison.
Bio‐integration of DRT appears to be best achieved by eliminating dead space below the dermal layer and hindering the penetration of microbes (11). Adjunctive NPWT over DRT's dermal layer provides positive contact between the newly transplanted skin substitute and wound bed, removes infectious materials beneath the graft, and serves as a dynamic protective barrier over the DRT. Previous research suggests that the early application of NPWT with ROCF over DRT may reduce the time to second‐stage STSG (10).
According to a study analysing wound care costs, major cost drivers for wound care include time to healing, staff time, length of stay in the hospital, number of dressings, infections and long waiting time from diagnosis to treatment (12). The cost of wound dressing materials typically accounts for only 10–20% of total cost of treating a patient 12, 13. US Center for Medicare and Medicaid Services has targeted these costs and established promotion of seamless transitions across care settings as a major goal in its Care Transitions Project within the Quality Improvement Organization (14). Authors propose that the increased simplicity, portability and accessibility of this new technology, compared with traditional NPWT, are advancements towards the goal of better managing grafted patients through the continuum of care.
The obviated wait for insurance authorisation and product delivery of SP‐NPWT allowed patients to be discharged on the same day of graft placement, thereby avoiding an inpatient admission. Our prior methods of obtaining reimbursement for rental NPWT over skin grafts resulted in an average per patient hospital stay of 6 days, as exhibited in the control group. According to Gabriel et al.(15), the estimated difference between the outpatient Ambulatory Payment Classification (APC) payment amount for a Level V Skin Repair ($1535) and the average inpatient skin graft diagnosis‐related group (DRG) payment ($11 080) represents a potential $9545 per patient savings to the healthcare system (Table 4). In our experience, the off‐the‐shelf, versus rental, model of NPWT procurement was more cost effective for this otherwise‐healthy patient population because a hospital admission was avoided in all cases. However, our results are based on a single hospital's procurement procedures, and a cost comparison was not within the scope of this study.
Table 4.
Outpatient versus inpatient STSG based on reimbursement classification * (Adapted from Gabriel et al.(15))
| SP‐NPWT outpatient APC payment | NPWT inpatient DRG payment | SP‐NPWT savings | |
|---|---|---|---|
| Cost of STSG (per patient) | $1535 † | $11 080 ‡ | $9545 |
*The above model uses selected study data to estimate the outpatient cost of using SP‐NPWT versus the inpatient cost of traditional NPWT on STSGs. This model is an illustration and not a guarantee of actual individual costs, savings, outcomes or results. Results are based on the selected study data and may not be typical. Individual results may vary. The hospital and/or clinician are advised to use this model as an illustration only to assist in an overall assessment of products and pricing.
†Outpatient APC Code 137 ‘Level V Skin Repair’ payment.
‡Calculated by averaging the 2011 reimbursement payments for DRGs 573–578 (573–$16 763; 574–$9644; 575–$5628; 576–$20 268; 577–$8797; 578–$5379; average length of stay for the six skin graft DRGs is 8·1 days).
The same contraindications, warnings and precautions apply with SP‐NPWT as with all other NPWT/ROCF systems. Likewise, SP‐NPWT has the same performance specifications as traditional NPWT/ROCF systems, affecting similar mechanisms of action. SP‐NPWT is indicated for low exudating (<80 ml/day), small‐to‐medium‐sized wounds, grafts and flaps in the acute care setting. Vacuum pressure helps prevent fluid collection beneath the graft and fosters continuous, firm contact between the undersurface of a skin graft and the recipient bed, facilitating plasmatic imbibition and revascularisation (16). NPWT is particularly advantageous over difficult recipient beds, such as jointed areas, because of its splinting effect.
This series showed SP‐NPWT as a valuable tool in achieving reconstructive goals, and SP‐NPWT has since become our standard NPWT over skin grafts or DRT. Preliminary data suggest that compared with traditionally accessed NPWT devices this SP‐NPWT system may provide a quicker, seamless transition to home, resulting in decreased hospital stay and potential cost savings to the healthcare system. However, this study is limited by its non‐randomised, uncontrolled nature, as well as small patient population size and observer bias in estimating graft take. Considerably more controlled research is necessary to measure efficacy of SP‐NPWT in adjunctive management of various wound types.
Acknowledgements
The authors thank Jason Chan (KCI) for statistical analysis support and Karen Beach (KCI), and Julissa Ramos (KCI) for medical writing support.
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