Use of a New Acellular Dermal Matrix for Treatment of Nonhealing Wounds in the Lower Extremities of Patients With Diabetes

Introduction. Acellular dermal matrices (ADMs) have successfully been used in the treatment of nonhealing wounds in patients with diabetes. Methods. A new decellularized biological scaffold derived from human skin, D-ADM, (DermACELL, LifeNet Health, Virginia Beach, VA), has shown increased cell infiltration, host tissue integration, and vascularization in comparison to other ADMs. This clinical investigation evaluated the wound closing properties of D-ADM on 18 full-thickness lower extremity wounds in 15 patients with diabetes over a period of 12 weeks. Results. A complete wound closure (100% epithelialization) rate of 58% (7/12) and an average duration of 10 weeks was demonstrated. Wound healing, defined as ≥ 95% wound closure, was established in 83% of the wounds (10/12) by the end of the study treatment. Conclusion. These results compare favorably with other methods of advanced wound care treatment options that utilize skin substitutes to accelerate the healing of difficult-to-treat or chronic wounds. 

  Nonhealing wounds of the foot and ankle, one serious complication of poorly controlled diabetes, present a clinical challenge. Without medical treatment, chronic wounds can further deteriorate, resulting in infection, discomfort, and pain. If the infection spreads to nearby bone, surgery may be required to remove part of the bone, or to amputate the foot and possibly part of the leg. Recently, it has become more common to treat these wounds using human acellular dermal matrices (ADMs).^1-3 A new decellularization process has been developed yielding a human ADM cleaned of ≥ 97% DNA and cellular constituents. Theoretically, decellularization removes potentially immunogenic material and provides a clean scaffold for host cellular and vascular in-growth. The resultant biological scaffold, an ADM, is provided at room temperature, hydrated, sterile, and ready to use. It is hypothesized that this process will yield an equivalent or superior material for chronic wound treatment than currently available matrices. Thus, in this study, the advanced ADM was used to treat chronic wounds in the lower extremity of the diabetic patient and the progress of wound healing was assessed.

  In this study, 15 patients (18 ulcers) underwent the informed consent process utilizing an Institutional Review Board-approved Subject Consent Form. After meeting all inclusion criteria and none of the exclusion criteria, each patient was treated with a decellularized-acellular dermal matrix (D-ADM) (DermACELL, LifeNet Health, Virginia Beach, VA). Patients were included if their wounds had persisted for at least 6 weeks (wound duration in the study ranged from 2 months to 5 years with an average of 2 years); showed signs of adequate local blood circulation; and were ≥ 1 cm² in area and < 1 cm deep. Other inclusionary criteria included presence of full-thickness wounds to the foot or ankle, secondary to either insulin-dependent or noninsulin-dependent diabetes mellitus; recent HgA1C < 12; and ability to comply with off-loading and dressing change requirements. Exclusionary criteria included patient classification as minors, prisoners, and pregnant women; evidence of clinical infection (unless being treated at the time of D-ADM application); necrotizing fasciitis; deep abscesses in the soft tissue; gas gangrene; need for any additional concomitant dressing materials other than the ones approved for this study; and treatment with a living skin equivalent within the last 4 weeks prior to initiation of D-ADM treatment. Four patients (6 ulcers) were excluded from the analysis because they had either new blister formation or an increase in wound size due to noncompliance with the off-loading instructions. All wounds were noted as healing at the end of the treatment period.   Wounds were thoroughly debrided with a sharp blade. The D-ADM was prepared using a combination of nondenaturing anionic detergent (N-Lauroyl sarcosinate, [NLS]), recombinant endonuclease (Benzonase Nuclease, Merck, EMD Millipore, Darmstadt, Germany), and antibiotics (eg, polymixin B, vancomycin, and lincomycin) and terminally sterilized with a low dosage of gamma irradiation at low temperatures to a Sterility Assurance Level of 10^-6. The D-ADM was trimmed accordingly, applied to the wound, and secured by suture or Steri-strip (3M Health Care Skin & Wound Care, St. Paul, MN) and nonadherent dressing. The nonadherent dressing was covered with moistened gauze and a light compression bandage. Patients were evaluated weekly in the clinic for up to 12 weeks after D-ADM application. The wounds were measured at each visit by a trained clinician. Dressings were left in place for a minimum of 5 days and a maximum of 7 days, and were changed by the clinician at the weekly follow-up visit. Single applications of the D-ADM were employed for each wound, except in 3 cases. The reapplication was due to patient noncompliance with the off-loading requirements in 1 case, and clinician election in 2 cases, in an attempt to increase the rate of healing. Of those 3 cases, 2 wounds exhibited > 95% closure at the end of the treatment period. The other wound had exhibited 93% closure 8 weeks after treatment with the D-ADM, and had reopened when the patient presented for a follow-up visit 9 weeks after treatment. At 12 weeks, the end of treatment, that wound was healing and had almost 50% closure.

