Subthalamic nucleus deep brain stimulation with a multiple independent constant current-controlled device in Parkinson's disease (INTREPID): a multicentre, double-blind, randomised, sham-controlled study.

BACKGROUND: Deep brain stimulation (DBS) of the subthalamic nucleus is an established therapeutic option for managing motor symptoms of Parkinson's disease. We conducted a double-blind, sham-controlled, randomised controlled trial to assess subthalamic nucleus DBS, with a novel multiple independent contact current-controlled (MICC) device, in patients with Parkinson's disease. METHODS: This trial took place at 23 implanting centres in the USA. Key inclusion criteria were age between 22 and 75 years, a diagnosis of idiopathic Parkinson's disease with over 5 years of motor symptoms, and stable use of anti-parkinsonian medications for 28 days before consent. Patients who passed screening criteria were implanted with the DBS device bilaterally in the subthalamic nucleus. Patients were randomly assigned in a 3:1 ratio to receive either active therapeutic stimulation settings (active group) or subtherapeutic stimulation settings (control group) for the 3-month blinded period. Randomisation took place with a computer-generated data capture system using a pre-generated randomisation table, stratified by site with random permuted blocks. During the 3-month blinded period, both patients and the assessors were masked to the treatment group while the unmasked programmer was responsible for programming and optimisation of device settings. The primary outcome was the difference in mean change from baseline visit to 3 months post-randomisation between the active and control groups in the mean number of waking hours per day with good symptom control and no troublesome dyskinesias, with no increase in anti-parkinsonian medications. Upon completion of the blinded phase, all patients received active treatment in the open-label period for up to 5 years. Primary and secondary outcomes were analysed by intention to treat. All patients who provided informed consent were included in the safety analysis. The open-label phase is ongoing with no new enrolment, and current findings are based on the prespecified interim analysis of the first 160 randomly assigned patients. The study is registered with ClinicalTrials.gov, NCT01839396. FINDINGS: Between May 17, 2013, and Nov 30, 2017, 313 patients were enrolled across 23 sites. Of these 313 patients, 196 (63%) received the DBS implant and 191 (61%) were randomly assigned. Of the 160 patients included in the interim analysis, 121 (76%) were randomly assigned to the active group and 39 (24%) to the control group. The difference in mean change from the baseline visit (post-implant) to 3 months post-randomisation in increased ON time without troublesome dyskinesias between the active and control groups was 3·03 h (SD 4·52, 95% CI 1·3-4·7; p<0·0001). 26 serious adverse events in 20 (13%) patients occurred during the 3-month blinded period. Of these, 18 events were reported in the active group and 8 in the control group. One death was reported among the 196 patients before randomisation, which was unrelated to the procedure, device, or stimulation. INTERPRETATION: This double-blind, sham-controlled, randomised controlled trial provides class I evidence of the safety and clinical efficacy of subthalamic nucleus DBS with a novel MICC device for the treatment of motor symptoms of Parkinson's disease. Future trials are needed to investigate potential benefits of producing a more defined current field using MICC technology, and its effect on clinical outcomes. FUNDING: Boston Scientific.

Does post-operative symptomatic lead edema associated with subthalamic DBS implantation impact long-term clinical outcomes?

INTRODUCTION: Post-operative, non-hemorrhagic, non-infectious symptomatic delayed edema around the DBS lead is an uncommon complication of DBS surgery. We investigated whether this complication impacts clinical outcomes or has long-term sequelae. METHODS: All Parkinson's disease (PD) patients with subthalamic nucleus (STN) DBS implantation who developed delayed symptomatic lead edema were identified. UPDRS part III motor, Parkinson's Disease Questionnaire (PDQ-39) total and MoCA scores were analyzed to assess motor outcome, quality of life and cognitive status at 1 year. RESULTS: A total of 260 patients underwent 482 STN lead placements. Of these, 16 patients (20 leads, 4.1% of total 482 leads) developed this delayed complication. None of the patients had edema on immediate post-operative scan. Patients presented with varied symptoms including speech difficulty (n = 8), mild confusion (n = 6), headaches (n = 4), gait difficulty (n = 4) and seizures (n = 3). The mean duration for the diagnosis was 5.8 days after lead implantation and the mean duration for which follow-up CT scans reported complete/near complete resolution or improvement of edema was 4.7 weeks (range 2-10 weeks). At 1-year post-DBS, UPDRS motor scores improved significantly (42.5%, p < .001); quality of life improved, but the change was not statistically significant (21.3%, p = .197). There was no decline in cognitive function at 1 year (26.6 vs 26.4, p = .567). No long-term complication related to lead edema occurred in these patients. CONCLUSION: Symptomatic lead edema after DBS surgery is an uncommon complication which typically resolves over time. In our series, there were no long-term sequelae of this complication and clinical outcomes were comparable to that reported in the literature.

