An evaluation of neuroplasticity and behavior after deep brain stimulation of the nucleus accumbens in an animal model of depression.

BACKGROUND: Recent interest has demonstrated the nucleus accumbens (NAcc) as a potential target for the treatment of depression with deep brain stimulation (DBS). OBJECTIVE: To demonstrate that DBS of the NAcc is an effective treatment modality for depression and that chemical and structural changes associated with these behavioral changes are markers of neuroplasticity. METHODS: A deep brain stimulator was placed in the NAcc of male Wistar-Kyoto rats. Groups were divided into sham (no stimulation), intermittent (3 h/d for 2 weeks), or continuous (constant stimulation for 2 weeks). Exploratory and anxietylike behaviors were evaluated with the open-field test before and after stimulation. Tissue samples of the prefrontal cortex (PFC) were processed with Western blot analysis of markers of noradrenergic activity that included the noradrenergic synthesizing enzyme tyrosine hydroxylase. Analysis of tissue levels for catecholamines was achieved with high-performance liquid chromatography. Morphological properties of cortical pyramidal neurons were assessed with Golgi-Cox staining. RESULTS: Subjects undergoing intermittent and continuous stimulation of the NAcc exhibited an increase in exploratory behavior and reduced anxietylike behaviors. Tyrosine hydroxylase expression levels were decreased in the PFC after intermittent and continuous DBS, and dopamine and norepinephrine levels were decreased after continuous stimulation. Golgi-Cox staining indicated that DBS increased the length of apical and basilar dendrites in pyramidal neurons of the PFC. CONCLUSION: Deep brain stimulation induces behavioral improvement in and neurochemical and morphological alterations of the PFC that demonstrate changes within the circuitry of the brain different from the target area of stimulation. This observed dendritic plasticity may underlie the therapeutic efficacy of this treatment

Spinal Shock: Differentiation from Neurogenic Shock and Key Management Approaches

The conceptual differentiation of spinal and neurogenic shock tends to be misunderstood among clinicians. In order to better illustrate the differences in definition, presentation, and development of spinal shock (SS) from neurogenic and other forms of shock, we present herein a clinically relevant summary of typical characteristics of SS. First described in the eighteenth century, the continued investigation into the disease process and the response of neural structures to spinal cord trauma have led to a more complete description and understanding. We will begin in the first part of the chapter describing the etiology of SS, including a working definition, as it pertains to complete spinal cord injuries (SCIs). This is followed by the summary of pathophysiology and clinical presentations associated with each clinical phase of SS. Finally, we explore treatment options and considerations as they relate to incomplete SCI. We hope that by presenting a clear and well-delineated overview of SS, we will allow the clinician to better understand and more accurately predict the evolution of this process. This, in turn, should facilitate the ability to deliver better care for the patient

Routine replacement of a vagal nerve stimulator generator leading to asystole

A 52-year-old female with a longstanding history of drug-resistant epilepsy that included focal impaired awareness seizure presented at end of service of her vagus nerve stimulator (VNS) generator. She had undergone a generator replacement in 2010 without complication. However, her latest replacement was accompanied by multiple bouts of asystole. We discuss the case, possible causes of the asystole, and its relevance to the future of VNS generator replacement and epilepsy treatment. Keywords: VNS, Asystole, Generator, Replacemen

Awake vs. Asleep Placement of Spinal Cord Stimulators: A Cohort Analysis of Complications Associated With Placement

Introduction: Patients will typically undergo awake surgery for permanent implantation of SCS in an attempt to optimize electrode placement using patient feedback about the distribution of stimulation-induced paresthesia. The present study compared efficacy of first-time electrode placement under awake conditions with that of neurophysiologically-guided placement under general anesthesia. Methods: A retrospective review was performed of 387 SCS surgeries among 259 patients which included 167 new stimulator implantation to determine whether first time awake surgery for placement of spinal cord stimulators is preferable to non-awake placement. Results: The incidence of device failure for patients implanted using neurophysiologically-guided placement under general anesthesia was one-half that for patients implanted awake (14.94% vs 29.7%). Conclusion: Non-awake surgery is associated with fewer failure rates and therefore fewer re-operations, making it a viable alternative. Any benefits of awake implantation should carefully be considered in the future

Development of an Educational Curriculum for Spinal Cord Stimulation.