  As shown in Table 1, complete wound closure was observed in 7 of the 12 ulcers treated within the study, for a 58% closure rate. Substantial wound healing ( ≥ 95%) was noted in 10 of the 12 ulcers for a rate of 83%. Among these patients, there was an average duration to closure of 10 weeks and integration of the D-ADM with surrounding tissue.   Patient 9. A 47-year-old female presented with a nonhealing ulcer on the plantar first medial head with a Wagner Grade 2 (Figure 2a). The patient reported existence of the ulcer for at least 1.5 years prior and indicated it was nonresponsive to conventional treatment. Following sharp edge debridement at initial presentation, D-ADM was applied (Figure 2b), secured with sutures, and covered with a nonadherent dressing (Adaptic, Johnson & Johnson, Somerville, NJ) and moistened gauze (Kerlix, Covidien, Mansfield, MA), followed by a secure wrapping with a compression bandage (Coban, 3M Health Care Skin & Wound Care, St. Paul, MN). The patient went on to a successful outcome with a single application of D-ADM, as noted by complete wound closure at week 12 (Figure 2c).   Patient 12. A 50-year-old female presented with 2 nonhealing wounds secondary to diabetes with a Wagner Grade 2. The wounds (Figure 3a) had existed for at least 2 years prior to treatment. Following sharp edge debridement, D-ADM was applied (Figure 3b), secured with sutures, and covered with a nonadherent dressing (Adaptic, Johnson & Johnson, Somerville, NJ) and moistened gauze (Kerlix, Covidien, Mansfield, MA), followed by a secure wrapping with a compression bandage (Coban, 3M Health CareSkin & Wound Care, St. Paul, MN). At 3 weeks following this single application, the wounds had substantially healed (Figure 3c). By week 9, the 2 wounds exhibited 95%-100% wound closure and healing with a single application of D-ADM.

The D-ADM provides a biocompatible scaffold to facilitate healing in a wide variety of applications. Acellular dermal matrices have shown success in treating hernias,^4-7 massive rotator cuff tears,^8-10 tendon repair,^11-13 and breast reconstruction.^14-16 They also represent a viable alternative treatment for soft tissue repair.^17,18 Numerous studies have shown superior results when using ADMs for treating nonhealing wounds of diabetic patients.^19,20   While other D-ADMs have been clinically available, the one assessed in this study represents new treatment technologies. The patented²¹ process used to prepare this specific D-ADM includes the use of anionic detergents and an endonuclease resulting in a material with more than 97% nucleic acid removal and acellular histological appearance.²² In addition, this new graft is preserved and stored at room temperature, allowing the allograft to be maintained and delivered fully hydrated and at ambient temperature to the surgical suite or outpatient procedure room. Other dermal allografts must be shipped and stored frozen at subzero temperatures or freeze-dried, requiring solvent rehydration before implantation. Also important, the D-ADM used in this study is terminally sterilized with low dose gamma irradiation to provide a medical-device grade Sterility Assurance Level of 10-6.   The results of the 11 patients (12 wounds) treated with D-ADM compare favorably with other methods of advanced wound care and other ADMs. Winters et al¹ reported the treatment of 100 wounds in 75 patients with diabetes with a mean complete healing time of 13.8 weeks after using processed donated allograft human dermis (Graftjacket Regenerative Tissue Matrix, KCI, San Anontio, TX) compared to the mean complete healing time of 10 weeks after using D-ADM. Although the definition of wound healing was different for each study (> 95% for the patients treated with D-ADM and > 90% healed for the patients treated with the donated allograft human dermis) the D-ADM had a comparable overall rate of closure (83% in D-ADM vs 91% in donated allograft human dermis) at 12 weeks.   The favorable average time of closure in patients treated with D-ADM may be due in part to a superior biologic scaffold compared to other ADMs. In an in vivo rat model study, Capito et al²³ compared the cellular reaction to AlloDerm (LifeCell Corp, Branchburg, NJ), DermaMatrix (Synthes CMF, West Chester, PA), Integra Dermal Regeneration Template (Integra LifeSciences Corporation, Plainsboro, NJ), and D-ADM. After postoperative days 7, 14, and 21, D-ADM had a significantly higher cell density than the other 3 ADMs.²³ Moreover, wounds treated with D-ADM had almost twice as many vascular vessels at postoperative day 7 than the other ADMs tested in the study. Capito and coauthors²³ also found that, among the products tested, D-ADM had the statistically significant highest rate of cellular infiltration over the course of their study. While not conclusive, these results may indicate that the accelerated cellular response may be shortening the time needed for full wound closure. A future study should explore this further, as wound healing time is becoming an increasingly important benchmark for clinicians.²⁴

  As ADMs increasingly become the surgeon’s method of choice in treating diabetic foot ulcers, it becomes more important to select the best-performing biological scaffold. This study shows favorable closure rates combined with a decreased time needed for complete closure when using D-ADM. While a second clinical investigation with a larger sample size would be beneficial, the preliminary results and patient case reports indicate a valuable treatment option for treating foot ulcers in patients with diabetes.

The authors are from the Baptist Hospital, Pensacola, FL. Layne Yonehiro, MD, FACS, FACPM is from the Baptist Hospital, Pensacola, FL and Andrews Research and Education Institute, Gulf Breeze, FL.

Address correspondence to: Layne Yonehiro, MD, FACS, FACPM Andrews Research and Education Institute 1020 Gulf Breeze Parkway Gulf Breeze, FL 32561 Layne.yonehiro@gmail.com

Disclosure: The authors disclose this study was funded by a grant to the Andrews Research and Education Institute from LifeNet Health.