Autologous suction blister grafting for chronic leg ulcers

The effect of a basic skin care product on the structural strength of the dermo-epidermal junction: An exploratory, randomised, controlled split-body trial

Skin ageing is associated with various structural alterations including a decreased strength of the dermo‐epidermal adhesion increasing the risk for shear type injuries (skin tears). Topical applications of basic skin care products seem to reduce skin tear incidence. The suction blister method leads to the artificial and controlled separation of dermis and epidermis. Therefore, time to blister formation may be used as outcome measuring the strength of dermo‐epidermal adhesion. We conducted an exploratory, randomised, controlled trial with a split‐body design on forearms in healthy female subjects (n = 12; mean age 70.3 [SD 2.1] years). Forearms assigned to the intervention were treated twice daily with petrolatum for 8 weeks. Suction blisters were induced on forearms after 4 and 8 weeks and time to blister formation was measured. Stratum corneum and epidermal hydration were measured and epidermal thickness was assessed via optical coherence tomography. Time to blistering was longer and stratum corneum as well as epidermal hydration was consistently higher in intervention skin areas. We conclude that topical application of basic skin care products may improve mechanical adhesion of the dermo‐epidermal junction and that the parameter “time to blistering” is a suitable outcome to measure dermo‐epidermal adhesion strength in clinical research.

Epidermal graft encourages wound healing by down-regulation of gap junctional protein and activation of wound bed without graft integration as opposed to split-thickness skin graft

Wound coverage by split-thickness skin graft (SSG) and epidermal graft (EG) shortens healing time, with comparable outcomes. However, the healing mechanism of EG is not as well understood as SSG. The difference in the healing mechanisms of EG and SSG was investigated using gap junctional proteins, proliferative marker, and cytokeratin markers. Paired punch biopsies were taken from the wound edge and wound bed from patients undergoing EG and SSG at weeks 0 and 1 to investigate wound edge keratinocyte migratory activities (connexins 43, 30, and 26), wound bed activation (Ki67), and the presence of graft integration to the wound bed (cytokeratins 14 and 6). Twenty-four paired biopsies were taken at weeks 0 and 1 (EG, n = 12; SSG, n = 12). Wound edge biopsies demonstrated down-regulation of connexins 43 (P = .023) and 30 (P = .027) after EG, indicating accelerated healing from the wound edge. At week 1, increased expression of Ki67 (P < .05) was seen after EG, indicating activation of cells within the wound bed. Keratinocytes expressing cytokeratins 6 and 14 were observed on all wounds treated with SSG but were absent at week 1 after EG, indicating the absence of graft integration following EG. Despite EG and SSG both being autologous skin grafts, they demonstrate different mechanisms of wound healing. EG accelerates wound healing from the wound edges and activates the wound bed despite not integrating into the wound bed at week 1 post-grafting as opposed to SSG, hence demonstrating properties comparable with a bioactive dressing instead of a skin substitute.

Re-epithelialization and immune cell behaviour in an ex vivo human skin model

A large body of literature is available on wound healing in humans. Nonetheless, a standardized ex vivo wound model without disruption of the dermal compartment has not been put forward with compelling justification. Here, we present a novel wound model based on application of negative pressure and its effects for epidermal regeneration and immune cell behaviour. Importantly, the basement membrane remained intact after blister roof removal and keratinocytes were absent in the wounded area. Upon six days of culture, the wound was covered with one to three-cell thick K14⁺Ki67⁺ keratinocyte layers, indicating that proliferation and migration were involved in wound closure. After eight to twelve days, a multi-layered epidermis was formed expressing epidermal differentiation markers (K10, filaggrin, DSG-1, CDSN). Investigations about immune cell-specific manners revealed more T cells in the blister roof epidermis compared to normal epidermis. We identified several cell populations in blister roof epidermis and suction blister fluid that are absent in normal epidermis which correlated with their decrease in the dermis, indicating a dermal efflux upon negative pressure. Together, our model recapitulates the main features of epithelial wound regeneration, and can be applied for testing wound healing therapies and investigating underlying mechanisms.

