Subthalamic Nucleus Activity Influences Sensory and Motor Cortex during Force Transduction.

The subthalamic nucleus (STN) is proposed to participate in pausing, or alternately, in dynamic scaling of behavioral responses, roles that have conflicting implications for understanding STN function in the context of deep brain stimulation (DBS) therapy. To examine the nature of event-related STN activity and subthalamic-cortical dynamics, we performed primary motor and somatosensory electrocorticography while subjects (n = 10) performed a grip force task during DBS implantation surgery. Phase-locking analyses demonstrated periods of STN-cortical coherence that bracketed force transduction, in both beta and gamma ranges. Event-related causality measures demonstrated that both STN beta and gamma activity predicted motor cortical beta and gamma activity not only during force generation but also prior to movement onset. These findings are consistent with the idea that the STN participates in motor planning, in addition to the modulation of ongoing movement. We also demonstrated bidirectional information flow between the STN and somatosensory cortex in both beta and gamma range frequencies, suggesting robust STN participation in somatosensory integration. In fact, interactions in beta activity between the STN and somatosensory cortex, and not between STN and motor cortex, predicted PD symptom severity. Thus, the STN contributes to multiple aspects of sensorimotor behavior dynamically across time.

GABA bouton subpopulations in the human dentate gyrus are differentially altered in mesial temporal lobe epilepsy.

Medically intractable temporal lobe epilepsy is a devastating disease, for which surgical removal of the seizure onset zone is the only known cure. Multiple studies have found evidence of abnormal dentate gyrus network circuitry in human mesial temporal lobe epilepsy (MTLE). Principal neurons within the dentate gyrus gate entorhinal input into the hippocampus, providing a critical step in information processing. Crucial to that role are GABA-expressing neurons, particularly parvalbumin (PV)-expressing basket cells (PVBCs) and chandelier cells (PVChCs), which provide strong, temporally coordinated inhibitory signals. Alterations in PVBC and PVChC boutons have been described in epilepsy, but the value of these studies has been limited due to methodological hurdles associated with studying human tissue. We developed a multilabel immunofluorescence confocal microscopy and a custom segmentation algorithm to quantitatively assess PVBC and PVChC bouton densities and to infer relative synaptic protein content in the human dentate gyrus. Using en bloc specimens from MTLE subjects with and without hippocampal sclerosis, paired with nonepileptic controls, we demonstrate the utility of this approach for detecting cell-type specific synaptic alterations. Specifically, we found increased density of PVBC boutons, while PVChC boutons decreased significantly in the dentate granule cell layer of subjects with hippocampal sclerosis compared with matched controls. In contrast, bouton densities for either PV-positive cell type did not differ between epileptic subjects without sclerosis and matched controls. These results may explain conflicting findings from previous studies that have reported both preserved and decreased PV bouton densities and establish a new standard for quantitative assessment of interneuron boutons in epilepsy.NEW & NOTEWORTHY A state-of-the-art, multilabel immunofluorescence confocal microscopy and custom segmentation algorithm technique, developed previously for studying synapses in the human prefrontal cortex, was modified to study the hippocampal dentate gyrus in specimens surgically removed from patients with temporal lobe epilepsy. The authors discovered that chandelier and basket cell boutons in the human dentate gyrus are differentially altered in mesial temporal lobe epilepsy.

Inverse national trends of laser interstitial thermal therapy and open surgical procedures for refractory epilepsy: a Nationwide Inpatient Sample-based propensity score matching analysis.

