Data for pressure ulcers and skin infections after cochlear implantation

Bacterial biofilm formation on headpieces of Cochlear implants

INTRODUCTION

Bacterial biofilm formation on medical devices, such as Cochlear implants (CI), can lead to chronic infections. Not only the inner parts of the implant but also the externally located headpiece might be associated with prolonged superficial skin eczema resulting in the inability of wearing the headpiece. In this study, the surface of three CI headpieces from different manufacturers were examined for bacterial biofilm formation.

MATERIALS AND METHODS

Two bacterial species associated with implant-related infections were tested: Pseudomonas aeruginosa (ATCC9027) and Staphylococcus aureus (ATCC6538). Biofilms were formed over 24 h in tryptic soy broth at 36 °C. Biofilm formation was detected in form of biomass measurement by crystal violet staining. CI headpiece dummies of three manufacturers were used.

RESULTS

Both tested bacterial species formed biofilms on the examined CI headpiece-surfaces in a species-dependent manner with higher biofilm formation of P. aeruginosa. For both, S. aureus and P. aeruginosa, biofilm formation on the CI components was comparable to a polystyrene control surface. Between the three manufacturers, no significant difference in biofilm formation was found.

DISCUSSION

The tested bacteria displayed biofilm formation on the CI headpieces in a species-specific manner with higher amount of biofilm formed by P. aeruginosa. The biofilm formation was comparable between the manufacturers. In this study, an enhanced biofilm formation on CI headpieces could not be demonstrated. These in vitro tests suggest a minor role of bacterial biofilm on the CI headpiece in skin infections under the CI headpiece.

Post-implantation clinical cost analysis between transcutaneous and percutaneous bone conduction devices

INTRODUCTION

Bone conduction devices (BCD) are effective for hearing rehabilitation in patients with conductive and mixed hearing loss or single-sided deafness. Transcutaneous bone conduction devices (tBCD) seem to lead to fewer soft tissue complications than percutaneous BCDs (pBCD) but have other drawbacks such as MRI incompatibility and higher costs. Previous cost analyses have shown a cost advantage of tBCDs. The purpose of this study is to compare long-term post-implantations costs between percutaneous and transcutaneous BCDs.

MATERIALS AND METHODS

Retrospective data from 77 patients implanted in a tertiary referral centre with a pBCD (n = 34), tBCD (n = 43; passive (tpasBCD; n = 34) and active (tactBCD; n = 9) and a reference group who underwent cochlear implantation (CI; n = 34), were included in a clinical cost analysis. Post-implantation costs were determined as the sum of consultation (medical and audiological) and additional (all post-operative care) costs. Median (cumulative) costs per device incurred for the different cohorts were compared at 1, 3 and 5 years after implantation.

RESULTS

After 5 years, the total post-implantation costs of the pBCD vs tpasBCD were not significantly different (€1550.7 [IQR 1174.6-2797.4] vs €2266.9 [IQR 1314.1-3535.3], p = 0.185), nor was there a significant difference between pBCD vs tactBCD (€1550.7 [1174.6-2797.4] vs €1428.8 [1277.3-1760.4], p = 0.550). Additional post-implantation costs were significantly highest in the tpasBCD cohort at all moments of follow-up.

CONCLUSION

Total costs related to post-operative rehabilitation and treatments are comparable between percutaneous and transcutaneous BCDs up to 5 years after implantation. Complications related to passive transcutaneous bone conduction devices appeared significantly more expensive after implantation due to more frequent explantations.

Autologous fat grafting as a minimally invasive technique to avoid cochlear implant extrusion

OBJECTIVES

Infection of the skin-muscle flap is one of the most severe risks of cochlear implantation. The aim of this paper is to describe a novel and minimally invasive procedure to avoid cochlear implant (CI) extrusion.

METHODS

A 79-year-old woman with severe comorbidities developed a pressure injury of the skin-muscle flap overlying the CI receiver/stimulator (R/S) nine years after surgery. Skin thinning and failure of conventional pressure injury management led the patient to a high risk of CI extrusion. Therefore, she underwent a single procedure of autologous fat grafting under local anesthesia to increase scalp thickness and vascularization over the CI R/S.

RESULTS

Within one month, complete healing of the pressure injury was observed, and the patient was able to safely use her CI. No further signs of infection and skin deterioration were detected at the 15-months follow-up.

DISCUSSION

Fat grafting has been proven to promote neoangiogenesis and tissue regeneration. To the best of our knowledge, this is the first report of fat grafting utilized in the skin-muscle flap area to avoid incipient CI R/S extrusion.

CONCLUSION

The described case demonstrates the efficacy of this salvage procedure to avoid major surgery and the additional costs related to CI reimplantation.