Deep Brain Stimulation Procedures Research Articles

Pallidal deep brain stimulation for DYT6 dystonia

BackgroundMutations of the THAP1 gene were recently shown to underlie DYT6 torsion dystonia. Little is known about the response of this dystonia subtype to deep brain stimulation (DBS) at the...

Hardware-related infections after deep brain stimulation surgery: review of incidence, severity and management in 212 single-center procedures in the first year after implantation

Device-related infection is a common occurrence after deep brain stimulation (DBS) surgery, and may result in additional interventions and a loss of efficacy of therapy. This retrospective review aimed to evaluate the incidence, severity and management of device-related infections in 212 DBS procedures performed in our institute. Data on 106 patients, in whom 212 DBS procedures were performed between 2001 and 2011 at our institute by a single neurosurgeon (M.P.), were reviewed to assess the incidence, severity, management and clinical characteristics of infections in the first year after the implantation of a DBS system. Infections occurred in 8.5% of patients and 4.2% of procedures. Of the nine infections, eight involved the neurostimulator and extensions, and one the whole system. The infections occurred 30.7 days after implantation: 7 within 30 days and 2 within 6 months. Infected and uninfected patients were comparable in terms of age, sex, indication for DBS implantation and neurostimulator location. In eight cases, the system components involved were removed and re-implanted after 3 months, while in one case the complete hardware was removed and not re-implanted. The overall incidence of postoperative infections after DBS system implantation was 4.2%; this rate decreased over time. All infections required further surgery. Correct and timely management of partial infections may result in successful salvage of part of the system.

Site of deep brain stimulation and jaw velocity in Parkinson disease

While deep brain stimulation (DBS) has proven to be an effective treatment for many symptoms of Parkinson disease (PD), a deterioration of axial symptoms frequently occurs, particularly for speech and swallowing. These unfavorable effects of DBS may depend on the site of stimulation. The authors made quantitative measures of jaw velocity to compare the relative effectiveness of DBS in the globus pallidus internus (GPi) or the subthalamic nucleus (STN). This was a randomized, double-blind, and longitudinal study, with matched healthy controls. The peak velocities of self-scaled and externally scaled jaw movements were studied in 27 patients with PD before and after 6 months of bilateral DBS in the GPi or the STN. A mixed-effects model was used to identify differences in jaw velocity before DBS surgery (baseline) while off and on levodopa therapy, and after 6 months of DBS (postoperative) during 4 treatment conditions (off- and on-levodopa states with and without DBS). Self-scaled jaw velocity was impaired by the DBS procedure in the STN; velocity was significantly decreased across all postoperative conditions compared with either the off- or on-levodopa baseline conditions. In contrast, the postoperative velocity in the GPi group was generally faster than the baseline off-levodopa state. Turning the DBS off and on had no effect on jaw velocity in either group. Unlike baseline, levodopa therapy postoperatively no longer increased jaw velocity in either group, and this lack of effect was not related to postoperative changes in dose. The externally scaled jaw velocity was little affected by PD, but DBS still slightly affected performance, with the STN group significantly slower than the GPi group for most conditions. The authors' results suggest that either the electrode implant in STN or the subsequent period of continuous STN stimulation negatively affected voluntary jaw velocity, including the loss of the preoperative levodopa-induced improvement. While the GPi group showed some improvement in voluntary jaw velocity postoperatively, their performance during the combination of DBS and levodopa was not different from their best medical management presurgery. The results have implications for DBS target selection, particularly for those patients with oromotor dysfunctions.

