The purpose of this clinical study is to evaluate the preliminary safety and effectiveness of using a cortical recording device (ECoG) combined with lumbar targeted epidural electrical stimulation (EES) of the spinal cord to restore voluntary motor functions of lower limbs in participants with chronic spinal cord injury suffering from mobility impairment.

The goal is to establish a direct bridge between the motor intention of the participant and the the spinal cord below the lesion, which should not only improve or restore voluntary control of legs movement and support immediate locomotion, but also promote neurological recovery when combined with neurorehabilitation.

In a current first-in-human clinical trial, called STIMO (ClinicalTrials.gov, NCT02936453), Electrical Epidural Stimulation (EES) of the spinal cord is applied to enable individuals with chronic severe spinal cord injury (SCI) to complete intensive locomotor neurorehabilitation training. In this clinical feasibility study, EES immediately enhances walking function and, with repeated use as part of the EES-assisted neurorehabilitation program, improves leg motor control and neurological recovery in severe SCI participants to a certain extent. Linking brain activity to spinal stimulation, as shown in preclinical and clinical studies, enhances usability of EES and neurological recovery.

Clinatec (CEA, Grenoble, France) has developed an implantable electrocorticogram (ECoG) recording device with a 64-channel epidural electrode array called WIMAGINE capable of recording electrical signals from the motor cortex for an extended period and with a high signal to noise ratio. This ECoG-based system allowed tetraplegic patients to control an exoskeleton (Clinicaltrials.gov, NCT 02550522) with up to 8 degrees of freedom for the upper limb control. This device has been implanted in 5 chronic participants so far; one of them has been using this system both at the hospital and at home for more than 3 years.

The ECoG WIMAGINE technology has been combined with EES in the current first-in-human clinical trial STIMO-BSI (Brain Spine Interface) (Clinicaltrials.gov, NTC04632290): with the WIMAGINE technology, cortical motor intentions for leg movements are recorded, and real-time decoding translates brain signals into EES commands. This digital bridge empowered a chronic SCI participant, who has been part of the STIMO clinical trial, to regain leg motor control by volitional fine-tuned EES amplitudes enabling standing, walking and adapting to diverse terrains, demonstrating the efficacy of the BSI. Moreover, BSI-assisted neurorehabilitation mediated neurological improvements after three years of stable performance of the patient, that persisted even when the BSI was switched off.

In this study, the investigators will assess the preliminary safety and effectiveness of ECoG-controlled EES in individuals with chronic SCI who have not previously participated in STIMO clinical trial, to establish a direct bridge between the motor intention and the spinal cord below the lesion. This could improve or restore voluntary control of legs movement as well as promote neurological recovery when combined with neurorehabilitation. The WIMAGINE ECoG system will be coupled with the ARC-IM purpose-built spinal cord stimulation technology in the ARC-BSI Lumbar system. An equivalent technology (ARC-BSI Cervical system) is currently used in the ongoing UP2 clinical study (Clinicaltrials.gov, NCT05665998) for upper limb rehabilitation in patients with cervical spinal cord injury.

Inclusion Criteria:

1. Must provide Informed Consent as documented by signature (Appendix Informed Consent Form) prior to any study-related procedures,
2. Must be at least 18 years old and no older than 60 years old at the time of enrolment,
3. Must be suffering from non-progressive traumatic spinal cord injury,
4. Must be graded A, B, C, or D in the American Spinal Injury Association (ASIA) Impairment Scale (AIS) classification,
5. Must have completed primary standard of care rehabilitation,
6. Must have stable medical, physical and psychological condition as considered by the investigator,
7. Must be lesioned at T10 or above, based on AIS level determination by the investigator, with preservation of conus function,
8. Must have sustained the injury at least 12 months before signing the consent form,
9. Must have residual upper limb function (capable of using a manual wheelchair),
10. Must be able to understand and interact with the study team in French or English,
11. Must agree to comply in good faith with all conditions of the study and to attend all scheduled appointments,
12. Must use safe contraception for women of childbearing capacity.

Exclusion Criteria:

1. Must not be pregnant nor breast feeding,
2. Must not have the intention to become pregnant during the course of the study,
3. Must not have brain damage,
4. Must not have history of epilepsy,
5. Must not have participated in another clinical study using drugs or medical devices within the 30 days preceding and during the present study,
6. Must not have previously been injected with stem cells in the spinal cord,
7. Must not have any hematological disorders with increased risk for surgical intervention,
8. Must not require ventilator support,
9. Must not have limitation of walking function based on accompanying (Central Nervous System (CNS)) disorders (systemic malignant disorders, cardiovascular disorders restricting physical training, peripheral nerve disorders),
10. Must not suffer from spinal cord injury from other etiology than traumatic (ischemic, tumoral, autoimmune, etc.),
11. Must not display spinal stenosis or post traumatic damage at location of implantation,
12. Must not require the use of an intrathecal baclofen pump,
13. Must not be implanted with a device such as pacemakers or defibrillators,
14. Must not have any indication that would require Magnetic Resonance Imaging (MRI),
15. Must not suffer from congenital nor acquired lower limb abnormalities (affection of joints or bones).
16. Must not be the investigator himself, his/her family members, employees or other dependent persons.