Intraoperative Microelectrode Recording Research Articles

Intraoperative microelectrode recording during asleep deep brain stimulation of subthalamic nucleus for Parkinson Disease. A case series with systematic review of the literature

The use of microelectrode recording (MER) during deep brain stimulation (DBS) for Parkinson Disease is controversial. Furthermore, in asleep DBS anesthesia can impair the ability to record single-cell electric activity.The purpose of this study was to describe our surgical and anesthesiologic protocol for MER assessment during asleep subthalamic nucleus (STN) DBS and to put our findings in the context of a systematic review of the literature. Sixty-three STN electrodes were implanted in 32 patients under general anesthesia. A frameless technique using O-Arm scanning was adopted in all cases. Total intravenous anesthesia, monitored with bispectral index, was administered using a target controlled infusion of both propofol and remifentanil. A systematic review of the literature with metanalysis on MER in asleep vs awake STN DBS for Parkinson Disease was performed. In our series, MER could be reliably recorded in all cases, impacting profoundly on electrode positioning: the final position was located within 2 mm from the planned target only in 42.9% cases. Depth modification > 2 mm was necessary in 21 cases (33.3%), while in 15 cases (23.8%) a different track was used. At 1-year follow-up we observed a significant reduction in LEDD, UPDRS Part III score off-medications, and UPDRS Part III score on medications, as compared to baseline. The systematic review of the literature yielded 23 papers; adding the cases here reported, overall 1258 asleep DBS cases using MER are described. This technique was safe and effective: metanalysis showed similar, if not better, outcome of asleep vs awake patients operated using MER. MER are a useful and reliable tool during asleep STN DBS, leading to a fine tuning of electrode position in the majority of cases. Collaboration between neurosurgeon, neurophysiologist and neuroanesthesiologist is crucial, since slight modifications of sedation level can impact profoundly on MER reliability.

Aging suppresses subthalamic neuronal activity in patients with Parkinson's disease.

Age is a primary risk factor for Parkinson's disease (PD); however, the effects of aging on the Parkinsonian brain remain poorly understood, particularly for deep brain structures. We investigated intraoperative micro-electrode recordings from the subthalamic nucleus (STN) of PD patients aged between 42 and 76 years. Age was associated with decreased oscillatory beta power and non-oscillatory high-frequency power, independent of PD-related variables. Single unit firing and burst rates were also reduced, whereas the coefficient of variation and the structure of burst activity were unchanged. Phase synchronization (debiased weighed phase lag index [dWPLI]) between sites was pronounced in the beta band between electrodes in the superficial STN but was unaffected by age. Our results show that aging is associated with reduced neuronal activity without changes to its temporal structure. We speculate that the loss of activity in the STN may mediate the relationship between PD and age.

Single neurons in the thalamus and subthalamic nucleus process cardiac and respiratory signals in humans

Visceral signals are constantly processed by our central nervous system, enable homeostatic regulation, and influence perception, emotion, and cognition. While visceral processes at the cortical level have been extensively studied using non-invasive imaging techniques, very few studies have investigated how this information is processed at the single neuron level, both in humans and animals. Subcortical regions, relaying signals from peripheral interoceptors to cortical structures, are particularly understudied and how visceral information is processed in thalamic and subthalamic structures remains largely unknown. Here, we took advantage of intraoperative microelectrode recordings in patients undergoing surgery for deep brain stimulation (DBS) to investigate the activity of single neurons related to cardiac and respiratory functions in three subcortical regions: ventral intermedius nucleus (Vim) and ventral caudalis nucleus (Vc) of the thalamus, and subthalamic nucleus (STN). We report that the activity of a large portion of the recorded neurons (about 70%) was modulated by either the heartbeat, the cardiac inter-beat interval, or the respiration. These cardiac and respiratory response patterns varied largely across neurons both in terms of timing and their kind of modulation. A substantial proportion of these visceral neurons (30%) was responsive to more than one of the tested signals, underlining specialization and integration of cardiac and respiratory signals in STN and thalamic neurons. By extensively describing single unit activity related to cardiorespiratory function in thalamic and subthalamic neurons, our results highlight the major role of these subcortical regions in the processing of visceral signals.