Frameless deep brain stimulation using intraoperative O-arm technology

Object Correct lead location in the desired target has been proven to be a strong influential factor for good clinical outcome in deep brain stimulation (DBS) surgery. Commonly, a surgeon's first reliable assessment of such location is made on postoperative imaging. While intraoperative CT (iCT) and intraoperative MR imaging have been previously described, the authors present a series of frameless DBS procedures using O-arm iCT. Methods Twelve consecutive patients with 15 leads underwent frameless DBS placement using electrophysiological testing and O-arm iCT. Initial target coordinates were made using standard indirect and direct assessment. Microelectrode recording (MER) with kinesthetic responses was performed, followed by microstimulation to evaluate the side-effect profile. Intraoperative 3D CT acquisitions obtained between each MER pass and after final lead placement were fused with the preoperative MR image to verify intended MER movements around the target area and to identify the final lead location. Tip coordinates from the initial plan, final intended target, and actual lead location on iCT were later compared with the lead location on postoperative MR imaging, and euclidean distances were calculated. The amount of radiation exposure during each procedure was calculated and compared with the estimated radiation exposure if iCT was not performed. Results The mean euclidean distances between the coordinates for the initial plan, final intended target, and actual lead on iCT compared with the lead coordinates on postoperative MR imaging were 3.04 ± 1.45 mm (p = 0.0001), 2.62 ± 1.50 mm (p = 0.0001), and 1.52 ± 1.78 mm (p = 0.0052), respectively. The authors obtained good merging error during image fusion, and postoperative brain shift was minimal. The actual radiation exposure from iCT was invariably less than estimates of exposure using standard lateral fluoroscopy and anteroposterior radiographs (p < 0.0001). Conclusions O-arm iCT may be useful in frameless DBS surgery to approximate microelectrode or lead locations intraoperatively. Intraoperative CT, however, may not replace fundamental DBS surgical techniques such as electrophysiological testing in movement disorder surgery. Despite the lack of evidence for brain shift from the procedure, iCT-measured coordinates were statistically different from those obtained postoperatively, probably indicating image merging inaccuracy and the difficulties in accurately denoting lead location. Therefore, electrophysiological testing may truly be the only means of precisely knowing the location in 3D space intraoperatively. While iCT may provide clues to electrode or lead location during the procedure, its true utility may be in DBS procedures targeting areas where electrophysiology is less useful. The use of iCT appears to reduce radiation exposure compared with the authors' traditional frameless technique.

Hemorrhagic and Repositioning Risk Factors Related to Intraoperative Multitrack Microrecording on a Large Series of Patients Treated for Deep Brain Stimulation

Background Deep brain stimulation (DBS) is a commonly performed surgical technique used to treat various movement disorders. Despite DBS being nonablative and minimally invasive, numerous complications and side effects have been recorded, the most critical of which are intracranial ischaemic/hemorrhagic events. Methods We analyzed this complication in relation to simultaneous multitrack microrecording (MER) as observed in our experience. The possible contribution of MER to the precision of the DBS procedure was also evaluated. From October 1996 to January 2010, 532 consecutive procedures were performed at the Unit of Functional Neurosurgery, Division of Neurosurgery IRCCS Galeazzi in Milan, and at the Istituto Besta IRCCS in Milan by 2 of the Authors (D.S. and M.S.), on a total number of 272 patients. Findings Ischaemic/hemorrhagic complications were documented in 9 patients (1.6%), and 5 of them presented with a neurological syndrome. Overall mortality was 3 patients (1.1%), and was correlated with intracranial hemorrhage in 1 patient. Repositioning of incorrectly positioned electrodes was deemed necessary in 26 procedures (4.9%) on 23 patients (8.4%). Conclusions Although no consistent association was documented between the use of simultaneous intraoperative multitrack MER and hemorrhage, a statistically significant association was recorded between an incorrect positioning of the definitive leads, as reported in the postoperative magnetic resonance imaging controls or at the intraoperative computed tomographic (CT) scans, and the lack of intraoperative MER. DBS proves to be a safe and effective procedure even for novel indications. In our experience, no association was found between hemorrhagic risk and simultaneous multitrack MER.

