Intradiscal platelet-rich plasma for discogenic low back pain: a prospective cohort study of early clinical outcomes and quantitative MRI findings.

Discogenic low back pain (DLBP) is a major cause of disability. Platelet-rich plasma (PRP) has shown regenerative potential in preclinical models, but clinical results remain heterogeneous and early biological responses in humans are incompletely understood. We conducted a prospective cohort study (November 2023-October 2024) to evaluate early clinical outcomes and quantitative MRI (qMRI) changes after intradiscal PRP injection for DLBP. Symptom scores (VAS, ODI and FRI) and qMRI measures (whole-disc T2 and vertebral marrow fat fraction in adjacent vertebrae) were assessed at baseline and at 1, 3 and 6 months. A composite minimal clinically important difference (MCID) was predefined as a ≥ 30% reduction from baseline in both VAS and ODI. Longitudinal changes were analyzed using linear mixed-effects models, and baseline-to-6-month changes were correlated using Pearson tests. Forty-five patients were recruited and 29 completed follow-up. VAS, ODI and FRI decreased significantly over time (all P < 0.001), and 79.3% achieved the composite MCID at 6 months. Vertebral marrow fat fraction adjacent to the treated disc declined significantly (P < 0.001) and correlated with improvements in VAS, ODI and FRI (r ≈ 0.46-0.56; P < 0.01), whereas changes in whole-disc T2 were small and not associated with symptom change. No treatment-related complications were observed. Intradiscal PRP appeared safe and clinically promising over 6 months, with qMRI suggesting an early effect on the peridiscal metabolic environment.