Pallidal deep brain stimulation for dystonia: a long term study.

Background Pallidal deep brain stimulation (globus pallidus internus (GPi) DBS) is the best therapeutic option for disabling isolated idiopathic (IID) and inherited (INH) dystonia. Acquired dystonia (AD) may also benefit from GPi DBS. Efficacy and safety in the long-term remained to be established. Objective To retrospectively assess long-term clinical outcomes and safety in dystonic patients who underwent GPi DBS. Methods Patients were videotaped and assessed preoperatively and postoperatively (1-year and at last available follow-up) using the Burke-Fahn-Marsden Dystonia Rating Scale (motor score (BFMDRS-M); disability score (BFMDRS-D)). Results Sixty-one patients were included (follow-up 7.9 +/- 5.9 years; range 1-20.7). In IID and INH (n=37), the BFMDRS-M improved at first (20.4 +/- 24.5; p<0.00001) and last (22.2 +/- 18.2; p<0.001) follow-ups compared with preoperatively (50.5 +/- 28.0). In AD (n=19), the BFMDRS-M ameliorated at 1-year (40.8 +/- 26.5; p<0.02) and late follow-ups (44.3 +/- 24.3; p<0.04) compared with preoperatively (52.8 +/- 24.2). In INH dystonia with other neurological features (n=4) there was no motor benefit. In IID and INH, the BFMDRS-D improved at 1-year (9.5 +/- 7.5; p<0.0002) and late follow-ups (10.4 +/- 7.8; p<0.016) compared with preoperatively (13.3 +/- 6.9). In AD, the BFMDRS-D reduced at 1-year (12.0 +/- 8.1; p<0.01) and late follow-ups (12.7 +/- 6.1; p=0.2) compared with preoperatively (14.35 +/- 5.7). Most adverse events were hardware related. Conclusions GPi DBS is an effective and safe treatment in most patients with dystonia.