OBJECTIVE: Surgery for medically refractory epilepsy (RE) is an underutilized treatment modality, despite its efficacy. Laser interstitial thermal therapy (LITT), which is minimally invasive, is increasingly being utilized for a variety of brain lesions and offers comparable seizure outcomes. The aim of this study was to report the national trends of open surgical procedures for RE with the advent of LITT. METHODS: Data were extracted using the ICD-9/10 codes from the Nationwide Inpatient Sample (NIS, 2012-2016) in this retrospective study. Patients with a primary diagnosis of RE who underwent either open surgeries (lobectomy, partial lobectomy, and amygdalohippocampectomy) or LITT were included. Patient demographics, complications, hospital length of stay (LOS), discharge disposition, and index hospitalization costs were analyzed. Propensity score matching (PSM) was used to analyze outcomes. RESULTS: A cohort of 128,525 in-hospital patients with RE was included and 5.5% (n = 7045) of these patients underwent either open surgical procedures (94.3%) or LITT (5.7%). LITT is increasingly being performed at a rate of 1.09 per 1000 epilepsy admissions/year, while open surgical procedures are decreasing at a rate of 10.4/1000 cases/year. The majority of procedures were elective (92%) and were performed at large-bed-size hospitals (86%). All LITT procedures were performed at teaching facilities and the majority were performed in the South (37%) and West (30%) regions. The median LOS was 1 day for the LITT cohort and 4 days for the open cohort. Index hospitalization charges were significantly lower following LITT compared to open procedures ($108,332 for LITT vs $124,012 for open surgery, p < 0.0001). LITT was associated with shorter median LOS, high likelihood of discharge home, and lower median index hospitalization charges compared to open procedures for RE on PSM analysis. CONCLUSIONS: LITT is increasingly being performed in favor of open surgical procedures. LITT is associated with a shorter LOS, a higher likelihood of being discharged home, and lower index hospitalization charges compared to open procedures. LITT is a safe treatment modality in carefully selected patients with RE and offers an opportunity to increase the utilization of surgical treatment in patients who may be opposed to open surgery or have contraindications that preclude open surgery.

Subthalamic Nucleus Neurons Differentially Encode Early and Late Aspects of Speech Production.

Basal ganglia-thalamocortical loops mediate all motor behavior, yet little detail is known about the role of basal ganglia nuclei in speech production. Using intracranial recording during deep brain stimulation surgery in humans with Parkinson's disease, we tested the hypothesis that the firing rate of subthalamic nucleus neurons is modulated in sync with motor execution aspects of speech. Nearly half of 79 unit recordings exhibited firing-rate modulation during a syllable reading task across 12 subjects (male and female). Trial-to-trial timing of changes in subthalamic neuronal activity, relative to cue onset versus production onset, revealed that locking to cue presentation was associated more with units that decreased firing rate, whereas locking to speech onset was associated more with units that increased firing rate. These unique data indicate that subthalamic activity is dynamic during the production of speech, reflecting temporally-dependent inhibition and excitation of separate populations of subthalamic neurons.SIGNIFICANCE STATEMENT The basal ganglia are widely assumed to participate in speech production, yet no prior studies have reported detailed examination of speech-related activity in basal ganglia nuclei. Using microelectrode recordings from the subthalamic nucleus during a single-syllable reading task, in awake humans undergoing deep brain stimulation implantation surgery, we show that the firing rate of subthalamic nucleus neurons is modulated in response to motor execution aspects of speech. These results are the first to establish a role for subthalamic nucleus neurons in encoding of aspects of speech production, and they lay the groundwork for launching a modern subfield to explore basal ganglia function in human speech.

Insights into complication rates, reoperation rates, and healthcare utilization associated with use of recombinant human bone morphogenetic protein-2 in patients with spine infections.