Novel signal-dependent filter bank method for identification of multiple basal ganglia nuclei in Parkinsonian patients

Microelectrode recordings are a valuable tool for assisting localization targets during deep brain stimulation procedures in Parkinson's disease neurosurgery. Attempts to automate and standardize this process have been limited by variability in patient neurophysiology and strong dynamics of microelectrode recordings. In this paper, a methodology for the identification of basal ganglia nuclei is presented that is based on a signal-dependent filter bank method using microelectrode recordings. The method is a customized realization of the discrete wavelet transform via the lifting scheme that is optimally tuned by genetic algorithms. Using this method, unique mother wavelet functions that exhibit an adaptable spectrum to the microelectrode recording dynamic are generated. Additionally, by extracting morphological features from the space-transformed microelectrode recording, it is possible to integrate them into three-dimensional (3D) feature spaces with maximum class separability. Finally, high discriminant feature spaces are fed into basic classifiers to recognize up to four basal nuclei. Comparison with several existing wavelets highlights the characteristics of new mother wavelets. Additionally, classification results show that identification of addressed nuclei in the basal ganglia can be performed with 95% confidence.

Twiddler’s syndrome in a patient with a deep brain stimulation device for generalized dystonia

Deep brain stimulation (DBS) is the technique of neurostimulation of deep brain structures for the treatment of conditions such as essential tremor, dystonia, Parkinson’s disease and chronic pain syndromes. The procedure uses implanted deep brain stimulation electrodes connected to extension leads and an implantable pulse generator (IPG). Hardware failure related to the DBS procedure is not infrequent, and includes electrode migration and disconnection. We describe a patient who received bilateral globus pallidus internus DBS for dystonia with initially good clinical response, but the device eventually failed. Radiographs showed multiple twisting of the extension leads with disconnection from the brain electrodes and a diagnosis of Twiddler’s syndrome was made. Twiddler’s syndrome was first described in patients with cardiac pacemakers. Patients with mental disability, elderly and obese patients are at increased risk. Twiddler’s syndrome should be suspected whenever there is a failure of the DBS device to relieve symptoms previously responsive to stimulation. Surgical correction is usually required.

The incidence of deep brain stimulator hardware infection: the effect of change in antibiotic prophylaxis regimen and review of the literature

The complication of hardware infection related to deep brain stimulator implantation (or revision) varies between 0 and 15.2% in the literature. However, no national guidelines exist at present to define an average or acceptable rate of infection associated with, nor the preferred antibiotic prophylaxis required for, this procedure. The aim of this study was to examine the effect of changing the antibiotic prophylaxis regimen used in a single neurosurgical centre on the incidence and outcome of hardware infection. A prospective cohort of 38 patients undergoing deep brain stimulation (DBS) implantation or internal pulse generator (IPG) replacement and receiving perioperative vancomycin (including intravenous gentamicin on induction) and pouch-installed gentamicin, was compared to a historical cohort of 35 patients receiving perioperative cefuroxime in the same unit. The infection rate over 2 years in the prospective group for DBS surgery was 0 compared to 1 (5.6%) in the historical cohort (p = 0.11, χ2); the infection rate for IPG replacements was 1(3.6%) in the prospective cohort, versus 3 (17.6%) in the historical (p = 0.44, χ2). In this article, we have also systematically reviewed the literature to date and derived an average infection rate of 4.7% (PI 0.9–22%, Random Effects Meta-analysis, Stata) for 35 studies comprising 3550 patients. There is no significant difference in infection rates between DBS procedures that are primarily internalised (n = 9) compared to those in which there is a period of electrode externalisation (n = 23) (p = 0.9, Meta-regression analysis, Stata).

Analysis of hemorrhagic risk factors during deep brain stimulation surgery for movement disorders: comparison of the circumferential paired and multiple electrode insertion methods

The most serious complication of deep brain stimulation (DBS) surgery is intracranial hemorrhage. The authors have assessed risk factors for hemorrhage in DBS surgery and compared two types of microelectrode insertion technique on hemorrhagic risk. A total of 171 DBS procedures were performed on 110 patients (58 females, 52 males) by the same neurosurgeon at a single center between May 2005 and May 2010. We used two microelectrode insertion methods: multiple microelectrode insertion (MMI) and circumferential paired microelectrode insertion (CPMI). We analyzed the correlation between bleeding rates and gender, age, hypertension, target location, simultaneous bilateral procedure and electrode insertion method. Of the 171 DBS procedures, 138 were on 85 patients with Parkinson's disease, 16 were in 15 patients with essential tremor and 17 were on ten patients with dystonia. There were nine postoperative hemorrhagic events (5.26%), of which three were symptomatic (1.75%), and one permanent neurological deficit event (0.58%). Compared with the bleeding rate in the MMI method (9/106, 8.5%), there was no instance of bleeding with the CPMI method (0/65, 0%) (p = 0.04). In other factors, the correlation with hemorrhage was not found. Use of the CPMI method significantly decreased the rate of bleeding. This new surgical technique seems to be safe and accurate and may be recommended as another surgical option.

