3-T MR-guided focused ultrasound thalamotomy for tremor in patients with a cardiac pacemaker: case series and review of the literature.

MR-guided focused ultrasound (MRgFUS) has proven its efficacy and safety for the treatment of essential tremor (ET) and/or Parkinson's disease (PD). However, having a cardiac pacemaker has been considered an exclusion criterion for the use of MRgFUS. Only 2 patients with a cardiac pacemaker treated with MRgFUS have been previously reported, both treated using 1.

Magnetic Resonance-Guided Focused Ultrasound (MRgFUS)-Thalamotomy for Essential Tremor: Lesion Location and Clinical Outcomes.

Background: Factors predicting clinical outcomes after MR-guided focused ultrasound (MRgFUS)-thalamotomy in patients with essential tremor (ET) are not well known.

Objective: To examine the clinical outcomes and their relationship with patients' baseline demographic and clinical features and lesion characteristics at 6-month follow-up in ET patients.

Methods: A total of 127 patients were prospectively evaluated at 1 (n = 122), 3 (n = 102), and 6 months (n = 78) after MRgFUS-thalamotomy.

Trial of Globus Pallidus Focused Ultrasound Ablation in Parkinson's Disease.

Background: Unilateral focused ultrasound ablation of the internal segment of globus pallidus has reduced motor symptoms of Parkinson's disease in open-label studies.

Methods: We randomly assigned, in a 3:1 ratio, patients with Parkinson's disease and dyskinesias or motor fluctuations and motor impairment in the off-medication state to undergo either focused ultrasound ablation opposite the most symptomatic side of the body or a sham procedure. The primary outcome was a response at 3 months, defined as a decrease of at least 3 points from baseline either in the score on the Movement Disorders Society-Unified Parkinson's Disease Rating Scale, part III (MDS-UPDRS III), for the treated side in the off-medication state or in the score on the Unified Dyskinesia Rating Scale (UDysRS) in the on-medication state.

The role of tractography in the localisation of the Vim nucleus of the thalamus and the dentatorubrothalamic tract for the treatment of tremor.

Introduction: The ventralis intermedius (VIM) nucleus of the thalamus is the usual surgical target for tremor. However, locating the structure may be difficult as it is not visible with conventional imaging methods; therefore, surgical procedures typically use indirect calculations correlated with clinical and intraoperative neurophysiological findings. Current ablative surgical procedures such as Gamma-Knife thalamotomy and magnetic resonance-guided focused ultrasound require new alternatives for locating the VIM nucleus.

Development and Performance Evaluation of a Clinical Predictive Model to Estimate the Risk of Red Blood Cell Requirements in Brain Tumor Surgery.

Background: The identification of factors associated with perioperative red blood cell (RBC) transfusion provides an opportunity to optimize the patient and surgical plan, and to guide perioperative crossmatch and RBC orders. We examined the association among potential bleeding risk factors and RBC requirements to develop a novel predictive model for RBC transfusion in patients undergoing brain tumor surgery.

Methods: This retrospective study included 696 adults who underwent brain tumor surgery between 2008 and 2018.

Factors Associated with Headache and Nausea During Magnetic Resonance-Guided Focused Ultrasound for Tremor.

Background: During magnetic resonance-guided focused ultrasound for essential or parkinsonian tremor, adverse events (headache, nausea/vomiting, or anxiety) may alter the outcome of the procedure despite being mostly transient and mild.

Objectives: Our aim was to analyze the relationship between demographic, procedural, and anesthetic characteristics with magnetic resonance/ultrasound-related events.

Methods: This was a retrospective study at the Clinica Universidad de Navarra of patients undergoing thalamotomy with magnetic resonance-guided focused ultrasound between September 2018 and October 2019.

Effects of dexmedetomidine on subthalamic local field potentials in Parkinson's disease.

Background: Dexmedetomidine is frequently used for sedation during deep brain stimulator implantation in patients with Parkinson's disease, but its effect on subthalamic nucleus activity is not well known. The aim of this study was to quantify the effect of increasing doses of dexmedetomidine in this population.

Methods: Controlled clinical trial assessing changes in subthalamic activity with increasing doses of dexmedetomidine (from 0.

Revisiting Forel Field Surgery.

Background: Lesioning the Forel field or the subthalamic region is considered a possible treatment for tremoric patients with Parkinson disease, essential tremor, and other diseases. This surgical treatment was performed in the 1960s to 1970s and was an alternative to thalamotomy. Recently, there has been increasing interest in the reappraisal of stimulating and/or lesioning these targets, partly as a result of innovations in imaging and noninvasive ablative technologies, such as magnetic resonance-guided focused ultrasonography.

The role of tractography in the localization of the Vim nucleus of the thalamus and the dentato-rubro-thalamic tract for the treatment of tremor.

Introduction: The ventralis intermedius (Vim) nucleus of the thalamus is the usual surgical target for tremor. However, locating the structure may be difficult as it is not visible with conventional imaging methods; therefore, surgical procedures typically use indirect calculations correlated with clinical and intraoperative neurophysiological findings. Current ablative surgical procedures such as Gamma-Knife thalamotomy and magnetic resonance-guided focused ultrasound require new alternatives for locating the Vim nucleus.

History and future challenges of the subthalamic nucleus as surgical target: Review article.

For many years the subthalamic nucleus had a poor reputation among neurosurgeons as a result of the acute movement disorders that develop after its lesion or manipulation through different surgical procedures. However, this nucleus is now considered a key structure in relation to parkinsonism, and it is currently one of the preferred therapeutic targets for Parkinson's disease. The implication of the subthalamic nucleus in the pathophysiology of chorea and in the parkinsonian state is thought to be related to its role in modulating the basal ganglia, a fundamental circuit in movement control.