OBJECTIVEUse of recombinant human bone morphogenetic protein-2 (rhBMP-2) in patients with spine infections is controversial. The purpose of this study was to identify long-term complications, reoperations, and healthcare utilization associated with rhBMP-2 use in patients with spine infections.METHODSThis retrospective study extracted data using ICD-9/10 and CPT codes from MarketScan (2000-2016). Patients were dichotomized into 2 groups (rhBMP-2, no rhBMP-2) based on whether rhBMP-2 was used during fusion surgery for spinal infections. Outcomes of interest were reoperation rates (index level, other levels), readmission rates, discharge disposition, length of stay, complications, and healthcare resource utilization at the index hospitalization and 1, 3, 6, 12, and 24 months following discharge. Outcomes were compared using nonparametric 2-group tests and generalized linear regression models.RESULTSThe database search identified 2762 patients with > 24 months' follow-up; rhBMP-2 was used in 8.4% of their cases. The patients' median age was 53 years, 52.43% were female, and 15.11% had an Elixhauser Comorbidity Index ≥ 3. Patients in the rhBMP-2 group had higher comorbidity indices, incurred higher costs at index hospitalization, were discharged home in most cases, and had lower complication rates than those in the no-rhBMP-2 group. There was no statistically significant between-groups difference in complication rates 1 month following discharge or in reoperation rates at 3, 6, 12, and 24 months following the procedure. Patients in the no-rhBMP-2 group incurred higher utilization of outpatient services and medication refill costs at 1, 3, 6, 12, and 24 months following surgery.CONCLUSIONSIn patients undergoing surgery for spine infection, rhBMP-2 use was associated with lower complication rates and higher median payments during index hospitalization compared to cases in which rhBMP-2 was not used. There was no significant between-groups difference in reoperation rates (index and other levels) at 3, 6, 12, and 24 months after the index operation. Patients treated with rhBMP-2 incurred lower utilization of outpatient services and overall payments. These results indicate that rhBMP-2 can be used safely in patients with spine infections with cost-effective utilization of healthcare resources and without an increase in complications or reoperation rates.

Management trends for anaplastic meningioma with adjuvant radiotherapy and predictors of long-term survival.

OBJECTIVEThe purpose of this study was to describe effects of adjuvant radiotherapy (RT) for anaplastic meningiomas (AMs) on long-term survival, and to analyze patient and RT characteristics associated with long-term survival.METHODSThe authors queried a retrospective cohort of patients with AM from the National Cancer Database (NCDB) diagnosed between 2004 and 2015 to describe treatment trends. For outcome analysis, patients with at least 10 years of follow-up were included, and they were stratified based on adjuvant RT status and propensity matched to controls for covariates. Survival curves were compared. A data-driven approach was used to find a biologically effective dose (BED) of RT with the largest difference between survival curves. Factors associated with long-term survival were quantified.RESULTSThe authors identified 2170 cases of AM in the NCDB between 2004 and 2015. They observed increased use of adjuvant RT in patients treated with higher doses. A total of 178 cases met the inclusion criteria for outcome analysis. Forty-five percent (n = 80) received adjuvant RT. Patients received a BED of 80.23 ± 16.6 Gy (mean ± IQR). The median survival time was not significantly different (32.8 months for adjuvant RT vs 38.5 months for no RT; p = 0.57, log-rank test). Dichotomizing the patients at a BED of 81 Gy showed maximal difference in survival distribution with a decrease in median survival in favor of no adjuvant RT (31.2 months for adjuvant RT vs 49.7 months for no RT; p = 0.03, log-rank test), but this difference was not significant after false discovery rate correction. Age was a significant predictor for long-term survival.CONCLUSIONSAMs are aggressive tumors that carry a poor prognosis. Conventional adjuvant RT improves local control. However, the effect of adjuvant radiation on overall survival is unclear. Further investigation into this area is warranted.

Outcomes of decompression and fusion for treatment of spinal infection

Objective: Spine infection including vertebral osteomyelitis, discitis, paraspinal musculoskeletal infection, and spinal abscess refractory to medical management poses significant challenges to the treating physician. Surgical management is often required in patients suffering neurological deficits or spinal deformity with significant pain. To date, best practices have not been elucidated for the optimization of health outcomes and resource utilization in the setting of surgical intervention for spinal infection. The authors conducted the present study to assess the magnitude of reoperation rates in both fusion and nonfusion groups as well as overall health resource utilization following surgical decompression for spine infection. Methods: The authors performed an analysis using MarketScan (2001­2015) to identify health outcomes and healthcare utilization metrics of spine infection following surgical intervention with decompression alone or combined with fusion. Adult patients underwent surgical management for primary or secondary spinal infection and were followed up for at least 12 months postoperatively. Assessed outcomes included reoperation, healthcare utilization and payment at the index hospitalization and within 12 months after discharge, postoperative complications, and infection recurrence. Results: A total of 2662 patients in the database were eligible for inclusion in this study. Rehospitalization for infection was observed in 3.99% of patients who had undergone fusion and in 11.25% of those treated with decompression alone. Reoperation was needed in 12.7% of the patients without fusion and 8.16% of those with fusion. Complications within 30 days were more common in the nonfusion group (24.64%) than in the fusion group (16.49%). Overall postoperative payments after 12 months totaled $33,137 for the nonfusion group and $23,426 for the fusion group. Conclusions: In this large cohort study with a 12-month follow-up, the recurrence of infection, reoperation rates, and complications were higher in patients treated with decompression alone than in those treated with decompression plus fusion. These findings along with imaging characteristics, disease severity, extent of bony resection, and the presence of instability may help surgeons decide whether to include fusion at the time of initial surgery. Further studies that control for selection bias in appropriately matched cohorts are necessary to determine the additive benefits of fusion in spinal infection management.