Bilateral subthalmic nucleus deep brain stimulation with microelectrode recordings in the setting of mild inherited hemophilia B: a case report.

Hemophilia B is an X linked recessive deficiency of factor IX that presents with a range of clinical severity that co-relates with factor levels. Although guidelines exist to guide perioperative hemostasis in such patients, there is scarce data on elective high-risk neurosurgeries, resulting in a reluctance to offer these patients elective neurosurgeries. These patients thus rarely if ever undergo such procedures. We report a unique case of undiagnosed mild hemophilia B in a gentleman that was found incidentally at age 64 during pre-operative workup. This gentleman had intractable Parkinson's disease for which subthalmic deep brain stimulation was indicated. He was found to have a prolonged APTT on initial lab testing. After subsequent workup, and having excluded the presence of inhibitors, he was diagnosed with Hemophilia B. With the use of Factor IX concentrates (AlphaNine®) and close clinical, laboratory, and radiological monitoring a plan was made for this patient to undergo this procedure. Our patient successfully underwent subthalmic deep brain stimulation with microelectrode recordings and intraoperative test stimulation in a two-step procedure, followed by single channel implantable neurostimulator and extension wire implantations 2 weeks later. The successful peri-operative course of this patient using this novel approach is described, and the need for future data in this regard is emphasized.

Deep brain stimulation of the subthalamic nucleus in Parkinson's disease patients over 75 years of age.

INTRODUCTION: Deep brain stimulation (DBS) is an effective therapy for Parkinson's disease (PD). However, its effect in older patients is not extensively studied, as they are often excluded from DBS surgery due to concerns of complications or reduced benefit. We assessed clinical outcomes after subthalamic nucleus (STN) DBS in older patients (age > 75 years) with PD. METHODS: All PD patients above 75 years who underwent STN-DBS between 1999 and 2015 were included. Unified Parkinson's Disease Rating Scale (UPDRS) scores and Parkinson's Disease Questionnaire (PDQ-39) scores were assessed up to 4 years after surgery. Other measures included were complications/adverse events, levodopa equivalent dose, and cognitive function. RESULTS: A total of 30 patients underwent 52 lead placements. Mean age at surgery was 77.5 years (range 75.0-84.5 years). Post-DBS, motor scores improved by 30.8% after 1-year and 27.3% after a mean of 2.5 years (p < .001). All motor sub-scores improved, however axial signs did not change over time. OFF time and dyskinesia duration reduced significantly (p < .001), whereas quality of life, activities of daily living and cognitive function did not significantly change. The following adverse events were noted: transient post-operative confusion (36% of patients), gait difficulty (13.3% of patients), hemorrhage (3.8% of leads), personality changes (3.3% of patients), lead revision (1.9% of leads), seizure (1.9% of leads), and infection (1.9% of leads). CONCLUSIONS: STN-DBS improves motor outcomes in patients over 75 years of age; however, there was no change in quality of life. Although post-surgical transient confusion was common, there were no serious adverse events and the incidence of other complications was typical for DBS surgery.

Rates, causes, risk factors, and outcomes of readmission following deep brain stimulation for movement disorders: Analysis of the U.S. Nationwide Readmissions Database.