Bilateral subthalamic deep brain stimulation using single track microelectrode recording

Microelectrode recording (MER) is widely used during deep brain stimulation (DBS) procedures because MER can identify structural borders and eloquent structures, localize somatotopic arrangements, and provide an outline of the three-dimensional shapes of target nuclei. However, MER may cause intracranial hemorrhage. We preformed single track MER during DBS procedures, analyzed the accuracy of electrode positioning with MRI, and compared the amount of air and the potential risk of intracranial hemorrhage. A total of 46 electrodes were placed in 23 patients who suffered from advanced Parkinson's disease and who underwent bilateral subthalamic nucleus DBS using single track MER. Each patient's Unified Parkinson's Disease Rating Scale (UPDRS) score and levo-dopa equivalent dosage (LED) were estimated pre- and postoperatively. The accuracy of electrode positioning and fontal air thickness was measured by a pre- or postoperative magnetic resonance imaging (MRI) merging technique. The mean electrode positioning error was 0.92mm (0.3-2.94mm). The mean frontal air thickness on postoperative MRI was 3.85mm (0-10.3mm), which did not affect the electrode accuracy statistically (p = 0.730). A total of nine electrodes required repositioning after single-track MER because they affected microstimulation or because an abnormally short STN length was observed during MER. In this series, one patient suffered from an intracranial hemorrhage after surgery that appeared to be due to venous infarction rather than related to MER. Although MER can facilitate accurate positioning of electrodes, multi-track MER may increase the risk of intracranial hemorrhage. The accuracy of electrode positioning appears to be acceptable under single track MER during STN DBS with careful electrophysiological and neurological monitoring. The risk of intracranial hemorrhage appears to be minimal, especially in elderly patients with atrophic brains.

Long-term experience with intraoperative microrecording during DBS neurosurgery in STN and GPi

BackgroundIntraoperative microelectrode recording (MER) for targeting during deep brain stimulation (DBS) procedures has been evaluated over a period of 4 years, in 57 consecutive patients with Parkinson’s disease, who received DBS in the subthalamic nucleus (STN-DBS), and 28 consecutive patients with either dystonia (23) or Parkinson’s disease (five), in whom the internal segment of the globus pallidus (GPi-DBS) was targeted.MethodsThe procedure for DBS was a one-stage bilateral stereotactic approach using a combined electrode for both MER and macrostimulation. Up to five micro/macro-electrodes were used in an array with a central, lateral, medial, anterior, and posterior position. Final target location was based on intraoperative test stimulation.FindingsFor the STN, the central trajectory was chosen for implantation in 50% of the cases and for the globus pallidus internus (GPi) in 57% of the cases. Furthermore, in 64% of the cases, the channel selected for the permanent electrode corresponded with the trajectory having the longest segment of STN MER activity. For the GPi, this was the case in 61%. The mean and standard deviation of the deepest contact point with respect to the magnetic resonance imaging (MRI)-based target for the STN was 2.1 ± 1.5 mm and for the GPi was −0.5 ± 1.2 mm.ConclusionsMER facilitates the selection of the final electrode location in STN-DBS and GPi-DBS, and based on the observed MER activity, a pre-selection could be made as to which channel would be the best candidate for macro-test stimulation and at which depth should be stimulated. The choice of the final location is based on intraoperative test stimulation, and it is demonstrated that regularly it is not the central channel that is chosen for implantation. On average, the target as defined by MER activity intensity was in accordance with the MRI-based targets both for the STN and GPi. However, the position of the best MER activity did not necessarily correlate with the locus that produced the most beneficial clinical response on macroelectrode testing intraoperatively.

