AAOS Now

Published 3/25/2022
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Patrick Daly

Utilizing a Synthetic Bioactive Glass Fiber for Lumbar Posterolateral Spine Fusion

In an interim analysis of bone grafting with a synthetic bioactive glass fiber material presented at the AAOS 2022 Annual Meeting, 50 spine patients treated with the resorbable bioactive glass matrix achieved a successful outcome at one year, with an average fusion rate of 94.0 percent and improved clinical outcomes.

Lead author and presenter Brandon Strenge, MD, FAAOS, orthopaedic spine surgeon and founding member of the Orthopaedic Institute of Western Kentucky in Paducah, Ky., told AAOS Now that bone grafting with this material has yielded “excellent outcomes” in several of his patients. He and collaborators evaluated the posterolateral lumbar fusion (PLF) rate of the 45S5 bioactive glass fiber–based synthetic bone graft substitute (Fibergraft from Prosidyan, Inc.).

These interim results were “highly promising,” said Dr. Strenge, who had anticipated results consistent with his favorable personal experiences. He added that it is always impressive and meaningful to see results “duplicated across multiple sites and specialties.”

The full ongoing study includes 102 prospective patients across nine U.S. centers with at least two years of follow-up data. Enrolled patients had a diagnosis of spinal stenosis/spondylolisthesis requiring fusion or degenerative disk disease (DDD) with or without radiculopathy at one or two levels (L2-S1). Eligible patients had previously not responded to nonsurgical treatment.

The primary outcome of interest was the achievement of successful spinal fusion, assessed by an independent radiologist at 12 months via radiograph and CT scan. Additional efficacy endpoints in the study included average improvement in patient-reported outcomes and patient satisfaction, whereas safety endpoints included neurological status and occurrence of adverse events.

Concurrent interbody fusion with the bioactive synthetic graft was performed in 86.0 percent of subjects. According to Dr. Strenge and colleagues, on-label use of the graft in the posterolateral spine led to successful fusion of 95.7 percent of levels and 94 percent of patients overall, assessed via CT scan.

The researchers highlighted that the bioactive graft yielded a favorable fusion rate with no device-related adverse events. All subjects showed stability on flexion/extension films, though five of the subjects had to undergo revision surgery. Indications for revision included adjacent segment disease (ASD; n = 1), revision of hardware (n = 1), instrumentation failure plus ASD (n = 1), and pseudoarthrosis (n = 2). The subjects showed significantly improved visual analog scale and Oswestry Disability Index scores from baseline to month three, which were maintained through six and 12 months (P <0.05). lastly, the patients appeared to be satisfied with the procedure, with 80 percent responding “very satisfied” and 20 percent responding “somewhat satisfied.”></0.05).>

Additionally, although the study only assessed clinical outcomes, “There is a potentially powerful economic story to tell as well,” said Dr. Strenge, who added, “Economics in biologics is the next frontier.” He suggested that future investigations “could extrapolate the overall value of utilizing bioactive synthetic graft substitutes as opposed to higher-priced biologics, which can also come with higher rates of adverse events and a lack of clinical efficacy.”

The study’s authors noted that their interim results suggested that the novel graft substitute outperformed previously published data on autogenous bone grafting, which reported a PLF rate range of 14 percent to 95 percent. Dr. Strenge theorized that the wide range in fusion rates using the autogenous bone grafts was “likely dependent on several factors, such as quality of the bone graft used, bone graft volume, and other patient-specific factors.” The interim report closed with the promise of further information after more patients reach the one- and two-year evaluation timepoints.

Dr. Strenge’s coauthors of “A Prospective, Multicenter, Clinical Evaluation of a Bioactive Fiber-based Bone Graft Material in Lumbar Posterolateral Spine Fusion: An Interim Analysis at One Year Utilizing CT Scan and Xray Evaluation” are Carmina Flores Angeles, MD, PhD; Philip S. Yuan, MD, FAAOS; Amandeep Bhalla, MD; David Essig, MD, FAAOS; and Hamid Hassanzadeh, MD.

Patrick Daly is a freelance writer for AAOS Now.