The Analgesic Efficacy of Intradiscal Injection of Bone Marrow Aspirate Concentrate and Culture-Expanded Bone Marrow Mesenchymal Stromal Cells in Discogenic Pain: A Systematic Review

Review of Recent Treatment Strategies for Lumbar Disc Herniation (LDH) Focusing on Nonsurgical and Regenerative Therapies

Conservative treatment is primarily performed for the treatment of patients with lumbar disc herniation (LDH), but if it does not respond, surgical treatment can be performed. Surgical intervention has a positive effect on the rapid improvement of LDH symptoms. However, the effectiveness of surgical versus conservative treatment for LDH is controversial, especially regarding long-term effects. Recently, a treatment using platelet-rich plasma (PRP), bone marrow aspirate concentrate (BMAC), low-intensity pulsed ultrasound (LIPUS), etc., has been actively conducted as a treatment to avoid side effects of surgery and promote tissue regeneration. In this paper, the literature evaluating the effectiveness of non-surgical treatment options is reviewed with an emphasis on the effectiveness of clinical application. Several clinical studies have shown that PRP, biomaterials, BMAC, and LIPUS treatment promote tissue regeneration and alleviate symptoms. Although PRP-applied studies have suggested disc height changes, cell therapy and LIPUS treatment have many shortcomings in clinical aspects of tissue regeneration. Therefore, it is necessary to establish a unified, safe protocol and standardize the method of presenting results to confirm the clinical effect of the treatment for impaired intervertebral regeneration in patients with intervertebral disc degeneration (IDD), including LDH.

Biologic Therapies for Discogenic Pain

PURPOSE OF REVIEW

The purpose of this review is to provide an update on recent developments in the field of regenerative medicine, specifically focusing on emerging data related to biologics, including platelet-rich plasma and mesenchymal cells, for the treatment of discogenic back pain.

RECENT FINDINGS

There has been a notable surge of interest in biologics, as evidenced by a wealth of recent reviews and studies. While serious adverse events are generally uncommon, considerable heterogeneity exists in study designs. More robust investigations are warranted to thoroughly evaluate the safety and efficacy of biologics in treating discogenic back pain. Continued research and funding are needed to better understand the underlying mechanisms of disc degeneration and to develop targeted therapies that can alleviate and reduce the burden of this debilitating condition. Biologics may offer effective treatments for discogenic pain; however, more multi-center, prospective, double-blinded, randomized placebo-controlled trials are essential to further establish their effectiveness.

Evidence-based orthobiologic practice: Current evidence review and future directions

The field of orthopedic and regenerative medicine is rapidly evolving with the increasing utilization of orthobiologic. These biologically derived therapies, including platelet-rich plasma, mesenchymal stem cells, bone marrow aspirate concentrate, stromal vascular fraction (SVF), and autologous chondrocyte implantation, are gaining traction for their potential to enhance the body's natural healing processes. They offer a promising alternative to traditional surgical interventions for musculoskeletal injuries and degenerative conditions. Current evidence suggests significant benefits of orthobiologics in treating conditions like osteoarthritis, tendon injuries, and spinal disorders, yet inconsistencies in treatment protocols and outcomes persist. The global market for orthobiologics is projected to grow substantially, driven by advancements in biologic therapies such as adipose-derived stem cells and SVF, and the demand for minimally invasive treatments. Despite their promise, regulatory and ethical challenges, as well as the need for high-quality, standardized research, remain significant obstacles. Future directions in the field include advancements in delivery systems, personalized medicine approaches, and the exploration of novel sources like induced pluripotent stem cells, aiming for more targeted and effective treatments. Collaborative efforts are crucial to overcoming these challenges and ensuring the safe and effective application of orthobiologics in clinical practice.

Evidence-Based Clinical Practice Guidelines on Regenerative Medicine Treatment for Chronic Pain: A Consensus Report from a Multispecialty Working Group

Purpose

Injectable biologics have not only been described and developed to treat dermal wounds, cardiovascular disease, and cancer, but have also been reported to treat chronic pain conditions. Despite emerging evidence supporting regenerative medicine therapy for pain, many aspects remain controversial.

Methods

The American Society of Pain and Neuroscience (ASPN) identified the educational need for an evidence-based guideline on regenerative medicine therapy for chronic pain. The executive board nominated experts spanning multiple specialties including anesthesiology, physical medicine and rehabilitation, and sports medicine based on expertise, publications, research, and clinical practice. A steering committee selected preliminary questions, which were reviewed and refined. Evidence was appraised using the United States Preventive Services Task Force (USPSTF) criteria for evidence level and degree of recommendation. Using a modified Delphi approach, consensus points were distributed to all collaborators and each collaborator voted on each point. If collaborators provided a decision of "disagree" or "abstain", they were invited to provide a rationale in a non-blinded fashion to the committee chair, who incorporated the respective comments and distributed revised versions to the committee until consensus was achieved.

