Restoring Hand Functions in People with Tetraplegia through Multi-Contact, Fascicular, and Auto-Pilot Stimulation: A Proof-of-Concept Demonstration.

Two multi-contact epineural electrodes were placed around radial and median nerves of two subjects with high tetraplegia C4, American Spinal Injury Association Impairment Scale (AIS) A, group 0 of the International Classification for Surgery of the Hand in Tetraplegia. The purpose was to study the safety and capability of these electrodes to generate synergistic motor activation and functional movements and to test control interfaces that allow subjects to trigger pre-programmed stimulation sequences. The device consists of a pair of neural cuff electrodes and percutaneous cables with two extracorporeal connection cables inserted during a surgical procedure and maintained for 28 days. Continuity tests of the electrodes, selectivity of movements induced, motor capacities for grasping and gripping, conformity of the control order, tolerance, and acceptability were assessed. Neither of the two participants showed general and local comorbidity. Acceptability was optimal. None of the stimulation configurations generated contradictory movements. The success rate in task execution by the electro-stimulated hand exceeded the target of 50% (54% and 51% for patients 1 and 2, respectively). The compliance rate of the control orders in both patients was >90% using motion inertial measurement unit (IMU)-based detection and 100% using electromyography (EMG)-based detection in patient 1. These results support the relevance of neural stimulation of the tetraplegic upper limb with a more selective approach, using multi-contact epineural electrodes with nine and six contact points for the median and radial nerve respectively.

Functional and/or hygienic surgery of the hypertonic upper limb.

Neuro-orthopedic complications of the upper limb affect all of its joints and lead to a multitude of clinical pictures. The clinical assessment, which should be multidisciplinary, will have to answer basic questions to define the goal(s) and the appropriate surgical strategy. What is the patient's and family's complaint? What is the possible utility of the deformities? What is the type of deformity? Is it reducible or not? What is the contribution of the upper limb deformities versus that of any associated injuries to the discomfort? Several difficulties exist in the clinical assessment: evaluation of the antagonists especially the wrist extensor muscles; the intrinsic deformity component, which can be masked by the extrinsic component when retracted, the muscles responsible for a wrist flexion contracture and the complex shoulder deformities. Many patients have multiple deformities, which creates a problem for the hierarchy of corrections depending on the objectives. The answer to these questions helps to define a clear objective that will be formalized in a contract with the patient and subsequently to define the surgical strategy. Surgery is based on a simple principle: relax the muscles on the side of the deformity, either by selective neurotomy if there is a simple hypertonia, or by a tendon procedure if the muscle is retracted; compensate for the antagonists if they are deficient, and potentially stabilize the joint. Conservative procedures are preferred to preserve the possibility of functional recovery in the future. The wide range of medical and surgical solutions allows the patient's care to be personalized. In the upper limb, the results are better for hygienic, positioning, and analgesic objectives. They remain more difficult to obtain for functional objectives, due to the biomechanical complexity of gripping.