EFFICACY AND SAFETY OF STEM CELLS IN STANDALONE LUMBAR INTERBODY FUSION FOR RECURRENT DISC HERNIATIONS

1. Abstract

Objective: This study aimed to evaluate the therapeutic effectiveness and safety of allogeneic stem cell injections in the intervertebral discs of patients with recurrent disc herniations.

Methods: An observational cohort study involved 75 patients with a history of recurrent lumbar disc herniations. During their revision endoscopic transforaminal discectomy surgery, participants received allogeneic cortico-cancellous bone graft infused with allogeneic Mesenchymal Stem Cells (MSCs) placed into the affected hollow intervertebral vacuum discs to achieve un-instrumented spinal fusion aimed at improving clinical outcomes by lowering the risk of recurrent disc herniation at the index level. The primary outcome measure was the interbody fusion grading. Secondary outcomes included: 1) pain intensity (measured by the Visual Analog Scale), 2) functional disability evaluated using the Oswestry Disability Index., and 3) quality of life assessed by the modified Macnab criteria questionnaire. Assessments were made at baseline, 3, 6, 12, and 24 months post-treatment.

Results: At the 24-month follow-up, 40 patients (53.3%) reported excellent, 24 (32.0%) indicated good, and 11 (14.7%) declared fair functional Macnab outcomes. VAS Leg pain was substantially reduced from a preoperative mean of 8.86 ± 1.086 to 3.00 ± 4.423, signifying a mean decrease of 5.27 ± 2.15 (p < 0.001). The ODI decreased from 55.88 ± 17.12 to 16.40 ± 8.17. Of the 75 patients undergoing interbody fusion, 37 (48.7%) achieved complete fusion (Grade I) with evidence of remodeling and trabecular bone in the fusion space. Twenty-four patients (31.6%) had a Grade II fusion, indicating an intact graft that was not fully remodeled or incorporated. Grade III fusion, characterized by an intact graft with potential lucency at both ends, was observed in 6 patients (7.9%). In comparison, three patients (3.9%) experienced a Grade IV fusion, which was absent due to graft collapse or resorption. Incidental durotomies, nerve root injuries, wound complications, and postoperative instability was absent. No significant adverse events related to stem cell therapy were reported.

Conclusion: Lumbar interbody fusion with allogenic mesenchymal stem cell enriched corticocancellous bone graft in patients with recurrent disc herniations is a safe and effective treatment, leading to reduced pain, improved function, and quality of life. These findings suggest that stem cell-enriched standalone bone grafts could be a viable alternative to conventional lumbar spinal fusion treatments, offering a new avenue for managing patients with this challenging condition without spinal implants. Further research is needed to understand the long-term implications and mechanisms underlying the regenerative potential of stem cell therapy in spinal disorders.

Keywords: Safety and Efficacy of Stem Cell Therapy, Intervertebral Disc Regeneration, Recurrent Disc Herniation, Autologous Stem, Spinal Regenerative Medicine, Clinical Trial Outcomes, Disc Degeneration Treatment, Minimally Invasive Procedures, Functional Disability Reduction