scholarly journals Modulation of activity and conduction in single dorsal column axons by kilohertz-frequency spinal cord stimulation

2017 ◽  
Vol 117 (1) ◽  
pp. 136-147 ◽  
Author(s):  
Nathan D. Crosby ◽  
John J. Janik ◽  
Warren M. Grill
Keyword(s):  
Spinal Cord ◽  
Chronic Pain ◽  
Spinal Cord Stimulation ◽  
Pain Perception ◽  
Conduction Block ◽  
Dorsal Column ◽  
Platinum Electrodes ◽  
Sprague Dawley ◽  
Transient Nature ◽  
Central Nervous System Activity

Kilohertz-frequency spinal cord stimulation (KHF-SCS) is a potential paresthesia-free treatment for chronic pain. However, the effects of KHF-SCS on spinal dorsal column (DC) axons and its mechanisms of action remain unknown. The objectives of this study were to quantify activation and conduction block of DC axons by KHF-SCS across a range of frequencies (1, 5, 10, or 20 kHz) and waveforms (biphasic pulses or sinusoids). Custom platinum electrodes delivered SCS to the T10/T11 dorsal columns of anesthetized male Sprague-Dawley rats. Single DC axons and compound action potentials were recorded during KHF-SCS to evaluate SCS-evoked activity. Responses to KHF-SCS in DC axons included brief onset firing, slowly accommodating asynchronous firing, and conduction block. The effects of KHF-SCS mostly occurred well above motor thresholds, but isolated units were activated at amplitudes shown to reduce behavioral sensitivity in rats. Activity evoked by SCS was similar across a range of frequencies (5–20 kHz) and waveforms (biphasic and sinusoidal). Stimulation at 1-kHz SCS evoked more axonal firing that was also more phase-synchronized to the SCS waveform, but only at amplitudes above motor threshold. These data quantitatively characterize the central nervous system activity that may modulate pain perception and paresthesia, and thereby provide a foundation for continued investigation of the mechanisms of KHF-SCS and its optimization as a therapy for chronic pain. Given the asynchronous and transient nature of DC activity, it is unlikely that the same mechanisms underlying conventional SCS (i.e., persistent, periodic DC activation) apply to KHF-SCS. NEW & NOTEWORTHY Kilohertz-frequency spinal cord stimulation (KHF-SCS) is a new mode of SCS that may offer better pain relief than conventional SCS. However, the mechanism of action is poorly characterized, especially the effects of stimulation on dorsal column (DC) axons, which are the primary target of stimulation. This study provides the first recordings of single DC axons during KHF-SCS to quantify DC activity that has the potential to mediate the analgesic effects of KHF-SCS.

Computational Analysis of Kilohertz Frequency Spinal Cord Stimulation for Chronic Pain Management

2015 ◽  
Vol 122 (6) ◽  
pp. 1362-1376 ◽  
Author(s):  
Scott F. Lempka ◽  
Cameron C. McIntyre ◽  
Kevin L. Kilgore ◽  
Andre G. Machado
Keyword(s):  
Spinal Cord ◽  
Cerebrospinal Fluid ◽  
Computer Model ◽  
Spinal Cord Stimulation ◽  
Dorsal Root ◽  
Fluid Layer ◽  
Large Diameter ◽  
Conduction Block ◽  
Systematic Investigation ◽  
Dorsal Column

Abstract Background: Kilohertz frequency spinal cord stimulation (KHFSCS) is an emerging therapy for treating refractory neuropathic pain. Although KHFSCS has the potential to improve the lives of patients experiencing debilitating pain, its mechanisms of action are unknown and thus it is difficult to optimize its development. Therefore, the goal of this study was to use a computer model to investigate the direct effects of KHFSCS on specific neural elements of the spinal cord. Methods: This computer model consisted of two main components: (1) finite element models of the electric field generated by KHFSCS and (2) multicompartment cable models of axons in the spinal cord. Model analysis permitted systematic investigation into a number of variables (e.g., dorsal cerebrospinal fluid thickness, lead location, fiber collateralization, and fiber size) and their corresponding effects on excitation and conduction block thresholds during KHFSCS. Results: The results of this study suggest that direct excitation of large-diameter dorsal column or dorsal root fibers require high stimulation amplitudes that are at the upper end or outside of the range used in clinical KHFSCS (i.e., 0.5 to 5 mA). Conduction block was only possible within the clinical range for a thin dorsal cerebrospinal fluid layer. Conclusions: These results suggest that clinical KHFSCS may not function through direct activation or conduction block of dorsal column or dorsal root fibers. Although these results should be validated with further studies, the authors propose that additional concepts and/or alternative hypotheses should be considered when examining the pain relief mechanisms of KHFSCS.

scholarly journals The use of high-dose cervical spinal cord stimulation in the treatment of chronic upper extremity and neck pain

