gwon Youn

The Effect of High-Frequency Stimulation on Sensory Thresholds in Chronic Pain Patients.

Background: High-frequency stimulation (HFS) has recently gained attention as an alternative to parameters used in traditional spinal cord stimulation (SCS). Because HFS is paresthesia free, the gate theory of pain control as a basis of SCS has been called into question. The mechanism of action of HFS remains unclear. Objective: We compare the effects of HFS and traditional SCS on quantitative sensory testing parameters to provide insight into how HFS modulates the nervous system. Methods: Using quantitative sensory testing, we measured thermal detection and pain thresholds and mechanical detection and pressure pain thresholds, as well as vibratory detection, in 20 SCS patients off stimulation (OFF), on traditional stimulation (ON) and on HFS in a randomized order. Results: HFS significantly increased the mechanical detection threshold compared to OFF stimulation (p < 0.001) and traditional SCS (p = 0.01). Pressure pain detection and vibratory detection thresholds also significantly increased with HFS compared to ON states (p = 0.04 and p = 0.01, respectively). In addition, HFS significantly decreased 10- and 40-gram pinprick detection compared to OFF states (both p = 0.01). No significant differences between OFF, ON and HFS states were seen in thermal and thermal pain detection. Conclusion: HFS is a new means of modulating chronic pain. The mechanism by which HFS works seems to differ from that of traditional SCS, offering a new platform for innovative advancements in treatment and a greater potential to treat patients by customizing waveforms.

Successful Use of High-Frequency Spinal Cord Stimulation Following Traditional Treatment Failure

Introduction: High-frequency spinal cord stimulation (HFSCS) offers an alternative treatment for chronic refractory pain syndromes nonresponsive to traditional spinal cord stimulation (SCS). Following the conflicting findings of preliminary HFSCS clinical studies performed at 5-10 kHz, this study is the first to report successful clinical usage of 1-kHz frequency SCS with a standard generator. Patients: We used HFSCS in 2 patients who had inadequate relief with traditional SCS. Patient 1 was initially programmed at 40 Hz and a pulse width of 330 μs with bipolar stimulation. After multiple setting adjustments with inadequate pain relief, the patient was reprogrammed to HFSCS at settings of 1.15 kHz, 120 μs, and 5 V. Patient 2 was initially programmed at a frequency of 1.2 kHz and a pulse width of 120 μs, which she favored over the standard setting of 40 Hz and 390 μs pulse width. HFSCS provided optimal pain alleviation and increased quality of life for both patients. Conclusions: HFSCS at the frequency of 1 kHz offers a new tool for treatment of chronic pain in patients with traditional stimulation settings. Furthermore, most standard SCS batteries are capable of delivering stimulation in this frequency range.

The Role of Invasive Pain Management Modalities in the Treatment of Chronic Pain.

Invasive analgesic therapies provide an alternative to medical management of chronic pain. With the increasing incidence of chronic pain not only in the United States but worldwide, more therapies have evolved to address the growing need for pain relief options. These therapies include spinal injections, nerve blocks, radiofrequency ablation, neurostimulation, and intrathecal drug delivery.

353 High-Intensity Ultrasound for the Treatment of Vincristine-Induced Neuropathic Pain.

INTRODUCTION Vincristine is a commonly used chemotherapeutic agent but is associated with debilitating peripheral neuropathy that is often refractory to traditional medication. We explore 1 neuromodulatory option, high-intensity focused ultrasound (HIFU), which may work by altering neuronal activity. Thus, we focus on the efficacy of HIFU in treating vincristine-induced neuropathy (VIN) in the animal model. METHODS VIN rodents were created using a previously used animal model, and neuropathy was confirmed by mechanical and thermal testing using Von Frey Filaments (VFF), Randal-Selitto (RS), hot plate (HP), and tail-flick tests (TF). The VFF and RS tests are measures of innocuous and noxious mechanical thresholds, respectively, and the HP and TF are measures of paw and tail withdrawal times to thermal stimuli. These tests were performed before neuropathy induction, after a 2-week induction period, at 24 hours after HIFU and at 48 hours after HIFU. HIFU was applied to the L5 dorsal root ganglion of the left hind paw at 3 W for 2 minutes. RESULTS Although we only have 1 animal in our HIFU group thus far, our preliminary data suggest that HIFU increases mechanical and thermal thresholds compared with HIFU sham animals (n = 5). Specifically, innocuous and noxious mechanical thresholds were increased as measured with the VFF and RS tests, and thermal thresholds were also increased as measured by the HP test at 48 hours after HIFU application. Our HIFU animal did not exhibit increased TF thresholds. CONCLUSION Our preliminary data suggest that high-intensity ultrasound may be an effective way to increase mechanical and thermal thresholds in VIN.INTRODUCTION:Vincristine is a commonly used chemotherapeutic agent but is associated with debilitating peripheral neuropathy that is often refractory to traditional medication. We explore 1 neuromodulatory option, high-intensity focused ultrasound (HIFU), which may work by altering neuronal activity