OBJECTIVE: Deep brain stimulation (DBS) surgery has proven benefit for several movement disorders and medically-refractory psychiatric conditions and is considered a fairly safe procedure. We sought to determine the national rates, causes, predictors, and outcomes associated with 30-day and 90-day readmission. PATIENTS AND METHODS: The Nationwide Readmissions Database was queried (January-September 2013) using ICD-9-CM codes, identifying patients who underwent DBS for movement disorder (Parkinson's disease [PD], essential tremor [ET], or dystonia). Variables included categorical age, gender, insurance, comorbidities, type of movement disorder, length of stay (LOS), total costs, and discharge disposition. RESULTS: A total of 3392 DBS patients were identified [PD (70.7%), ET (25.6%), dystonia (3.7%)]. The mean age was 64.8 ±â€¯0.4 years old and 37% were female. The rates of unplanned readmissions was 1.9% at 30-days and 4.3% at 90 days. The overall NRD incidence (all patient populations) of 30-day readmission is 11.6%. Readmissions most frequently resulted from surgical complications including hematoma and attention to surgical wounds. Elderly, obese, and those with comorbidities such as history of stroke or CAD are at highest risk. The average LOS, mean total cost, and rate of adverse discharge were worse for 30-day (9 days, $64,520, 71.7%) compared to 90-day readmission (6 days, $52,183, 56.5%). CONCLUSION: All-cause, unplanned readmission for DBS was 1.9% within 30-days and 4.3% within 90-days. Risk factors for readmission in our study, such as advanced age and multiple medical comorbidities, are not unique to DBS. Unplanned readmissions are much rarer following DBS compared to most hospital discharges but can occasionally lead to additional costs and rare complications including hematoma, stroke, and wound infection. DBS should continue to be viewed as a safe and effective treatment modality for a wide range of neurological ailments.

Symptomatic, non-infectious, non-hemorrhagic edema after subthalamic nucleus deep brain stimulation surgery for Parkinson's disease.

OBJECT: We review our experience with Parkinson's disease (PD) patients who underwent subthalamic nucleus (STN) deep brain stimulation (DBS) and then developed noninfectious, non-hemorrhagic, delayed, symptomatic brain edema associated with a DBS lead. METHODS: All PD patients who underwent STN DBS lead implantation from 2007 to 2015 were included. The same neurosurgeon performed all surgeries, typically in staged fashion, utilizing single pass microelectrode recordings (MER) within a stereotactic frame. A brain CT was obtained in recovery and subsequently if indicated. RESULTS: There were 189 patients who underwent 363 STN lead implantations among which 35 (9.6%) represent re-implantations of removed leads in 28 (14.8%) patients. Among the 363 STN leads implanted, there were 12 (3.3%) cases of delayed symptomatic edema associated with a DBS lead involving 10 (5.3%) of the patients studied. Of the 328 leads representing first-time operations, there were 9 (2.1%) cases of delayed symptomatic edema in 7 (3.7%) patients, one of whom (14.3%) presented with seizures. For lead re-implantations, there were 3 (8.6%) cases of the brain edema in 3 (10.7%) patients; all presenting with seizures. For the 35 re-implantations, the trajectory to target was the same or very similar via the same burr hole as prior surgery in 17 (48.6%); 3 (17.6%) of whom developed edema. There was no case of brain edema in the 18 re-operated cases using a different burr opening. Edema patients were treated with a course of anticonvulsant medication and dexamethasone. Lead-associated edema resolved over generally a 4 to 6-week course. CONCLUSIONS: Noninfectious, non-hemorrhagic, delayed, symptomatic brain edema occurs in approximately 3% of implanted leads and is more common in re-implantations (9%) compared to new implantations (2%). In re-implantations, the edema is more common when the same trajectory is used (18%) compared to a new trajectory (0%). The edema generally occurs 3 to 8 days after implantation, although immediate post-op CT is normal and seizures are a common presenting feature.

Deep brain stimulation for Parkinson's disease: current status and future outlook.

Parkinson's disease is a neurodegenerative condition secondary to loss of dopaminergic neurons in the substantia nigra pars compacta. Surgical therapy serves as an adjunct when unwanted medication side effects become apparent or additional therapy is needed. Deep brain stimulation emerged into the forefront in the 1990s. Studies have demonstrated improvement in all of the cardinal parkinsonian signs with stimulation. Frameless and 'mini-frame' stereotactic systems, improved MRI for anatomic visualization, and intraoperative MRI-guided placement are a few of the surgical advances in deep brain stimulation. Other advances include rechargeable pulse generators, voltage- or current-based stimulation, and enhanced abilities to 'steer' stimulation. Work is ongoing investigating closed-loop 'smart' stimulation in which stimulation is predicated on neuronal feedback.

