This prospective clinical study will investigate the ability of different spine imaging characteristics to predict ambulation recovery responsiveness using epidural spinal cord stimulator (SCS) in patients with chronic incomplete spinal cord injury (SCI). Epidural spinal cord stimulation below the level of injury can restore previously lost lower extremity voluntary motor function for some patients. The goal of this study is to establish whether spine imaging can be utilized as a biomarker to predict which patients will respond to spinal cord stimulation.
Ten patients with chronic spinal cord injury who are scheduled to receive a spinal cord stimulator for refractory chronic pain will be recruited throughout the Mass General Brigham health system. At baseline, participants will undergo a neurologic strength exam, Magnetic Resonance Imaging (MRI) of the spine and brain, electromyography (EMG) of the lower extremities, and will complete a battery of pain, motor function and quality of life questionnaires. Phase 1: The SCS Optimization phase consists of weekly research visits during the first month post-SCS implant. Settings of the spinal cord stimulator parameters will be modified for activation and optimal voluntary control of lower extremity muscles. Phase 2: The Individualized Neurorehabilitation phase consists of 4 weekly visits for a 5-month period. Participants will undergo neurorehabilitation with the stimulation settings turned on for motor control. Neurorehabilitation will be individualized and will progressively increase participants' physical activity, including assisted/independent standing, stepping and ambulation within safe limits. Participants will undergo monthly muscle strength and surface EMG testing. At the end of each research visit or neurorehabilitation session, SCS settings will be adjusted to the original pain management parameters. At the 6-month follow up participants will undergo a neurologic strength exam, MRI of the spine and brain, EMG of the lower extremities and a battery of questionnaires. After the last follow up visit, participants will have the opportunity to continue a long-term follow up or exit the study. SCS parameters will be adjusted to the pain management settings.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
OTHER
All patients will receive a spinal cord stimulator and undergo adjustment of stimulation parameters for optimal voluntary lower extremity motor control during research visits. Muscle strength will be assessed with the stimulation turned on and off.
Incidence of treatment-related adverse events
The primary endpoint of this study is the safety of stimulation parameters for motor function assessed with the number of adverse events for the duration of the study. Relatedness of adverse events to treatment is determined by the principal investigator.
Time frame: 0-6 months after baseline
Muscle Strength
The ability to restore previously lost voluntary motor function of the lower extremity will be measured with the Medical Research Council (MRC) grade and compared to baseline. MRC grades range from 0 (no visible muscle contraction) to 5 (normal muscle strength against full resistance). A higher grade indicates a better outcome.
Time frame: 1-6 months after baseline
Neuroimaging volumetric measures
Assessment of the functional integrity of corticospinal tracts with spine and brain Magnetic Resonance Imaging (MRI) will be performed at baseline and at the last follow up. MRI volumetric measures are quantified in mm\^2.
Time frame: 0-6 months after baseline
Voluntary Motor Function
Functional change assessed with the total score on the American Spinal Injury Association Impairment Scale (AIS) of each participant before spinal cord stimulation (SCS) and after SCS augmented with neurorehabilitation therapy. The AIS scale ranges from A (no sensory or motor function is preserved in sacral segments of S4-S5) to E (sensation and motor testing are normal in all segments), with A representing the worst outcome and E representing the best outcome.
Time frame: 0-6 months after baseline
Optimized stimulation amplitude for voluntary motor function
Stimulation amplitude required for voluntary motor function measured in mA (miliAmperes) when supine, assisted/independent standing, stepping, walking.
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Masking
NONE
Enrollment
10
Time frame: 1-6 months after baseline
Optimized stimulation frequency for voluntary motor function
Stimulation frequency required for voluntary motor function measured in Hz (Hertz) when supine, assisted/independent standing, stepping, walking.
Time frame: 1-6 months after baseline
Optimized stimulation pulse width for voluntary motor function
Stimulation pulse width required for voluntary motor function measured in microseconds when supine, assisted/independent standing, stepping, walking.
Time frame: 1-6 months after baseline
Locomotive ability
Ability to stand, step, or walk either assisted or unassisted assessed with the Walking Index for Spinal Cord Injury II (WISCI II) scale. The WISCI II scale ranges from minimum score of 0 (unable to stand) to maximum score of 20 (ambulates with no devices, brace or assistance). A higher score represents a better outcome.
Time frame: 1-6 months after baseline
Serious adverse events
Serious adverse events related to the post-SCS implant neurorehabilitation therapy.
Time frame: 1-6 months after baseline