2019 ◽  
Vol 10 ◽  
pp. 109
Author(s):  
Trey A. Baird ◽  
Chris S. Karas
Keyword(s):  
Spinal Cord ◽  
Chronic Pain ◽  
Upper Extremity ◽  
Spinal Cord Stimulation ◽  
Cervical Spinal Cord ◽  
Dorsal Column ◽  
High Dose ◽  
Before And After ◽  
Stage Process ◽  
Dorsal Column Stimulation

Background: Dorsal column spinal cord stimulation is used for the treatment of chronic neuropathic pain of the axial spine and extremities. Recently, high-dose (HD) thoracic dorsal column stimulation for paresthesias has been successful. This study evaluates the utility of HD stimulation in the cervical spine for managing upper neck and upper extremity pain and paresthesias. Methods: Three patients suffering from cervical and upper extremity chronic pain were assessed. Each underwent a two-stage process that included a trial period, followed by permanent stimulator implantation. Therapy included the latest HD stimulation settings including a pulse width of 90 μs, a frequency setting of 1000 Hz, and an amplitude range of 1.5 amps–2.0 amps. Pain relief was measured utilizing relative percent pain improvement as self-reported by each patient before and after surgery. Results: After permanent implantation, (range 15–21 months), all three patients continued to experience persistent pain and paresthesia relief (70%–90%). Conclusions: In three patients, HD cervical spinal cord stimulation successfully controlled upper extremity chronic pain/paresthesias.

scholarly journals Use of Observational Mechanical Gateway Connector in Spinal Cord Stimulation Trials

2011 ◽  
Vol 6;14 (6;12) ◽  
pp. 525-530
Author(s):  
Chong H. Kim
Keyword(s):  
Spinal Cord ◽  
Chronic Pain ◽  
Pain Score ◽  
Spinal Cord Stimulation ◽  
Treatment Options ◽  
Dorsal Column ◽  
Small Sample ◽  
Constant Current ◽  
Average Pain ◽  
Average Pain Score

Background: Spinal cord stimulation (SCS) is an established treatment option for chronic pain. Prior to permanent implantation, temporary trials are performed to evaluate the SCS treatment. Currently there are multiple manufacturers with varying fundamental differences in delivery and resultant paresthesias. However, trials are typically limited to one manufacturer for the patient to evaluate. Objective: To evaluate the role of the Observational Mechanical Gateway (OMG) Connector for patients undergoing SCS trials. Study Design: Retrospective cohort design study. Patients undergoing SCS trials were offered at the end of the 7 day trial to experience stimulation using the OMG Connector. Setting: Academic university-based pain management center. Method: Participants were trialed using the OMG Connector at the end of the 7 day spinal cord stimulation trial. Data based on participants’ preference were collected. Results: The average pain score at baseline was 7.3 on a 10-point scale overall, with improvement during the SCS trial to 2.9 overall; 3.5 in Medtronic (MT); and 2.4 in St. Jude (SJ) SCS trials (P = 0.04). The average pain score with OMG was 2.6 overall; 2.8 in MT; and 2.4 in SJ (P = 0.28). In terms of overall coverage of pain distribution, paresthesia and overall satisfaction, the P values were 0.24, 0.21 and 0.33 respectively. Overall, 12 of 16 participants underwent permanent implantation. One of the 4 failed trials was successfully retrialed with the OMG Connector. Limitations: Small sample of participants and the duration of the OMG Connector trial. Conclusions: The OMG Connector offers patients another opportunity to better access the available treatment options during the SCS trial period. Key words: Spinal cord stimulation, OMG Connector, paresthesia, neurostimulation, constant current, constant voltage, chronic pain, dorsal column

Retrospective analysis on the effect of spinal cord stimulation on opioid consumption

2020 ◽  
Author(s):  
Awinita Barpujari ◽  
Michael A Erdek
Keyword(s):  
Spinal Cord ◽  
Chronic Pain ◽  
Retrospective Analysis ◽  
Spinal Cord Stimulation ◽  
Alternative Therapy ◽  
Opioid Consumption ◽  
Opioid Use ◽  
Number Of Patients ◽  
Chronic Pain Conditions ◽  
Post Trial