MDS-UPDRS to assess non-motor symptoms after STN DBS for Parkinson's disease.

OBJECTIVE: To determine if the non-motor sections of the Movement Disorder Society's (MDS) version of the Unified Parkinson's Disease Rating Scale (UPDRS) could supplement the original UPDRS as a patient completed assessment of changes in non-motor symptoms in Parkinson's disease (PD) patients after bilateral subthalamic nucleus (STN) deep brain stimulation (DBS). METHODS: Thirty PD patients who underwent bilateral STN DBS were assessed using the total UPDRS and the non-motor sections of the MDS-UPDRS prior to surgery and one year following surgery. This study focuses on non-motor symptoms as assessed by Part I of the UPDRS and Part 1A and 1B of the MDS-UPDRS. RESULTS: One year following surgery, no individual non-motor symptoms or the total mentation score of the UPDRS were significantly changed. In comparison, the MDS-UPDRS showed significant improvements in sleep and urinary problems and a trend towards improvement in anxiety, constipation, daytime sleepiness, fatigue and pain. CONCLUSIONS: This study provides evidence that the MDS-UPDRS non-motor sections, when completed by the patients, can supplement the original version of the UPDRS as an effective method of measuring changes in non-motor symptoms after DBS. It also reinforces the benefits of bilateral STN DBS on non-motor symptoms of PD.

Long-term efficacy and safety of thalamic stimulation for drug-resistant partial epilepsy.

OBJECTIVE: To report long-term efficacy and safety results of the SANTE trial investigating deep brain stimulation of the anterior nucleus of the thalamus (ANT) for treatment of localization-related epilepsy. METHODS: This long-term follow-up is a continuation of a previously reported trial of 5- vs 0-V ANT stimulation. Long-term follow-up began 13 months after device implantation with stimulation parameters adjusted at the investigators' discretion. Seizure frequency was determined using daily seizure diaries. RESULTS: The median percent seizure reduction from baseline at 1 year was 41%, and 69% at 5 years. The responder rate (≥50% reduction in seizure frequency) at 1 year was 43%, and 68% at 5 years. In the 5 years of follow-up, 16% of subjects were seizure-free for at least 6 months. There were no reported unanticipated adverse device effects or symptomatic intracranial hemorrhages. The Liverpool Seizure Severity Scale and 31-item Quality of Life in Epilepsy measure showed statistically significant improvement over baseline by 1 year and at 5 years (p < 0.001). CONCLUSION: Long-term follow-up of ANT deep brain stimulation showed sustained efficacy and safety in a treatment-resistant population. CLASSIFICATION OF EVIDENCE: This long-term follow-up provides Class IV evidence that for patients with drug-resistant partial epilepsy, anterior thalamic stimulation is associated with a 69% reduction in seizure frequency and a 34% serious device-related adverse event rate at 5 years.

Deep brain stimulation lead-contact heating during 3T MRI: single- versus dual-channel pulse generator configurations.

BACKGROUND: Magnetic resonance imaging (MRI) after deep brain stimulation (DBS) carries the risk of heating at the lead-contacts within the brain. OBJECTIVE/HYPOTHESIS: To compare the effect of single- and dual-channel DBS implantable pulse generator (IPG) configurations on brain lead-contact heating during 3T MRI. METHODS: A phantom with bilateral brain leads and extensions connected to two single-channel IPGs or a dual-channel right or left IPG was utilized. Using a transmit/receive head coil, seven scan sequences were conducted yielding a range of head-specific absorption rates (SAR-H). Temperature changes (ΔT) at the bilateral 0 and 3 lead-contacts were recorded, and normalized temperatures (ΔT/SAR-H) and slopes defining the ΔT/SAR-H over the SAR-H range were compared. RESULTS: Greater heating was strongly correlated with higher SAR-H in all configurations. For each scan sequence, the ΔT/SAR-H of single-channel left lead-contacts was significantly greater than the ΔT/SAR-H of either dual-channel configuration. The slope defining the relationship between ΔT and SAR-H for the single-channel left lead (1.68°C/SAR-H) was significantly greater (p < 0.0001) than the ΔT/SAR-H slope for the single-channel right lead (0.97°C/SAR-H), both of which were significantly greater (p < 0.0001) than the ΔT/SAR-H slopes of left or right leads (range 0.68 to 0.70°C/SAR-H) in the dual-channel configurations. There were no significant differences in ΔT/SAR-H slope values between the dual-channel configurations. CONCLUSION: DBS hardware configuration using bilateral single-channel versus unilateral dual-channel IPGs significantly affects DBS lead-contact heating during 3T MRI brain scanning.