Subthalamotomy for Parkinson's disease: clinical outcome and topography of lesions.

Objective: Subthalamotomy is an effective alternative for the treatment of Parkinson's disease (PD). However, uncertainty about the optimal target location and the possibility of inducing haemichorea-ballism have limited its application. We assessed the correlation between the topography of radiofrequency-based lesions of the subthalamic nucleus (STN) with motor improvement and the emergence of haemichorea-ballism.

Thalamic deep brain stimulation for orthostatic tremor: A multicenter international registry.

Background: We report the accumulated experience with ventral intermediate nucleus deep brain stimulation for medically refractory orthostatic tremor.

Methods: Data from 17 patients were reviewed, comparing presurgical, short-term (0-48 months), and long-term (≥48 months) follow-up. The primary end point was the composite activities of daily living/instrumental activities of daily living score.

Effect of Dexmedetomidine and Propofol on Basal Ganglia Activity in Parkinson Disease: A Controlled Clinical Trial.

Background: Deep brain stimulation electrodes can record oscillatory activity from deep brain structures, known as local field potentials. The authors' objective was to evaluate and quantify the effects of dexmedetomidine (0.2 μg·kg·h) on local field potentials in patients with Parkinson disease undergoing deep brain stimulation surgery compared with control recording (primary outcome), as well as the effect of propofol at different estimated peak effect site concentrations (0.

Sedation During Surgery for Movement Disorders and Perioperative Neurologic Complications: An Observational Study Comparing Local Anesthesia, Remifentanil, and Dexmedetomidine.

Background: The anesthetic management of patients requiring surgery for movement disorders needs to balance microrecording quality and patient cooperation with safety and comfort. Anesthetics can alter microrecording, although the effect on outcome is debatable. They also provide a rested and cooperative patient and minimize complications such as intracranial hemorrhage by providing better hemodynamic control.

Stimulation sites in the subthalamic nucleus and clinical improvement in Parkinson's disease: a new approach for active contact localization.

OBJECTIVE Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is widely used in patients with Parkinson's disease (PD). However, which target area of this region results in the highest antiparkinsonian efficacy is still a matter of debate. The aim of this study was to develop a more accurate methodology to locate the electrodes and the contacts used for chronic stimulation (active contacts) in the subthalamic region, and to determine the position at which stimulation conveys the greatest clinical benefit.

[Neuroprotective subthalamotomy in Parkinson's disease. The role of magnetic resonance-guided focused ultrasound in early surgery].

Subthalamic nucleus hyperactivity in Parkinson's disease may be a very early phenomenon. Its start is not well known, and it may occur during the pre-symptomatic disease stage. Glutamatergic hyperactivity may be neurotoxic over the substantia nigra compacta dopaminergic neurons.

Oscillatory activity in the basal ganglia and deep brain stimulation.

Over the past 10 years, research into the neurophysiology of the basal ganglia has provided new insights into the pathophysiology of movement disorders. The presence of pathological oscillations at specific frequencies has been linked to different signs and symptoms in PD and dystonia, suggesting a new model to explain basal ganglia dysfunction. These advances occurred in parallel with improvements in imaging and neurosurgical techniques, both of which having facilitated the more widespread use of DBS to modulate dysfunctional circuits.

Factors Associated with Tremor Changes during Sedation with Dexmedetomidine in Parkinson's Disease Surgery.

Introduction: Dexmedetomidine is an α2-agonist recently proposed as a potentially ideal drug for sedation during the surgical treatment of Parkinson's disease (PD). This report documents the incidence of changes in motor symptoms (especially tremor) in PD patients sedated with dexmedetomidine for deep brain stimulation or ablation procedures.

Methods: We reviewed a retrospective cohort of 22 patients who underwent surgery for PD with dexmedetomidine sedation at a single institution from 2010 to 2014.

Arginine NO-dependent and NO-independent effects on hemodynamics.

L-arginine administration decreases mean arterial blood pressure (MABP), presumably by excess nitric oxide (NO) synthesis. However, some reports indicate that d-arginine, not a substrate of NO synthase (NOS), also induces hypotension. To clarify this phenomenon, the hemodynamic effects of L- and D-arginine and their modification by NOS inhibition with L-nitroarginine methyl ester (L-NAME) were assessed.

High beta activity in the subthalamic nucleus and freezing of gait in Parkinson's disease.

Objective: Oscillatory activity in the beta band is increased in the subthalamic nucleus (STN) of Parkinson's disease (PD) patients. Rigidity and bradykinesia are associated with the low-beta component (13-20Hz) but the neurophysiological correlate of freezing of gait in PD has not been ascertained.

Methods: We evaluated the power and coherence of the low- and high-beta bands in the STN and cortex (EEG) of PD patients with (p-FOG) (n=14) or without freezing of gait (n-FOG) (n=8) in whom electrodes for chronic stimulation in the STN had been implanted for treatment with deep brain stimulation.

Short and long term outcome of bilateral pallidal stimulation in chorea-acanthocytosis.

Background: Chorea-acanthocytosis (ChAc) is a neuroacanthocytosis syndrome presenting with severe movement disorders poorly responsive to drug therapy. Case reports suggest that bilateral deep brain stimulation (DBS) of the ventro-postero-lateral internal globus pallidus (GPi) may benefit these patients. To explore this issue, the present multicentre (n=12) retrospective study collected the short and long term outcome of 15 patients who underwent DBS.