Paresthesia‐Free Spinal Nerve Root Stimulation for the Treatment of Chronic Neuropathic Pain

ObjectiveStimulation of the dorsal spinal roots, or spinal nerve root stimulation (SNRS), is a neuromodulation modality that can target pain within specific dermatomal distributions. The use of paresthesia-free stimulation has been described with conventional dorsal column spinal cord stimulation, although has yet to be described for SNRS. This objective of this study was to investigate the efficacy of paresthesia-free high-frequency (1000–1200 Hz) SNRS in the treatment of intractable, dermatomal neuropathic pain.Materials and MethodsA retrospective chart review was performed on 14 patients implanted with SNRS in varying distributions: Ten patients initially received tonic stimulation and crossed over to a paresthesia-free paradigm and four patients received only paresthesia-free stimulation. The primary outcome was reduction in pain severity (visual analog scale [VAS]), measured at baseline and follow-up to 24 months with paresthesia-free stimulation.ResultsAll 14 patients who received paresthesia-free stimulation had significant improvement in pain severity at a mean follow-up of 1.39 ± 0.15 years (VAS 7.46 at baseline vs. 3.25 at most recent follow-up, p < 0.001). Ten patients were initially treated with tonic stimulation and crossed over to paresthesia-free stimulation after a mean of 61.7 months. Baseline pain in these crossover patients was significantly improved at last follow-up with tonic stimulation (VAS 7.65 at baseline vs. 2.83 at 48 months, p < 0.001), although all patients developed uncomfortable paresthesias. There was no significant difference in pain severity between patients receiving tonic and paresthesia-free stimulation.ConclusionsWe present real-world outcomes of patients with intractable dermatomal neuropathic pain treated with paresthesia-free, high-frequency SNRS. We demonstrate its effectiveness in providing pain reduction at a level comparable to tonic SNRS up to 24 months follow-up, without producing uncomfortable paresthesias.     

Cerebrovascular and neurological perspectives on adrenoceptor and calcium channel modulating pharmacotherapies

Adrenoceptor and calcium channel modulating medications are widely used in clinical practice for acute neurological and systemic conditions. It is generally assumed that the cerebrovascular effects of these drugs mirror that of their systemic effects – and this is reflected in how these medications are currently used in clinical practice. However, recent research suggests that there are distinct cerebrovascular-specific effects of these medications that are related to the unique characteristics of the cerebrovascular anatomy including the regional heterogeneity in density and distribution of adrenoceptor subtypes and calcium channels along the cerebrovasculature. In this review, we critically evaluate existing basic science and clinical research to discuss known and putative interactions between adrenoceptor and calcium channel modulating pharmacotherapies, the neurovascular unit, and cerebrovascular anatomy. In doing so, we provide a rationale for selecting vasoactive medications based on lesion location and lay a foundation for future investigations that will define neuroprotective paradigms of adrenoceptor and calcium channel modulating therapies to improve neurological outcomes in acute neurological and systemic disorders.     

The combined relations of gender,enculturation, and depressive symptoms with health risk behaviors in Mexican-Americans: a moderated mediation analysis

ABSTRACT

Objectives: The present study investigated the relationships of enculturation and depressive symptoms with health risk behavior engagement in Mexican-American college students and examined how these relationships differed by gender. Previous research has noted consistent gender differences in health risk behavior (e.g. alcohol use, substance use, and risky sexual behavior) among Latina/os, and emphasized the role of U.S. acculturation in this difference. Research examining the role of heritage cultural retention (i.e. enculturation), and including the added influence of mental health variables, such as depressive symptoms, is currently lacking. This study sought to address this gap.

Design: A large sample (N?=?677) of Mexican-American college students from four universities (located in New York, California, Florida, and Texas) completed an online questionnaire assessing health risk behaviors and corresponding variables.

Results: We found that males who endorsed more behavioral enculturation and depressive symptoms were more likely to engage in health risk behavior than all others in the sample. Contrary to previous literature, no relationship was found between behavioral enculturation and health risk behavior in females.

Conclusion: The current study found behavioral enculturation to be associated with depressive symptoms, and in turn with health risk behaviors among the males in our sample. Additional research will be needed to identify the mechanism underlying the relationship between enculturation and depressive symptoms as well as between depressive symptoms and risky behavior.     

User experiences with second-generation 32-gauge × 4 mm vs. thinner comparator pen needles: prospective randomized trial

Abstract

Objective

Two similarly designed studies compared user experiences with a second-generation extra-thin-wall, 5-bevel 32?G?×?4?mm pen needle (PN) with redesigned hub versus four thinner commercially available PNs.     

Postsynaptic and spiking activity of pyramidal cells,the principal neurons in the rat hippocampal CA1 region,does not control the resultant BOLD response: a combined electrophysiologic and fMRI approach

The specific role of postsynaptic activity for the generation of a functional magnetic resonance imaging (fMRI) response was determined by a simultaneous measurement of generated field excitatory postsynaptic potentials (fEPSPs) and blood oxygen level-dependent (BOLD) response in the rat hippocampal CA1 region during electrical stimulation of the contralateral CA3 region. The stimulation electrode was placed either in the left CA3a/b or CA3c, causing the preferentially basal or apical dendrites of the pyramidal cells in the right CA1 to be activated. Consecutive stimulations with low-intensity stimulation trains (i.e., 16 pulses for 8 seconds) resulted in clear postsynaptic responses of CA1 pyramidal cells, but in no significant BOLD responses. In contrast, consecutive high-intensity stimulation trains resulted in stronger postsynaptic responses that came along with minor (during stimulation of the left CA3a/b) or substantial (during stimulation of the left CA3c) spiking activity of the CA1 pyramidal cells, and resulted in the generation of significant BOLD responses in the left and right hippocampus. Correlating the electrophysiologic parameters of CA1 pyramidal cell activity (fEPSP and spiking activity) with the resultant BOLD response revealed no positive correlation. Consequently, postsynaptic activity of pyramidal cells, the most abundant neurons in the CA1, is not directly linked to the measured BOLD response.     

The relationship between childhood maltreatment and psychopathology in adults undergoing bariatric surgery

Background

A history of childhood maltreatment and psychopathology are common in adults with obesity.