Deep brain stimulation for essential tremor.

Essential tremor is the most common tremor disorder and is characterized by a postural and kinetic tremor. Most commonly, the disease involves the upper extremities, although other body parts may be affected. Essential tremor is seen most often in adults and may markedly limit abilities to perform daily activities. Medications often fail to control the tremor adequately. In the past, ventral intermediate nucleus of the thalamus (VIM) thalamotomy was the surgery of choice for medication-resistant patients with disabling tremor. With technological advances, deep brain stimulation (DBS) to the VIM has replaced thalamotomy as the operation of choice for patients with essential tremor, given the heightened risk of permanent neurological deficits associated with ablative surgery. Multiple studies have demonstrated that unilateral VIM DBS has significant short- and long-term benefits for targeted tremor. Unilateral VIM DBS may also improve head and voice tremor, although most commonly bilateral stimulation is required for adequate control. However, bilateral thalamic stimulation is associated with a higher incidence of neurological deficits, particularly speech and gait problems. Investigations of DBS of other brain target areas for essential tremor, such as the posterior subthalamic area and the subthalamic nucleus, are ongoing.

Long-term benefits in quality of life after unilateral thalamic deep brain stimulation for essential tremor.

OBJECT: The goal of this study was to evaluate short- and long-term benefits in quality of life (QOL) after unilateral deep brain stimulation (DBS) for essential tremor (ET). METHODS: Patients who received unilateral DBS of the ventral intermediate nucleus of the thalamus between 1997 and 2010 and who had at least 1 follow-up evaluation at least 1 year after surgery were included. Their QOL was assessed with the Parkinson Disease Questionnaire-39 (PDQ-39), and ET was measured with the Fahn-Tolosa-Marin tremor rating scale (TRS) prior to surgery and then postoperatively with the stimulation in the on mode. RESULTS: Ninety-one patients (78 at 1 year; 42 at 2-7 years [mean 4 years]; and 22 at >7-12 years [mean 9 years]) were included in the analysis. The TRS total, targeted tremor, and activities of daily living (ADL) scores were significantly improved compared with presurgical scores up to 12 years. The PDQ-39 ADL, emotional well-being, stigma, and total scores were significantly improved up to 7 years after surgery compared with presurgical scores. At the longest follow-up, only the PDQ-39 stigma score was significantly improved, and the PDQ-39 mobility score was significantly worsened. CONCLUSIONS: Unilateral thalamic stimulation significantly reduces ET and improves ADL scores for up to 12 years after surgery, as measured by the TRS. The PDQ-39 total score and the domains of ADL, emotional well-being, and stigma were significantly improved up to 7 years. Although scores were improved compared with presurgery, other than stigma, these benefits did not remain significant at the longest (up to 12 years) follow-up, probably related in part to changes due to aging and comorbidities.

The importance of testing deep brain stimulation lead impedances before final lead implantation.

BACKGROUND: In the setting of a deep brain stimulation (DBS) lead with defective electrical circuitry, potential patient morbidity and additional surgery may be avoided if impedance testing of the brain lead is performed prior to final lead implantation. In the present report, detection of a short circuit upon lead placement and prior to lead anchoring was detected utilizing recently released DBS hardware and software (Medtronic, Minneapolis, MN). This report suggests that neurosurgeons need to be aware and consider the use of the newly available DBS testing equipment. METHODS: During the first DBS lead placement in a 69-year-old man with advanced idiopathic Parkinson's disease undergoing bilateral subthalamic nucleus DBS over staged procedures, test stimulation and lead impedance testing were accomplished prior to lead anchoring. An external neurostimulator (ENS) was affixed to an updated clinician programmer and connected to the DBS lead with a screening cable specific for the ENS and DBS. RESULTS: Impedance testing demonstrated a short circuit involving the 1 and 3 lead-electrode bipolar combination in a visually intact lead. The lead was replaced, repeat impedance testing and test stimulation were completed and the intact lead was secured. Subsequent DBS surgeries were completed uneventfully. The lead abnormality was verified by the manufacturer. CONCLUSIONS: This case highlights a new method to test DBS lead circuitry at the time of placement. The method may also be employed to directly test lead integrity when localizing a DBS system short or open circuit of unclear etiology. Our case suggests that the method is valuable and should be utilized.