Variability in the utility of predictive models in predicting patient-reported outcomes following spine surgery for degenerative conditions: a systematic review.

OBJECTIVEThere is increasing emphasis on patient-reported outcomes (PROs) to quantitatively evaluate quality outcomes from degenerative spine surgery. However, accurate prediction of PROs is challenging due to heterogeneity in outcome measures, patient characteristics, treatment characteristics, and methodological characteristics. The purpose of this study was to evaluate the current landscape of independently validated predictive models for PROs in elective degenerative spinal surgery with respect to study design and model generation, training, accuracy, reliability, variance, and utility.METHODSThe authors analyzed the current predictive models in PROs by performing a search of the PubMed and Ovid databases using PRISMA guidelines and a PICOS (participants, intervention, comparison, outcomes, study design) model. They assessed the common outcomes and variables used across models as well as the study design and internal validation methods.RESULTSA total of 7 articles met the inclusion criteria, including a total of 17 validated predictive models of PROs after adult degenerative spine surgery. National registry databases were used in 4 of the studies. Validation cohorts were used in 2 studies for model verification and 5 studies used other methods, including random sample bootstrapping techniques. Reported c-index values ranged from 0.47 to 0.79. Two studies report the area under the curve (0.71-0.83) and one reports a misclassification rate (9.9%). Several positive predictors, including high baseline pain intensity and disability, demonstrated high likelihood of favorable PROs.CONCLUSIONSA limited but effective cohort of validated predictive models of spine surgical outcomes had proven good predictability for PROs. Instruments with predictive accuracy can enhance shared decision-making, improve rehabilitation, and inform best practices in the setting of heterogeneous patient characteristics and surgical factors.

Dynamics of human subthalamic neuron phase-locking to motor and sensory cortical oscillations during movement.

Coupled oscillatory activity recorded between sensorimotor regions of the basal ganglia-thalamocortical loop is thought to reflect information transfer relevant to movement. A neuronal firing-rate model of basal ganglia-thalamocortical circuitry, however, has dominated thinking about basal ganglia function for the past three decades, without knowledge of the relationship between basal ganglia single neuron firing and cortical population activity during movement itself. We recorded activity from 34 subthalamic nucleus (STN) neurons, simultaneously with cortical local field potentials and motor output, in 11 subjects with Parkinson's disease (PD) undergoing awake deep brain stimulator lead placement. STN firing demonstrated phase synchronization to both low- and high-beta-frequency cortical oscillations, and to the amplitude envelope of gamma oscillations, in motor cortex. We found that during movement, the magnitude of this synchronization was dynamically modulated in a phase-frequency-specific manner. Importantly, we found that phase synchronization was not correlated with changes in neuronal firing rate. Furthermore, we found that these relationships were not exclusive to motor cortex, because STN firing also demonstrated phase synchronization to both premotor and sensory cortex. The data indicate that models of basal ganglia function ultimately will need to account for the activity of populations of STN neurons that are bound in distinct functional networks with both motor and sensory cortices and code for movement parameters independent of changes in firing rate.NEW & NOTEWORTHY Current models of basal ganglia-thalamocortical networks do not adequately explain simple motor functions, let alone dysfunction in movement disorders. Our findings provide data that inform models of human basal ganglia function by demonstrating how movement is encoded by networks of subthalamic nucleus (STN) neurons via dynamic phase synchronization with cortex. The data also demonstrate, for the first time in humans, a mechanism through which the premotor and sensory cortices are functionally connected to the STN.