Do patient's get angrier following STN, GPi, and thalamic deep brain stimulation

Objective The objective of the study was to examine whether deep brain stimulation (DBS) of the subthalamic nucleus (STN), the globus pallidus internus (GPi), and/or the ventralis intermedius thalamic nucleus (Vim) was associated with making patients angrier pre to post-surgical intervention. Background Secondary outcome analysis of the NIH COMPARE Parkinson's Disease DBS trial revealed that participants were angrier and had more mood and cognitive side effects following DBS. Additionally blinded on/off analysis did not change anger scores. The sample size was small but suggested that STN DBS may have been worse than GPi in provoking anger. We endeavored to examine this question utilizing a larger dataset (the UF INFORM database), and also we included a third surgical target (Vim), which has been utilized for a different disease, essential tremor. Methods Consecutive patients from the University of Florida Movement Disorders Center who were implanted with unilateral DBS for Parkinson's disease (STN or GPi) or essential tremor (Vim) were included. Patients originally implanted at outside institutions were excluded. Pre-operative and 4- to 6-month post-operative Visual Analog Mood Scale (VAMS) scores for all three groups were compared; additionally, pre-operative and 1- to 3-month scores were compared for STN and GPi patients. A linear regression model was utilized to analyze the relationship between the VAMS anger score and the independent variables of age, years with symptoms, Mini-Mental Status Examination (MMSE) score, handedness, ethnicity, gender, side of surgery, target of surgery, baseline Dementia Rating Scale (DRS) total score, baseline Beck Depression Index (BDI) score, micro- and macroelectrode passes, and years of education. Levodopa equivalent dosages and dopamine agonist use were analyzed for a potential impact on anger scores. Results A total of 322 unilateral DBS procedures were analyzed, with STN ( n = 195), Vim ( n = 71), and GPi ( n = 56) making up the cohort. An ANOVA was used to detect significant differences among the three targets in the changes pre- to post-operatively. Similar to the COMPARE dataset, at 4 months, the only subscore of VAMS to reveal a significant difference between the three targets was the angry subscore, with GPi revealing a mean (standard) change of 2.38 (9.53); STN, 4.82 (14.52); and Vim, −1.17 (11.51) ( p = 0.012). At 1–3 months post-operation, both STN and GPi groups were significantly angrier ( p = 0.004), but there was no significant difference between the two groups. However, GPi patients were significantly more confused as compared to STN patients ( p = 0.016). The linear regression model which sought independent explanatory variables revealed a relationship between the VAMS anger score and the surgical target and the disease duration. The mean changes for STN and GPi DBS pre- to post-operation were 11.67 ( p = 0.001) and 8.21 ( p = 0.022) units more than those with Vim, respectively. For every year added of disease duration, the VAMS anger score increased by 0.24 ( p = 0.022). For the GPi and STN groups, number of microelectrode passes was significantly associated with angry score changes ( p = 0.014), with the anger score increasing 2.29 units per microelectrode pass. Independent variables not associated with the VAMS anger score included the surgery side, handedness, gender, ethnicity, education, age at surgery, MMSE, DRS, and BDI scores. Although the STN group significantly decreased in LED when compared to GPi, there was no relationship to anger scores. Similarly, dopamine agonist use was not different between STN and GPi groups and did not correlate with the VAMS anger score changes. Conclusions STN and GPi DBS for Parkinson's disease were associated with significantly higher anger scores pre- to post-DBS as compared to Vim for essential tremor. Anger score changes in STN and GPi patients seem to be associated with microelectrode passes, suggesting that it may be a lesional effect. PD patients with longer disease duration may be particularly susceptible, and this should be kept in mind when discussing the potential of DBS surgery for an individual patient. Essential tremor patients who on average have much longer disease durations did not get angrier. The changes in anger scores were not related to LED change or dopamine agonist use. Whether the induction of anger is disease-specific or target-specific is not currently known; however, our data would suggest that PD patients implanted in STN or GPi are at a potential risk. Finally, on closer inspection of the COMPARE DBS data, VAMS anger scores did not change on or off DBS, suggesting that anger changes may be more of a lesional effect rather than a stimulation induced one (Okun et al., 2009).