Clinical evaluation of a stereotactic system for single-stage deep brain stimulation surgery under general anesthesia: technical note.

Conventional frame-based stereotactic systems have circumferential base frames, often necessitating deep brain stimulation (DBS) surgery in two stages: intracranial electrode insertion followed by surgical re-preparation and pulse generator implantation. Some patients do not tolerate awake surgery, underscoring the need for a safe alternative for asleep DBS surgery. A frame-based stereotactic system with a skull-mounted "key" in lieu of a circumferential base frame received US FDA clearance. The authors describe the system's application for single-stage, asleep DBS surgery in 8 patients at their institution and review its workflow and technical considerations. Eight patients underwent DBS lead insertion and IPG implantation in a single surgical preparation under general anesthesia using the system. Postoperative CT imaging confirmed lead placement. Eight patients underwent implantation of 15 total leads targeting the ventral intermediate nucleus (4 patients), globus pallidus internus (GPi; 3 patients), and subthalamic nucleus (STN; 1 patient). Intraoperative microelectrode recording was conducted for GPi and STN targets. Postoperative CT imaging revealed a mean ± SD radial error of 1.24 ± 0.45 mm (n = 15 leads), without surgical complications. The stereotactic system facilitated safe and effective asleep, single-stage DBS surgery, maintaining traditional lead accuracy standards.

Combining ultrasound and microelectrode recordings for postoperative localization of subthalamic electrodes in Parkinson’s disease

ObjectiveTo assess transcranial sonography (TCS) as stand-alone tool and in combination with microelectrode recordings (MER) as a method for the postoperative localization of deep brain stimulation (DBS) electrodes in the subthalamic nucleus (STN). MethodsIndividual dorsal and ventral boundaries of STN (n = 12) were determined on intraoperative MER. Postoperatively, a standardized TCS protocol was applied to measure medio-lateral, anterior-posterior and rostro-caudal electrode position using visualized reference structures (midline, substantia nigra). TCS and combined TCS-MER data were validated using fusion-imaging and clinical outcome data. ResultsTest-retest reliability of standard TCS measures of electrode position was excellent. Computed tomography and TCS measures of distance between distal electrode contact and midline agreed well (Pearson correlation; r = 0.86; p < 0.001). Comparing our “gold standard” of rostro-caudal electrode localization relative to STN boundaries, i.e. combining MRI-based stereotaxy and MER data, with the combination of TCS and MER data, the measures differed by 0.32 ± 0.87 (range, −1.35 to 1.25) mm. Combined TCS-MER data identified the clinically preferred electrode contacts for STN-DBS with high accuracy (Coheńs kappa, 0.86). ConclusionsCombined TCS-MER data allow for exact localization of STN-DBS electrodes. SignificanceOur method provides a new option for monitoring of STN-DBS electrode location and guidance of DBS programming in Parkinson’s disease.

Dorsal subthalamic nucleus targeting in deep brain stimulation: microelectrode recording versus 7-Tesla connectivity.

Connectivity-derived 7-Tesla MRI segmentation and intraoperative microelectrode recording can both assist subthalamic nucleus targeting for deep brain stimulation in Parkinson's disease. It remains unclear whether deep brain stimulation electrodes placed in the 7-Tesla MRI segmented subdivision with predominant projections to cortical motor areas (hyperdirect pathway) achieve superior motor improvement and whether microelectrode recording can accurately distinguish the motor subdivision. In 25 patients with Parkinson's disease, deep brain stimulation electrodes were evaluated for being inside or outside the predominantly motor-connected subthalamic nucleus (motor-connected subthalamic nucleus or non-motor-connected subthalamic nucleus, respectively) based on 7-Tesla MRI connectivity segmentation. Hemi-body motor improvement (Movement Disorder Society Unified Parkinson's Disease Rating Scale, Part III) and microelectrode recording characteristics of multi- and single-unit activities were compared between groups. Deep brain stimulation electrodes placed in the motor-connected subthalamic nucleus resulted in higher hemi-body motor improvement, compared with electrodes placed in the non-motor-connected subthalamic nucleus (80% versus 52%, P < 0.0001). Multi-unit activity was found slightly higher in the motor-connected subthalamic nucleus versus the non-motor-connected subthalamic nucleus (P < 0.001, receiver operating characteristic 0.63); single-unit activity did not differ between groups. Deep brain stimulation in the connectivity-derived 7-Tesla MRI subthalamic nucleus motor segment produced a superior clinical outcome; however, microelectrode recording did not accurately distinguish this subdivision within the subthalamic nucleus.

