STIMO is a First-in-Man (FIM) study to confirm the safety and feasibility of a closed-loop Epidural Electrical Stimulation (EES) in combination with overground robot assisted rehabilitation training for patients with chronic incomplete spinal cord injury (SCI).

Patients will participate during 8-12 months, during which there will be:

• Pre-implant evaluations (6-8 weeks)
• Device implantation and stimulation optimization (6-8 weeks)
• Overground rehabilitation training with EES (5-6 months). In the period after implantation, participants need to be present for testing and training, 4 days per week at the CHUV University Hospital in Lausanne (lodging can be provided). It is possible to complement the neuro-rehabilitative training at CHUV with training outside the rehabilitation room by making use of the Home-use system.

At the end of the protocol, the study aims to make the patients walk better and faster. As this is the first study of its kind, success is not guaranteed. However, the potential benefits outweigh the potential risks.

An optional extension of the study up to 3 years is offered. During this period, the patient can continue the training with the Home-use system.

STIMO is a First-in-Man (FIM) study with the objective to confirm the safety and feasibility of a closed-loop Epidural Electrical Stimulation (EES) in combination with overground robot assisted rehabilitation training for patients with chronic incomplete spinal cord injury (SCI), as it was previously successfully demonstrated in animals.

The study consists of two phases:

A. Main study

The main study lasts about 8-12 months for each individual participant, from signing informed consent to the final test in the study This period can be divided into 3 distinct phases:

• Pre-implant : about 6-8 weeks from informed consent to implant. During this phase, patient will participate during a total of 6 distinct days of evaluations, of which 5 days in Lausanne and 1 day at the assessment center in Zurich. The patient will also participate to 3 weeks of pre-implantation training in a Body Weight Support (BWS) system.
• Implant and stimulation optimization: about 6-8 weeks, including the implantation of the epidural lead and the neurostimulator. In this phase, the optimal stimulation parameters will be determined for the flexing and stretching of both legs. During this period, participants need to be present at the CHUV University Hospital in Lausanne 4-5 days per week (lodging can be provided).
• Rehabilitation training and final evaluation: 4 days per week of rehabilitation training during a period of 5 months, followed by a final evaluation lasting 4 days in Lausanne and 1 day in Zurich. In this phase, the patients receive intensive overground rehabilitation training using a body weight support device in combination with EES, with the aim of significantly improving their walking capabilities. During this period, participants need to be present at the CHUV University Hospital in Lausanne (lodging can be provided) 4 days per week.

Once the patient has shown the ability to stand or walk safely without robotic assistance, he/she is offered the possibility to complement his/her neuro-rehabilitative training using EES outside the robotic environment and rehabilitation room by making use of the Home-use system.

B. Optional study extension (3 years)

The patient has the possibility to continue his/her neuro-rehabilitative training with the home-use system for an additional period of 3 years after the end of clinical rehabilitation period. During this period, evaluation measures and technical check-ups are made at regular time points. The patient is contacted monthly to ensure a normal training conduct and a safety follow-up.

At the end of the protocol, the study aims to make the patients walk better and faster. Improvements are quantified through pre-defined measures assessed prior to implant and at the end of the main study as well as at regular time points during the optional study extension.

As this is the first study of its kind, success is not guaranteed. However, the potential benefits outweigh the potential risks.

Inclusion Criteria:

• Age 18-65 (women or men)
• Incomplete SCI graded as AIS A,B,C & D
• Level of lesion: T10 and above, based on AIS level determination by the PI, with preservation of conus function
• The intact distance between the cone and the lesion must be at least 60mm
• Focal spinal cord disorder caused by either trauma or epidural, subdural or intramedullary bleeding
• Minimum 12 months post-injury
• Completed in-patient rehabilitation program
• Able to stand with walker or 2 crutches
• Stable medical and physical condition as considered by Investigators
• Adequate care-giver support and access to appropriate medical care in patient's home community
• Agree to comply in good faith with all conditions of the study and to attend all required study training and visits
• Must participate in two training sessions before enrolment
• Must provide and sign Informed Consent prior to any study related procedures

Exclusion Criteria:

• Limitation of walking function based on accompanying (CNS) disorders (systemic malignant disorders, cardiovascular disorders restricting physical training, peripheral nerve disorders)
• History of significant autonomic dysreflexia
• Cognitive/brain damage
• Epilepsy
• Patient who has spinal canal stenosis
• Patient who uses an intrathecal Baclofen pump.
• Patient who has any active implanted cardiac device such as pacemaker or defibrillator.
• Patient who has any indication that would require diathermy.
• Patient who has any indication that would require MRI.
• Patient that have an increased risk for defibrillation
• Severe joint contractures disabling or restricting lower limb movements.
• Haematological disorders with increased risk for surgical interventions (increased risk of haemorrhagic events).
• Participation in another locomotor training study.
• Congenital or acquired lower limb abnormalities (affection of joints and bone).
• Women who are pregnant (pregnancy test obligatory for woman of childbearing potential) or breast feeding or not willing to take contraception.
• Known or suspected non-compliance, drug or alcohol abuse.
• Spinal cord lesion due to either a neurodegenerative disease or a tumour.
• Patient has other anatomic or co-morbid conditions that, in the investigator's opinion, could limit the patient's ability to participate in the study or to comply with follow-up requirements, or impact the scientific soundness of the study results.
• Patient is unlikely to survive the protocol follow-up period of 12 months.