The impact of bilateral subthalamic stimulation on non-motor symptoms of Parkinson's disease.

OBJECTIVE: To evaluate the impact of bilateral subthalamic nucleus (STN) deep brain stimulation (DBS) on the prevalence of non-motor symptoms reported by Parkinson's disease (PD) patients one year following surgery and to examine whether there was an association between number of non-motor symptoms reported and quality of life (QoL). METHODS: Twenty-four patients who received bilateral STN DBS and had follow-up evaluations one year after surgery were included in this study. Patients' motor function was evaluated with the Unified Parkinson's Disease Rating Scale, non-motor symptoms were assessed with the Non-Motor Symptom questionnaire (NMSQuest) and quality of life was assessed with the PDQ-39. RESULTS: There was a mean of 12 non-motor symptoms reported prior to surgery which was significantly reduced to a mean of 7 symptoms one year after surgery. Autonomic symptoms were the most frequently reported and demonstrated the greatest reductions following surgery. Twenty-seven of the 30 items represented in the NMSQuest were reported less frequently one year after surgery compared to before surgery. The reduction in non-motor symptoms was significantly correlated with total QoL scores and the subscales of mobility, activities of daily living, cognition and bodily discomfort. CONCLUSIONS: Non-motor symptoms are common in patients with advanced PD. The number of non-motor symptoms was significantly decreased one year following bilateral STN DBS which was associated with a significant improvement in QoL. Further studies focused on specific non-motor symptoms are warranted in order to fully understand the impact and mechanisms of STN DBS on these symptoms.

Transient, symptomatic, post-operative, non-infectious hypodensity around the deep brain stimulation (DBS) electrode.

Post-operative edema around a deep brain stimulation (DBS) lead is a rare presentation. Post-operative edema that is symptomatic, self-limiting and not due to infection, in particular, is rarely reported as a separate entity. We aim to discuss the morphological characteristics of post-operative edema around a DBS lead with an insight into possible etiologies and management. We present eight patients with symptomatic, self-limiting peri-electrode edema post-DBS electrode implantation who presented post-operatively with distinct clinical presentations with imaging that revealed a hypodense area in the white matter surrounding the DBS electrode. Local and systemic tests for infection were negative. The edema resolved over time without surgical intervention. The etiology of the edema remains obscure. The transient nature of the edema and benign course with rapid and full resolution in all our patients cautions against any hasty decision to explant the electrode, in the absence of any obvious signs of infection.

Head positioning and risk of pneumocephalus, air embolism, and hemorrhage during subthalamic deep brain stimulation surgery.

PURPOSE: The objective of the present study was to evaluate the risk of pneumocephalus, venous air embolism (VAE), and intracranial hemorrhage in subthalamic nucleus (STN) deep brain stimulation (DBS) patients operated in the strict supine (head and body flat) position. METHODS: This was a retrospective review of clinical records and brain imaging of patients who underwent STN DBS between January 2007 and June 2009 at the University of Kansas Medical Center. RESULTS: A total of 61 patients underwent 114 lead implantations (53 staged bilateral and 8 unilateral). No case involved a transventricular route. Intracranial air volumes ranged from 0 to 7.02 cm³ (mean 0.98 ± 1.42 cm³). Pneumocephalus volumes were highly skewed with no air present after 44 (38.6%) lead implantations, >0 to 1 cm³ in 35 (30.7%), >2 to 3 cm³ in 17 (14.9%), and >3 cm³ (average 4.97 cm³) in 9 (7.9%). There was no incidence of clinically apparent VAE or symptomatic intracranial hemorrhage. There was no association between age, degree of atrophy, sagittal angle of surgical approach, number of microelectrode runs (MERs), distance of gyrus from inner skull bone at the entry point, or surgical side and pneumocephalus. However, the majority of lead implantations (100 leads; 88%) required only one MER and there were minimal measurable distances between entered gyrus and adjacent bone. CONCLUSIONS: Our data suggest that strict supine positioning during STN DBS surgery results in minimal intracranial air and is not associated with VAE or symptomatic intracranial hemorrhage when the operative method described is used.

