Effect of Epidural Stimulation on Muscle Activation and Sensory Perception

NCT04157400 | Completed Results FDA Device

• 1 other identifier: 00089881
• Study Type: interventional
• Target: 5
• Locations: 1 country
• Sites: 1

Brief Summary

Each year, an estimated 34,000 individuals undergo epidural spinal cord stimulation (SCS) surgery to address debilitating chronic low back and leg pain (CLBLP). Although the commercial application of SCS to treat CLBLP was approved by the FDA in 1989, only in the past decade have significant advancements in stimulator technology been introduced. For instance, traditional SCS devices achieved reduction in pain using a type of stimulation known as low-frequency tonic stimulation (LFTS, below 100 Hz), which was dependent on induction of paresthesias (i.e., a tingling sensation) over the areas of pain perception. However, investigators now know that LFTS compromises sensory information flowing back to the spinal cord, which can be important in other spinal cord functions such as proprioception and movement. On the other hand, recent innovations in stimulator technology now provide the capability to apply stimulation frequencies up to 10,000 Hz along with complex waveform patterns - known as high frequency burst stimulation or HFBS - that can mitigate pain perception without the induction of paresthesias and the negative consequences on proprioception and movement. We propose to study the effects of these recently introduced features in SCS technology on motor and sensory spinal thresholds, proprioception and movement in subjects with CLBLP. The spinal cord relies on input from the motor cortex and surrounding extremities to initiate specific muscle recruitment, and recent evidence suggests that preservation of temporally specific proprioceptive information via dorsal column primary afferent fibers is critical for natural motor behaviors such as ambulation. Since the spinal cord is exposed during the placement of the SCS device, information about a subject's motor and sensory spinal pathways can be easily obtained during the regular course of the procedure and compared to proprioceptive and motor responses once the subject is awake and moving with the device turned on. Our lab specializes in electrophysiological recordings in subjects undergoing spinal cord stimulator (SCS) implantation for CLBLP, while MUSC's Locomotion Laboratory specializes in quantifying proprioception and movement in human subjects. In this proposal, investigators will apply these techniques to subjects with CLBLP to determine effects of spinal neuromodulation on motor and sensory thresholds, proprioception, and kinematics.

Conditions

Chronic Pain

Outcome Measures

Primary Outcomes (3)

• Electromyography Response Amplitude

  During intraoperative testing of varying stimulation parameters, the research team plans to collect evoked potentials via electromyography (EMG) as the primary outcome for step one. Evoked potential amplitude, recorded at specific muscles of interest, will be collected for nerve root activation threshold. The research team plans to look at musculature receiving innervation from varying levels of the spinal cord in order to determine any difference among stimulation type regarding nerve root isolation.

  Data collection for step one is expected to last approximately fifteen minutes during the spinal cord stimulation surgery.

• Proprioception Testing

  Proprioception signaling will be tested using a Biodex machine that can apply passive flexion/extension at the knee while the subject reports 1) Feeling of movement and 2) Direction of movement. Specific data of interest will be the amount of degrees of flexion/extension of the knee that have occurred before the subject perceives the movement, which is reflective of proprioceptive signaling. Testing while experiencing varying types of stimulation will yield important information regarding physiological sensory modulation from the stimulator. The research team plans to use a repeated measures two-way ANOVA with epidural stimulation type and current amplitude of above and below EMG activation threshold to investigate effects on proprioception detection signaling.

  Data collection for step two is expected to last approximately two hours.

• Change in Electromyography Microvoltage Signal During Walking

  During gait analysis, the research team plans to collect surface electromyography (EMG) signals of lower extremity musculature to measure activation synergies and amplitudes. Segments of EMG that are recorded during walking will be analyzed with an algorithm that yields hierarchal complexities representing muscle synergies known as EMG moduling. The research team plans to use a two-way repeated measures ANOVA model in order to investigate the varying differences in stimulation type and effect on EMG module complexity to investigate the relationship between sensory pathway modulation and motor control during functional task.

  Data collection for step three is expected to last approximately two hours.

Study Arms (1)

Epidural Spinal Cord Stimulation

EXPERIMENTAL

Subjects with chronic pain that have been scheduled to receive spinal cord simulators for standard of care treatment.