Use of Cellutome for the healing of venous or mixed ulcers

Venous or mixed ulcers are common and invalidating. Cutaneous transplants may be necessary if conventional treatment is ineffective. We evaluated the performance of Cellutome in promoting the healing of venous or mixed ulcers 2 months after grafting. This was a retrospective, multi-centric, descriptive study of patients who had a venous or mixed ulcer for at least several months and who received an autologous skin graft using the Cellutome system at least 2 months before. The principle evaluation criterion was the state of the wound after 2 months (completely healed vs not healed). The secondary evaluation criterion was the percentage of wound healing after 2 months. A total of 47 patients were included in the study. The ulcers had evolved over an average of 18 months. The average surface area was 13.37 cm² . After 2 months, the grafts of 26 of 47 patients (55.3%) were completely healed. The grafts of 21 patients (44.6%) were not completely healed but showed an average rate of healing of 51%. Use of the Cellutome system for epidermal transplants promoted complete or improved healing after 2 months for 55.3% of patients with chronic venous or mixed ulcers. The limited data on the rate of healing of conventional transplants in the literature report rates of approximately 50%. The Cellutome system may therefore be of interest as the healing rate is similar to that of conventional techniques, but using a much simpler, painless procedure on an outpatient basis.

Systematic review and meta-analysis of the efficacy of epidermal grafting for wound healing

Autologous skin grafting is an important method for wound coverage; however, it is an invasive procedure and can cause donor site morbidity. Epidermal grafting (EG) enables epidermal transfer to wounds with minimal donor site morbidity. However, data to date have been heterogeneous. This study aims to synthesise the current evidence on EG for wound healing to establish the efficacy of this surgical technique. A comprehensive search in the MEDLINE, EMBASE and CENTRAL databases was conducted. The endpoints assessed were proportion of wounds healed and mean wound-healing time. This systematic review was conducted and reported according to the Meta-Analysis of Observational Studies in Epidemiology (MOOSE) guidelines. We identified 1568 articles, of which seven articles were included in this review - a total of 209 wounds in 190 patients. The mean wound duration was 17·06 weeks (95% CI 8·57-25·55). Of these, 71·5% (95% CI 56·7-84·2) of the wounds achieved complete healing. Mean time for complete wound healing was 5·53 weeks (95% CI 3·18-7·88). The mean donor site healing time was 7·48 days (95% CI 4·83-10·13), with no reported donor site morbidity. The current data are small and lack level 1 evidence.

An Automated and Minimally Invasive Tool for Generating Autologous Viable Epidermal Micrografts

OBJECTIVE:

A new epidermal harvesting tool (CelluTome; Kinetic Concepts, Inc, San Antonio, Texas) created epidermal micrografts with minimal donor site damage, increased expansion ratios, and did not require the use of an operating room. The tool, which applies both heat and suction concurrently to normal skin, was used to produce epidermal micrografts that were assessed for uniform viability, donor-site healing, and discomfort during and after the epidermal harvesting procedure.

DESIGN:

This study was a prospective, noncomparative institutional review board–approved healthy human study to assess epidermal graft viability, donor-site morbidity, and patient experience.

SETTING:

These studies were conducted at the multispecialty research facility, Clinical Trials of Texas, Inc, San Antonio.

PATIENTS:

The participants were 15 healthy human volunteers.

RESULTS:

The average viability of epidermal micrografts was 99.5%. Skin assessment determined that 76% to 100% of the area of all donor sites was the same in appearance as the surrounding skin within 14 days after epidermal harvest. A mean pain of 1.3 (on a scale of 1 to 5) was reported throughout the harvesting process.

CONCLUSIONS:

Use of this automated, minimally invasive harvesting system provided a simple, low-cost method of producing uniformly viable autologous epidermal micrografts with minimal patient discomfort and superficial donor-site wound healing within 2 weeks.

