[Treatment of dystonia by deep brain stimulation: a summary of 40 cases]

Bilateral pallidal deep brain stimulation (DBS) is an established treatment option for primary generalized and segmental dystonia. In the present study we evaluated the results of our dystonia patients treated by DBS.

The surgical results of forty consecutive dystonia patients underwent DBS implantation were analyzed (age: 43.7 +/- 17.7 years; sex: 22 men; etiology: 24 primary and 16 secondary dystonia; topography: 24 generalized, 12 segmental and four hemidystonia; disease duration: 16.1 +/- 9.3 years). Severity of dystonia measured by Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) and health-related quality of life measured by EQ-5D scale were obtained preoperatively and compared to the scores obtained at postoperative six months and subsequent yearly follow-ups. The average follow-up lasted 2.5 years (median, 0.5-8 years). In all cases the BFMDRS scores were re-evaluated by a rater blinded to the treatment. Treatment responsiveness was defined as an at least 25% improvement on the BFMDRS scores. Non-parametric Mann-Whitney, McNemar and Kruskal-Wallis tests were applied to test statistical significance.

Severity of dystonia improved from 31 to 10 points (median, 68% improvement, p < 0.01) in the primary dystonia group, whereas in secondary dystonia these changes were statistically insignificant (improvement from 40 to 31.5 points, 21.2%, p > 0.05). However, the health-related quality of life significantly improved in both groups (primary dystonia: 0.378 vs. 0.788 and secondary dystonia: 0.110 vs. 0.388, p < 0.01). Significantly more patients in the primary dystonia group responded to DBS treatment than those in the secondary dystonia group (83.3% vs. 37.5%, p < 0.01).

Our results are in accordance with previously published international findings demonstrating that DBS is a highly effective and long-lasting treatment option for primary dystonia. DBS is considerably less efficient in secondary dystonia; however, it still has a high impact on the quality of life presumably due to its pain-relieving effect.