The Risk of Bacterial Colonization Increases With Multiple Replacements of Implanted Pulse Generators for Deep Brain Stimulation

OBJECTIVES: Deep brain stimulation (DBS) has revolutionized the treatment of movement disorders, yet repeated implanted pulse generator (IPG) replacements due to battery depletion pose a risk for surgical site infections. This study investigates microbial colonization dynamics across consecutive IPG replacements and compares the pathogen detection rates of sonication and standard microbiological culture methods. MATERIALS AND METHODS: This retrospective observational study analyzed data from a prospectively maintained registry at a tertiary health care center. Patients who underwent two consecutive IPG replacements were included in this study. Intraoperative tissue cultures and sonication of explanted IPGs were performed to detect microbial colonization. Identified microorganisms were categorized into eight predefined groups. Statistical comparisons were conducted to assess differences in detection methods and temporal changes between the two surgeries. RESULTS: The mean interval between replacements was 2.3 ± 0.7 years. Pathogen detection significantly increased at the second replacement (29 vs 15 pathogens, p = 0.04), with 15 patients acquiring new bacterial colonization. Predominant microbes included coagulase-negative staphylococci (CNS) and Cutibacterium acnes, whereas high-virulence pathogens were rare. Sonication indicated a higher detection rate than standard cultures, particularly for CNS and C acnes, although the difference was not statistically significant (p = 0.08). Despite increased microbial detection, in no patient did a manifest IPG infection postoperatively develop. CONCLUSION: Repeated IPG replacements lead to an evolving microbial environment with increased colonization, particularly with low-virulence organisms. Sonication enhances pathogen detection but requires careful interpretation to differentiate colonization from infection. These findings highlight the need for optimized diagnostic strategies in patients who undergo multiple DBS hardware replacements. Future studies should explore the clinical impact of these microbiological changes on long-term outcomes.