BACKGROUND: Spinal cord stimulators (SCSs) are used for treating chronic pain. The number of SCSs implanted each year is on the increase. The North American Neuromodulation Society (NANS) education committee aimed to develop a SCS curriculum as a tool to guide physicians at different training levels, based on the most recent evidence. MATERIAL AND METHODS: A multidisciplinary (anesthesiology, physical medicine, neurosurgery, and neurology), taskforce representing the education committee of the NANS met to develop a SCS curriculum following the Accreditation Council for Graduate Medical Education (ACGME) milestones. The task force used the best available evidence and knowledge to develop the curriculum. Once developed, the SCS curriculum was then approved by the NANS board. RESULTS: The task force developed a SCS training curriculum. Milestones included patient care and procedural skills, system-based practice, medical knowledge, interpersonal communication, practice based learning and professionalism. Each milestone was defined for three categories, early learner, advanced learner, and practitioner. CONCLUSION: A multidisciplinary task force of the NANS education committee developed a SCS training curriculum that defines ACGME milestones for basic learners, advanced learners, and practitioners

Improved Psychosocial and Functional Outcomes and Reduced Opioid Usage Following Burst Spinal Cord Stimulation.

Burst spinal cord stimulation (B-SCS) has been shown to reduce neuronal firing in the anterior cingulate cortex through selective modulation of the medial pain pathway tract. This pain pathway communicates the affective component of pain processing. The purpose of this study was to assess the effect of B-SCS on psychosocial functioning and its influence on pain and quality of life. Eligible patients with chronic, intractable pain of the trunk, and/or lower limbs were enrolled. After a successful trial period, subjects received a permanent implant and returned for follow-up at 6- and 12-months. In total, 269 patients were enrolled at 22 centers. Trial success rate was 90%. Significant improvements in pain, physical, mental, and emotional functioning were observed from baseline to the 6- and 12-month follow-up (p  One-year outcomes after B-SCS show improvements across all evaluated psychological measures with the largest impact observed on catastrophizing and depression (the affective component of pain processing). These pain-related beliefs and behaviors, and not pain intensity, have been shown to put patients at greatest risk of a poor prognosis and quality of life

Radiosurgery for the treatment of dominant hemisphere periventricular heterotopia and intractable epilepsy in a series of three patients

AbstractPeriventricular heterotopia (PVH) is a neuronal migration disorder characterized by masses of gray matter located along the lateral ventricles that commonly cause epilepsy. The benefit of surgical resection of the PVH has been demonstrated in case reports to date; however, the location of the PVH in the paratrigonal region of the lateral ventricles can present significant surgical challenges. Noninvasive modalities of ablating this epileptogenic focus must therefore be considered. We present a small series of three patients who underwent stereotactic radiosurgery (SRS) for inoperable unilateral dominant hemisphere PVHs in order to illustrate the potential benefits and risks of this treatment modality. A total dose of 37.5–65Gy resulted in seizure freedom for at least 14months at the time of their last follow-up, even in patients harboring a second independent epileptic focus. Whether intracranial electrode recording truly offers added value is therefore uncertain. The two patients who received higher radiation doses suffered from symptomatic radiation necrosis and associated cerebral edema, requiring further medical intervention, and persistent monocular visual loss in one patient. While a longer interval prior to re-treatment may have been attempted, neither patient demonstrated radiographic findings typically associated with seizure remission. Refractory epilepsy due to PVH may be successfully treated with radiation therapy; but further work is needed to define the optimal dosing parameters in order to lower toxicity to normal tissue