Deep Brain Stimulation Battery Longevity: Comparison of Monopolar Versus Bipolar Stimulation Modes

Abstract

Background: Deep brain stimulation is an effective treatment for movement disorders, but it is relatively complex, invasive, and costly. Little is known about whether stimulation mode alters pulse generator (battery) longevity in routine clinical care.

Objective: To compare battery longevity during monopolar versus bipolar stimulation in patients who underwent deep brain stimulation for movement disorders.

Methods: We evaluated 2,902 programming adjustments and calculated the average stimulator settings for 393 batteries in 200 unique patients with Parkinson's disease and essential tremor. We classified the pulse generators into different stimulation modes (monopolar, bipolar, tripolar, double monopolar) and compared battery longevity with Kaplan Meier survival analyses using the log rank test. We exclusively implanted the Medtronic 3387 lead with adjacent electrode contacts separated by 1.5 mm.

Results: The mean pulse generator longevity was 47.6±1.6 months regardless of diagnosis or stimulation mode. Bipolar stimulation mode was associated with greater longevity than monopolar stimulation (56.1±3.4 versus 44.2±2.1 months, p=0.006). This effect was most pronounced when stimulation parameters were at low to moderate intensity settings. Double monopolar configuration was associated with less pulse generator longevity than conventional stimulation modes (37.8±5.6 versus 49.7±1.9, p=0.014).

Conclusion: IPGs initially programmed in bipolar mode provided one year of additional battery longevity versus monopolar mode in this large retrospective series of patients with essential tremor and Parkinson's disease. Given satisfactory efficacy for motor symptoms, bipolar stimulation mode is a feasible alternative programming strategy at the initiation of DBS therapy.

Keywords: Deep Brain Stimulation; Motor control; Parkinson’s disease; Tremor.

Figure 1

Flow chart illustrating patient classification into different groups based upon stimulation mode.

Figure 2

Bipolar stimulation is associated with greater pulse generator longevity than monopolar stimulation in patients with DBS for movement disorders. (A) Primary outcome comparing bipolar to monopolar stimulation in patients with subthalamic DBS for PD and thalamic stimulation for ET. Bipolar DBS is associated with approximately 1 year of additional battery longevity versus monopolar stimulation. (B) Subgroup analyses across different average stimulation intensities show that the most substantial effects of bipolar mode on Soletra (Medtronic, Inc., Minneapolis, MN) battery longevity occur at low‐to‐moderate overall stimulation intensities.

Figure 3

The distance between the anode and cathode contacts during bipolar stimulation alters pulse generator longevity. More widely spaced anode and cathode contacts during bipolar stimulation are associated with greater battery longevity versus either more narrowly spaced contacts or monopolar DBS. Importantly, these results arise from the use of only the Medtronic 3387 lead (Medtronic, Inc., Minneapolis, MN), with adjacent contacts separated by 1.5 mm.

Figure 4

Double monopolar stimulation is associated with less battery longevity than conventional stimulation modes in patients with DBS for movement disorders. Double monopolar mode reduces battery longevity by approximately 1 year relative to conventional modes (monopolar and bipolar) and tripolar stimulation.

Figure 5

Clinical outcomes do not differ significantly between bipolar and monopolar DBS in a sample of consecutive patients who underwent unilateral subthalamic stimulation for PD. There was no statistically significant difference in postoperative outcome between monopolar and bipolar stimulation modes measured by the UPDRS Parts 2 and 3 off medications, Part 4, and the time to stand from the seated position. There was a borderline significant improvement in the number of steps walked comfortably favoring bipolar over monopolar stimulation (P = 0.04). Data presented as means ± standard deviation. IQR, interquartile range; ADLs, activities of daily living.