Subthalamic nucleus deep brain stimulation in elderly patients--analysis of outcome and complications

Abstract

Background: There is an ongoing discussion about age limits for deep brain stimulation (DBS). Current indications for DBS are tremor-dominant disorders, Parkinson's disease, and dystonia. Electrode implantation for DBS with analgesia and sedation makes surgery more comfortable, especially for elderly patients. However, the value of DBS in terms of benefit-risk ratio in this patient population is still uncertain.

Methods: Bilateral electrode implantation into the subthalamic nucleus (STN) was performed in a total of 73 patients suffering from Parkinson's disease. Patients were analyzed retrospectively. For this study they were divided into two age groups: group I (age <65 years, n = 37) and group II (age > or = 65 years, n = 36). Examinations were performed preoperatively and at 6-month follow-up intervals for 24 months postoperatively. Age, UPDRS motor score (part III) on/off, Hoehn & Yahr score, Activity of Daily Living (ADL), L-dopa medication, and complications were determined.

Results: Significant differences were found in overall performance determined as ADL scores (group I: 48/71 points, group II: 41/62 points [preoperatively/6-month postoperatively]) and in the rate of complications (group I: 4 transient psychosis, 4 infections in a total of 8 patients, group II: 2 deaths [unrelated to surgery], 1 intracerebral hemorrhage, 7 transient psychosis, 3 infections, 2 pneumonia in a total of 13 patients), (p < 0.05). Interestingly, changes in UPDRS scores, Hoehn & Yahr scores, and L-dopa medication were not statistically different between the two groups.

Conclusion: DBS of the STN is clinically as effective in elderly patients as it is in younger ones. However, a more careful selection and follow-up of the elderly patients are required because elderly patients have a higher risk of surgery-related complications and a higher morbidity rate.

Figure 1

UPDRS motor scores (part III) in all patients before surgery (with/without medication) and at postoperative follow-up after 6, 12, and 24 months (preoperative medication on – preON, preoperative medication off: preOFF, postoperative stimulation on and medication on).

Figure 2

Hoehn and Yahr scores in all patients as well as in groups I and II preoperatively (with/without medication) and at follow-up after 6, 12, and 24 months; significant differences between pre- and postoperative scores in all groups (**, ^#, ^§ p < 0.05).

Figure 3

Activity of Daily Living scores in all patients as well as in groups I and II preoperatively (with/without medication) and at the different postoperative follow-up times; significant differences between pre- and postoperative scores in all groups (**, ^#, ^§ p < 0.05).

Figure 4

L-dopa equivalents (mg) in all patients as well as in groups I and II preoperatively and at the different postoperative follow-up times; significant differences between pre- and postoperative state in all groups (**, ^#, ^§ p < 0.01), 24 m group I: ns.