The Effect of Pulse Width and Contact Configuration on Paresthesia Coverage in Spinal Cord Stimulation

Abstract BACKGROUND: In spinal cord stimulation for the management of chronic, intractable pain, a satisfactory analgesic effect can be obtained only when the stimulation-induced paresthesias cover all painful body areas completely or partially. OBJECTIVE: To investigate the effect of stimulus pulse width (PW) and contact configuration (CC) on the area of paresthesia (PA), perception threshold (VPT), discomfort threshold (VDT), and usage range (UR) in spinal cord stimulation. METHODS: Chronic pain patients were tested during a follow-up visit. They were stimulated monopolarly and with the CC giving each patient the best analgesia. VPT, VDT, and UR were determined for PWs of 90, 210, and 450 microseconds. The paresthesia contours at VDT were drawn on a body map and digitized; PA was calculated; and its anatomic composition was described. The effects of PW and CC on PA, VPT, VDT, and UR were tested statistically. RESULTS: Twenty-four of 31 tests with low thoracic stimulation and 8 of 9 tests with cervical stimulation gave a significant extension of PA at increasing PW. In 14 of 18 tests (low thoracic), a caudal extension was obtained (primarily in L5-S2). In cervical stimulation the extension was predominantly caudal as well. In contrast to VPT and VDT, UR is not significantly different when stimulating with any CC. CONCLUSION: PA extends caudally with increasing PW. The mechanism includes that the larger and smaller dorsal column fibers have a different mediolateral distribution and that smaller dorsal column fibers have a smaller UR and can be activated only when PW is sufficiently large. A similar effect of CC on PA is unlikely as long as electrodes with a large intercontact distance are applied.

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Is Impedance a Parameter to be Taken into Account in Spinal Cord Stimulation?

January 2018 - Pain Physician ◽

10.36076/ppj.2007/10/533 ◽

2007 ◽

Vol 4;10 (7;4) ◽

pp. 533-540

Author(s):

David Abejon

Keyword(s):

Spinal Cord ◽

Spinal Cord Stimulation ◽

Pain Treatment ◽

Energy Requirement ◽

Age Groups ◽

Primary Objective ◽

Intractable Pain ◽

Perception Threshold ◽

Implanted Electrodes ◽

Significant Difference

Background: Over the last few decades, spinal cord stimulation (SCS) has become one of the main treatments in the therapeutic arsenal available to pain treatment units. New stimulation systems have been developed and the indications of neurostimulation have been expanded. The premises for a successful technique remain the same; good patient selection, good surgical technique, and good management of electrical parameters when programming. Design: An observational report. Objectives: The primary objective of the study was to determine the relationship between changes in impedance (R) and energy requirement (E) elicited by changes in patients posture. The postures analyzed were supine (S), sitting (SI), standing (ST), and walking (W). As a second objective, the difference produced in the energy requirement when changing posture was analyzed. Methods: A study was carried out in 70 patients with chronic intractable pain implanted with a neurostimulation system between January 2000 and March 2006. We define the perception threshold (Tp); the discomfort threshold (Td); and the therapeutic threshold (Tt). The amplitude of perception was measured in mA. With the resulting data, the therapeutic range (TR) was determined. After performing all measurements with the patient in the ST position, the neurostimulation system was shut off and the patient maintained in the other position for 5 minutes before performing the measurements. The variables R and E were compared by age groups, sex, implant duration, and the time since implant placement. Patients were divided into groups according to whether the location of the implanted electrodes was cervical or thoracic. The full analysis by age, sex, and implant duration was performed in the cervical and thoracic implant groups. Results: No correlation was found between impedance and posture. When the results for R and E were analyzed by sex and age, no statistical differences were found in any of the values in any position. The analysis of time since implant greater than or less than 6 months did not find differences in the energy requirement, although there was a significant difference in the impedance value when patients were in the S position. No significant differences were observed in the analysis by age groups. Key words: Impedance, posture change, spinal cord stimulation

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Patient-interactive, computer-controlled neurological stimulation system: clinical efficacy in spinal cord stimulator adjustment

Journal of Neurosurgery ◽

10.3171/jns.1992.76.6.0967 ◽

1992 ◽

Vol 76 (6) ◽

pp. 967-972 ◽

Cited By ~ 30

Author(s):

Richard B. North ◽

Kim Fowler ◽

Daniel J. Nigrin ◽

Richard Szymanski

Keyword(s):