Epidermal grafting for wound healing: a review on the harvesting systems, the ultrastructure of the graft and the mechanism of wound healing

Epidermal grafting for wound healing involves the transfer of the epidermis from a healthy location to cover a wound. The structural difference of the epidermal graft in comparison to the split-thickness skin graft and full-thickness skin graft contributes to the mechanism of effect. While skin grafting is an epidermal transfer, little is known about the precise mechanism of wound healing by epidermal graft. This paper aims to explore the evolution of the epidermal graft harvesting system over the last five decades, the structural advantages of epidermal graft for wound healing and the current hypotheses on the mechanism of wound healing by epidermal graft. Three mechanisms are proposed: keratinocyte activation, growth factor secretion and reepithelialisation from the wound edge. We evaluate and explain how these processes work and integrate to promote wound healing based on the current in vivo and in vitro evidence. We also review the ongoing clinical trials evaluating the efficacy of epidermal graft for wound healing. The epidermal graft is a promising alternative to the more invasive conventional surgical techniques as it is simple, less expensive and reduces the surgical burden for patients in need of wound coverage.

Clinical and Economic Benefits of Autologous Epidermal Grafting

Chronic wounds are an increasingly prevalent disease with a significant healthcare burden. These wounds often do not respond to standard of care therapy alone, requiring the use of adjuvant therapies. Epidermal grafting, previously utilized primarily for correction of leukoderma, is increasingly being recognized as a beneficial therapy for wounds, both acute and chronic. Epidermal grafting has been shown to be effective in the management of chronic wounds, with successful healing in refractory patients. It has not only been shown to be effective, but it is also associated with lower cost and morbidity than traditional skin grafting techniques as well as improved donor site healing. Through the use of a novel epidermal harvesting system, the CelluTome™ Epidermal Harvesting System (KCI, an Acelity company, San Antonio, TX), this treatment modality has become more standardized, reproducible, and easy to use as well as less time consuming, making its use in the clinical setting more convenient and beneficial. Epidermal grafting, therefore, represents a promising, efficacious, and cost-effective option for treatment of refractory non-healing wounds.

A Case Series of Complex Recalcitrant Wounds Treated with Epidermal Grafts Harvested from an Automated Device

Introduction: Epidermal grafting has several advantages over full-thickness or split-thickness grafts in the treatment of complex non-healing wounds. These include the low risk of donor site complications, minimal patient discomfort, and abstention from the operating room. Traditionally, the lack of reliable epidermal harvesting techniques has limited its clinical utilization. The development of an automated suction blister epidermal graft (SBEG) harvesting device may facilitate clinical utilization of this technique. The authors present a case series of multimorbid patients who were poor surgical candidates and were treated with this technique.

Methods: A retrospective review of all patients treated with CelluTome™​ Epidermal Harvesting System (KCI, an Acelity company, San Antonio, TX) prior to May 2016 at our institution was conducted.

Results: A total of 12 patients underwent 14 epidermal grafting procedures. Multiple comorbidities were identified, including smoking (33%), immunosuppression by immunotherapy or steroids (25%), chronic venous insufficiency (25%), diabetes mellitus (25%), malignancy (25%), polysubstance abuse (17%), HIV/AIDS (17%), and peripheral artery disease (8%). Among the two acute wounds (≤ 3 months) and 10 chronic wounds, the average wound size was 49.1 cm² (± 77.6 cm²) and the median wound duration was 5.7 months (interquartile range: 4.1 - 15.8 months) before SBEG was attempted. These complex wounds had failed prior therapies, such as local wound care (100%), incision and drainage (58%), vacuum-assisted closure (33%), split-thickness skin graft (16%), and hyperbaric oxygen (8%). Following the procedure, all donor sites healed within one week. Three patients were lost to follow-up. Of the remaining nine patients, four patients had complete resolution of their wounds at a median follow-up of 13.1 weeks (interquartile range: 6.8-17.3 weeks). Among those with partial resolutions, the average wound size was 4.2 cm² (± 2.1 cm²) with an average wound reduction of 79% (± 23%). No donor or recipient site complications were observed.