Movement-related dynamics of cortical oscillations in Parkinson's disease and essential tremor.

Recent electrocorticography data have demonstrated excessive coupling of beta-phase to gamma-amplitude in primary motor cortex and that deep brain stimulation facilitates motor improvement by decreasing baseline phase-amplitude coupling. However, both the dynamic modulation of phase-amplitude coupling during movement and the general cortical neurophysiology of other movement disorders, such as essential tremor, are relatively unexplored. To clarify the relationship of these interactions in cortical oscillatory activity to movement and disease state, we recorded local field potentials from hand sensorimotor cortex using subdural electrocorticography during a visually cued, incentivized handgrip task in subjects with Parkinson's disease (n = 11), with essential tremor (n = 9) and without a movement disorder (n = 6). We demonstrate that abnormal coupling of the phase of low frequency oscillations to the amplitude of gamma oscillations is not specific to Parkinson's disease, but also occurs in essential tremor, most prominently for the coupling of alpha to gamma oscillations. Movement kinematics were not significantly different between these groups, allowing us to show for the first time that robust alpha and beta desynchronization is a shared feature of sensorimotor cortical activity in Parkinson's disease and essential tremor, with the greatest high-beta desynchronization occurring in Parkinson's disease and the greatest alpha desynchronization occurring in essential tremor. We also show that the spatial extent of cortical phase-amplitude decoupling during movement is much greater in subjects with Parkinson's disease and essential tremor than in subjects without a movement disorder. These findings suggest that subjects with Parkinson's disease and essential tremor can produce movements that are kinematically similar to those of subjects without a movement disorder by reducing excess sensorimotor cortical phase-amplitude coupling that is characteristic of these diseases.

Three-dimensional localization of cortical electrodes in deep brain stimulation surgery from intraoperative fluoroscopy.

Electrophysiological recordings from subdural electrocorticography (ECoG) electrodes implanted temporarily during deep brain stimulation (DBS) surgeries offer a unique opportunity to record cortical activity for research purposes. The optimal utilization of this important research method relies on accurate and robust localization of ECoG electrodes, and intraoperative fluoroscopy is often the only imaging modality available to visualize electrode locations. However, the localization of a three-dimensional electrode position using a two-dimensional fluoroscopic image is problematic due to the lost dimension orthogonal to the fluoroscopic image, a parallax distortion implicit to fluoroscopy, and variability of visible skull contour among fluoroscopic images. Here, we present a method to project electrodes visible on the fluoroscopic image onto a reconstructed cortical surface by leveraging numerous common landmarks to translate, rotate, and scale coregistered computed tomography (CT) and magnetic resonance imaging (MRI) reconstructed surfaces in order to recreate the coordinate framework in which the fluoroscopic image was acquired, while accounting for parallax distortion. Validation of this approach demonstrated high precision with an average total Euclidian distance between three independent reviewers of 1.65±0.68mm across 8 patients and 82 electrodes. Spatial accuracy was confirmed by correspondence between recorded neural activity over sensorimotor cortex during hand movement. This semi-automated interface reliably estimates the location of temporarily implanted subdural ECoG electrodes visible on intraoperative fluoroscopy to a cortical surface.

Magnetoencephalography-based identification of functional connectivity network disruption following mild traumatic brain injury.

Mild traumatic brain injury (mTBI) leads to long-term cognitive sequelae in a significant portion of patients. Disruption of normal neural communication across functional brain networks may explain the deficits in memory and attention observed after mTBI. In this study, we used magnetoencephalography (MEG) to examine functional connectivity during a resting state in a group of mTBI subjects (n = 9) compared with age-matched control subjects (n = 15). We adopted a data-driven, exploratory analysis in source space using phase locking value across different frequency bands. We observed a significant reduction in functional connectivity in band-specific networks in mTBI compared with control subjects. These networks spanned multiple cortical regions involved in the default mode network (DMN). The DMN is thought to subserve memory and attention during periods when an individual is not engaged in a specific task, and its disruption may lead to cognitive deficits after mTBI. We further applied graph theoretical analysis on the functional connectivity matrices. Our data suggest reduced local efficiency in different brain regions in mTBI patients. In conclusion, MEG can be a potential tool to investigate and detect network alterations in patients with mTBI. The value of MEG to reveal potential neurophysiological biomarkers for mTBI patients warrants further exploration.

