Surgical Concepts and Long-term Outcomes of Thalamic Deep Brain Stimulation in Patients with Severe Tourette Syndrome: A Single-center Experience

Abstract

Tourette syndrome (TS) is a developmental neuropsychiatric disorder that is characterized by tic movements. Deep brain stimulation (DBS) may be a treatment option for severe cases refractory to medical and behavioral therapies. In this study, we reviewed the surgical techniques used for DBS in patients with severe TS and its clinical outcomes and sought to determine the optimal surgical procedure and current issues based on our experience and the literature. A total of 14 patients, consisting of 13 men and 1 woman, who underwent centromedian thalamic DBS and were followed up for a mean duration of 2.3 ± 1.0 years, participated in this study. The mean Yale Global Tic Severity Scale severity score significantly improved from 41.4 ± 7.0 at baseline to 19.8 ± 11.4 at 6 months (P = 0.01) and 12.7 ± 6.2 at the last follow-up (P < 0.01). Moreover, the mean Yale Global Tic Severity Scale impairment score significantly improved from 47.1 ± 4.7 at baseline to 23.1 ± 11.1 at 6 months (P < 0.01) and 7.6 ± 2.9 at the last follow-up (P < 0.01). However, there were problems with continuous postoperative monitoring (three cases were lost to follow-up) and surgery-related adverse events, including one case each of lead misplacement and a delayed intracerebral hemorrhage due to severe self-injurious tics. This study aimed to highlight not only the clinical efficacy of DBS for TS but also its challenges. Clinicians should understand the three-dimensional brain anatomy so that they can perform precise surgical procedures, avoid adverse events, and achieve favorable outcomes of DBS for TS.

Keywords: Tourette syndrome; adverse events; deep brain stimulation; microlesion effect; thalamus.

Fig. 1

Representative preoperative stereotactic targeting images (case 8). Purple and red dotted lines indicate the right and left lead trajectories, respectively, in the preoperative planning. A. Axial T1-weighted image with contrast. B. Coronal T1-weighted image with contrast. C. Sagittal T1-weighted image with contrast. D. Axial FGATIR image. E. Coronal FGATIR image. F. Sagittal FGATIR image. CM, centromedian nucleus; FGATIR, fast gray matter acquisition T1 inversion recovery; MD, mediodorsal nucleus; MTT, mammillothalamic tract; RN, red nucleus (Adapted from reference 6).

Fig. 2

YGTSS scores at baseline, 6 months, and the last follow-up. F/U, follow-up; YGTSS, Yale Global Tic Severity Scale

Fig. 3

Deep brain stimulation electrode positions in a normalized brain space. Lead electrodes with the CM nucleus (peach), red nucleus (red), MD nucleus (purple), and VL nucleus (yellow). The lead electrodes of each patient were displayed in different colors.

Fig. 4

Precision mapping of implanted deep brain stimulation electrodes in an atlas. In each panel, the upper row shows the coronal plane and the lower row shows the axial plane. Colored lines enclose areas of the thalamic nuclei (centromedian nucleus, peach; red nucleus, red; mediodorsal nucleus, purple). Montreal Neurological Institute coordinates are shown above each image. (A) Heat map of overlapping microlesion areas. Color bar: percent overlap among patients. (B) Improvement-related area. Color bar: percent improvement in tic symptoms (Adapted from reference 7).