Introduction: Infection and erosion following implantable pulse generator (IPG) placements are associated with morbidity and cost for patients with deep brain stimulator (DBS) systems. We provide detailed characterization of infection and erosion events in a large cohort who underwent DBS for movement disorders.
Methods: We retrospectively reviewed consecutive IPG placements and replacements in patients who underwent DBS for movement disorders at the University of Alabama at Birmingham between 2013-2016. Previous IPG procedures occurring before 2013 in these patients were also captured. We performed descriptive statistics, survival analyses, and logistic regression by employing generalized linear mixed effects models to examine risk factors for our primary outcomes: infection within one year or erosion within two years of IPG placement.
Results: We evaluated 384 patients who underwent 995 total IPG procedures (46.4% of these were initial placements) with a median follow up of 2.9 years. Reoperation for infection occurred after 27 (2.7%) procedures in 21 (5.5%) patients. No difference in infection rate was observed for initial placement versus replacement (p=0.838). Reoperation for erosion occurred after 16 (1.6%) procedures in 15 (3.9%) patients. Median time to reoperation for infection and erosion was 51 (IQR: 24-129) and 149 (IQR: 112-285) days, respectively. Four patients with infection (19.0%) developed a second infection requiring a same-sided reoperation, two of whom developed a third. Intraoperative vancomycin powder was used in 158 cases and did not decrease infection risk (3.2% infected with vancomycin v. 2.6% without, p=0.922 by Log-Rank test). On logistic regression, previous infection increased risk for infection (OR 35.0, 95% CI 7.9-156.2, p<0.0001) and lower patient BMI was a risk factor for erosion (for BMI =< 24: OR 3.1, 95% CI 1.1-8.6, p=0.03).
Conclusions: IPG infection and erosion following DBS are uncommon but clinically significant events. Their respective timelines and risk factors suggest different etiologies and thus different potential corrective procedures.
Patient Care: This research effort highlights the importance of proper patient selection and patient counseling prior to DBS procedures. Specifically, patients may be counseled more thoroughly about risk of infection and erosion events and their respective timelines. Furthermore, surgeons may use this risk factor information to guide patient selection for surgical candidacy.
Learning Objectives: By the conclusion of this session, participants should be able to:
1. Understand the rates of, and timelines to, reoperation for IPG infection and erosion
2. Describe risk factors for IPG infection (prior infection) and erosion (lower patient BMI)
3. Recognize that device infection and erosion are dissimilar events with different timelines and risk factors