Subthalamic nucleus physiology is correlated with deep brain stimulation motor and non-motor outcomes.

Subthalamic nucleus deep brain stimulation is commonly indicated for symptomatic relief of idiopathic Parkinson's disease. Despite the known improvement in motor scores, affective, cognitive, voice and speech functions might deteriorate following this procedure. Recent studies have correlated motor outcomes with intraoperative microelectrode recordings. However, there are no microelectrode recording-based tools with predictive values relating to long-term outcomes of integrative motor and non-motor symptoms. We conducted a retrospective analysis of the outcomes of patients with idiopathic Parkinson's disease who had subthalamic nucleus deep brain stimulation at Tel Aviv Sourasky Medical Centre (Tel Aviv, Israel) during 2015-2016. Forty-eight patients (19 women, 29 men; mean age, 58 ± 8 years) who were implanted with a subthalamic nucleus deep brain stimulation device underwent pre- and postsurgical assessments of motor, neuropsychological, voice and speech symptoms. Significant improvements in all motor symptoms (except axial signs) and levodopa equivalent daily dose were noted in all patients. Mild improvements were observed in more posterior-related neuropsychological functions (verbal memory, visual memory and organization) while mild deterioration was observed in frontal functions (personality changes, executive functioning and verbal fluency). The concomitant decline in speech intelligibility was mild and only partial, probably in accordance with the neuropsychological verbal fluency results. Acoustic characteristics were the least affected and remained within normal values. Dimensionality reduction of motor, neuropsychological and voice scores rendered six principal components that reflect the main clinical aspects: the tremor-dominant versus the rigidity-bradykinesia-dominant motor symptoms, frontal versus posterior neuropsychological deficits and acoustic characteristics versus speech intelligibility abnormalities. Microelectrode recordings of subthalamic nucleus spiking activity were analysed off-line and correlated with the original scores and with the principal component results. Based on 198 microelectrode recording trajectories, we suggest an intraoperative subthalamic nucleus deep brain stimulation score, which is a simple sum of three microelectrode recording properties: normalized neuronal activity, the subthalamic nucleus width and the relative proportion of the subthalamic nucleus dorsolateral oscillatory region. A threshold subthalamic nucleus deep brain stimulation score >2.5 (preferentially composed of normalized root mean square >1.5, subthalamic nucleus width >3 mm and a dorsolateral oscillatory region/subthalamic nucleus width ratio >1/3) predicts better motor and non-motor long-term outcomes. The algorithm presented here optimizes intraoperative decision-making of deep brain stimulation contact localization based on microelectrode recording with the aim of improving long-term (>1 year) motor, neuropsychological and voice symptoms.

Susceptibility-Weighted MRI Approximates Intraoperative Microelectrode Recording During Deep Brain Stimulation of the Subthalamic Nucleus for Parkinson's Disease

Deep brain stimulation of the subthalamic nucleus (STN-DBS) for Parkinson's disease can be performed with intraoperative neurophysiological and radiographic guidance. Conventional T2-weighted magnetic resonance imaging sequences, however, often fail to provide definitive borders of the STN. Novel magnetic resonance imaging sequences, such as susceptibility-weighted imaging (SWI), might better localize the STN borders and facilitate radiographic targeting. We compared the radiographic location of the dorsal and ventral borders of the STN using SWI with intraoperative microelectrode recording (MER) during awake STN-DBS for Parkinson's disease. Thirteen consecutive patients who underwent placement of 24 STN-DBS leads for Parkinson's disease were analyzed retrospectively. Preoperative targeting was performed with SWI, and MER data were obtained from intraoperative electrophysiology records. The boundaries of the STN on SWI were identified by a blinded investigator. The final electrode position differed significantly from the planned coordinates in depth but not in length or width, indicating that MER guided the final electrode depth. When we compared the boundaries of the STN by MER and SWI, SWI accurately predicted the entry into the STN but underestimated the length and ventral boundary of the STN by 1.2 mm. This extent of error approximates the span of a DBS contact and could affect the placement of directional contacts within the STN. MER might continue to have a role in STN-DBS. This could potentially be mitigated by further refinement of imaging protocols to better image the ventral boundary of the STN.