Aim: Spinal cord stimulation (SCS) is used to clinically manage and/or treat several chronic pain etiologies. A limited amount is known about the influence on patients' use of opioid pain medication. This retrospective analysis evaluated SCS effect on opioid consumption in patients presenting with chronic pain conditions. Materials & methods: Sixty-seven patients underwent a temporary trial device, permanent implant or both. Patients were divided for assessment based on the nature of their procedure(s). Primary outcome was change in morphine equivalent dose (MED), ascertained from preoperative and postoperative medication reports. Results: Postoperative MED was significantly lower in patients who received some form of neuromodulation therapy. Pretrial patients reported an average MED of 41.01 ± 10.23 mg per day while post-trial patients reported an average of 13.30 ± 5.34 mg per day (p < 0.001). Pre-implant patients reported an average MED of 39.14 ± 13.52 mg per day while post-implant patients reported an average MED of 20.23 ± 9.01 mg per day (p < 0.001). There were no significant differences between pre-trial and pre-implant MED, nor between post-trial and post-implant MED. Of the 42 study subjects who reported some amount of pre-intervention opioid use, 78.57% indicated a lower MED (n = 33; p < 0.001), 16.67% indicated no change (n = 7) and 4.76% (n = 2) indicated a higher MED, following intervention. Moreover, SCS therapy resulted in a 26.83% reduction (p < 0.001) in the number of patients with MED >50 mg per day. Conclusion: Spinal cord stimulation may reduce opioid use when implemented appropriately. Neuromodulation may represent alternative therapy for alleviating chronic pain which may avoid a number of deleterious side effects commonly associated with opioid consumption.

Spinal Cord Stimulation for Relief of Chronic Pain in Vasospastic Disorders of the Upper Limbs

1989 ◽  
Vol 5 (2) ◽  
pp. 312
Author(s):  
F. J. ROBAINA ◽  
M. DOMINGUEZ ◽  
M. DIAZ ◽  
J. L. RODRIGUEZ ◽  
J. A. DE VERA
Keyword(s):  
Spinal Cord ◽  
Chronic Pain ◽  
Spinal Cord Stimulation ◽  
Upper Limbs

Spinal Cord Stimulation: A Contemporary Series

Neurosurgery ◽  
1991 ◽  
Vol 28 (1) ◽  
pp. 65-71 ◽  
Author(s):  
Roberto Spiegelmann ◽  
William A. Friedman
Keyword(s):  
Spinal Cord ◽  
Chronic Pain ◽  
Pain Relief ◽  
Literature Review ◽  
General Anesthesia ◽  
Detailed Analysis ◽  
Spinal Cord Stimulation ◽  
Significant Pain ◽  
Experience Pain

Abstract Forty-three patients with chronic pain disorders of different causes were selected for spinal cord stimulation. All underwent implantation of a ribbon electrode through a small laminotomy, under general anesthesia. Thirteen patients (30%) failed to obtain significant pain relief during a period of trial stimulation, and their electrodes were removed. The remainder underwent a definitive implant and were followed for a mean of 13 months (range, 3-33 months). Nineteen of them (63%) continued to experience pain relief. A detailed analysis of this series, as well as a literature review, is presented.

scholarly journals Vitamin D Deficiency Induces Chronic Pain and Microglial Phenotypic Changes in Mice

2021 ◽  
Vol 22 (7) ◽  
pp. 3604
Author(s):  
Nicola Alessio ◽  
Carmela Belardo ◽  
Maria Consiglia Trotta ◽  
Salvatore Paino ◽  
Serena Boccella ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Vitamin D ◽  
Chronic Pain ◽  
Vitamin D Deficiency ◽  
Morphological Analysis ◽  
Pain Perception ◽  
Ex Vivo ◽  
Ros Generation ◽  
Peroxisome Proliferator ◽  
Neuroprotective Effects

The bioactive form of vitamin .D, 1,25-dihydroxyvitamin D (1,25D3), exerts immunomodulatory actions resulting in neuroprotective effects potentially useful against neurodegenerative and autoimmune diseases. In fact, vitamin D deficiency status has been correlated with painful manifestations associated with different pathological conditions. In this study, we have investigated the effects of vitamin D deficiency on microglia cells, as they represent the main immune cells responsible for early defense at central nervous system (CNS), including chronic pain states. For this purpose, we have employed a model of low vitamin D intake during gestation to evaluate possible changes in primary microglia cells obtained from postnatal day(P)2-3 pups. Afterwards, pain measurement and microglia morphological analysis in the spinal cord level and in brain regions involved in the integration of pain perception were performed in the parents subjected to vitamin D restriction. In cultured microglia, we detected a reactive—activated and proliferative—phenotype associated with intracellular reactive oxygen species (ROS) generation. Oxidative stress was closely correlated with the extent of DNA damage and increased β-galactosidase (B-gal) activity. Interestingly, the incubation with 25D3 or 1,25D3 or palmitoylethanolamide, an endogenous ligand of peroxisome proliferator-activated-receptor-alpha (PPAR-α), reduced most of these effects. Morphological analysis of ex-vivo microglia obtained from vitamin-D-deficient adult mice revealed an increased number of activated microglia in the spinal cord, while in the brain microglia appeared in a dystrophic phenotype. Remarkably, activated (spinal) or dystrophic (brain) microglia were detected in a prominent manner in females. Our data indicate that vitamin D deficiency produces profound modifications in microglia, suggesting a possible role of these cells in the sensorial dysfunctions associated with hypovitaminosis D.

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