Why the Back and Spine Are a Focus of Stem Cell Research
The spine is a stack of bones called vertebrae, and between most of them sits an intervertebral disc: a firm outer ring with a soft, water-rich center that cushions the bones and lets the back bend. Low back pain is one of the most common reasons people seek care, and a 2023 review describes back pain as the single leading cause of disability worldwide.[1] A 2024 randomized trial opens with a similar figure, noting that chronic low back pain affects more than 600 million people worldwide.[13]
The same review notes that there is no gold-standard treatment that restores the physiological function of degenerated discs, and it describes stem cells as a strategy under study for degenerative disc disease.[1] Researchers therefore ask whether cells, or the signals they release, change how a degenerated disc behaves.
What Mesenchymal Stem Cells Are
Mesenchymal stem cells, shortened to MSCs and also called mesenchymal stromal cells, are adult cells that trials draw from bone marrow and fat.[7] In 2006 the International Society for Cellular Therapy set minimal criteria for calling a cell a human MSC: it must adhere to plastic in culture, carry the surface markers CD105, CD73 and CD90 while lacking CD45, CD34, CD14 or CD11b, CD79alpha or CD19 and HLA-DR, and be able to form bone, fat and cartilage cells in a dish.[2]
Researchers are especially interested in what MSCs release. In a 2017 paper, Arnold Caplan argued that MSCs home to sites of injury or disease and secrete bioactive factors that are immunomodulatory and trophic, and proposed the name "medicinal signaling cells" to reflect that.[3]
For a plain-language introduction to the cells themselves, read what stem cells are and what mesenchymal stem cells are on the GIOSTAR blog, or see the stem cell therapy page.
How Researchers Study Stem Cells and the Back and Spine
A study starts with a written plan, called a protocol, that sets out who can take part, what each group receives and what the researchers will measure. Three examples from ClinicalTrials.gov: a completed phase 2 study comparing an intradiscal injection of autologous bone marrow MSCs with a sham procedure enrolled 48 people,[17] a phase 3 study of rexlemestrocel-L combined with hyaluronic acid against saline lists 300 planned participants,[18] and a phase 2 study of a cell product called BRTX-100 against saline lists 99 planned participants.[19]
Studies of the disc compare a group that receives cells with a group that receives a sham procedure or a saline injection, as in the trials and reviews below.[4][12] In a double-blind study, neither the participants nor the researchers measuring the results know who is in which group until the study ends. Studies of spinal fusion work differently: two randomized trials compared a graft containing cells with the standard graft, and the main measure was whether the bones fused.[14][15] You can read more in how stem cell research works.
What the Evidence Base Looks Like
The evidence on MSCs and the spine comes in three layers: pooled analyses of many studies, individual randomized trials, and registered studies that are still running or unpublished. The layers do not all say the same thing, and the differences are part of the science.
Systematic reviews and meta-analyses
A systematic review searches the literature by a fixed method and a meta-analysis pools the numbers. Recent ones on cell-based injections for disc-related low back pain report:
- 2026, Asian Spine Journal. 7 randomized trials comparing intradiscal MSC injection with sham or placebo.[4] Pain scores on the visual analog scale and the Oswestry Disability Index (a standard back-disability questionnaire) improved more with MSC injection, and the difference grew with longer follow-up.[4] There were no significant differences in adverse events.[4] The authors described the gains as modest.[4]
- 2024, Pain Physician. 8 randomized trials of intradiscal platelet-rich plasma or MSC injections and 8 observational studies.[5] The authors rated the evidence quality as fair, at Level III, with limited certainty, and listed the scarcity of rigorous studies as a limitation.[5]
- 2018, Pain Physician. 21 injection studies, 12 of them into the lumbar disc.[6] Disc injections of platelet-rich plasma and MSCs reached Level 3 evidence on a five-level scale, and the authors noted a lack of rigorous randomized trials.[6]
- 2025, Neurospine. 10 published clinical studies with 736 participants, using bone marrow and adipose-derived MSCs.[7] Questionnaires indicated modest improvements in pain, disability and function, and MRI occasionally showed increased disc hydration or a stable or better Pfirrmann grade.[7] The review also listed 8 ongoing trials with 498 participants.[7]
- 2022, The Spine Journal. 12 studies of intradiscal biologics.[8] The authors graded the quality of evidence as very low, noted that the single trial of MSCs was negative, and reported a pooled 6-month success rate of 53.5% for MSCs, which fell to 40.7% in a worst-case analysis.[8]
- 2025, International Journal of Spine Surgery. 8 articles with 283 cases.[9] Oswestry and visual analog scale scores and Pfirrmann grade improved after intradiscal stem cell therapy.[9]
- 2026, European Spine Journal. 13 randomized trials of biologic injections for degenerative spinal pain.[10] Autologous bone marrow concentrate and MSC preparations did not show superiority over sham for the main pain and function outcomes, while allogeneic mesenchymal precursor cells showed improvements through 36 months in the trial the review cited.[10] The authors called allogeneic precursor cells investigational and asked for larger multicenter trials.[10]