Intraoperative physiology augments atlas-based data in awake deep brain stimulation

BackgroundDeep brain stimulation (DBS) is commonly performed with patients awake to perform intraoperative microelectrode recordings and/or macrostimulation testing to guide final electrode placement. Supplemental information from atlas-based databases derived from...

MER and increased operative time are not risk factors for the formation of pneumocephalus during DBS

Although only recently directional leads have proven their potential to compensate for sub-optimally placed electrodes, optimal lead positioning remains the most critical factor in determining Deep Brain Stimulation (DBS) outcome. Pneumocephalus is a recognized source of error, but the factors that contribute to its formation are still a matter of debate. Among these, operative time is one of the most controversial. Because cases of DBS performed with Microelectrode Recordings (MER) are affected by an increase in surgical length, it is useful to analyze whether MER places patients at risk for increased intracranial air entry. Data of 94 patients from two different institutes who underwent DBS for different neurologic and psychiatric conditions were analyzed for the presence of postoperative pneumocephalus. Operative time and use of MER, as well as other potential risk factors for pneumocephalus (age, awake vs. asleep surgery, number of MER passages, burr hole size, target and unilateral vs. bilateral implants) were examined. Mann-Whitney U and Kruskal-Wallis tests were utilized to compare intracranial air distributions across groups of categorical variables. Partial correlations were used to assess the association between time and volume. A generalized linear model was created to predict the effects of time and MER on the volume of intracranial air, controlling for other potential risk factors identified: age, number of MER passages, awake vs. asleep surgery, burr hole size, target, unilateral vs. bilateral surgery. Significantly different distributions of air volume were noted between different targets, unilateral vs. bilateral implants, and number of MER trajectories. Patients undergoing DBS with MER did not present a significant increase in pneumocephalus compared to patients operated without (p = 0.067). No significant correlation was found between pneumocephalus and time. Using multivariate analysis, unilateral implants exhibited lower volumes of pneumocephalus (p = 0.002). Two specific targets exhibited significantly different volumes of pneumocephalus: the bed nucleus of the stria terminalis with lower volumes (p < 0.001) and the posterior hypothalamus with higher volumes (p = 0.011). MER, time, and other parameters analyzed failed to reach statistical significance. Operative time and use of intraoperative MER are not significant predictors of pneumocephalus during DBS. Air entry is greater for bilateral surgeries and may be also influenced by the specific stimulated target.

Intraoperative electrophysiological monitoring determines the final electrode position for pallidal stimulation in dystonia patients.

Bilateral deep brain stimulation (DBS) of the globus pallidus internus (GPi) is an effective treatment for refractory dystonia. Neuroradiological target and stimulation electrode trajectory planning with intraoperative microelectrode recordings (MER) and stimulation are used. With improving neuroradiological techniques, the need for MER is in dispute mainly because of the suspected risk of hemorrhage and the impact on clinical post DBS outcome. The aim of the study is to compare the preplanned GPi electrode trajectories with final trajectories selected for electrode implantation after electrophysiological monitoring and to discuss the factors potentially responsible for differences between preplanned and final trajectories. Finally, the potential association between the final trajectory selected for electrode implantation and clinical outcome will be analyzed. Forty patients underwent bilateral GPi DBS (right-sided implants first) for refractory dystonia. The relationship between preplanned and final trajectories (MicroDrive system) was correlated with patient (gender, age, dystonia type and duration) and surgery characteristics (anesthesia type, postoperative pneumocephalus) and clinical outcome measured using CGI (Clinical Global Impression parameter). The correlation between the preplanned and final trajectories together with CGI was compared between patients 1-20 and 21-40 for the learning curve effect. The trajectory selected for definitive electrode implantation matched the preplanned trajectory in 72.5% and 70% on the right and left side respectively; 55% had bilateral definitive electrodes implanted along the preplanned trajectories. Statistical analysis did not confirm any of the studied factors as predictor of the difference between the preplanned and final trajectories. Also no association between CGI and final trajectory selected for electrode implantation in the right/left hemisphere has been proven. The percentages of final electrodes implanted along the preplanned trajectory (the correlation between anatomical planning and intraoperative electrophysiology results) did not differ between patients 1-20 and 21-40. Similarly, there were no statistically significant differences in CGI (clinical outcome) between patients 1-20 and 21-40. The final trajectory selected after electrophysiological study differed from the preplanned trajectory in a significant percentage of patients. No predictor of this difference was identified. The anatomo-electrophysiological difference was not predictive of the clinical outcome (as measured using CGI parameter).

