Decreasing battery life in subthalamic deep brain stimulation for Parkinson's disease with repeated replacements: Just a matter of energy delivered?

BACKGROUND: People with Parkinson's disease (PD) treated with deep brain stimulation (DBS) with non-rechargeable implantable pulse generators (IPGs) require elective IPG replacement operations involving surgical and anesthesiologic risk. Life expectancy and the number of replacements per patient with DBS are increasing.

OBJECTIVE: To determine whether IPG longevity is influenced by stimulation parameters alone or whether there is an independent effect of the number of battery replacements and IPG model.

METHODS: PD patients treated with bilateral subthalamic DBS were included if there was at least one IPG replacement due to battery end of life. Fifty-five patients had one or two IPG replacements and seven had three or four replacements, (80 Kinetra® and 23 Activa-PC® ). We calculated longevity corrected for total electrical energy delivered (TEED) and tested for the effect of IPG model and number of previous battery replacements on this measure.

RESULTS: TEED-corrected IPG longevity for the 1st implanted IPG was 51.3 months for Kinetra® and 35.6 months for Activa-PC® , which dropped by 5.9 months and 2.8 months, respectively with each subsequent IPG replacement (p < 10- 6 for IPG model and p < 10- 3 for IPG number).

CONCLUSIONS: Activa-PC® has shorter battery longevity than the older Kinetra® , battery longevity reduces with repeated IPG replacements and these findings are independent of TEED. Battery longevity should be considered both in clinical decisions and in the design of new DBS systems. Clinicians need accessible, reliable and user-friendly tools to provide online estimated battery consumption and end of life. Furthermore, this study supports the consideration of using rechargeable IPGs in PD.