Network effects of deep brain stimulation.

The ability to differentially alter specific brain functions via deep brain stimulation (DBS) represents a monumental advance in clinical neuroscience, as well as within medicine as a whole. Despite the efficacy of DBS in the treatment of movement disorders, for which it is often the gold-standard therapy when medical management becomes inadequate, the mechanisms through which DBS in various brain targets produces therapeutic effects is still not well understood. This limited knowledge is a barrier to improving efficacy and reducing side effects in clinical brain stimulation. A field of study related to assessing the network effects of DBS is gradually emerging that promises to reveal aspects of the underlying pathophysiology of various brain disorders and their response to DBS that will be critical to advancing the field. This review summarizes the nascent literature related to network effects of DBS measured by cerebral blood flow and metabolic imaging, functional imaging, and electrophysiology (scalp and intracranial electroencephalography and magnetoencephalography) in order to establish a framework for future studies.

Coagulopathy in Penetrating Ballistic Cranial Trauma: A 7-Year Experience.

BACKGROUND AND OBJECTIVES: Penetrating ballistic cranial trauma (PBCT) carries significant mortality when compared with blunt trauma. The development of coagulopathy in PBCT is a strong predictor of mortality. The goal of the study was to describe the incidence and risk factors of coagulopathy in PBCT and to report the value of tranexamic acid administration in PBCT. METHODS: We retrospectively analyzed 270 patients who presented with PBCT to a single, Level 1 trauma center between 2016 and 2023. RESULTS: A total of 47% (127/270) of patients with PBCT developed coagulopathy at presentation. Fifty-seven patients received tranexamic acid at presentation, which did not affect the development of coagulopathy. Coagulopathic patients were more likely to have more serious injury patterns (bihemispheric [adjusted odds ratio, aOR: 2.6 CI: 1.4-4.9, P = .004] or transventricular trajectories [aOR: 4.9 CI: 1.9-19.6, P = .03]). In addition, they presented with a larger base deficit (aOR: 0.9 CI: 1.002-1.2 per mEq/L, P = .006) which negatively correlated with the international normalized ratio (ρ: -0.46, P < .0001, Spearman correlation). Using thromboelastography helped to identify an additional 20% of patients who presented with normal coagulation on conventional testing. CONCLUSION: Coagulopathy is prevalent in approximately 50% of patients with PBCT and is persistent despite treatment in a substantial subset of patients. The addition of thromboelastography with its increased coagulopathy sensitivity can potentially guide treatment more efficiently than traditional coagulopathy laboratory tests and fibrinogen alone. Patients with a significant base deficit on arterial blood gas are at higher risk for coagulopathy.

Morphometric Study of the Posterior Fossa: Identification of Practical Parameters for Tailored Selection of Surgical Routes to the Petroclival Region.

Introduction The petroclival region is an integral part of the skull base. It can harbor different pathologies and provides access to the petroclival junction and cerebellopontine angle. We present the results of the morphometric analysis of the posterior fossa and a prediction model to enable skull base surgeons to choose an optimal surgical corridor considering patient's bony anatomy. Methods Ninety patients (14 to assess interobserver reliability) with temporal bone computed tomography were selected. Exclusion criteria included patients <18 years of age, radiographic evidence of trauma, infection, or previous surgery. The images were analyzed using OsiriX MD (Bernex, Switzerland). We recorded clival length, vertical angle, and surface area, and petroclival angle, petrous apex, and translabyrinthine corridors volume. Results The average age was 49.5 years (55%) for males. The mean clival length and surface areas were 44.2 mm (standard deviation [SD] ± 4.1) and 8.1 cm 2 (SD ± 1.3). The mean petrous apex and translabyrinthine corridors volumes were 2.2 cm 3 (SD ± 0.6) and 10.1 cm 3 (SD ± 3.7). The mean petroclival angle at the internal auditory canal (IAC) was 154.9 degrees (SD ± 9). The clival length correlated positively with clival surface area (rho = 0.6, p <0.05), petrous apex volume (rho = 0.3, p < 0.05), and translabyrinthine volume (rho = 0.3, p < 0.05). Conclusion The petroclival region is complex and with high variability of surgical significance. The use of preoperative measurements of the clival length and petroclival angle as part of surgical planning that could help the surgeon to choose an optimal surgical corridor by overcoming the anatomical variability elements.

