A study on the effect of platelet-rich plasma (PRP) to promote bone fusion in lateral interbody fusion of the lumbar spine using artificial bone.

Background: Lateral lumbar interbody fusion (LLIF) via a retroperitoneum approach has gained popularity due to minimal invasiveness, which avoids resection of the spinous process and laminae. However, as challenges in grafting autogenous bone persist, artificial bone has been tested in Japan to fill the spinal cage. Platelet-rich plasma (PRP) contains growth factors and anti-inflammatory cytokines to promote cellular proliferation and repair damaged tissues. While the effects of PRP on tendon and ligament repair are widely known, any effects on bone healing are scarcely reported. However, PRP-loaded artificial bone carries potential to improve intervertebral bone fusion.

Objective: This study assessed whether PRP enhances intervertebral bone fusion in LLIF surgery using β-tricalcium phosphate artificial bone.

Methods: The current study was a prospective, randomized, controlled trial. We evaluated 13 consecutive patients undergoing LLIF surgery in our hospital. Patients received artificial bone impregnated with PRP or without PRP within the same fusion cage. The primary outcome was the intervertebral bone fusion rate at 6 and 12 months postoperatively, evaluated using CT imaging. The intervertebral bone fusion rates with and without PRP loading and with and without contact part between the endplate and the artificial bone were compared. Secondary outcomes included clinical evaluations using visual analog scale scores for low back pain, buttock-leg pain, and leg numbness from the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOA-BPEQ) and the Oswestry Disability Index (ODI), plus adverse events information.

Results: Of the 13 patients (29 vertebral segments) included, bone fusion was observed in 43.4% of the PRP group and 26.1% of the non-PRP group at 6 months (p = 0.216). At 12 months, fusion rates were 60.9% with PRP and 34.8% without PRP (p = 0.074). The fusion rate was significantly higher in cases with good contact between the vertebral endplate and the artificial bone (p = 0.0004). Clinical scores improved postoperatively. Adverse events were in accordance with expectations from LLIF surgery and no PRP-specific events occurred.

Conclusion: PRP did not significantly improve intervertebral bone fusion rates in LLIF surgeries, particularly in cases with poor contact between the vertebral endplate and artificial bone. While PRP may have a limited role in enhancing bone fusion, maintaining good contact between the vertebral endplate and artificial bone is crucial for successful outcomes. Further research is needed to explore optimal uses of PRP in spinal fusion surgeries.