Results

Sixteen questions were selected for guideline development. Questions that were addressed included type of injectable biologics and mechanism, evidence in treating chronic pain indications (eg, tendinopathy, muscular pathology, osteoarthritis, intervertebral disc disease, neuropathic pain), role in surgical augmentation, dosing, comparative efficacy between injectable biologics, peri-procedural practices to optimize therapeutic response and quality of injectate, federal regulations, and complications with mitigating strategies.

Conclusion

In well-selected individuals with certain chronic pain indications, use of injectable biologics may provide superior analgesia, functionality, and/or quality of life compared to conventional medical management or placebo. Future high-quality randomized clinical trials are warranted with implementation of minimum reporting standards, standardization of preparation protocols, investigation of dose-response associations, and comparative analysis between different injectable biologics.

Perspective on Intradiscal Therapies for Lumbar Discogenic Pain: State of the Science, Knowledge Gaps, and Imperatives for Clinical Adoption

Specific clinical diagnostic criteria have established a consensus for defining patients with lumbar discogenic pain. However, if conservative medical management fails, these patients have few treatment options short of surgery involving discectomy often coupled with fusion or arthroplasty. There is a rapidly-emerging research effort to fill this treatment gap with intradiscal therapies that can be delivered minimally-invasively via fluoroscopically guided injection without altering the normal anatomy of the affected vertebral motion segment. Viable candidate products to date have included mesenchymal stromal cells, platelet-rich plasma, nucleus pulposus structural allograft, and other cell-based compositions. The objective of these products is to repair, supplement, and restore the damaged intervertebral disc as well as retard further degeneration. In doing so, the intervention is meant to eliminate the source of discogenic pain and avoid surgery. Methodologically rigorous studies are rare, however, and based on the best clinical evidence, the safety as well as the magnitude and duration of clinical efficacy remain difficult to estimate. Further, we summarize the US Food and Drug Administration's (FDA) guidance regarding the interpretation of the minimal manipulation and homologous use criteria, which is central to designating these products as a tissue or as a drug/device/biologic. We also provide perspectives on the core evidence and knowledge gaps associated with intradiscal therapies, propose imperatives for evaluating effectiveness of these treatments and highlight several new technologies on the horizon.

Minimally Invasive Intradiscal Delivery of BM-MSCs via Fibrous Microscaffold Carriers

Current treatments of degenerated intervertebral discs often provide only temporary relief or address specific causes, necessitating the exploration of alternative therapies. Cell-based regenerative approaches showed promise in many clinical trials, but limitations such as cell death during injection and a harsh disk environment hinder their effectiveness. Injectable microscaffolds offer a solution by providing a supportive microenvironment for cell delivery and enhancing bioactivity. This study evaluated the safety and feasibility of electrospun nanofibrous microscaffolds modified with chitosan (CH) and chondroitin sulfate (CS) for treating degenerated NP tissue in a large animal model. The microscaffolds facilitated cell attachment and acted as an effective delivery system, preventing cell leakage under a high disc pressure. Combining microscaffolds with bone marrow-derived mesenchymal stromal cells demonstrated no cytotoxic effects and proliferation over the entire microscaffolds. The administration of cells attached to microscaffolds into the NP positively influenced the regeneration process of the intervertebral disc. Injectable poly(l-lactide-co-glycolide) and poly(l-lactide) microscaffolds enriched with CH or CS, having a fibrous structure, showed the potential to promote intervertebral disc regeneration. These features collectively address critical challenges in the fields of tissue engineering and regenerative medicine, particularly in the context of intervertebral disc degeneration.

Updates on Pathophysiology of Discogenic Back Pain

Discogenic back pain, a subset of chronic back pain, is caused by intervertebral disc (IVD) degeneration, and imparts a notable socioeconomic health burden on the population. However, degeneration by itself does not necessarily imply discogenic pain. In this review, we highlight the existing literature on the pathophysiology of discogenic back pain, focusing on the biomechanical and biochemical steps that lead to pain in the setting of IVD degeneration. Though the pathophysiology is incompletely characterized, the current evidence favors a framework where degeneration leads to IVD inflammation, and subsequent immune milieu recruitment. Chronic inflammation serves as a basis of penetrating neovascularization and neoinnervation into the IVD. Hence, nociceptive sensitization emerges, which manifests as discogenic back pain. Recent studies also highlight the complimentary roles of low virulence infections and central nervous system (CNS) metabolic state alteration. Targeted therapies that seek to disrupt inflammation, angiogenesis, and neurogenic pathways are being investigated. Regenerative therapy in the form of gene therapy and cell-based therapy are also being explored.