The Effects of Mechanical and Thermal Stimuli on Local Field Potentials and Single Unit Activity in Parkinson's Disease Patients

Chronic pain is a major, debilitating symptom of Parkinsons disease (PD). Although, deep brain stimulation (DBS) has been shown to improve pain outcomes, the mechanisms underlying this phenomenon are unclear. Microelectrode recording allows us to measure both local field potentials (LFPs) and single neuronal unit activity (SUA).

Hyperhidrosis associated with subthalamic deep brain stimulation in Parkinson's disease: Insights into central autonomic functional anatomy

INTRODUCTION There is limited evidence regarding the precise location and connections of thermoregulatory centers in humans. We present two patients managed with subthalamic nucleus (STN) Deep Brain Stimulation (DBS) for motor fluctuations in PD that developed reproducible hyperhidrosis with high frequency DBS. OBJECTIVE To describe the clinical features and analyze the location of the electrodes leading to autonomic activation in both patients. METHODS We retrospectively assessed the anatomical localization, electrode programming settings and effects of unilateral STN DBS leading to hyperhidrosis. RESULTS Unilateral stimulation of anterior and medially located contacts within the STN and zona incerta (Zi) caused bilateral, consistent, reproducible, and reversible sweating in our patients. Adequate control of motor symptoms without autonomic side effects was accomplished with alternative programming settings. CONCLUSION Stimulation of the medial Zi and medial and anterior STN causes hyperhidrosis in a pattern similar to that described in primates and rats. We speculate that central autonomic fibers originating in the lateral hypothalamic area project laterally to the ventral/medial Zi and then to brainstem nuclei following an medial and posterior trajectory in relationship to STN.

A Single Center Prospective Observational Study of Outcomes With Tonic Cervical Spinal Cord Stimulation

Spinal cord stimulation (SCS) has been a valuable resource for the treatment of chronic, nonmalignant pain that persists in the face of maximal medical management. A recent study demonstrated efficacy of cervical SCS in a multicenter registry. Here, in our single center study, we are able to delve into patient specifics, explore outcomes with percutaneous vs. paddle implants, and examine impact of patient symptomatology.

Failed Back Surgery Syndrome

Failed back surgery syndrome (FBSS) is defined as persistent or recurring low back pain following one or more spine surgeries. It is part of the worldwide epidemic of chronic pain which is estimated to affect 37 % of the general adult population with a 60–80 % lifetime prevalence. These numbers are only projected to rise as our elderly population expands, demonstrating the extent to which chronic low back pain impacts our society. The etiology of FBSS is driven by a complex relationship of not only biological and psychological factors, but also social and economic. These factors can be broken down into pre-, intra-, and postoperative categories. It is essential, however, that the correct procedure be selected for the appropriately screened and properly diagnosed patient. A thorough history and physical exam along with advanced imaging including MRI with gadolinium, flexion/extension X-rays, and CT can be beneficial in helping to diagnose FBSS.

Pallidal deep brain stimulation and intraoperative neurophysiology for treatment of poststroke hemiballism

Deep brain stimulation is a recognized and effective treatment for several movement disorders. Nevertheless, the efficacy of this intervention on abnormal movements secondary to structural brain pathologies is less consistent. In this report, we describe a case of hemiballism–hemichorea due to a peripartum ischemic stroke‐treated with deep brain stimulation of the globus pallidus internus. Patient observed marked improvement in her symptoms at long‐term follow‐up. Neurophysiologic data revealed lower globus pallidus internus firing rates compared to other hyperkinetic disorders. Pallidal deep brain stimulation is a plausible option for medically refractory hemiballism–hemichorea and cumulative data from multiple centers may be used to fully evaluate its efficacy.

Evaluation of Quantitative Measurement Techniques for Head Tremor With Thalamic Deep Brain Stimulation: QUANTITATIVE HEAD TREMOR MEASUREMENT

Ventralis intermedius thalamic deep brain stimulation (VIM DBS) has shown to be safe and effective for medically refractory essential tremor (ET). We evaluate the use of quantitative tremor measurement methods for head tremor in ET using a “smart” hat and a smartphone application.