Choice of anaesthesia in microelectrode recording-guided deep-brain stimulation for Parkinson’s disease (CHAMPION): study protocol for a single-centre, open-label, non-inferiority randomised controlled trial

IntroductionDeep brain stimulation (DBS) implantation under general anaesthesia (GA) has been applied to patients with Parkinson’s disease (PD) with severe comorbidities or disabling off-medication symptoms. However, general anaesthetics may affect...

Motor Function and Quality of Life Improvement following Asleep versus Awake Deep Brain Stimulation (DBS) Procedures (P4-11.009)

<h3>Objective:</h3> To compare real-world outcomes in patients with Parkinson’s disease (PD) whose Deep Brain Stimulation (DBS) leads were implanted using asleep procedures versus those patients that underwent the procedure using awake conditions. <h3>Background:</h3> DBS procedures are typically conducted with patients being awake to allow for intraoperative clinical testing and/or micro-electrode recording to confirm lead location. However, asleep DBS procedures (i.e., under general anesthesia) are becoming increasingly popular due, at least in part, to technological improvements in imaging allowing alternative lead placement confirmation and shorter procedure duration (Brodsky 2017, Chen 2018, Vinke 2022). <h3>Design/Methods:</h3> A sub-analysis of patients receiving their DBS lead implant under asleep versus awake conditions was conducted in an ongoing, large, multicenter, prospective real-world outcomes study (Vercise, Boston Scientific). Motor function (MDS-UDPRS III), quality of life (PDQ-39) and related outcomes (GIC) were collected at baseline and up to 3-years. Safety events were also collected. <h3>Results:</h3> To date, 157 patients (mean age 61.2±8.3 years; 69% male) were asleep and 433 (mean age 60.1±8.5 years; 66% male) were awake during lead placement. Patients in both groups presented with similar baseline age, duration of disease and disease state. Improvement in quality-of-life was noted in both groups with a 5.3-point improvement (n = 104) in asleep group and a 4.5-point improvement (n = 319) in awake group at 1-year. Similarly, an 18.8- and 20.9-point improvement in motor function was noted in the asleep and awake groups, respectively. <h3>Conclusions:</h3> Outcomes from this large dataset of real-world outcomes examining the outcomes following asleep versus awake DBS demonstrate an alignment with results from previous studies (Holewijn 2021; LaHue 2017). Patient outcomes show little to no difference between awake versus asleep groups. Sleep DBS procedures may offer potential for shortening the total time taken for DBS procedures and offer a viable alternative for patients. <b>Disclosure:</b> Jan Vesper has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Boston Scientific . Jan Vesper has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Medtronic . Jan Vesper has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for Abbott . Jan Vesper has received personal compensation in the range of $10,000-$49,999 for serving on a Speakers Bureau for Abbott . Jan Vesper has received research support from German Research Council. Dr. Deuschl has received personal compensation in the range of $5,000-$9,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Boston Scientific Cavion Functional Neuromodulation. The institution of Dr. Deuschl has received research support from Medtronic. Dr. Deuschl has received publishing royalties from a publication relating to health care. Lilly Chen has received personal compensation for serving as an employee of Boston Scientific . Roshini Jain has received personal compensation for serving as an employee of Boston Scientific. Roshini Jain has received stock or an ownership interest from Boston Scientific.