Developing Predictor Models of Postoperative Verbal Fluency After Deep Brain Stimulation Using Preoperative Neuropsychological Assessment.

BACKGROUND: Deep brain stimulation (DBS) for Parkinson disease provides significant improvement of motor symptoms but can also produce neurocognitive side effects. A decline in verbal fluency (VF) is among the most frequently reported side effects. Preoperative factors that could predict VF decline have yet to be identified. OBJECTIVE: To develop predictive models of DBS postoperative VF decline using a machine learning approach. METHODS: We used a prospective database of patients who underwent neuropsychological and VF assessment before both subthalamic nucleus (n = 47, bilateral = 44) and globus pallidus interna (n = 43, bilateral = 39) DBS. We used a neurobehavioral rating profile as features for modeling postoperative VF. We constructed separate models for action, semantic, and letter VF. We used a leave-one-out scheme to test the accuracy of the predictive models using median absolute error and correlation with actual postoperative scores. RESULTS: The predictive models were able to predict the 3 types of VF with high accuracy ranging from a median absolute error of 0.92 to 1.36. Across all three models, higher preoperative fluency, digit span, education, and Mini-Mental State Examination were predictive of higher postoperative fluency scores. By contrast, higher frontal system deficits, age, Questionnaire for Impulsive-Compulsive Disorders in Parkinson's disease scored by the patient, disease duration, and Behavioral Inhibition/Behavioral Activation Scale scores were predictive of lower postoperative fluency scores. CONCLUSION: Postoperative VF can be accurately predicted using preoperative neurobehavioral rating scores above and beyond preoperative VF score and relies on performance over different aspects of executive function.

Effects of deep brain stimulation target on the activation and suppression of action impulses.

OBJECTIVE: Deep brain stimulation (DBS) is an effective treatment to improve motor symptoms in Parkinson's disease (PD). The Globus Pallidus (GPi) and the Subthalamic Nucleus (STN) are the most targeted brain regions for stimulation and produce similar improvements in PD motor symptoms. However, our understanding of stimulation effects across targets on inhibitory action control processes is limited. We compared the effects of STN (n = 20) and GPi (n = 13) DBS on inhibitory control in PD patients. METHODS: We recruited PD patients undergoing DBS at the Vanderbilt Movement Disorders Clinic and measured their performance on an inhibitory action control task (Simon task) before surgery (optimally treated medication state) and after surgery in their optimally treated state (medication plus their DBS device turned on). RESULTS: DBS to both STN and GPi targets induced an increase in fast impulsive errors while simultaneously producing more proficient reactive suppression of interference from action impulses. CONCLUSIONS: Stimulation in GPi produced similar effects as STN DBS, indicating that stimulation to either target increases the initial susceptibility to act on strong action impulses while concomitantly improving the ability to suppress ongoing interference from activated impulses. SIGNIFICANCE: Action impulse control processes are similarly impacted by stimulating dissociable nodes in frontal-basal ganglia circuitry.

Preoperative and Postoperative Opioid Dependence in Patients Undergoing Anterior Cervical Diskectomy and Fusion for Degenerative Spinal Disorders.

