INTRODUCTION: Platelet-rich plasma (PRP) is an autologous blood concentrate containing a vast majority of bioactive proteins. PRP has been used for treatment of musculoskeletal pathologies, including muscle and tendon injuries and osteoarthritis. Recently, clinical application of PRP is also gaining popularity in treating degenerative disc disease. This study evaluated the efficacy and safety of PRP-releasate (PRPr) injection into degenerated discs of patients with discogenic low back pain (LBP).

METHODS: A randomized, double-blind, active-controlled clinical trial was conducted. Patients aged > 18 years who had LBP for more than three months with one or more lumbar discs (L3/L4 to L5/S1) with evidence of degeneration, as indicated by magnetic resonance imaging (MRI), and at least one symptomatic disc, confirmed using standardized provocative discography, were considered for inclusion. Sixteen patients (mean age: 32.2 ± 8.3 years old, 11 men, 5 women) with discogenic LBP were randomly assigned to receive an intradiscal injection of either autologous PRPr or corticosteroid (CS) (betamethasone sodium phosphate). Patients in both groups who wished to have PRPr treatment received an optional injection of PRPr eight weeks later. The primary outcome was change in visual analogue scale (VAS) from baseline at eight weeks post-injection. Secondary outcomes were pain, disability, quality of life (QOL), radiographic disc height, magnetic resonance imaging (MRI) grading of disc degeneration, the success rate of the treatment, and safety for up to 60 weeks.

RESULTS: VAS scores of both PRPr and CS groups decreased significantly over the observation period (P<0.01) (Fig. 1). VAS change at eight weeks did not significantly differ between PRPr (-30.9 mm) and CS (-26.3 mm) groups (P=0.6). Fifteen patients received the optional injection. Compared to the CS group, the PRPr group (PRPr double injection) had significantly improved disability score at 26 weeks (PRPr: -88.0%, CS: -42.1%, P<0.05), and walking ability scores at four and eight weeks (P<0.05, respectively). The mean change in radiographic disc height of the PRPr group tended to be higher than that of the CS group throughout, and a statistical significance was identified at week 60 (P<0.05). MRI grading score was unchanged from baseline. PRPr caused no clinically important adverse events, except for injection pain.

DISCUSSION: The intradiscal injection of PRPr showed clinically significant improvements in LBP intensity in patients with discogenic LBP, like those injected with glucocorticoid at eight weeks post-injection. PRPr treatment was safe and maintained improvements in pain, disability, and QOL for 60 weeks follow-up.