Long-term Investigation of Annulargrams and Intra-annular Fibrin to Treat Chronic Discogenic Low Back Pain and Radiculopathy: 1-, 2-, and 3-Year Outcome Comparisons of Patients with and without Prior Surgery
Authors: Murrell William D. 
Published: January 2025

BACKGROUND: Discogenic chronic low back pain (cLBP) and radiculopathy are the most prevalent causes of disability worldwide. Older spine treatments often lack reliability and are associated with adverse events. Among surgical treatment options, discectomies weaken discs, and fusions cause direct damage to adjacent discs, so both treatments accelerate disc degeneration. Other regenerative medicine treatments, including “stem cell” (centrifuged bone marrow aspirate, BMC), and platelet-rich plasma (PRP), lack fibrin’s bio-adhesive properties. Specifically, fibrin is a strong bio-adhesive, so it immediately integrates into disc defects and binds there, becoming a part of the disc and facilitating new disc tissue growth.

OBJECTIVES: To evaluate the safety and efficacy of this new pragmatic algorithm that both diagnoses and treats cLBP by (i) first identifying annulus fibrosus tears (fissures) in the region of symptoms and (ii) subsequently treating those tears by introducing fibrin to seal them and facilitate new tissue growth.

STUDY DESIGN: Retrospective cohort study that prospectively reported validated measures in a registry.

SETTING: Private, single-center, specialized, interventional pain management institution.

METHODS: The patients we decided to observe had suffered from cLBP with or without radiculopathy symptoms in their legs for greater than 6 months. Prior to enrollment, all patients underwent physical therapy and at least 4 invasive treatments without relief. Failed treatments included BMC or PRP injections, intradiscal or intraarticular zygapophyseal joints, or combinations of both. Fluoroscopically guided epidural injections of corticosteroids or PRP were additional failed treatments, as were radiofrequency neurotomies in the medial branch. Candidacy for enrollment was based on meeting the aforementioned criteria and by having magnetic resonance image (MRI) screenings (1.5 T) and plain-film radiographs performed 6 months before treatment. In addition, those MRI screenings and radiographs had to rule out the following concomitant conditions: (i) carcinoma, (ii) fracture, (iii) instability, or (iv) severe vertebral canal or intervertebral foramen stenosis.

RESULTS: Significant improvement was demonstrated at one, 2, and 3 years after treatment in all outcome measures. The mean duration of low back pain prior to treatment was 11.2 years. Patients’ mean age was 56 years. Thirty percent of the patients were female, and 70% were male. Both the failed surgery cohort and nonsurgery cohort demonstrated significant improvement after fibrin treatment, with the failed surgery cohort realizing greater relative improvement. Significant improvements in the Oswestry disability index (ODI), visual analog scale, and PROMIS® (mental and physical) scores were consistent across age, gender, comorbidity, and exposure status. At the 12-month follow-up, 50% of patients achieved minimal clinically important differences utilizing the ODI. No severe adverse events were reported.

LIMITATIONS: Limitations include patient demographic factors, outcome-measure sensitivity, and that the outcomes were reported prospectively and calculated retrospectively as one-, 2-, and 3-year time frames were attained. Although categorical analyses comparing the prior surgical cohort to the nonsurgical cohort were performed, other pre-enrollment treatments were not categorized for comparison.

CONCLUSIONS: Intra-annular fibrin bio-adhesive sealant demonstrates the ability to be an effective treatment for alleviating discogenic cLBP and radiculopathy for at least 3 years, even in patients who all failed multiple prior treatments, including discectomy, fusion, disc PRP, or BMC. The results suggest the benefits of fibrin sealant. Future investigations to consider include a randomized double-blind controlled trial and further categorical analyses.

KEY WORDS: Low back, radiculopathy, fibrin, disc herniation, degenerative disc, regenerative, annulargram, annulogram