Device: Intraoperative Parameter Testing; Device: Proprioception Testing During Stimulation; Device: Gait Analysis During Stimulation

Interventions

Intraoperative Parameter Testing DEVICE

Step 1: Recording and stimulation of spinal potentials during insertion of epidural spinal stimulator paddle Once the epidural paddle is placed, study procedures will begin by connecting the terminals of the paddle to an electrophysiological recording device for signal amplification and filtering. Using this recording setup, motor evoked potential (MEP) and somatosensory evoked potential (SSEP) protocols will be performed to determine motor and sensory thresholds, respectively. Next, the surgical procedure will resume and after the implantable pulse generator (IPG) has been placed, study procedures will begin again and include activation of both low-frequency tonic stimulation (LFTS) and high-frequency burst stimulation (HFBS) patterns from the inserted paddle while recording EMG signals.

Epidural Spinal Cord Stimulation

Proprioception Testing During Stimulation DEVICE

Step 3: Proprioception testing The research team will investigate the perceived change in knee joint angle and direction of movement reported by the subject in a Threshold to Detect Passive Movement (TTDPM). The TTDPM protocol will begin with the subject sitting in the Biodex testing seat, with the non-tested leg hanging freely and the tested leg strapped to the rotating arm of the dynamometer at the lower shank. The subject will be blinded as to the mode and intensity of stimulation: HFBS, LFTS, or no stim. The TTDPM will consist of at least 10 trials for each stimulation condition chosen based on SCM outcomes. The subject has control of a kill-switch that immediately halts movement of the rotating arm, which is to be activated once the subject perceives movement OR if the subject begins to feel any pain or discomfort throughout the task.

Epidural Spinal Cord Stimulation

Gait Analysis During Stimulation DEVICE

Step 4: Body weight support and treadmill (BWST) testing Similar to step 2, LFTS and HFBS patterns will be compared by systematically testing each individual contact on the paddle while investigating for changes in stepping speed, pattern and EMG moduling complexity. Regarding EMG module analysis, muscle activity will be recorded bilaterally via surface EMG from lower extremity musculature. Furthermore, subjects will also have active LED markers placed over their clothes in order to track whole body kinematics throughout this portion of the study. To optimize capture of steady state data on the treadmill, each subject will walk for approximately 10 sec prior to the 30 sec of data collection (40 sec per trial). This will allow capture of at least 10 consecutive steady state gait cycles (depending on cadence) per each amplitude selection for each stimulation delivery technique, which will be defined by parameters found during walking SCM.

Epidural Spinal Cord Stimulation

Eligibility Criteria

• Age: 18 Years - 80 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Subjects diagnosed with CLBLP by a pain specialist with a documented referral for evaluation of SCS surgery by the pain specialist
• Subjects with the ability to walk
• Age 18-80

You may not qualify if:

• Subjects with the inability to consent for themselves.
• Prior history of spinal neoplasm, infection, arteriovenous malformation and/or radiation to the spine

Sponsors & Collaborators

• Medical University of South Carolina: lead

Study Sites (1)

Medical University of South Carolina

Charleston, South Carolina, 29425, United States

Location

MeSH Terms

Conditions

Chronic Pain

Condition Hierarchy (Ancestors)

Pain; Neurologic Manifestations; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Results Point of Contact

• Title: Nathan Rowland
• Organization: MUSC

rowlandn@musc.edu

843-792-6590

Study Officials

• Nathan Rowland, MD

  Medical University of South Carolina

  PRINCIPAL INVESTIGATOR

Publication Agreements

• PI is Sponsor Employee: Yes

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Purpose: BASIC SCIENCE
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Assistant Professor

Study Record Dates

• First Submitted: November 4, 2019
• First Posted: November 8, 2019
• Study Start: November 26, 2019
• Primary Completion: November 1, 2021
• Study Completion: November 1, 2021
• Last Updated: February 15, 2023
• Results First Posted: February 15, 2023

Record last verified: 2023-01

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, SAP, ANALYTIC CODE
• Time Frame: Not yet determined
• Access Criteria: Not yet determined

Locations

US (1)