Spinal Cord ◽

Spinal Cord Stimulation ◽

Potential Operator ◽

Intractable Pain ◽

Stimulus Pulse ◽

Content Type ◽

Psychophysical Data ◽

Time Required ◽

Computerized System ◽

Fine Print

✓ Over the past 20 years, continuing technical advances have rendered spinal cord stimulation an easily implemented low-morbidity technique for the management of chronic intractable pain in properly selected patients. Percutaneous methods for the insertion of arrays of multiple epidural electrodes, which are driven by noninvasively programmable “multichannel” implanted devices, have been among the most important of these technical improvements. The same implanted electronics may be used with peripheral nerve or intracerebral electrodes. If the capabilities of this new hardware are to be used to full advantage, a major investment of time and effort is required to adjust the system postoperatively for optimum effect. Ideally, these adjustments should be based upon psychophysical data, obtained in a manner that minimizes influences such as potential operator bias or stimulus presentation-order effects. These requirements have been met by the development of a computerized system designed for direct patient interaction and for greater ease of operation than the standard external devices used with these implants. The system has been tested clinically in 25 patients with spinal cord stimulation for pain. It rapidly tests the available electrode combinations and stimulus pulse parameters at a rate comparable to or greater than that of a skilled human operator using the standard device. It records detailed graphic data and patient analog ratings at varying thresholds and implements “pain drawing” methods with novel input and analytical techniques. This patient-interactive computerized system has proved to be safe and effective clinically. The time required by the average patient working with this system to adjust the stimulator is comparable to or less than the time required by the same patient working with a physician's assistant. Psychophysical data collected by the system may be correlated with clinical observations. Ongoing development will permit delivery of novel pulse sequences and protocols to assess the mechanisms by which stimulation affords relief from pain.

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Management of Chronic and Neuropathic Pain with 10 kHz Spinal Cord Stimulation Technology: Summary of Findings from Preclinical and Clinical Studies

Biomedicines ◽

10.3390/biomedicines9060644 ◽

2021 ◽

Vol 9 (6) ◽

pp. 644

Author(s):

Vinicius Tieppo Francio ◽

Keith F. Polston ◽

Micheal T. Murphy ◽

Jonathan M. Hagedorn ◽

Dawood Sayed

Keyword(s):

Spinal Cord ◽

Neuropathic Pain ◽

Spinal Cord Stimulation ◽

High Frequency ◽

Pulse Width ◽

Clinical Evidence ◽

Dynamic Range ◽

Large Diameter ◽

Dorsal Column ◽

The Body

Since the inception of spinal cord stimulation (SCS) in 1967, the technology has evolved dramatically with important advancements in waveforms and frequencies. One such advancement is Nevro’s Senza® SCS System for HF10, which received Food and Drug and Administration (FDA) approval in 2015. Low-frequency SCS works by activating large-diameter Aβ fibers in the lateral discriminatory pathway (pain location, intensity, quality) at the dorsal column (DC), creating paresthesia-based stimulation at lower-frequencies (30–120 Hz), high-amplitude (3.5–8.5 mA), and longer-duration/pulse-width (100–500 μs). In contrast, high-frequency 10 kHz SCS works with a proposed different mechanism of action that is paresthesia-free with programming at a frequency of 10,000 Hz, low amplitude (1–5 mA), and short-duration/pulse-width (30 μS). This stimulation pattern selectively activates inhibitory interneurons in the dorsal horn (DH) at low stimulation intensities, which do not activate the dorsal column fibers. This ostensibly leads to suppression of hyperexcitable wide dynamic range neurons (WDR), which are sensitized and hyperactive in chronic pain states. It has also been reported to act on the medial pathway (drives attention and pain perception), in addition to the lateral pathways. Other theories include a reversible depolarization blockade, desynchronization of neural signals, membrane integration, glial–neuronal interaction, and induced temporal summation. The body of clinical evidence regarding 10 kHz SCS treatment for chronic back pain and neuropathic pain continues to grow. There is high-quality evidence supporting its use in patients with persistent back and radicular pain, particularly after spinal surgery. High-frequency 10 kHz SCS studies have demonstrated robust statistically and clinically significant superiority in pain control, compared to paresthesia-based SCS, supported by level I clinical evidence. Yet, as the field continues to grow with the technological advancements of multiple waveforms and programming stimulation algorithms, we encourage further research to focus on the ability to modulate pain with precision and efficacy, as the field of neuromodulation continues to adapt to the modern healthcare era.

