From Molecular State to Clinical Outcomes After Spinal Cord Injury: A Scoping Review of Selected Fluid Biomarkers and Rehabilitation Relevance

Human fluid biomarkers may complement neurological assessment after spinal cord injury (SCI), but their relevance to rehabilitation depends on the clinical relationship tested. This scoping review mapped selected neuroendocrine, inflammatory, neurotrophic and neural injury biomarkers in serum, plasma or cerebrospinal fluid. Five databases were searched on 8 October 2026; 17,317 records yielded 41 included reports. Findings were charted by phenotype, sampling window, assay, outcome and analytical denominator, with question-appropriate critical appraisal. Two reports randomized interventions, and 39 reports contributed nonrandomized biomarker analyses. Acute neural injury markers mainly addressed initial severity and later neurological status. Prognostic signals included neurofilament light, glial fibrillary acidic protein and tau, but all 10 prediction-model reports had high overall risk of bias; independent validation remained insufficiently established. Chronic endocrine, mobility and pain studies examined different constructs. Partial integration included biomarker–imaging models and trial-embedded associations; no identified report validated biomarker-guided rehabilitation dosing or a causal molecular–circuit–functional pathway. Reports with age-related eligibility uncertainty or combined neurotrauma were interpreted separately. Heterogeneous assays, overlapping cohorts, incomplete follow-up and incompletely quantified rehabilitation exposure limited inference. These data support focused prospective validation rather than routine biomarker-directed rehabilitation. Mandatory marker, matrix and outcome search terms constrain coverage; absence claims apply to the identified reports.