Prevention of the complication of DBS procedures

Objective To study the complication of deep brain stimulation(DBS)procedures in the treatment of movement disorders. Method Retropective analysis of The complications and side effects in 278patients(531 sides)treated by DBS. Results Complications of DBS were related with operational procedures,choice and location of targets and the hardware. Operative - related complications were intracranial hemorrhage,seizures,leakage of cerebrospinal fluid. Targets related complications were dyskinesia,dysarthria,ptosis. Hardware -related complications were lead break, migration, machine failure. Conclusions The complications of DBS could be reduced by severely operative procedures,adaptable methods and exact programming. Key words: Deep brain stimulation; Complications; Prevention

A closer look at unilateral versus bilateral deep brain stimulation: results of the National Institutes of Health COMPARE cohort

In this paper, the authors' aim was to examine reasons underpinning decisions to undergo, or alternatively forgo, a second-sided deep brain stimulation (DBS) implantation in patients with Parkinson disease (PD). Fifty-two patients with Parkinson disease (PD) were randomized to receive DBS to the subthalamic nucleus or globus pallidus internus (GPi) as part of the COMPARE trial. Forty-four patients had complete data sets. All patients were offered a choice at 6 months after unilateral implantation whether to receive a contralateral DBS implant. All patients had advanced PD. The mean patient age was 59.8 years (range 43-76 years), and the mean duration of disease was 12.2 years (range 5-21 years). The mean baseline Unified Parkinson's Disease Rating Scale (UPDRS)-III motor score was 42.7. The main outcome measures used in this study were the UPDRS-III Motor Scale and the UPDRS-IV Dyskinesia Scale. Twenty-one (48%) of the 44 patients in the cohort did not undergo bilateral implantation and have been successfully treated for an average of 3.5 years; of these, 14 (67%) had a GPi target. The most common reason for adding a second side was inadequacy to address motor symptoms. Patient satisfaction with motor outcomes after unilateral DBS implantation was the most common reason for not undergoing bilateral implantation. Those who chose a second DBS procedure had significantly higher baseline UPDRS-III motor and ipsilateral UPDRS-III scores, and a significantly lower asymmetrical index. The logistic regression analysis revealed that the odds of proceeding to bilateral DBS was 5.2 times higher for STN than for GPi DBS. For every 1% increase in asymmetry, the odds of bilateral DBS decreased [corrected] by 0.96. Unilateral DBS is an effective treatment for a subset of patients with PD. Baseline asymmetry is an important factor in the effectiveness and decision-making process between unilateral and bilateral DBS. Patients with GPi DBS in this cohort were more likely to choose to remain with unilateral implantation.

Minimizing Brain Shift in Stereotactic Functional Neurosurgery

Stereotactic functional neurosurgical interventions depend on precise anatomic targeting before lesioning or deep brain stimulation (DBS) electrode placement. To examine the degree of subcortical brain shift observed when adopting an image-guided approach to stereotactic functional neurosurgery. Coordinates for the anterior and posterior commissural points (AC and PC) were recorded on thin-slice stereotactic magnetic resonance imaging (MRI) scans performed before and immediately after DBS electrode implantation in 136 procedures. The changes in length of AC-PC and in stereotactic coordinates for AC and PC were calculated for each intervention. In patients with Parkinson disease undergoing bilateral subthalamic nucleus (STN) DBS with at least 6 months of follow-up, pre- and postoperative scores of the motor part of the Unified Parkinson's Disease Rating Scale (UPDRS-III) were reviewed. Mean (SD) change in AC-PC length (DeltaAC-PC) was 0.6 (0.4) mm. There was no statistically significant difference in DeltaAC-PC between groups when examining anatomic target subgroups (P =.95), age subgroups (P = .63), sex (P = .59), and unilateral versus bilateral implantation (P =.15). The mean (SD) vector changes for the commissural points were: -0.1 (0.3) mm in X, -0.4 (0.6) mm in Y, and -0.1 (0.7) mm in Z for the AC; and -0.1 (0.3) mm in X, -0.2 (0.7) mm in Y, and 0.0 (0.7) mm in Z for the PC. There was a negligible correlation between the magnitude of brain shift and percentage improvement in UPDRS-III off-medication in patients undergoing STN DBS for PD (R <0.01). Brain shift has long been considered an issue in stereotactic targeting during DBS procedures. However, with the image-guided approach and surgical technique used in this study, subcortical brain shift was extremely limited and did not appear to adversely affect clinical outcome.