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Intraoperative electrophysiological monitoring for C1–2 spinal cord stimulation

Journal of Neurosurgery Spine ◽

10.3171/2016.7.spine16103 ◽

2017 ◽

Vol 26 (2) ◽

pp. 183-189 ◽

Cited By ~ 4

Author(s):

Laura M. Muncie ◽

Nathaniel R. Ellens ◽

Emeline Tolod-Kemp ◽

Claudio A. Feler ◽

John S. Winestone

Keyword(s):

Spinal Cord ◽

General Anesthesia ◽

Spinal Cord Stimulation ◽

Case Series ◽

Pain Syndrome ◽

Dorsal Column ◽

Patient Comfort ◽

Retrospective Case ◽

Cervical Stimulation ◽

Endotracheal Anesthesia

OBJECTIVE This study is a retrospective case series involving C1–2 spinal cord stimulation in patients with complex regional pain syndrome (CRPS) under general endotracheal anesthesia. Currently, C1–2 paddle lead placement is an accepted practice, which provides effective cervical stimulation to ameliorate upper-extremity and sometimes lower-extremity symptoms experienced by patients with CRPS. However, this technique must be performed under general endotracheal anesthesia rather than in an awake or semiconscious state due to intraoperative safety concerns and patient comfort. The authors aim to provide additional data to support the following novel technique: the use of somatosensory evoked potential (SSEP) diminution data to assist with proper midline placement of C1–2 leads under general anesthesia. METHODS SSEP median nerve (MN) and posterior tibial nerve (PTN) data were collected from 6 patients undergoing placement of C1–2 leads under general anesthesia. Fluoroscopy was used as an initial guide for proper anatomical midline placement. This was followed by the activation of the spinal cord stimulator and simultaneous collection of primarily MN SSEPs as well as PTN SSEPs for physiological midline placement. Unilateral and bilateral reductions in SSEPs assisted with the correct lateralization of the lead to ensure effective postoperative coverage according to the patient's individual preoperative symptoms. RESULTS Six patients were monitored using SSEPs and repeatable, reliable MN and PTN baseline responses were obtained from all. A reduction in amplitude ranging from 5% to 87% was observed, confirming inhibition of dorsal column conduction, and an average pain relief of 63% at short-term and 64% at long-term follow-up was recorded with 6 of 6 and 5 of 6 patients responding, respectively. CONCLUSIONS Intraoperative SSEP collision study testing appears to be a safe technique to monitor placement of C1–2 paddle leads intraoperatively under general anesthesia.

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Pulse Width Programming in Spinal Cord Stimulation: A Clinical Study

January 2018 - Pain Physician ◽

10.36076/ppj.2010/13/321 ◽

2010 ◽

Vol 4;13 (4;7) ◽

pp. 321-335

Author(s):

Thomas L. Yearwood

Keyword(s):

Spinal Cord ◽

Spinal Cord Stimulation ◽

Pulse Width ◽

Pulse Generator ◽

Dorsal Column ◽

Patient Choice ◽

Leg Pain ◽

Clinical Value ◽

Number Of Patients ◽

Wide Range

Background: With advances in spinal cord stimulation (SCS) technology, particularly rechargeable implantable, patients are now being offered a wider range of parameters to treat their pain. In particular, pulse width (PW) programming ranges of rechargeable implantable pulse generators now match that of radiofrequency systems (with programmability up to 1000µs). The intent of the present study was to investigate the effects of varying PW in SCS. Objective: To understand the effects of PW programming in spinal cord stimulation (SCS). Design: Single-center, prospective, randomized, single-blind evaluation of the technical and clinical outcomes of PW programming. Setting: Acute, outpatient follow-up. Methods: Subjects using fully-implanted SCS for > 3 months to treat chronic intractable low back and/or leg pain. Programming of a wide range (50-1000μs) of programmed PW settings using each patient’s otherwise unchanged ‘walk-in’ program. Outcome Measures: Paresthesia thresholds (perception, maximum comfortable, discomfort), paresthesia coverage and patient choice of tested programs. Results: We found strength-duration parameters of chronaxie and rheobase to be 295 (242 – 326) μs and 2.5 (1.3 – 3.3) mA, respectively. The median PW of all patients’ ‘walk-out’ programs was 400μs, approximately 48% higher than median chronaxie (P = 0.01), suggesting that chronaxie may not relate to patient-preferred stimulation settings. We found that 7/19 patients selected new PW programs, which significantly increased their paresthesia-pain overlap by 56% on average (P = 0.047). We estimated that 10/19 patients appeared to have greater paresthesia coverage, and 8/19 patients appeared to display a ‘caudal shift’ of paresthesia coverage with increased PW. Limitations: Small number of patients. Conclusions: Variable PW programming in SCS appears to have clinical value, demonstrated by some patients improving their paresthesia-pain overlap, as well as the ability to increase and even ‘steer’ paresthesia coverage. Key words: Spinal cord stimulation, pulse width, paresthesia, dermatome, implantable pulse generator, neurostimulation, chronic pain, neuropathic, dorsal column, dorsal root, chronaxie.

