Bilateral Posterior Subthalamic Area Deep Brain Stimulation for Essential Tremor: A Case Series

Abstract

Background: Deep brain stimulation (DBS) of the posterior subthalamic area (PSA) provides a potentially effective treatment for medication-refractory essential tremor (ET). Objective: To study the clinical benefits and adverse-event profile of bilateral PSA-DBS for refractory ET. Methods: Seven patients with refractory ET underwent bilateral PSA-DBS surgery under general anesthesia between September 2017 and May 2018. Clinical outcome assessments, using the Essential Tremor Rating Scale, were performed at 1-, 6-, and 12-month follow-up, except for the last assessment of one patient who was followed up to 9 months. Analysis was focused on changes in patients' motor symptoms and quality of life following surgery as well as documenting the adverse-event profile associated with the surgical PSA-DBS treatment. Results: After surgery, patients' motor symptoms, including upper limb tremor and head tremor, were improved by 84.2% and their quality of life by 81.25% at 1-month follow-up. The clinical benefits to patients were maintained at 6-month and last follow-up. Adverse side effects included dysarthria (n = 4), balance disorder (n = 2), and paresthesia of the right limb (n = 1). No habituation effects were observed throughout the follow-up. Conclusion: Bilateral PSA-DBS seems to offer an effective and safe alternative treatment for medically intractable ET, warranting further research into its clinical utility, adverse-event profile, and comparative effectiveness.

Stimulation-Induced Side Effects of Deep Brain Stimulation in the Ventralis Intermedius and Posterior Subthalamic Area for Essential Tremor

“…Gait disturbance and dysarthria were significantly more frequent in those undergoing bilateral DBS than in those undergoing unilateral DBS ( Table 5 ). Previous studies have also reported that stimulation-induced side effects are more frequently observed after bilateral procedures than after unilateral procedures ( 18 , 51 – 55 ), with a 2- to 3-fold higher risk of dysarthria and ataxia associated with bilateral procedures ( 24 , 32 , 36 , 52 , 56 ). However, bilateral stimulation is more effective than unilateral stimulation for treating severe bilateral tremors and tremors combined with midline axial tremors (e.g., head tremors) and voice tremors ( 57 ).…”

Which one is the superior target? A comparison and pooled analysis between posterior subthalamic area and ventral intermediate nucleus deep brain stimulation for essential tremor

“…The detailed characteristics of included studies are shown in Table 1 . For sensitivity analysis, eight studies were included in the PSA‐DBS group 13 , 22 , 23 , 24 , 25 , 26 , 27 , 28 and fourteen studies were included in the VIM‐DBS group. 5 , 6 , 13 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 Due to the short term of follow‐up, three studies in the VIM‐DBS group were excluded from the main analysis.…”

“…The summary of SRCs was also an important evaluation indicator. A total of 439 SRCs were reported in 479 ET patients treated with PSA‐DBS and VIM‐DBS 6 , 9 , 13 , 22 , 25 , 26 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 (Table 3 ). The occurrence of SRCR of VIM‐DBS was statistically higher than that of PSA‐DBS (106.3 ± 12.4 vs. 48.2 ± 22.1%, p = 0.022).…”

“…A total of 439 SRCs were reported in 479 ET patients treated with PSA-DBS and VIM-DBS 6,9,13,22,25,26,[37][38][39][40][41][42][43][44][45][46][47][48][49] (Table 3). The occurrence of SRCR of VIM-DBS was statistically higher than that of PSA-DBS (106.3 ± 12.4 vs. 48.2 ± 22.1%, p = 0.022).…”

Deep Brain Stimulation for Tremor: Update on Long-Term Outcomes, Target Considerations and Future Directions

“…The most commonly reported stimulation-related adverse effect was dysarthria (20-57%), followed by spasms (34%) and postural instability (16-29%) of the electrodes implanted in the cZi/PSA. In addition, oculomotor side effects and paresthesias have been described in 19% and 11-14%, respectively [54,59,65,66].…”