Utility of a Continuous External Tissue Expander in Complex Pediatric Wound Reconstruction

Tissue expansion is a biological mechanism of the human body that has been documented in response to both physiological and pathological stimuli.¹ Examples can be seen within pregnancy, weight gain, expansion of skin over a growing tumor, and various cultural behaviors such as neck extension and lower lip expansion.¹ Though the mechanism of tissue expansion is not completely understood, studies have suggested the importance of cellular response to mechanical stress, extracellular and intracellular changes, proliferation of basal keratinocytes, collagens, growth factors, second messenger systems, integrins, ion channels, and cell-to-cell interactions.^2,3 Internal tissue expansion harnesses these concepts by implantation of an inflatable subcutaneous expander. This technique has gained popularity in areas of planned reconstruction such as breast expansion for implant placement, tissue expansion before flap transfer, or pediatric facial reconstruction for microtia.^4-6 A downside of internal tissue expansion, however, is the necessary planning that is needed that often prevents its use with traumatic wounds.⁴

A more novel technique, continuous external tissue expansion (CETE), has started to gain popularity in achievement of wound coverage.⁷ Despite the variation in hardware usage, this technique utilizes anchoring along the wound’s edge with mechanical tension of skin across the wound opening to facilitate wound closure.^7-10 In a recently published review of CETE by MacKay et al, 6 devices that have been utilized in external tissue expansion were compared against each other. One of the devices included in the review was DermaClose (Synovis Micro Companies Alliance, Inc). A common advantage of these devices was the utility in management of longstanding wounds. DermaClose was reported to only have 1 disadvantage, which was the need to undermine wound edges.⁷

DermaClose is a self-tightening external tissue expander that applies constant tension to wound edges (Figure 1) and is indicated in aiding the closure of full-thickness wounds of the skin.⁷ The device has proven efficacious in healing of complex wounds, both as a result of incisional complications and trauma.^7,11-13 In several reports, the device was found to improve outcomes including fewer postoperative complications, decreased time to wound closure, and better aesthetic results when compared to more traditional methods such as skin grafts, flaps, and secondary intention with granulation.^7,14-16 The use of the device has predominantly been reported in the adult population within specialty areas including podiatry, orthopedics, and microsurgery.^7,8 The reported uses in the pediatric population, though minimal, have also demonstrated the safety of this device in achieving healing and closure of complex wounds.^17,18

This article presents 3 cases in which the DermaClose device was used in pediatric patients to achieve closure of complex wounds that resulted after traumatic injury. Their article also describes the steps taken to review the literature with a summary of findings.

Per policy at the University of Mississippi Medical Center, a case series of 3 or fewer patients did not require approval from the Institutional Review Board (IRB) and was therefore not needed for this manuscript. As the patients included in this case series were minors, written consent for usage of clinical history and photographs was obtained through their legal guardians.

A systematic literature review was conducted by a single researcher through the US National Library of Medicine/National Institute of Health (NIH) database. Boolean search terms generated a total of 44 results (Table 1), 9 of which were duplicates. The remaining 34 results were examined against predetermined inclusion criteria. The majority of available data regarding tissue expansion involves the usage of internal expansion devices in pediatric patients or case reports on the adult population. Search results that fit either of these 2 categories were excluded, yielding 2 pertinent articles summarized in Table 2.

The DermaClose website (www.dermaclose.com) reports that the product has been used in over 17 000 cases with at least 46 published case reports and 20 clinical publications.^19,20 A review of the 32 case reports on the webpage found that 4 involved pediatric patients (Table 3).  The case reports including adult patients (aged 25 to 68 years) spanned multiple surgical fields, including plastics, trauma, vascular, orthopedics, foot/ankle, and general surgery.¹⁹ After reviewing the clinical publications listed on the website, no discussion of pediatric patients was found in any of the included manuscripts. Listed publications were found within 9 specialties over a period of 9 years, with the most recent published in 2016²⁰(Table 4).

Patient 1

A 12-year-old male suffered an open fracture of the distal third tibia and fibula after being an unrestrained passenger in a motor vehicle accident. The patient’s initial wound was 6 x 5 cm on the medial distal aspect of the right lower extremity with exposed tibia (Figure 2A). He underwent irrigation and debridement with an open reduction and internal fixation (ORIF) of the right tibia and layered closure of the wound. The patient struggled with wound healing until presenting with a discharging eschar approximately 1 month after injury, requiring removal of the hardware. The first DermaClose device was installed 6 weeks postinjury, followed by 1 adjustment (Figure 2B). The device was removed after being in place for 13 days with successful complex wound closure. Figure 2C shows the patient’s leg 7 months postinjury.

Patient 2

A 9-year-old male was involved in an all-terrain vehicle accident that resulted in an open fracture of the right distal tibia and fibula with a large anteromedial soft tissue injury measuring 15 x 8 cm (Figure 3A). The patient initially underwent intramedullary nailing with complex closure of the wound, followed by adjacent tissue transfer 3 days later. The DermaClose device was installed 2 weeks after injury (Figure 3B), followed by 2 adjustments in the subsequent week. It was then removed 10 days after initial placement and closed with a split-thickness skin graft (Figure 3C). The wound can be seen 2 months postinjury in Figure 3D.

