A case report of a cochlear implant infection - A reason to explant the device?

A Descriptive Study on Imperiled Cochlear Implant Salvage Using Double Flap Cover-What We Learned in 6 Years

Cochlear implant surgery is the standard of care for severe sensorineural hearing loss. Infection followed by implant extrusion is an infrequent complication of this surgery. The ideal treatment is explantation of the implant. However, implant removal and reimplantation is a challenging surgery and may have poor speech reception outcomes. The cost of a new implant especially in developing countries is also a deterrent. Our study dwells on the feasibility of salvaging exposed cochlear implants by a combination of pericranial flaps followed by a scalp flap cover. The study was done in a tertiary care hospital over a period of six years. Out of 303 cochlear implant surgeries, 12 patients had implant exposure and extrusion. Patients having meningitis and sepsis were excluded from the study. All patients underwent debridement and cover with double flap (Pericranial flaps and scalp rotation flap). The average operating time was 2.17 h. The surgery is technically simple with a short learning curve. It brings in rich blood supply and there is fair amount of tissue mobility. In 11 patients we were able to salvage the implant. Patients were followed for a period of 01 year post operatively. Our study suggests that salvage of infected implant should be attempted as it is feasible, durable and effective in appropriate patients.

The biofilm characteristics and management of skin flap infection following cochlear implantation

Objective

This study aims to assess the frequency, bacteriology, biofilm characteristics and management of skin flap infection (SFI) following cochlear implantation (CI).

Methods

The study enrolled 1,251 patients receiving CI in the First Affiliated Hospital of Fujian Medical University between August 2001 and March 2021. Scanning electron microscopy (SEM) was utilised to characterise the aetiology of infection. A proposed classification system was applied to optimise treatments for post-operative skin flap infection.

Results

After CI, SFI was reported in 16 patients (1.28%) and occurred more frequently in patients under 6 years of age. Of all SFI cases Staphylococcus aureus was the most common pathogen for flap infection, with 8 cases (50%) and bacterial biofilm was evident within the jelly-like substance on the surface of implanted devices in SFI patients. A two-stage classification was proposed to optimise the treatment schemes. Conservative therapy was recommended for stage I cases and surgical treatment for stage II patients.

Conclusions

Paediatric patients are more susceptible to SFI after CI, which may be attributed to the formation of bacterial biofilm. The proposed classification can facilitate the management of SFI.

Fluorescence in situ hybridization and microbial community profiling analysis of explanted cochlear implants

BACKGROUND

Cochlear implant (CI) infections affect a small, but significant number of patients. Unremitting infections can lead to explantation. Fluorescence in situ hybridization (FISH) and microbial community profiling (MCP) are methods of studying microbial environments of explanted devices that can provide information to reduce morbidity and costs of infected CIs.

AIMS/OBJECTIVES

To describe the results and clinical significance of bacterial analyses conducted on explanted CIs.

MATERIAL AND METHODS

Between 2013 and 2017, 12 explanted devices underwent microbiological analysis in addition to the manufacturer's device failure analysis. Patients' clinical history, infection status and outcome were reviewed and correlated with microbial analysis results.

RESULTS

From 2013 to 2017, 12 Cochlear™ devices from 11 patients underwent additional MCP or FISH analysis. Five devices were explanted due to suspected implant associated infection, and seven were explanted for other reasons. FISH analysis revealed biofilm presence on all infected devices, only partial correlation of cultures with biofilm composition and confirmation that biofilm formation occurs preferentially at particular device interfaces and geometries. MCP analysis presented challenges in data analysis inherent to its technique but correlated with cultures of infected devices and suggested a diverse microbial composition of explanted devices.

CONCLUSIONS AND SIGNIFICANCE

Microbial analysis of explanted devices can aid in further elucidating treatment approaches to infected CIs.

Bimodal Nanocomposite Platform with Antibiofilm and Self-Powering Functionalities for Biomedical Applications

Advances in microelectronics and nanofabrication have led to the development of various implantable biomaterials. However, biofilm-associated infection on medical devices still remains a major hurdle that substantially undermines the clinical applicability and advancement of biomaterial systems. Given their attractive piezoelectric behavior, barium titanate (BTO)-based materials have also been used in biological applications. Despite its versatility, the feasibility of BTO-embedded biomaterials as anti-infectious implantable medical devices in the human body has not been explored yet. Here, the first demonstration of clinically viable BTO-nanocomposites is presented. It demonstrates potent antibiofilm properties against Streptococcus mutans without bactericidal effect while retaining their piezoelectric and mechanical behaviors. This antiadhesive effect led to ∼10-fold reduction in colony-forming units in vitro. To elucidate the underlying mechanism for this effect, data depicting unfavorable interaction energy profiles between BTO-nanocomposites and S. mutans using the classical and extended Derjaguin, Landau, Verwey, and Overbeek theories is presented. Direct cell-to-surface binding force data using atomic force microscopy also corroborate reduced adhesion between BTO-nanocomposites and S. mutans. Interestingly, the poling process on BTO-nanocomposites resulted in asymmetrical surface charge density on each side, which may help tackle two major issues in prosthetics-bacterial contamination and tissue integration. Finally, BTO-nanocomposites exhibit superior biocompatibility toward human gingival fibroblasts and keratinocytes. Overall, BTO-embedded composites exhibit broad-scale potential to be used in biological settings as energy-harvestable antibiofilm surfaces.

Ideal Flap Cover for the Salvage of Exposed/Infected Cochlear Implants: A Case Series and Literature Review

With an increase in the number of cochlear implant surgeries there is bound to be an increase in the number of complications. A dreaded problem in any implant procedure is the implant exposure and infection. Explantation of the implant leads to an unpleasant situation to the patient and the surgeon owing to the high cost of the device. There are reports in the literature favouring the mandatory relocation or removal of the infected implants. On the other hand, there are convincing reports of implant salvage using skin, muscle or fascial flaps. In this paper we have analysed a series of cases referred to us from the departments of E.N.T for the management of implant exposure/infection. We have also reviewed similar case series reported in the literature. From 2014 to 2017 we operated six cases of exposed cochlear implant. We salvaged the implant in five cases, where we could do two layer coverage consisting of the inner temporoparietal fascial flap and outer scalp skin flap. In one case where the temporoparietal fascial flap could not be done as superficial temporal vessels were found to be injured in the previous surgery, the implant was removed due to persistent infection. All these cases were administered appropriate antibiotics for a minimum period of 3 weeks. Early double layer closure with inner temporoparietal fascial flap and outer scalp rotation flap coupled with appropriate antibiotics can salvage an infected, exposed implant.