Spinal Cord Stimulation for Lower Extremity Function

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.

Eligibility Criteria:
Inclusion Criteria:

* Age \>18 years
* Provides informed consent
* Eligible for and undergoes SCS implant for chronic low back or leg pain refractory to first-line therapy
* Stable SCI secondary to a single insult
* C6-T10 level of injury
* SCI has occurred \>12 months prior to enrollment
* Chronic low back pain refractory to first-line therapy
* Current AIS grade B-C, with spared sensation
* Willingness and ability to adhere to the protocol

Exclusion Criteria:

* History or diagnosis of Central Nervous System malignancy
* Diagnosis that is a contraindication to SCS implantation or surgery
* Diagnosis that precludes the subject from full participation in physical therapy
* Known osteopenia/osteoporosis
* Impairment in post-operative recovery per clinical evaluation by the principal investigator
* Inability to participate in the protocol, including but not limited to all study visits and assessments