Rigi10™ Malleable Penile Prosthesis
Also Known As
Implant-associated infection, medical device-related infection, prosthetic device infection, foreign body-related infection.
Definition
Device infection, also known as implant-associated infection, is a host immune response to one or more microbial pathogens colonizing an indwelling medical device.¹ It represents a significant complication following the surgical implantation of devices, which are increasingly used to improve quality of life and patient survival. The pathogenesis of device infections typically begins with the adherence of microorganisms to the foreign material of the implant. These microorganisms then undergo a complex metamorphosis, leading to the formation of a biofilm.¹ Biofilms are structured communities of microbial cells enclosed in a self-produced polymeric matrix, which adheres to the device surface. This biofilm structure provides a physical barrier and alters the phenotypic properties of the bacteria, rendering them more resistant to host immune defenses and antimicrobial therapies when used in isolation.¹ Consequently, the microorganisms residing on the device can proliferate, causing local tissue damage, such as loosening of the implanted device, wound dehiscence, or disruption of prosthetic components (e.g., heart valves). Systemic manifestations, including fever or embolic phenomena, can also occur.¹ A more specific definition of device infection might include the presence of clinical signs and symptoms of infection, intraoperative evidence of infection, and positive cultures from explanted device specimens.² It is estimated that 50-70% of healthcare-associated infections can be attributed to indwelling medical devices.² The difficulty in establishing a clear and universally accepted definition, along with challenges in diagnosis, often leads to an underestimation of the true prevalence of these infections.²
Clinical Context
Device infections are encountered across a wide range of medical specialties and are associated with significant morbidity and mortality.¹ They frequently necessitate prolonged hospitalization, extended courses of antimicrobial therapy, and often require surgical interventions to remove or replace the infected device, all of which can negatively impact a patient’s quality of life and increase healthcare costs.¹ The clinical presentation of a device infection can vary considerably depending on the type of device, the virulence of the infecting microorganism(s), and the host’s immune status. The onset of signs and symptoms can occur early after implantation, suggesting contamination at the time of surgery, or can be delayed, sometimes appearing months or even years later.¹
Diagnosing device infections can be challenging due to the lack of a consensus definition for what constitutes an infection and its severity, as well as the paucity of standardized diagnostic criteria.¹ Non-specific inflammatory markers such as erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) are often elevated but lack specificity for device infection.² While bacteremia can be a hallmark of intravascular device infections, biofilms can be present on devices without detectable bacteria in the bloodstream.² Obtaining optimal microbiological specimens, often through aspiration of fluid around the device or from cultures of the explanted device itself, is paramount for identifying the causative pathogens and tailoring antimicrobial therapy.¹
Management of device infections is complex and typically involves a multifaceted approach. Prolonged antimicrobial therapy, often for weeks or months, is almost always necessary.¹ However, due to the protective nature of biofilms, antimicrobial therapy alone is frequently insufficient to eradicate the infection, especially if the device remains in situ.¹ Surgical intervention, including debridement of infected tissue and removal of the infected device, is usually necessary for a definitive cure.¹ In certain limited circumstances, such as specific types of infections or when device removal poses a high risk to the patient, device salvage (attempting to treat the infection without removing the device) may be considered, though success rates vary.¹ For patients who are not candidates for surgical intervention or who decline further surgery, long-term or indefinite suppressive antimicrobial therapy may be an option to control the infection and prevent complications, although this approach does not typically lead to eradication.¹
Device infections can occur with a wide array of implanted materials, including but not limited to neurosurgical devices (e.g., shunts, deep brain stimulators), cardiac devices (e.g., pacemakers, implantable cardioverter-defibrillators, prosthetic heart valves, ventricular assist devices), orthopedic implants (e.g., joint prostheses, internal fixation devices), cochlear implants, breast implants, and penile prostheses.¹ The attributable mortality is highly device-dependent, ranging from less than 5% for some devices like dental implants to over 25% for infections involving mechanical heart valves.² The incidence of device-related infections is projected to increase due to factors such as the expanding use and types of implantable devices, the aging population, and the rising prevalence of comorbidities that can lead to immunocompromised states.²