Rehospitalization and emergency department use rates before and after vagus nerve stimulation for epilepsy: use of state databases to provide longitudinal data across multiple clinical settings.

OBJECTIVES: Data regarding rehospitalization and emergency department (ED) visits following vagus nerve stimulation (VNS) present data analysis challenges. We present a method that uses California's multiple databases to more completely assay VNS efficacy. MATERIALS AND METHODS: The Healthcare Cost and Utilization Project's California Inpatient and Ambulatory Surgery databases were assayed for all VNS surgeries from 2005 to 2009. Patients were selected by epilepsy diagnosis codes and VNS procedure codes. Patients (total N = 629) were tracked across multiple databases using unique identifiers. Thirty-day and one-year post-implantation rates of VNS complication and healthcare visits were abstracted, along with one-year preoperative hospital and ED use. Statistics included correction for multiple comparisons. RESULTS: The one-year reoperation rate for adult patients (N = 536) was 3.9%; during the second year, an additional 3.2% of patients had reoperations. Within the first 30 days, <2% of patients experienced a complication. Four percent of patients were readmitted to a hospital, and 11.6% of patients visited an ED. The most common reason for rehospitalization or ED visit was seizure. In the first year after VNS, total seizure-related visits (hospitalization and ED) were 17% lower (2.12 visits per year to 1.71; p = 0.03). In the second year following VNS, seizure-related visits were 42% lower (2.21 visits per year to 1.27, p = 0.01). Pediatric patients (N = 93) had comparable results. CONCLUSIONS: VNS surgery has low rates of complications and reoperations and is associated with reduced incidence of seizure-related ED visits and hospital admissions in the first and second postoperative years.

Optogenetic neuromodulation.

The recent development of optogenetics, a revolutionary research tool in neuroscience, portends an evolution of current clinical neuromodulation tools. A form of gene therapy, optogenetics makes possible highly precise spatial and temporal control of specific neuronal populations. This technique has already provided several new insights relevant to clinical neuroscience, from the physiological substrate of functional magnetic resonance imaging to the mechanism of deep brain stimulation in Parkinson's disease. The increased precision of optogenetic techniques also raises the possibility of eventual human use. Translational efforts have begun in primates, with success reported from multiple labs in rhesus macaques. These developments will remain of ongoing interest to neurologists and neurosurgeons.

Venous thromboembolism after thoracic/thoracolumbar spinal fusion.

OBJECTIVE: Venous thromboembolism (VTE), which includes deep venous thrombosis and pulmonary embolism, is a serious and potentially fatal surgical complication. The goal of our study was to examine preoperative characteristics, incidence, and outcomes of patients with VTE after elective thoracic/thoracolumbar level spine fusion. METHODS: We identified 430,081 patients from the Nationwide Inpatient Sample database who underwent spinal fusion between 2002 and 2008. Patients undergoing thoracic/thoracolumbar level fusion (n = 8617) were found to have the greatest concurrent rate of VTE. We then performed multivariate analyses on this cohort to identify predictors of and outcomes after VTE in patients undergoing thoracic/thoracolumbar level fusion. RESULTS: The overall VTE rate in spinal fusion surgery was 0.40% (cervical = 0.22%, thoracic/thoracolumbar = 1.90%, lumbar/lumbosacral = 0.49%, re-fusions = 0.64%, and fusions not otherwise specified = 0.84%). On multivariate logistic regression analysis of patients undergoing spinal fusion at the thoracic/thoracolumbar level, increasing age, Medicare insurance coverage (vs. private insurance), urban teaching hospital (vs. urban nonteaching hospital), combined anterior/posterior surgical approach (vs. posterior-only approach), and the presence of congestive heart failure or weight loss (Elixhauser comorbidity groups) were each independently associated with an increased odds ratio of VTE complication. VTE after thoracic/thoracolumbar surgery was significantly associated with longer hospital stays (16.6 vs. 6.74 days), increased total hospital costs ($260,208 vs. $115,474), and increased mortality (4.33% vs. 0.33%). CONCLUSIONS: Multivariate logistic regression analysis reveals age, insurance status, hospital type, combined anterior/posterior surgical approach, and the presence of congestive heart failure or weight loss to be independently associated with an increased odds ratio of VTE complication. This complication is associated with increased hospital costs, length of stay, and overall mortality.

Impact of age, injury severity score, and medical comorbidities on early complications after fusion and halo-vest immobilization for C2 fractures in older adults: a propensity score matched retrospective cohort study.

STUDY DESIGN: Propensity score matched retrospective cohort study. OBJECTIVE: To report early complication rates and associated risk factors in patients with C2 fractures who underwent fusion or halo immobilization. SUMMARY OF BACKGROUND DATA: There is limited data on the impact of age, injury severity score, and medical comorbidities on overall complication rates from surgical fixation versus halo-vest immobilization of C2 fractures. METHODS: The Nationwide Inpatient Sample database from 2002 to 2008 was queried to identify cohorts of adult patients (age ≥ 18 years) with C2 fractures without spinal cord injury who were treated with either fusion or halo-vest immobilization. Complication rates, hospital length of stay, and costs were compared in a propensity score matched sample. Multivariate analysis was used to identify predictors of in-hospital complications. RESULTS: A total of 3758 patients (1627 fusion and 2131 halo) were identified. Fusion was associated with greater overall complication rates (20.2% vs. 10.1%, P < 0.0001), increased length of stay (8.9 d vs. 6.4 d, P < 0.0001), higher charges ($80,000 vs. $41,000, P < 0.0001), but a lower rate of nonroutine discharge (52.6% vs. 62.6%, P < 0.0001). There was no difference in mortality between the fusion group (2.75%) and the halo group (3.33%). Age, injury score, and comorbidity increased complication rates by a similar degree (odds ratio) in both cohorts. Patients aged 80 years and older were 3.5 times more likely to have a complication than those younger than 60 years. CONCLUSION: Fusion patients had greater overall complication rates, increased length of stay, and greater resource utilization but were discharged home in a greater proportion. Both fusion and halo were associated with significant (more than 3-fold) increase in complication rates in elderly patients aged 80 years or older. Given the similar mortality rate between the fusion group and the halo group and the higher cost and complication rate in the fusion group, our study supports the use of halo-vest immobilization in patients where operative therapy is contraindicated.

