Is Intradiscal Injection of Autologous Bone Marrow Aspirate Concentrate Following Lumbar Microdiscectomy Safe?

Introduction: This study examines the safety of intradiscal bone marrow aspirate concentrate (BMAC) injections after microdiscectomy in lumbar disc herniation patients. While BMAC shows promise for early-stage disc degeneration, its post-microdiscectomy safety is unknown. The research evaluates clinical outcomes and adverse events to assess BMAC's safety in this context.

Methods: This prospective safety study examined patients with degenerative disc disease undergoing tubular lumbar microdiscectomy with concurrent BMAC injection. The primary outcome was safety via adverse events. Secondary outcomes included patient-reported measures (ODI, NRS for pain) and radiological assessments (T2 and T1-rho MRI) at pre-op, 3, 6, and 12 months. MRI analysis used Gaussian mixture modeling and manual segmentation to evaluate disc hydration, proteoglycan content, and nucleus pulposus size. Statistical analysis employed one-way ANOVA and generalized linear models.

Results: Twenty-seven patients (mean age: 39.7±14.7 years, 55.6% male) were included. One patient (3.7%) experienced same-site recurrent herniation; no other complications were reported. PROMs from 22 patients significantly improved (p < 0.0001) at all time points. Mean ODI decreased from 38 pre-operatively to 13.5 in one year. NRS-back scores improved from 7 to 1, and NRS-leg scores improved from 6 to 0. Radiological outcomes from 5 patients (15 discs) at one year showed increased T2 relaxation times (p < 0.05), while T1-rho mapping revealed decreased proteoglycan content at three months, increasing at one year. Strong correlations were found between T1-rho intensities and NRS scores.

Conclusion : Intradiscal BMAC injection following lumbar microdiscectomy appears safe, with significant improvements in pain and disability. Radiological findings suggest benefits in disc hydration and health. Future controlled studies are needed to confirm these findings and explore the long-term effects of BMAC on IVDs.