Negative pressure wound therapy limits downgrowth in percutaneous devices

Abstract

Maintenance of a soft tissue seal around percutaneous devices is challenged by the downgrowth of periprosthetic tissues—a gateway to potential infection. As negative pressure wound therapy (NPWT) is used clinically to facilitate healing of complex soft tissue pathologies, it was hypothesized that NPWT could limit downgrowth of periprosthetic tissues. To test this hypothesis, 20 hairless guinea pigs were randomly assigned into four groups (n = 5/group). Using a One‐Stage (Groups 1 and 3) or a Two‐Stage (Groups 2 and 4) surgical procedure, each animal was implanted with a titanium‐alloy subdermal device porous‐coated with commercially pure, medical grade titanium. Each subdermal device had a smooth titanium‐alloy percutaneous post. The One‐Stage procedure encompassed insertion of a fully assembled device during a single surgery. The Two‐Stage procedure involved the implantation of a subdermal device during the first surgery, and then three weeks later, insertion of a percutaneous post. Groups 1 and 2 served as untreated controls and Groups 3 and 4 received NPWT. Four weeks postimplantation of the post, the devices and surrounding tissues were harvested, and histologically evaluated for downgrowth. Within the untreated control groups, the Two‐Stage surgical procedure significantly decreased downgrowth (p = 0.027) when compared with the One‐Stage procedure. Independent of the surgical procedures performed, NPWT significantly limited downgrowth (p ≤ 0.05) when compared with the untreated controls.

Influence of negative pressure wound therapy on peri‐prosthetic tissue vascularization and inflammation around porous titanium percutaneous devices

“…Each animal was implanted with a historically successful percutaneous device . Briefly, each device consisted of a machined smooth titanium alloy (Ti 6 Al 4 V) percutaneous post, and a subdermal device consisting of a Ti 6 Al 4 V core with a commercially pure titanium porous coating (K‐coating, Thortex Inc., Portland, OR).…”

“…One such strategy is to use Negative Pressure Wound Therapy (NPWT). In a translational animal model, NPWT has been shown to improve downgrowth outcomes around percutaneous devices . This result was not surprising since NPWT is used to facilitate the healing of chronic and “hard to heal” wounds such as diabetic ulcers .…”

“…Despite clinical success in open wounds, there is a relative lack of data regarding the use of NPWT with percutaneous devices. One recent study suggested that NPWT has the ability to reduce epidermal downgrowth over percutaneous devices in a guinea pig model . Mitchell et al showed that a negative pressure treatment of −80 to −100 mmHg applied through gauze and semi‐occlusive dressings over percutaneous devices was able to limit downgrowth .…”

“…One recent study suggested that NPWT has the ability to reduce epidermal downgrowth over percutaneous devices in a guinea pig model . Mitchell et al showed that a negative pressure treatment of −80 to −100 mmHg applied through gauze and semi‐occlusive dressings over percutaneous devices was able to limit downgrowth . One shortcoming of the study was that apart from performing downgrowth measurements, the effects of NPWT on wound healing characteristics such as blood vessels and inflammation within peri‐prosthetic tissues were neither studied, nor characterized.…”

“…Therefore, the goal of this study was to investigate the effects of NPWT on the vascularization and inflammation of peri‐prosthetic soft‐tissues and to reproducibly limit epidermal downgrowth around percutaneous devices. Unlike the previous study which used a guinea pig model to investigate the effects of NPWT on peri‐prosthetic tissues, this study utilized a rat model due to the availability of molecular‐level analysis tools. This study tested two hypotheses.…”