Typical variations of subthalamic electrode location do not predict limb motor function improvement in Parkinson's disease

J Clin Neurosci. 2009 Jun;16(6):771-8; discussion 779. doi: 10.1016/j.jocn.2008.10.011. Epub 2009 Mar 25.

Abstract

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is an effective treatment for patients with medically refractory Parkinson's disease (PD). The degree to which the anatomic location of the DBS electrode tip determines the improvement of contralateral limb movement function has not been defined. This retrospective study was performed to address this issue. Forty-two DBS electrode tips in 21 bilaterally implanted patients were localized on postoperative MRI. The postoperative and preoperative planning MRIs were merged with the Stealth FrameLink 4.0 stereotactic planning workstation (Medtronic Inc., Minneapolis, MN, USA) to determine the DBS tip coordinates. Stimulation settings were postoperatively optimized for maximal clinical effect. Patients were videotaped 1 year postoperatively and assessed by a movement disorder neurologist blinded to electrode tip locations. The nine limb-related components of the Unified PD Rating Scale Part III were tabulated to obtain a limb score, and the electrode tip locations associated with the 15 least and 15 greatest limb scores were evaluated. Two-tailed t-tests revealed no significant difference in electrode tip location between the two groups in three-dimensional distance (p=0.759), lateral-medial (x) axis (p=0.983), anterior-posterior (y) axis (p=0.949) or superior-inferior (z) axis (p=0.894) from the intended anatomical target. The range of difference in tip location and limb scores was extensive. Our results suggest that anatomic targeting alone may provide the same clinical efficacy as is achieved by "fine-tuning" DBS placement with microelectrode recording to a specific target.

MeSH terms

  • Adult
  • Aged
  • Deep Brain Stimulation / methods*
  • Deep Brain Stimulation / standards
  • Electrodes, Implanted / standards
  • Extremities / innervation
  • Extremities / physiology*
  • Female
  • Humans
  • Magnetic Resonance Imaging
  • Male
  • Middle Aged
  • Movement / physiology*
  • Outcome Assessment, Health Care / methods
  • Parkinson Disease / physiopathology
  • Parkinson Disease / therapy*
  • Preoperative Care
  • Recovery of Function / physiology*
  • Retrospective Studies
  • Stereotaxic Techniques
  • Subthalamic Nucleus / anatomy & histology
  • Subthalamic Nucleus / physiology*
  • Treatment Outcome