BACKGROUND: Anterior cervical diskectomy and fusion (ACDF) is a procedure for effectively relieving radiculopathy. Opioids are commonly overprescribed in postsurgical settings and prescriptions vary widely among providers. We identify trends in opioid dependence before and after ACDF. METHODS: We used the Truven Health MarketScan data to identify adult patients undergoing ACDF for degenerative cervical spine conditions between 2009 and 2015. Patients were segregated in four cohorts of preoperative and postoperative opioid nondependence (ND) or dependence (D) with 15 months of postoperative follow-up. RESULTS: A total of 25,403 patients with median age of 52 years (18-92) who underwent ACDF met the inclusion criteria. Breakdown of the four cohorts was as follows: prior nondependent who remain nondependent (NDND): 62.76% (n = 15,944); prior nondependent who become dependent (NDD): 4.6% (n = 1,168); prior dependent who become nondependent (DND): 14.03% (n = 3,564); and prior dependent who remain dependent (DD): 18.61% (n = 4,727). Opioid dependence decreased 9.43% postoperatively. Overall payments and 30-day readmissions increased 1.96 and 1.79 times for opioid dependent versus nondependent cohorts, respectively. Adjusted payments at 3 to 15 months were significantly increased for dependent cohorts with 3.56-fold increase for the DD cohort when compared with the NDND cohort. Length of stay, complications, medication refills, outpatient measures, and hospital admissions were also higher in those groups with postoperative opioid dependence when compared with those who were not opioid dependent. CONCLUSIONS: Opioid dependence after ACDF is associated with increased hospital readmissions, complication rates at 30 days, and payments within 3 months and 3 to 15 months postdischarge. Overall opioid dependence was decreased after ACDF procedure, however, a smaller number of opioid-dependent and opioid-naive patients became dependent postoperatively and should be followed carefully.

Trends in the Management Paradigms of Intracranial Meningioma.

Objective Intracranial meningiomas are the most common primary brain tumor. Treatment paradigms have evolved over time. There are limited number of population-based studies that examine this modern evolution. Here, we describe the trends of management of intracranial meningiomas using a national database. Methods The data were obtained from the National Cancer Database for the years 2004 to 2015, the collected variables included: patients' age, gender, insurance type, income, comorbidity score, the tumor size and grade, and treatment modality (observation, surgery, radiotherapy, or combination therapy). We performed statistical analyses to detect association between unique variables and outcomes. In addition, we performed mortality analyses for various treatment modalities. Results A total of 199,096 patients with a diagnosis of intracranial meningioma were included, the majority of patients were white females, mean age of 61 years, and half of the tumors were ≤ 3 cm. Observation was the most commonly used management modality followed by surgical resection, radiotherapy, and combination therapy. For the entire time period, there was an increased use of observation as a primary management method. Predictors of mortality included increased age, larger tumor size, higher tumor grade, treatment at a community hospital, and higher comorbidity scores. Conclusion Population-based studies of intracranial meningiomas are uncommon; our study is one of the few reports that examine the changes in the modern management paradigms of meningioma in the United States over time. Additionally, we shed light on the factors that affected survival of patients with this condition.

Evaluation of Predictive Models for Complications following Spinal Surgery.

BACKGROUND: Complications rates vary across spinal surgery procedures and are difficult to predict due to heterogeneity in patient characteristics, surgical methods, and hospital volume. Incorporation of predictive models for complications may guide surgeon decision making and improve outcomes. METHODS: We evaluate current independently validated predictive models for complications in spinal surgery with respect to study design and model generation, accuracy, reliability, and utility. We conducted our search using Preferred Reporting Items for Systematic Review and Meta-analysis guidelines and the Participants, Intervention, Comparison, Outcomes, Study Design model through the PubMed and Ovid Medline databases. RESULTS: A total of 18 articles met inclusion criteria including 30 validated predictive models of complications after adult spinal surgery. National registry databases were used in 12 studies. Validation cohorts were used in seven studies for verification; three studies used other methods including random sample bootstrapping techniques or cross-validation. Reported area under the curve (AUC) values ranged from 0.37 to 1.0. Studies described treatment for deformity, degenerative conditions, inclusive spinal surgery (neoplasm, trauma, infection, deformity, degenerative), and miscellaneous (disk herniation, spinal epidural abscess). The most commonly cited risk factors for complications included in predictive models included age, body mass index, diabetes, sex, and smoking. Those models in the deformity subset that included radiographic and anatomical grading features reported higher AUC values than those that included patient demographics or medical comorbidities alone. CONCLUSIONS: We identified a cohort of 30 validated predictive models of complications following spinal surgery for degenerative conditions, deformity, infection, and trauma. Accurate evidence-based predictive models may enhance shared decision making, improve rehabilitation, reduce adverse events, and inform best practices.