Observational Studies+ Transforming Research and Clinical Knowledge in SCI (TRACK-SCI)+ Traumatic Incomplete Tetraplegia without Instability: A Prospective Multicenter Feasibility Study of Outcomes and Prognosis (IN-TWIN) (closed for enrollment)+ High Density Electrode Recording as a Novel Biomarker for Human Spinal Cord Injury (Electrode SCI) Clinical Trials+ Duraplasty for Acute Traumatic Spinal Cord Injury (DATSCI) + Safety of Transcutaneous Electrical Stimulation Potentiating Recovery in Acute Spinal Cord Injury Syndromes (STEP-RAISE)