105 Value of Atlas-Based Data and Intraoperative Testing in Deep Brain Stimulation

INTRODUCTION: Deep brain stimulation (DBS) is commonly performed awake to collect intraoperative microelectrode recordings (MER) and macrostimulation to optimize efficacy and minimize side effects (Bour et al, 2010). With supplementary information from an atlas-based database (CranialVault), efficacy heat maps guide initial targeting, intraoperative final electrode position (FEP) selection and post-operative programming (D’Haese et al, 2012). A better understanding of how this data is integrated to inform all stages of DBS can assist in reducing OR time, optimizing electrode position, expediting programming, and enhancing patient outcomes. METHODS: 451 individual patients who underwent DBS for Parkinson’s Disease, Essential Tremor or Dystonia, treated with 822 individual leads, at Vanderbilt University Medical Center between 2011-2021 were included. Intraoperative testing data including MER firing rate, macrostimulation efficacy and coordinates of FEP were retrieved from the CranialVault database. Average coordinates of planned target, midpoint and bottom of FEP, active contact and centroid of heat maps per target in patient space were calculated and visualized. Medical charts were reviewed for 1-year post-operative outcomes. RESULTS: The distribution of FEPs per target include 55.2% of leads placed in center track. Average coordinates in patient space of planned target, centroid of heatmap, midpoint and bottom of FEP and active contact were recorded. MER data demonstrates how multiunit activity changes at different depths relative to target, per target. Patients who achieve 4th quartile efficacy intraoperatively are more likely to achieve maximal benefit at 1-year post-op (p = 0.003, chi-squared). CONCLUSIONS: Atlas-based data and intraoperative testing is valuable, often leads to changes in FEP and can predict post-operative outcomes.

Patterns of neural activity and clinical outcomes in a juvenile Huntington's Disease patient undergoing Deep Brain Stimulation of the subthalamic nucleus

BackgroundHuntington's disease (HD) is a hereditary neurodegenerative disease leading to cognitive and motor impairment. HD depends on basal ganglia dysfunctions, but the role of subthalamic nucleus (STN) neurons is not completely known. Drug-resistant motor symptoms of HD can be alleviated by neuromodulation of the basal ganglia through Deep Brain Stimulation (DBS) of STN. DBS target selection is supported by intra-operative microelectrode recordings (MER). MER have been previously used to characterize neural dynamics of STN in several movement disorders and can provide information on firing patterns underlying HD. MethodsWe analyzed MER data acquired during bilateral DBS of STN in a juvenile HD female patient with hypokinetic motor symptoms (generalized dystonia, stiffness, and severe gait impairment). Firing patterns of STN in HD were characterized by isolating single neuron activities (n = 23) and measuring their regularity, bursting, and oscillatory behavior. Multi-unit activity recordings spectrum was used to estimate the presence of network oscillations. ResultsSTN neurons displayed irregular dynamics and intense and sparse bursting. Only 3/23 neurons presented oscillatory activity. However, network oscillations were detected, in particular in the beta (12–30 Hz) band. After bilateral STN-DBS surgery, the Unified Huntington's Disease Rating Scale decreased from 60 to 54. ConclusionsThe most salient difference between HD and other movement disorders in STN activity is the presence of a weakly synchronized oscillatory mode, in which oscillations are evident at the network level but not at the single neuron level.

Frameless Robot-Assisted Asleep Centromedian Thalamic Nucleus Deep Brain Stimulation Surgery in Patients with Drug-Resistant Epilepsy: Technical Description and Short-Term Clinical Results.