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Efficacy and Safety of Spinal Cord Stimulation in Patients With Chronic Intractable Pain

Case Medical Research ◽

10.31525/ct1-nct03858790 ◽

2019 ◽

Author(s):

Keyword(s):

Spinal Cord ◽

Spinal Cord Stimulation ◽

Intractable Pain ◽

Efficacy And Safety

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1-kHz high-frequency spinal cord stimulation alleviates chronic refractory pain after spinal cord injury: a case report

JA Clinical Reports ◽

10.1186/s40981-021-00451-x ◽

2021 ◽

Vol 7 (1) ◽

Author(s):

Chiaki Yamada ◽

Aiko Maeda ◽

Katsuyuki Matsushita ◽

Shoko Nakayama ◽

Kazuhiro Shirozu ◽

...

Keyword(s):

Spinal Cord ◽

Spinal Cord Injury ◽

Neuropathic Pain ◽

Spinal Cord Stimulation ◽

High Frequency ◽

Cervical Vertebrae ◽

Intractable Pain ◽

Target Area ◽

Positive Effects ◽

Cord Injury

Abstract Background Patients with spinal cord injury (SCI) frequently complain of intractable pain that is resistant to conservative treatments. Here, we report the successful application of 1-kHz high-frequency spinal cord stimulation (SCS) in a patient with refractory neuropathic pain secondary to SCI. Case presentation A 69-year-old male diagnosed with SCI (C4 American Spinal Injury Association Impairment Scale A) presented with severe at-level bilateral upper extremity neuropathic pain. Temporary improvement in his symptoms with a nerve block implied peripheral component involvement. The patient received SCS, and though the tip of the leads could not reach the cervical vertebrae, a 1-kHz frequency stimulus relieved the intractable pain. Conclusions SCI-related symptoms may include peripheral components; SCS may have a considerable effect on intractable pain. Even when the SCS electrode lead cannot be positioned in the target area, 1-kHz high-frequency SCS may still produce positive effects.

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Successful application of burst spinal cord stimulation for refractory upper limb pain: a case series

Journal of International Medical Research ◽

10.1177/03000605211004035 ◽

2021 ◽

Vol 49 (3) ◽

pp. 030006052110040

Author(s):

Kuen Su Lee ◽

Yoo Kyung Jang ◽

Gene Hyun Park ◽

In Jae Jun ◽

Jae Chul Koh

Keyword(s):

Spinal Cord ◽

Upper Limb ◽

Spinal Cord Stimulation ◽

Therapeutic Potential ◽

Case Series ◽

Limb Amputation ◽

Intractable Pain ◽

Limb Pain ◽

Cord Injury ◽

Upper Limb Pain

Spinal cord stimulation (SCS) has been used to treat sustained pain that is intractable despite various types of treatment. However, conventional tonic waveform SCS has not shown promising outcomes for spinal cord injury (SCI) or postamputation pain. The pain signal mechanisms of burst waveforms are different to those of conventional tonic waveforms, but few reports have presented the therapeutic potential of burst waveforms for the abovementioned indications. This current case report describes two patients with refractory upper limb pain after SCI and upper limb amputation that were treated with burst waveform SCS. While the patients could not obtain sufficient therapeutic effect with conventional tonic waveforms, the burst waveforms provided better pain reduction with less discomfort. However, further studies are necessary to better clarify the mechanisms and efficacy of burst waveform SCS in patients with intractable pain.

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