Risks of Intradiscal Orthobiologic Injections: A Review of the Literature and Case Series Presentation

Background: Intervertebral disc disease (IDD) is responsible for a large portion of back pain with historically suboptimal treatments for long-term improvement. IDD pathogenesis is thought to arise at a cellular and biochemical level, making biologically based injections an area of clinical interest. Although human studies have shown promise, emerging data suggest there may be risks inherent to such injections that were previously unrecognized. The aim of this review is to summarize the known risks to date and provide mitigation steps to reduce potential complications in the future. In addition, we present a small case series of serious adverse events (SAEs) from our clinical practice.

Methods: A literature review was performed to identify human intradiscal autologous biologic injection studies to date, including mesenchymal signaling cells (MSCs) and platelet-rich plasma (PRP) preparations, which were reviewed for complications. Cases of complication following intradiscal orthobiologic injection were identified from a single outpatient center and reviewed.

Results: Publications of MSC-based intradiscal injection documented 136 total patients treated with two SAEs reported, one infection and one progressive disc herniation. Publications of PRP intradiscal injection included 194 patients with one SAE reported. We also review three cases of previously unpublished SAEs, including one case of confirmed infection with Cutibacterium acnes (C acnes) and two presumed cases of discitis without pathogen confirmation. Bone marrow concentrate was the injectate in all three cases.

Conclusions: Although biologic intradiscal injection shows promise for the treatment of discogenic back pain, there are inherent risks to be considered and mitigated. We currently recommend a leukocyte-rich PRP and a two-needle delivery technique coupled with intradiscal gentamicin to mitigate the risk of postinjection spondylodiscitis. Further research is needed using large registries to not only track clinical outcomes but also complication rates.