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

Adverse event (AE) rates for deep brain stimulation (DBS) are variable, due to various methodologies used for identifying, collecting, and reporting AEs. This lack of a prospective, standardized AE collection method is a shortcoming in the advancement of DBS. In this paper the authors disclose the standardized and prospectively recorded AE data from their institution, correlated with clinical outcome and quality of life (QOL) measures. All patients who underwent operations at the authors' institution for Parkinson disease (PD), essential tremor, dystonia, other tremor, and obsessive-compulsive disorder were included. Complications occurring intraoperatively or within the first 180 days following surgery were recorded, analyzed, and classified as mild, moderate, or severe, regardless of their perceived relationship to the procedure. The presence, frequency, and severity of AEs were compared with the following outcome measurements: postoperative change in the QOL scales (Medical Outcomes Study 36-Item Short-Form Survey, 39-Item PD Questionnaire); motor scales (Tremor Rating Scale, Unified Dystonia Rating Scale, Unified PD Rating Scale); and Patient Global Impression Scale (PGIS). Two hundred seventy DBS procedures were performed in 198 patients. Three hundred AEs were recorded in 146 (54.1%) of the 270 procedures, and the AEs were recorded in 119 (60.1%) of 198 patients. Of the 198 patients, the maximum severity of AEs was mild in 28 (14.1%), moderate in 35 (17.7%), and severe in 56 (28.3%). Of the 300 AEs, 102 (34.1%) of 299 were mild, 106 (35.5%) were moderate, and 91 (30.4%) were severe. The AEs were classified as probably not stimulation induced in 10 (3.4%) of 297, probably in 44 (14.9%), unclear for 89 (30%), and not applicable to stimulation in 154 (51.9%). Adverse events were also classified as probably related to surgery in 111 (37.2%) of 298, possibly related in 96 (32.2%), and probably not related to surgery in 91 (30.5%). There was no significant difference (p = 0.22) in QOL outcomes among patients who had no AEs compared with those who experienced mild, moderate, or severe AEs. There was no significant difference in QOL outcomes between patients who did not experience an AE compared with those who experienced any AE. There was no significant difference in the mean General PGIS score between patients without an AE versus those with any AE, as well as on the Symptom-Specific PGIS. Motor function outcomes did not vary between patients with or without AEs. For patients with PD with or without AEs, there was no significant difference in preoperative off-medicine Unified PD Rating Scale score and postoperative 6-month on-medication/on-stimulation change scores (p = 0.59). For patients with tremor there were no differences between those with or without AEs on the Tremor Rating Scale for motor function or activities of daily living. Patients with dystonia with and without AEs showed no differences in the Unified Dystonia Rating Scale. Prospectively and systematically recording AEs may result in higher AE rates, but this does not correlate with poorer QOL, motor function, or patient-oriented outcome scores.

Gamma knife radiosurgery for movement disorders: a concise review of the literature

Medication is the predominant method for the management of patients with movement disorders. However, there is a fraction of patients who experience limited relief from pharmaceuticals or experience bothersome side-effects of the drugs. Deep brain stimulation (DBS) and surgical lesioning of the thalamus and basal ganglia are respected neurosurgical procedures, with valued success rates and a very low incidence of complications. Despite these positive outcomes, DBS and surgical lesioning procedures are contraindicated for some patients. Stereotactic radiosurgery with the Gamma Knife (GK) has been used as a lesioning technique for patients seeking a non-invasive treatment alternative and for medication-intolerable patients, who are unable to undergo DBS or lesioning due to comorbid medical conditions. Tremors of various etiologies are treated using GK thalamotomy, which targets the ventralis intermedius nucleus. GK thalamotomy produces favorable outcomes when treating tremors, with success rates ranging from 80-100%. In contrast, GK pallidotomy targets the internal globus pallidus, and is used in treating bradykinesia, rigidity, and dyskinesia. Although radiosurgery has proven beneficial for tremors, radiosurgical pallidotomy for bradykinesia, rigidity, and dyskinesia remains questionable, with mixed success rates in the literature that ranges from 0-87%. We suggest that GK thalamotomy be offered along with other neurosurgical approaches as a feasible treatment option to patients who prefer the non-invasive nature of radiosurgery and to those who are unqualified candidates for the neurosurgical alternatives. Also, we advise that patients with bradykinesia, rigidity, and dyskinesia be educated about the variability in the literature pertaining to GK pallidotomy before proceeding with treatment.

