Unilateral thalamic deep brain stimulation in essential tremor demonstrates long-term ipsilateral effects

https://doi.org/10.1016/j.parkreldis.2013.08.001Get rights and content

Abstract

Introduction

Deep Brain Stimulation (DBS) of thalamus in essential tremor (ET) is effective for the treatment of contralateral tremors. Bilateral DBS controls tremors on both sides but is associated with increased morbidity and risks. We evaluated if unilateral surgery had ipsilateral benefits on tremors and thus could be a potentially safer alternative to bilateral DBS.

Methods

Medication refractory ET patients undergoing unilateral thalamic DBS were included and longitudinally followed. Tremor rating scale was used to record total motor, arm tremor and activities of daily living (ADL) scores at baseline, six months and at last visit (three or more years after surgery). Postoperative scores were recorded with DBS turned OFF and ON.

Results

Twenty-two patients with a mean follow-up 3.4 ± 0.14 years were enrolled. When baseline scores were compared to scores with the DBS turned ON, significant improvements were noted in total tremor (40%), ADL (67%) and arm tremor scores both on the ipsilateral and the contralateral side at six months and at the last visit of follow-up (all p < 0.05). Ipsilateral arm tremor (∼56%) improvements were milder compared to the contralateral side (∼73%) tremors.

Conclusion

Unilateral thalamic DBS in ET demonstrates significant long-term benefits for ipsilateral arm tremors and can be offered to higher risk and to select patients.

Section snippets

Background

Essential tremor (ET) is one of the most common movement disorders [1] and is clinically characterized by bilateral postural and action tremors affecting the arms in 94% cases and less frequently it affects the head, voice, trunk and legs [1]. Approximately 50% of the ET patients are reported to be refractory to oral medications [2], and for these patients deep brain stimulation (DBS) of the thalamus has become a well-established FDA approved treatment modality [4].

ET is a bilateral disease,

Patients

ET patients who underwent unilateral thalamic DBS at University of Florida Center for Movement Disorders & Neurorestoration (from July 2002 to July 2011) and who were followed for at least three years were enrolled. These patients signed informed consent to deposit their results from clinical testing into an Institutional Review Board approved database for research. Data was analyzed retrospectively. Patients originally implanted at outside institutions were excluded from the analysis.

According

Demographics

Over a period of 9 years, (2002–2011), we found 67 patients with refractory ET had undergone thalamic DBS surgery at our center. Fifty-four of these patients had unilateral DBS and 22 patients presented for follow-up more than 3 years after surgery. A retrospective analysis was performed on these twenty-two patients (12 males, 10 females). The mean age was 71 (±2.6) years and 17 patients were right handed (Table 1). Ten patients reported social drinking and one reported regular alcohol

Discussion

Many DBS centers advocate bilateral placement of DBS leads in the Vim nucleus of the thalamus [5], [8], [9], [10]. The implantation of the second sided lead is typically aimed at treating and controlling disabling tremors on the contralateral side. Recently, there have been increasing reports of side effects and complications related to bilateral surgeries including dysarthria, dysphagia and gait/balance impairment. Therefore, the risks and benefits of bilateral DBS implantation should be

Conclusions

Unilateral thalamic DBS for medication refractory ET demonstrates significant improvements in the ipsilateral arm tremors. The benefits are milder on the ipsilateral side compared to the contralateral side but sustained at long-term follow-up. The selection of unilateral vs. bilateral thalamic DBS should be tailored to an individual patient's risk and benefit analysis. The underlying mechanisms that can explain ipsilateral effects of unilateral DBS will require further study.

Acknowledgments

This work was support by Grant-in Aid for Clinical Research from St. Luke's Life Science Institute of Japan, Japan Society for Promotion of Science, University of Florida CTSI, and the UF INFORM database.

References (28)

  • T. Morishita et al.

    Identification and management of deep brain stimulation intra- and postoperative urgencies and emergencies

    Parkinsonism Relat Disord

    (2010)
  • R.R. Tasker

    Deep brain stimulation is preferable to thalamotomy for tremor suppression

    Surg Neurol

    (1998)
  • E.D. Louis et al.

    Risk of tremor and impairment from tremor in relatives of patients with essential tremor: a community-based family study

    Ann Neurol

    (2001)
  • V. Borges et al.

    Essential tremor: clinical characterization in a sample of 176 patients

    Arq Neuropsiquiatr

    (1994)
  • R. Pahwa et al.

    Comparison of thalamotomy to deep brain stimulation of the thalamus in essential tremor

    Mov Disord

    (2001)
  • R. Pahwa et al.

    Long-term evaluation of deep brain stimulation of the thalamus

    J Neurosurg

    (2006)
  • P. Blomstedt et al.

    Thalamic deep brain stimulation in the treatment of essential tremor: a long-term follow-up

    Br J Neurosurg

    (2007)
  • K. Zhang et al.

    Long-term results of thalamic deep brain stimulation for essential tremor

    J Neurosurg

    (2010)
  • J.D. Putzke et al.

    Thalamic deep brain stimulation for essential tremor: recommendations for long-term outcome analysis

    Can J Neurol Sci

    (2004)
  • W. Ondo et al.

    Thalamic deep brain stimulation: comparison between unilateral and bilateral placement

    Arch Neurol

    (2001)
  • W. Ondo et al.

    Thalamic deep brain stimulation: effects on the nontarget limbs

    Mov Disord

    (2001)
  • T. Morishita et al.

    Brain penetration effects of microelectrodes and deep brain stimulation leads in ventral intermediate nucleus stimulation for essential tremor

    J Neurosurg

    (2010)
  • A.P. Burdick et al.

    Relationship between higher rates of adverse events in deep brain stimulation using standardized prospective recording and patient outcomes

    Neurosurg Focus

    (2010)
  • M.A. Stacy et al.

    Assessment of interrater and intrarater reliability of the Fahn–Tolosa–Marin tremor rating scale in essential tremor

    Mov Disord

    (2007)
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