Pig dorsum model for examining impaired wound healing at the skin-implant interface of percutaneous devices

Abstract

Percutaneous medical devices are indispensable in contemporary clinical practice, but the associated incidence of low to moderate mortality infections represents a significant economic and personal cost to patients and healthcare providers. Percutaneous osseointegrated prosthetics also suffer from a similar risk of infection, limiting their clinical acceptance and usage in patients with limb loss. We hypothesized that transepidermal water loss management (TEWL) at the skin-implant interface may improve and maintain a stable skin-to-implant interface. In this study, skin reactions in a 3-month, pig dorsum model were assessed using standard histology, immunohistochemistry, and quantitative image analysis. Immunohistochemical analysis of peri-implant tissue explants showed evidence of: continuous healing (cytokeratin 6+), hypergranulation tissue (procollagen+), hyper-vascularity (Collagen 4+), and the presence of fibrocytes (CD45+ and procollagen type 1+). Importantly, the gross skin response was correlated to a previous load-bearing percutaneous osseointegrated prosthetic sheep study conducted in our lab. The skin responses of the two models indicated a potentially shared mechanism of wound healing behavior at the skin-implant interface. Although TEWL management did not reduce skin migration at the skin-implant interface, the correlation of qualitative and quantitative measures validated the pig dorsum model as a high-throughput platform for translational science based percutaneous interface investigations in the future.

A decomposable silica-based antibacterial coating for percutaneous titanium implant

“…10 If the healing process is hampered by the ingress of bacteria into the tissue, it can lead to a localized infection of the implants, soft tissue damage, and ultimately implant failure. 11,12 This undesirable outcome brings overwhelming troubles for both clinicians and patients. 13 Therefore, it is imperative that a solution be found to functionalize percutaneous devices with anti-infection abilities.…”

Negative pressure wound therapy limits downgrowth in percutaneous devices

“…Data have shown that the chronic inflammatory responses associated with the wound microenvironments were present at the skin/device interface regardless of implant indwelling time or animal model used . Further investigation of the periprosthetic interface with use of immunohistochemistry had revealed the presence of cytokeratin 6—commonly expressed by the migrating keratinocytes—and the presence of hypergranular tissue . These findings indicated a complex wound healing phenomenon and the presence of pro‐inflammatory responses at the interface.…”

Evaluation of soft‐tissue response around laser microgrooved titanium percutaneous devices

“…During cutaneous wound healing, epidermal cells at the wound edges, supported by the underlying granulation tissue, undergo proliferation and migration in order to cover the defect (Landen, Li, & Stahle, ; Werner, Krieg, & Smola, ). Around percutaneous devices, proliferation and migration of epidermal cells due to unresolved and ongoing wound healing may contribute to epidermal downgrowth (Holt et al, ; Iglhaut et al, ; von Recum, ). Thus, the histological characteristics observed in this study including the presence of a double epidermis and the granulation tissue, may provide evidence that the peri‐prosthetic epidermal tissue was in a state of continuous wound healing, which contributed to the observed downgrowth.…”