This purpose of this work is to give a detailed description of a surgical technique for frameless robot-assisted asleep deep brain stimulation (DBS) of the centromedian thalamic nucleus (CMT) in drug-resistant epilepsy (DRE). Ten consecutively enrolled patients who underwent CMT-DBS were included in the study. The FreeSurfer "Thalamic Kernel Segmentation" module and experience target coordinates were used for locating the CMT, and quantitative susceptibility mapping (QSM) images were used to check the target. The patient's head was secured with a head clip, and electrode implantation was performed with the assistance of the neurosurgical robot Sinovation®. After opening the dura, the burr hole was continuously flushed with physiological saline to stop air from entering the skull. All procedures were performed under general anesthesia without intraoperative microelectrode recording (MER). The mean age of the patients at surgery and onset of seizures was 22years (range 11-41years) and 11years (range 1-21years), respectively. The median duration of seizures before CMT-DBS surgery was 10years (2-26years). CMT was successfully segmented, and its position was verified by experience target coordinates and QSM images in all ten patients. The mean surgical time for bilateral CMT-DBS in this cohort was 165 ± 18min. The mean pneumocephalus volume was 2 cm3. The median absolute errors in the x-, y-, and z-axes were 0.7mm, 0.5mm, and 0.9mm, respectively. The median Euclidean distance (ED) and radial error (RE) was 1.3 ± 0.5mm and 1.0 ± 0.3mm, respectively. No significant difference was found between right- and left-sided electrodes regarding the RE nor the ED. After a mean 12-month follow-up, the average reduction in seizures was 61%, and six patients experienced a ≥ 50% reduction in seizures, including one patient who had no seizures after the operation. All patients tolerated the anesthesia operation, and no permanent or serious complications were reported. Frameless robot-assisted asleep surgery is a precise and safe approach for placing CMT electrodes in patients with DRE, shortening the surgery time. The segmentation of the thalamic nuclei enables the precise location of the CMT, and the flow of physiological saline to seal the burr holes is a good way to reduce the influx of air. CMT-DBS is an effective method to reduce seizures.

Intraoperative microelectrode recording under general anesthesia guided subthalamic nucleus deep brain stimulation for Parkinson's disease: One institution's experience.

Microelectrode recording (MER) guided subthalamic nucleus deep brain stimulation (STN-DBS) under local anesthesia (LA) is widely applied in the management of advanced Parkinson's disease (PD). Whereas, awake DBS under LA is painful and burdensome for PD patients. We analyzed the influence of general anesthesia (GA) on intraoperative MER, to assess the feasibility and effectiveness of GA in MER guided STN-DBS. Retrospective analysis was performed on the PD patients, who underwent bilateral MER guided STN-DBS in Wuhan Union Hospital from July 2019 to December 2021. The patients were assigned to LA or GA group according to the anesthetic methods implemented. Multidimensional parameters, including MER signals, electrode implantation accuracy, clinical outcome and adverse events, were analyzed. A total of 40 PD patients were enrolled in this study, including 18 in LA group and 22 in GA group. There were no statistically significant differences in patient demographics and baseline characteristics between two groups. Although, the parameters of MER signal, including frequency, inter-spike interval (ISI) and amplitude, were obviously interfered under GA, the waveforms of MER signals were recognizable and shared similar characteristics with LA group. Both LA and GA could achieve effective electrode implantation accuracy and clinical outcome. They also shared similar adverse events postoperatively. GA is viable and comparable to LA in MER guided STN-DBS for PD, regarding electrode implantation accuracy, clinical outcome and adverse events. Notably, GA is more friendly and acceptable to the patients who are incapable of enduring intraoperative MER under LA.

Profiling the low-beta characteristics of the subthalamic nucleus in early- and late-onset Parkinson's disease.

Low-beta oscillation (13-20 Hz) has rarely been studied in patients with early-onset Parkinson's disease (EOPD, age of onset ≤50 years). We aimed to explore the characteristics of low-beta oscillation in the subthalamic nucleus (STN) of patients with EOPD and investigate the differences between EOPD and late-onset Parkinson's disease (LOPD). We enrolled 31 EOPD and 31 LOPD patients, who were matched using propensity score matching. Patients underwent bilateral STN deep brain stimulation (DBS). Local field potentials were recorded using intraoperative microelectrode recording. We analyzed the low-beta band parameters, including aperiodic/periodic components, beta burst, and phase-amplitude coupling. We compared low-beta band activity between EOPD and LOPD. Correlation analyses were performed between the low-beta parameters and clinical assessment results for each group. We found that the EOPD group had lower aperiodic parameters, including offset (p = 0.010) and exponent (p = 0.047). Low-beta burst analysis showed that EOPD patients had significantly higher average burst amplitude (p = 0.016) and longer average burst duration (p = 0.011). Furthermore, EOPD had higher proportion of long burst (500-650 ms, p = 0.008), while LOPD had higher proportion of short burst (200-350 ms, p = 0.007). There was a significant difference in phase-amplitude coupling values between low-beta phase and fast high frequency oscillation (300-460 Hz) amplitude (p = 0.019). We found that low-beta activity in the STN of patients with EOPD had characteristics that varied when compared with LOPD, and provided electrophysiological evidence for different pathological mechanisms between the two types of PD. These differences need to be considered when applying adaptive DBS on patients of different ages.

