Experience of pallidal deep brain stimulation in dystonia at a tertiary care centre in India: An initial experience

Dystonia is one of the most prevalent forms of movement disorders and is characterized by sustained or intermittent muscle contractions causing abnormal, often repetitive, movements, postures, or both. Dystonia causes significant morbidity with an adverse impact on the quality of life. When dystonia is medically refractory, causing severe pain and impairment in activities of daily living, deep brain stimulation (DBS) of the globus pallidus interna (GPi) is a potential option to reduce disability.

This is a chart review of patients who underwent DBS for dystonia (from 2009 to 2015) at our tertiary referral centre. A total of ten patients (7 males, 3 females) underwent DBS for non-parkinsonian conditions. The patients were selected after failure of adequate medical management. All the patients had a severe disability with normal cognitive (Mini-Mental State Examination) and psychiatric profile. They also had to have a suitable GPi for DBS based on magnetic resonance imaging.

The mean baseline Burke-Fahn-Marsden dystonia movement score of the 10 patients selected for surgery was 60.3 ± 27.3 (ranging from 19 to 104). On repeated-measures analysis of variance, there was significant difference in the different time points (pre-DBS, post-DBS at 3 months, 6 months, and 1 year) F (3, 5) = 7.68, P = 0.026. The data showed that there was a maximum improvement after 1 year of stimulation (pre-DBS vs. 3 months 12.9 ± 1.9 vs 8.8 ± 2.1, P = 0.01; pre-DBS vs. 6 months 12.9 ± 1.9 vs 7.4 ± 1.6, P = 0.04; pre-DBS vs. 1 year, 12.9 ± 1.9 vs. 7 ± 2.4.

In medically refractory primary or secondary dystonia patients, bilateral GPi DBS can be considered as an option. Patients with disabling symptoms that significantly deteriorate activities of daily life may consider DBS before these symptoms become fixed.