Conclusions: The automated SBEG harvesting device is an effective and safe option for treating complex non-healing wounds in multimorbid patients who may be poor surgical candidates. This procedure demonstrates minimal contraindications to its use and donor or recipient site complications.

Epidermal skin grafting

Autologous skin grafts, such as full- and split-thickness, have long been part of the reconstructive ladder as an option to close skin defects. Although they are effective in providing coverage, they require the need for a trained surgeon, use of anaesthesia and operating room and creation of a wound at the donor site. These drawbacks can be overcome with the use of epidermal skin grafts (ESGs), which can be harvested without the use of anaesthesia in an office setting and with minimal to no scarring at the donor site. ESGs consist only of the epidermal layer and have emerged as an appealing alternative to other autologous grafts for the treatment of acute and chronic wounds. In this article, we provide an overview of epidermal grafting and its role in wound management.

The CelluTome epidermal graft-harvesting system: a patient-reported outcome measure and cost evaluation study

Conventional split skin grafts (SSG) require anaesthesia, specialist equipment and can have high donor site (DS) morbidity. The CelluTome epidermal graft-harvesting device is a novel alternative, providing pain-free epidermal skin grafts (ESG) in the outpatient setting, with projected minimal DS trauma and improved patient satisfaction. This study aimed to compare ESG with SSG by evaluating patient-related outcome measures (PROMs) and the cost implications of both. Twenty patients answered a graft satisfaction questionnaire that evaluated: donor/graft site noticeability, aesthetic concerns, adverse problems and patient satisfaction. Cost/patient was calculated based on total operative expenses and five clinic follow-ups. In 100% of the ESG cases, there were no DS noticeability or adverse problems compared to 25% in the SSG group. Complete satisfaction with DS appearance was observed in 100% of the ESG cases (50% SSG). Noticeability, adverse problems and overall satisfaction were significantly better in ESG cases (P < 0.05). Graft site parameters were comparable with similar healing outcomes. The cost per patient for ESG was £431 and £1489 for SSG, with an annual saving of £126 960 based on 10 grafts/month. For the right patient, CelluTome provides comparable wound healing, with reduced DS morbidity and higher patient satisfaction.

A prospective, multicentre study on the use of epidermal grafts to optimise outpatient wound management

Current wound management through the use of a split-thickness skin graft often requires hospital admission, a period of immobility, attentive donor site wound care and pain management. This study evaluates the feasibility of using a novel epidermal graft-harvesting device (CelluTome) that allows pain-free epidermal skin grafting in the outpatient clinic setting. A prospective series of 35 patients was performed in 2 centres, involving 10 acute and 25 chronic wounds. All patients were subjected to epidermal grafting in the outpatient specialist clinic, without the use of anaesthesia, and allowed to return home after the procedure. Completely healed wounds were noted in 22 patients (62·9%). The overall mean time for 50% and 100% reduction in wound size was 3·31 ± 2·33 and 5·91 ± 3·48 weeks, respectively. There was no significant difference in healing times between the acute and chronic wounds (50% reduction in wound size; acute 2·20 ± 0·91 weeks versus chronic 3·73 ± 2·63 weeks, P = 0·171. Hundred percent reduction in wound size; acute 4·80 ± 1·61 weeks versus chronic 6·83 ± 4·47 weeks, P = 0·183). The mean time for donor site healing was 5·49 ± 1·48 days. The mean pain score during graft harvest was 1·42 ± 0·95, and the donor site Vancouver Scar Scale was 0 for all cases at 6 weeks. This automated device offers autologous skin harvesting in the outpatient setting with minimal or no pain and a scar free donor site, equally benefiting both the acute and chronic wounds. It has the potential to save NHS resources by eliminating the need for theatre space and a hospital bed while at the same time benefiting patient care.