✓The authors present a unique case of hyperhidrosis as a side effect of a misplaced deep brain stimulation (DBS) electrode near the ventrointermedius (Vim) nucleus in a patient with essential tremor. Magnetic resonance imaging of the brain showed electrode placement in the left anterior thalamus traversing the hypothalamus. High-frequency electrical stimulation possibly resulted in unilateral activation of the efferent sympathetic pathways in the zona incerta. Although a rare complication, hypothalamic dysfunction may occur as a stimulation-related side effect of Vim-DBS.
Deep Brain Stimulation
Alan Diamond, Christopher Kenney, Michael Almaguer, and Joseph Jankovic
Christopher Kenney, Richard Simpson, Christine Hunter, William Ondo, Michael Almaguer, Anthony Davidson, and Joseph Jankovic
The object of this study was to assess the long-term safety of deep brain stimulation (DBS) in a large population of patients with a variety of movement disorders.
All patients treated with DBS at the authors' center between 1995 and 2005 were assessed for intraoperative, perioperative, and long-term adverse events (AEs).
A total of 319 patients underwent DBS device implantation. Of these 319, 182 suffered from medically refractory Parkinson disease; the other patients had essential tremor (112 patients), dystonia (19 patients), and other hyperkinetic movement disorders (six patients). Intraoperative AEs were rare and included vasovagal response in eight patients (2.5%), syncope in four (1.2%), severe cough in three (0.9%), transient ischemic attack in one (0.3%), arrhythmia in one (0.3%), and confusion in one (0.3%). Perioperative AEs included headache in 48 patients (15.0%), confusion in 16 (5.0%), and hallucinations in nine (2.8%). Serious intraoperative/perioperative AEs included isolated seizure in four patients (1.2%), intracerebral hemorrhage in two patients (0.6%), intraventricular hemorrhage in two patients (0.6%), and a large subdural hematoma in one patient (0.3%). Persistent long-term complications of DBS surgery included dysarthria (4.0%), worsening gait (3.8%), cognitive dysfunction (4.0%), and infection (4.4%). Revisions were completed in 25 patients (7.8%) for the following reasons: loss of effect, lack of efficacy, infection, lead fracture, and lead migration. Hardware-related complications included 12 lead fractuxres and 10 lead migrations.
The authors conclude that in their 10-year experience, DBS has proven to be safe for the treatment of medically refractory movement disorders.
Jerzy Slowinski, Ryan J. Uitti, John D. Putzke, and Robert E. Wharen Jr.
Rajesh Pahwa, Kelly E. Lyons, Steven B. Wilkinson, Richard K. Simpson Jr., William G. Ondo, Daniel Tarsy, Thorkild Norregaard, Jean P. Hubble, Donald A. Smith, Robert A. Hauser, and Joseph Jankovic
The effects of thalamic deep brain stimulation (DBS) on essential tremor (ET) and Parkinson disease (PD) have been well documented, but there is a paucity of long-term data. The aim of this study was to evaluate the longterm safety and efficacy of DBS of the ventralis intermedius nucleus (VIM) of the thalamus for PD and ET.
Thirty-eight of 45 patients enrolled at five sites completed a 5-year follow-up study. There were 26 patients with ET and 19 with PD undergoing 29 unilateral (18 ET/11 PD) and 16 bilateral (eight ET/eight PD) procedures. Patients with ET were evaluated using the Tremor Rating Scale, and patients with PD were evaluated using the Unified Parkinson’s Disease Rating Scale. The mean age of patients with ET was 70.2 years and 66.3 years in patients with PD. Unilaterally implanted patients with ET had a 75% improvement of the targeted hand tremor; those with bilateral implants had a 65% improvement in the left hand and 86% in the right compared with baseline. Parkinsonian patients with unilateral implants had an 85% improvement in the targeted hand tremor and those with bilateral implants had a 100% improvement in the left hand and 90% improvement in the right. Common DBS-related adverse events in patients receiving unilateral implants were paresthesia (45%) and pain (41%), and in patients receiving implants bilaterally dysarthria (75%) and balance difficulties (56%) occurred. Device-related surgical revisions other than IPG replacements occurred in 12 (27%) of the 45 patients.
Thalamic stimulation is safe and effective for the long-term management of essential and parkinsonian tremors. Bilateral stimulation can cause dysarthria and incoordination and should be used cautiously.