Patient 3

A 4-year-old female presented after being attacked by a dog, resulting in a 10 x 7 cm full-thickness soft tissue degloving injury with loss of scalp tissue and denuded calvarium (Figure 4A). She also suffered various facial lacerations and fractures of the inferior orbital wall, nasal, and maxillary bones. The patient was initially taken to the operating room for irrigation and debridement of wounds with simple closures where indicated, as well as placement of a skin substitute over the scalp avulsion. After undergoing a subsequent irrigation and excisional debridement, the patient had 2 DermaClose devices installed approximately 2 weeks after injury. The patient underwent a total of 3 replacements/adjustments of the DermaClose device before final removal at 5 weeks after initial injury (Figure 4B). The wound was then given adequate time to form granulation tissue (4 months postinjury, Figure 4C). At 9 months after the initial injury, the area of granulation tissue measured 5.5 x 4 cm and was deemed substantial enough for placement of split-thickness skin graft. The patient’s scalp 11 months after the injury can be seen in Figure 4D.

A systematic review of the available literature on the use of DermaClose in pediatric wounds yielded minimal results. The lack of pediatric data is likely due to the relative newness of this product coupled with a general lack of use within this population. Difficulty with literature review was also encountered as a result of the terminology used in previous reports of external tissue expansion. A search for “DermaClose” through the US National Library of Medicine/National Institute of Health database yielded a total of 7 publications, while searching for “external tissue expansion” yielded over 600 results. Regardless, the pertinent pediatric literature that was found, though scarce, reported success with external tissue expansion in pediatric patients with DermaClose. Furthermore, reports discouraging its use were not found in either the adult or pediatric populations. This article further supports the success of the DermaClose product, aims to bridge the gap of insufficient data on its use in pediatric patients with wounds that are the result of traumatic injury, and highlights the need for further investigation of its use in traumatic pediatric wounds.

Of the 3 cases presented in this article, 2  involved the lower extremity. There have been several accounts of DermaClose use in the adult population for closure of lower extremity wounds such as diabetic ulcers, amputations, fasciotomies, and open fractures.^{7,11-12,16,27} There are also reports of closure of the donor-site wound of anterolateral thigh (ALT) flaps in both adult and pediatric populations.^7-8,18 In 2 of the cases reported in this article, DermaClose was applied and achieved closure after an attempt at complex wound closure with conservative management had failed, suggesting that it should be considered for initial use in complex or difficult wounds to avoid wound closure failure.

The third patient presented in this article had injury to the scalp. Although examples of scalp wound closure by DermaClose have been reported in adult patients, the wounds in these cases have occurred after planned surgical resection of malignancies rather than traumatic injuries.^22,25,29 Preoperative use of DermaClose has also been reported in 6 adult patients who underwent reconstructive cranioplasty for cranial defects greater than 5 cm in diameter and experienced low morbidity rates and high satisfaction rates.³⁰ The scalp wound of the third pediatric patient in this report was a very complex injury, requiring the longest time of the three pediatric patients presented to achieve wound closure. Despite this difficultly, closure was still achieved. It could be argued that the same, if not a heightened, level of difficulty may have been met had DermaClose not been used in the wound healing strategy. Additionally, the successful outcome of this case, despite its challenges, should function as an example and support the use of DermaClose in pediatric scalp wounds both of equal and lesser severity.

The importance of repeated reinstallations of the device to achieve closure in larger wounds is a major point in the pediatric cases presented in this report. Summary of the 3 patients’ wounds can be seen in Table 5. The wound with the smallest width (patient 1) was able to be closed after 1 reinstallation. Though a direct correlation was not observed between wound size and number of reinstallations within these cases, it should be anticipated that the number of reinstallations may generally increase as the size of the wound increases as well. However, the number of reinstallations and days to removal might also depend on other factors such as wound shape, wound-edge jaggedness, skin laxity, wound location, and cleanliness of the wound at device application and throughout the healing process.

Though a strict threshold for wound size that would require reapplications cannot be determined from this case series, a generalized algorithm for management of traumatic injuries with complex wounds is proposed in Figure 5.

This algorithm prioritizes wound cleanliness first over achieving wound closure. Until the wound has been deemed clean through appropriate irrigation and debridement, application of negative pressure therapy and/or dressing changes should be used as primary treatment. After the wound is free of debris and signs of infection, installation of DermaClose can be performed. The DermaClose device should be inspected daily with anticipation of returning to the operating room for undermining of adjacent skin and device reapplication every 7 days until closure is achieved. Individual judgement will have to be used in each case, as each patient’s skin may respond differently to the device. In this report, for example, patient 1 had one adjustment over a period of 13 days, while the second patient had 2 adjustments within a period of 10 days.

The 3 cases presented in this article demonstrate the efficacy and safety of DermaClose for continuous external tissue expansion as an alternate or additional therapy for treatment of wounds in pediatric patients with traumatic injuries. The DermaClose device was able to drastically decrease the size of the wounds in all cases. In larger wounds, the use of repetitive and/or multiple device application should be considered for optimal outcomes. An algorithm for approach to wound care has also been proposed. Wound size and general skin laxity in the area of the wound should be taken into consideration. In the cases where complete closure was not achieved with DermaClose alone, however, the use of split-thickness skin grafting and local wound care were ultimately used. Nevertheless, traditional, more invasive methods such as full-thickness tissue transfer or thigh flaps for wound coverage were avoided. Use of DermaClose is recommended initially for maximal benefit of wound approximation, and individual judgement on a case-by-case basis should be used when contemplating utilization of additional wound-healing techniques such as secondary intention and split-thickness skin grafts. The patients presented in this report experienced no adverse events as a result of the use of DermaClose and achieved better aesthetic results in the same if not less amount of time as would be expected with traditional wound-healing methods.

Medical Center, Division of Plastic and Reconstructive Surgery, Jackson, Mississippi; ³University of Mississippi School of Medicine, Jackson, Mississippi; ⁴University of Mississippi Medical Center, Division of Pediatrics, Grenada, Mississippi

Correspondence: Bobby L. May, MD; blm66@duke.edu

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