Localization of deep brain stimulation trajectories via automatic mapping of microelectrode recordings to MRI

Objective. Suboptimal electrode placement during subthalamic nucleus deep brain stimulation (STN DBS) surgery may arise from several sources, including frame-based targeting errors and intraoperative brain shift. We present a computer algorithm that can accurately localize intraoperative microelectrode recording (MER) tracks on preoperative magnetic resonance imaging (MRI) in real-time, thereby predicting deviation between the surgical plan and the MER trajectories. Approach. Random forest (RF) modeling was used to derive a statistical relationship between electrophysiological features on intraoperative MER and voxel intensity on preoperative T2-weighted MR imaging. This model was integrated into a larger algorithm that can automatically localize intraoperative MER recording tracks on preoperative MRI in real-time. To verify accuracy, targeting error of both the planned intraoperative trajectory (‘planned’) and the algorithm-derived trajectory (‘calculated’) was estimated by measuring deviation from the final DBS lead location on postoperative high-resolution computed tomography (‘actual’). Main results. MR imaging and MERs were obtained from 24 STN DBS implant trajectories. The cross-validated RF model could accurately distinguish between gray and white matter regions along MER trajectories (AUC 0.84). When applying this model within the localization algorithm, the calculated MER trajectory estimate was found to be significantly closer to the actual DBS lead when compared to the planned trajectory recorded during surgery (1.04 mm vs 1.52 mm deviation, p < 0.002), with improvement shown in 19/24 cases (79%). When applying the algorithm to simulated DBS trajectory plans with randomized targeting error, up to 4 mm of error could be resolved to <2 mm on average (p < 0.0001). Significance. This work presents an automated system for intraoperative localization of electrodes during STN DBS surgery. This neuroengineering solution may enhance the accuracy of electrode position estimation, particularly in cases where high-resolution intraoperative imaging is not available.

Comparison of dural puncture and dural incision in deep brain stimulation surgery: A simple but worthwhile technique modification.

The accuracy of the deep brain stimulation (DBS) electrode placement is influenced by a myriad of factors, among which pneumocephalus and loss of cerebrospinal fluid that occurs with dural opening during the surgery are considered most important. This study aimed to describe an effective method for decreasing pneumocephalus by comparing its clinical efficacy between the two different methods of opening the dura. We retrospectively compared two different methods of opening the dura in 108 patients who underwent bilateral DBS surgery in our center. The dural incision group comprised 125 hemispheres (58 bilateral and 9 unilateral) and the dural puncture group comprised 91 (41 bilateral and 9 unilateral). The volume of intracranial air, dural opening time, intraoperative microelectrode recordings (MERs), postoperative electrode displacement, clinical efficacy, and complications were examined. Spearman correlation analysis was employed to identify factors associated with the volume of intracranial air and postoperative electrode displacement. The volume of intracranial air was significantly lower (0.35 cm3 vs. 5.90 cm3) and dural opening time was significantly shorter (11s vs. 35s) in the dural puncture group. The volume of intracranial air positively correlated with dural opening time. During surgery, the sensorimotor area was longer (2.47 ± 1.36 mm vs. 1.92 ± 1.42 mm) and MERs were more stable (81.82% vs. 47.73%) in the dural puncture group. Length of the sensorimotor area correlated negatively with the volume of intracranial air. As intracranial air was absorbed after surgery, significant anterior, lateral, and ventral electrode displacement occurred; the differences between the two groups were significant (total electrode displacement, 1.0mm vs. 1.4mm). Electrode displacement correlated positively with the volume of intracranial air. Clinical efficacy was better in the dural puncture group than the dural incision group (52.37% ± 16.18% vs. 43.93% ± 24.50%), although the difference was not significant. Our data support the hypothesis that opening the dura via puncture rather than incision when performing DBS surgery reduces pneumocephalus, shortens dural opening time, enables longer sensorimotor area and more stable MERs, minimizes postoperative electrode displacement, and may permit a better clinical efficacy.