Morbidity and mortality of C2 fractures in the elderly: surgery and conservative treatment.

BACKGROUND: Closed C2 fractures commonly occur after falls or other trauma in the elderly and are associated with significant morbidity and mortality. Controversy exists as to best treatment practices for these patients. OBJECTIVE: To compare outcomes for elderly patients with closed C2 fractures by treatment modality. METHODS: We retrospectively reviewed 28 surgically and 28 nonsurgically treated cases of closed C2 fractures without spinal cord injury in patients aged 65 years of age or older treated at Stanford Hospital between January 2000 and July 2010. Comorbidities, fracture characteristics, and treatment details were recorded; primary outcomes were 30-day mortality and complication rates; secondary outcomes were length of hospital stay and long-term survival. RESULTS: Surgically treated patients tended to have more severe fractures with larger displacement. Charlson comorbidity scores were similar in both groups. Thirty-day mortality was 3.6% in the surgical group and 7.1% in the nonsurgical group, and the 30-day complication rates were 17.9% and 25.0%, respectively; these differences were not statistically significant. Surgical patients had significantly longer lengths of hospital stay than nonsurgical patients (11.8 days vs 4.4 days). Long-term median survival was not significantly different between groups. CONCLUSION: The 30-day mortality and complication rates in surgically and nonsurgically treated patients were comparable. Elderly patients faced relatively high morbidity and mortality regardless of treatment modality; thus, age alone does not appear to be a contraindication to surgical fixation of C2 fractures.

Decreased number of parvalbumin and cholinergic interneurons in the striatum of individuals with Tourette syndrome.

Corticobasal ganglia neuronal ensembles bring automatic motor skills into voluntary control and integrate them into ongoing motor behavior. A 5% decrease in caudate (Cd) nucleus volume is the most consistent structural finding in the brain of patients with Tourette syndrome (TS), but the cellular abnormalities that underlie this decrease in volume are unclear. In this study the density of different types of interneurons and medium spiny neurons (MSNs) in the striatum was assessed in the postmortem brains of 5 TS subjects as compared with normal controls (NC) by unbiased stereological analyses. TS patients demonstrated a 50%-60% decrease of both parvalbumin (PV)+ and choline acetyltransferase (ChAT)+ cholinergic interneurons in the Cd and the putamen (Pt). Cholinergic interneurons were decreased in TS patients in the associative and sensorimotor regions but not in the limbic regions of the striatum, such that the normal gradient in density of cholinergic cells (highest in associative regions, intermediate in sensorimotor and lowest in limbic regions) was abolished. No significant difference was present in the densities of medium-sized calretinin (CR)+ interneurons, MSNs, and total neurons. The selective deficit of PV+ and cholinergic striatal interneurons in TS subjects may result in an impaired cortico/thalamic control of striatal neuron firing in TS.

Annotation: Tourette syndrome: a relentless drumbeat--driven by misguided brain oscillations.

OBJECTIVE: This annotation reviews recent evidence that points to the likely role of aberrant neural oscillations in the pathogenesis of Tourette syndrome (TS). METHODS: The available anatomic and electrophysiological findings in TS are reviewed in the context of an emerging picture of the crucial role that neural oscillations play in maintaining normal central nervous system (CNS) function. RESULTS: Neurons form behavior-dependent oscillating networks of various sizes and frequencies that bias input selection and facilitate synaptic plasticity, mechanisms that cooperatively support temporal representation as well as the transfer and long-term consolidation of information. Coherent network activity is likely to modulate sensorimotor gating as well as focused motor actions. When these networks are dysrhythmic, there may be a loss of control of sensory information and motor action. The known electrophysiological effects of medications and surgical interventions used to treat TS likely have an ameliorative effect on these aberrant oscillations. Similarly, a strong case can be made that successful behavioral treatments involve the willful training regions of the prefrontal cortex to engage in tic suppression and the performance of competing motor responses to unwanted sensory urges such that these prefrontal regions become effective modulators of aberrant thalamocortical rhythms. CONCLUSIONS: A deeper understanding of neural oscillations may illuminate the complex, challenging, enigmatic, internal world that is TS.

Altered parvalbumin-positive neuron distribution in basal ganglia of individuals with Tourette syndrome.

Tourette syndrome (TS) is a childhood neuropsychiatric disorder characterized by motor and vocal tics. Imaging studies found alterations in caudate (Cd) and putamen volumes. To investigate possible alterations in cell populations, postmortem basal ganglia tissue from individuals with TS and normal controls was analyzed by using unbiased stereological techniques. A markedly higher total neuron number was found in the globus pallidus pars interna (GPi) of TS. In contrast, a lower neuron number and density was observed in the globus pallidus pars externa and in the Cd. An increased number and proportion of the GPi neurons were positive for the calcium-binding protein parvalbumin in tissue from TS subjects, whereas lower densities of parvalbumin-positive interneurons were observed in both the Cd and putamen of TS subjects. This change is consistent with a developmental defect in tangential migration of some GABAergic neurons. The imbalance in striatal and GPi inhibitory neuron distribution suggests that the functional dynamics of cortico-striato-thalamic circuitry are fundamentally altered in severe, persistent TS.