Socioeconomic Trends in Deep Brain Stimulation (DBS) Surgery

We evaluated trends in deep brain stimulation (DBS) for the 14-year period from 1993 to 2006. We utilized the Nationwide Inpatient Sample data base from the Healthcare Cost and Utilization Project, Agency for Healthcare Research and Quality. A total of 34,792 patients underwent DBS surgery from 1993 to 2006. There were 756 DBS cases performed in 1993 compared with 4200 DBS procedures performed in 2006. Significant increases in nationwide DBS volume coincided with regulatory approval for new indications-Parkinson's disease and dystonia, respectively. Cost of DBS surgery increased from $38,840 in 1993 to $69,329 in 2006. The majority of cases were done in metropolitan areas (97%) at large academic centers (91%) at a national bill of $291 MM. Future studies will need to include the socioeconomic impact of the technology on disease status, patient access, and costs as it expands to novel indications.

Surgical management of Parkinson’s disease

There has been a renaissance in the surgical treatment of Parkinson’s disease (PD) over the last 15–20 years as a result of the long-term complications of L-DOPA use. The current cornerstone of surgical treatment for PD is high-frequency deep-brain stimulation (DBS) of the subthalamic nucleus (STN) using implantable electrodes and an implantable pulse generator/battery. Among well-selected patients, that is, patients with idiopathic PD, L-DOPA-responsive symptoms and no significant psychiatric comorbidities or cognitive decline, STN DBS can provide improvements in motor symptoms and quality of life, with low risks of adverse effects. In this article, we briefly describe the evolution of surgical treatments for PD, and the rationale for current DBS procedures. We also provide details of our practice, including patient selection, surgical technique and postoperative stimulation programming and medication adjustment. Current and possible future alternatives to DBS of the STN are also discussed.

Delayed awakening in dystonia patients undergoing deep brain stimulation surgery

We aimed to identify the incidence, duration and causes of delayed emergence from anesthesia in patients with dystonia undergoing surgery for deep brain stimulation (DBS) placement. A retrospective review of patients with dystonia who underwent DBS placement was conducted and the following characteristics were noted: age, gender, comorbid conditions, American Society of Anesthesiologists classification, anesthetic agents used, amount of initial dose, amount of infusion dose, duration of the infusion and the time needed for emergence. Twenty-four patients underwent 33 DBS procedures for dystonia. Propofol was administered to 21 patients, in 29 of the 33 procedures. Dexmedetomidine was administered to three patients, in four procedures. The average propofol loading dose was 0.7 mg/kg, and the infusion rate was 80 μg/kg per minute (min), for an average duration of 89 min. The average time of emergence was 36 min. Only 31% of patients emerged from propofol anesthesia during the expected time frame, 69% of patients had some degree of delayed emergence, and 24% had a significant delay in emergence. Delayed emergence was more common in younger patients due to the higher loading doses these patients received. This study shows a 69% incidence of delayed emergence in dystonia patients undergoing DBS surgery. It also suggests an association between delayed emergence and younger patients who receive higher loading doses. A possible cause of delayed emergence is excessive anesthetic potentiation of the low output pallidal state in dystonia which may depress the pallido-thalamo-cortical circuitry. Delayed emergence could also result from depression of the previously affected ventral pallidal inputs to the septo-hippocampal system that mediates general anesthesia and awareness. Complex neurotransmitter disturbances may also be involved.