Use of brain MRI after deep brain stimulation hardware implantation.

The objective of this study was to examine the experience with and safety of brain 1.5 Tesla (T) magnetic resonance imaging (MRI) in deep brain stimulation (DBS) patients. This was a retrospective review of brain MRI scanning performed on DBS patients at the University of Kansas Medical Center between January 1995 and December 2007. A total of 249 DBS patients underwent 445 brain 1.5 T MRI scan sessions encompassing 1,092 individual scans using a transmit-receive head coil, representing the cumulative scanning of 1,649 DBS leads. Patients with complete implanted DBS systems as well as those with externalized leads underwent brain imaging. For the majority of scans, specific absorption rates localized to the head (SAR(H)) were estimated and in all cases SAR(H) were higher than that specified in the present product labeling. There were no clinical or hardware related adverse events secondary to brain MRI scanning. Our data should not be extrapolated to encourage MRI scanning beyond the present labeling. Rather, our data may contribute to further defining safe MRI scanning parameters that might ultimately be adopted in future product labeling as more centers report in detail their experiences.

Assessment of the variability in the anatomical position and size of the subthalamic nucleus among patients with advanced Parkinson's disease using magnetic resonance imaging.

PURPOSE: Targeting of the subthalamic nucleus (STN) during deep brain stimulation (DBS) surgery using standard atlas coordinates is used in some centers. Such coordinates are accurate for only a subgroup of patients, and subgroup size depends on the extent of inter-individual variation in STN position/size and degree to which atlas represents average anatomical relations. Few studies have addressed this issue. METHODS: Sixty-two axial T(2)-weighted magnetic resonance (MR) images of the brain (1.5 T) were obtained before STN-DBS in 62 patients (37 males) with Parkinson's disease using a protocol optimized for STN visualization. Image distortion was within sub-millimeter range. Midcommissural point (MCP)-derived coordinates of STN borders, STN center, and other brain landmarks were obtained using stereotactic software. MR-derived measurements were compared to Schaltenbrand and Wahren Atlas. RESULTS: We evaluated 117 best-visualized STNs. STN dimensions and coordinates of its center were highly variable. STN lateral coordinate ranged 8.7 mm-14.5 mm from MCP, A-P coordinate 3.5 mm posterior to 0.5 mm anterior to MCP, and vertical coordinate 1.3 mm-6 mm below MCP. The antero-posterior nucleus dimension varied by 8 mm and lateral-medial dimension by 5.8 mm. Differences between mean values of MR-derived data sets and Atlas values were statistically significant but moderate, excluding AC-PC length, for which the Atlas value was below the 1st percentile of the MR data set. The STN lateral coordinate strongly correlated with the width of the third ventricle (r = 0.73, p < 0.001). CONCLUSIONS: It is now possible to directly evaluate STNs at 1.5 T with minimal image distortion, which reveals variation in STN position and dimensions in the range of nucleus size. This puts under question the rationale of use of standard STN coordinates during DBS surgery.

Effect of deep brain stimulation of the subthalamic nucleus upon the contralateral subthalamic nucleus in Parkinson disease.

High frequency stimulation (HFS) of the subthalamic nucleus (STN) is an effective treatment of idiopathic Parkinson disease (PD). Exactly how HFS works remains unclear. Although HFS of the STN is most effective in improving contralateral motor functions, clinical studies have shown bilateral beneficial effects suggesting that unilateral STN HFS affects both ipsilateral and contralateral basal ganglia networks. In this study we evaluated the effect of STN HFS upon the contralateral STN in 14 PD subjects. The neural recordings were done during stereotaxic neurosurgery for implantation of deep brain stimulation electrodes in the second STN. Neuronal activity of the STN was analyzed before and during two minutes of HFS. There was a significant increase in the multiunit spiking activity of the STN during HFS in the contralateral STN. Our study provides direct electrophysiological evidence that the STN HFS is associated with increased activity of the contralateral STN. These findings suggest that increased STN output underlies therapeutic mechanisms of action of HFS.