- 2024, JOR Spine. 68 studies with at least 1,974 treated patients.[11] Cell and platelet-rich plasma injections were associated with clinically meaningful pain and disability changes up to 2 years, but the authors noted high levels of bias, mixed designs and only a minimal number of randomized trials.[11]
- 2023, International Journal of Molecular Sciences. 21 reports, only one of them a randomized trial.[1] The authors found no evidence to support use in humans and called for studies of efficacy, safety and patient selection.[1]
Read together, the reviews agree that the field is early and that most studies are small.[1][5][11] They disagree on how large any effect is: the 2026 meta-analysis of sham-controlled trials reported modest gains, while the 2022 and 2023 reviews graded the evidence as very low or found none to support use.[1][8]
Individual randomized trials
- 2017, Transplantation. 24 patients with chronic back pain from lumbar disc degeneration received allogeneic bone marrow MSCs injected into the disc or a sham injection in the paravertebral muscles, and were followed for a year.[12] Treated patients improved quickly compared with controls, the improvement appeared restricted to a group of responders that included 40% of the cohort, and Pfirrmann grade improved in the treated group and worsened in controls.[12] It is registered as NCT01860417.[12]
- 2024, Pain Physician. 40 patients were randomized to a saline trigger point injection, intradiscal platelet-rich plasma or intradiscal bone marrow concentrate.[13] Both active groups improved in pain and function, all placebo patients reported less than 50% pain relief and crossed over, and no patient had adverse effects.[13] The authors listed the small number of patients and the open-label design as limitations.[13]
- 2020, The Spine Journal. 73 patients having lumbar interbody fusion were randomized to expanded bone marrow MSCs on allograft bone or to the standard iliac crest graft.[14] CT-based posterior fusion was higher with the cell graft at 6 months (92.3% versus 45.7%) and not significantly higher at 12 months (76.5% versus 65.7%).[14] Pain and disability scores improved after surgery with no difference between groups.[14]
- 2014, The Spine Journal. 80 patients having instrumented posterolateral lumbar fusion received allograft chips alone or mixed with bone marrow concentrate.[15] On CT at 24 months, 80% of the concentrate group and 40% of the allograft group showed at least unilateral bridging bone.[15]
- 2017, Stem Cell Research and Therapy. A single-arm phase 1 study of 10 patients who received adipose-derived MSCs with a hyaluronic acid derivative in the disc.[16] No procedure or cell-related adverse events were seen over 12 months, and the authors called for a randomized trial in a larger population.[16] It is registered as NCT02338271.[16]
Most of these trials are small, use different cell sources and preparations, and follow patients for 12 months or two years.[12][13][14][15] The spinal fusion trials measure bone healing, which is a different question from back pain.[14][15]
What Stem Cell Studies of the Back and Spine Track
Studies of MSCs and the spine usually track four kinds of information:
- What participants report. Standard questionnaires and scales such as the visual analog scale and the Oswestry Disability Index ask about pain and daily function.
- What imaging shows. MRI lets researchers look at disc hydration and the Pfirrmann grade, a scale of disc degeneration, and CT shows whether bone has fused after a fusion operation.[7][14]
- How participants tolerated the procedure. The reviews above tally adverse events, and the 2026 meta-analysis found no significant differences between groups in treatment-emergent adverse events.[4]
- How long the study followed participants. The trials above followed participants for 12 to 36 months.[10][12][14]
How to Read a Stem Cell Study of the Back and Spine
A few details tell you a lot about any study:
- The design. Whether it was randomized and blinded, and whether the comparison group received a sham procedure, saline or another active treatment.
- The size. How many people took part in each group.
- The follow-up. How long participants were followed after the procedure.
- The cells. Where they came from (bone marrow, fat), whether they were grown in culture, and whether the product was a concentrate or a purified cell type. The 2026 European Spine Journal review reported different results for bone marrow concentrate and for allogeneic precursor cells.[10]
- The certainty. Reviews that grade the quality of evidence, such as the 2022 Spine Journal review,[8] tell you how much the pooled number could move with new trials.
- The registration. The 2025 Neurospine review searched ClinicalTrials.gov and counted 8 ongoing trials alongside the 10 published studies.[7]
Where to Find Stem Cell Studies of the Back and Spine
Registered studies are listed publicly on ClinicalTrials.gov. Start with a search for mesenchymal stem cell studies of the intervertebral disc on ClinicalTrials.gov, and read published results on PubMed. Every source in this guide is listed under References with its PubMed and DOI links.
Other joints and tissues are studied too. Read the companion guides on the knee, the shoulder, the hip and the elbow and tendons.
Regulatory Status
A 2026 review of FDA regulation of biologics finds that enforcement has been uneven.[20] Our stem cell therapy is not approved by the FDA.
Further reading: the FDA's consumer page on regenerative medicine therapies, fda.gov (a regulator page; not a numbered reference).
