Bilateral GPE-DBS for Refractory Tourette Syndrome

Introduction: Although frequently self-limited, when persistent, Tourette syndrome (TS) presents a high intractability rate. Ablative surgery presents a relatively low significant improvement and a high neurological morbidity. DBS for the treatment of TS was first performed by Visser-Vandewalle et al. in 1999. We have previously suggested that GPe is hyperactive in TS. Based on this hypothesis, we performed bilateral GPe-DBS in 12 consecutive TS patients.

Methods: 12 patients, 11M/1F, ages 18–47 years, refractory to the best conservative management, have been operated on. Preoperative assessment included MR, PET-scan or SPECT, neurological/neuropsychological/psychiatric evaluations, YGTSS and YBOCS, all of them repeated postoperatively. Target (central GPe) coordinates were obtained from IR MR axial/coronal slices, CT-scan and image fusion. Physiological mapping was performed through MER (2 patients) and macroelectrode stimulation. YGTSS and YBOCS were applied by a unique rater, being both patient and rater blind to the IPG status. Patients were video-recorded pre- and postoperatively.

Results: Target coordinates were usually 3.0–4.5 mm posterior/3.0–4.0 mm above/20.0–22.0 mm lateral to AC. Postoperative MR was used to confirm adequate electrode positioning in every patient. The best stimulation parameters were: monopolar (most dorsal contacts), 2.5–3.5 V, 100–160 Hz, and 90–150 usec. Follow-up was 1–8 years. Tics (responders = 9/12 patients) and obsessive-compulsive behavior (responders = 5/7 patients) improved a mean of 78% and 65%, respectively, according to the YGTSS and Y-BOCS. Complications: asymptomatic perielectrode edema (n = 1), depression (n = 1).

Conclusions: The results reported support the hypothesis of GPe hyperactivity in TS and indicate that GPe-DBS provides symptomatic relief at least as good as the other techniques currently under trial.