Efficacy of a Standalone Microporous Ceramic Versus Autograft in Instrumented Posterolateral Spinal Fusion

Abstract

a , on behalf of the Dutch Clinical Spine Research Group à Study Design. in the rest of the article written as patient-and observer-blinded, multicenter, randomized, intrapatient controlled, noninferiority trial. Objective. The aim of this study was to determine noninferiority of a biphasic calcium-phosphate (AttraX 1 Putty) as a bone graft substitute for autograft in instrumented posterolateral fusion (PLF). Summary of Background Data. Spinal fusion with autologous bone graft is a frequently performed surgical treatment. Several drawbacks of autografting have driven the development of numerous alternatives including synthetic ceramics. However, clinical evidence for the standalone use of these materials is limited. Methods. This study included 100 nontraumatic adults who underwent a primary, single-or multilevel, thoracolumbar, instrumented PLF. After instrumentation and preparation for grafting, the randomized allocation side of AttraX 1 Putty was disclosed. Autograft was applied to the contralateral side of the fusion trajectory, so each patient served as his/her own control. For the primary efficacy outcome, PLF was assessed at 1-year follow-up on computed tomography scans. Each segment and side was scored as fused, doubtful fusion, or nonunion. After correction for multilevel fusions, resulting in a single score per side, the fusion performance of AttraX 1 Putty was tested with a noninferiority margin of 15% using a 90% confidence interval (CI). Results. There were 49 males and 51 females with a mean age of 55.4 AE 12.0 (range 27-79) years. Two-third of the patients underwent a single-level fusion and 62% an additional interbody fusion procedure. The primary analysis was based on 87 patients, including 146 instrumented segments. The fusion rate of AttraX 1 Putty was 55% versus 52% at the autograft side, with an overall fusion rate of 71%. The 90% CI around the difference in fusion performance excluded the noninferiority margin (difference ¼ 2.3%, 90% CI ¼ À9.1% to þ13.7%). Conclusion. The results of this noninferiority trial support the use of AttraX 1 Putty as a standalone bone graft substitute for autograft in instrumented thoracolumbar PLF.

Increasing Fusion Rate Between 1 and 2 Years After Instrumented Posterolateral Spinal Fusion and the Role of Bone Grafting

“…In addition to the events described in the 1-year article, 18 eight serious adverse events were registered between 1 and 2 years of follow-up. Two patients were diagnosed with failed back surgery syndrome, one patient underwent revision surgery for pseudoarthrosis and screw loosening, and another patient had a deep wound infection after revision surgery.…”

“…This product is made of a microporous biphasic calcium phosphate. 18 The study was approved by the Medical Ethics Review Committee of the UMC Utrecht and local board of each participating hospital and registered in ClinicalTrials.gov (NCT01982045). At 1-year follow-up, non-inferiority of AttraX ® Putty versus autograft in terms of PLF performance based on a margin of 15% was demonstrated.…”

“…At 1-year follow-up, non-inferiority of AttraX ® Putty versus autograft in terms of PLF performance based on a margin of 15% was demonstrated. 18 The present study focuses on predefined secondary analyses of the fusion status and clinical outcomes at 2-year follow-up with specific attention to the role of the bone grafts.…”

“…Each side of each instrumented segment, as well as each interbody cage, was scored in 3 planes by 2 blinded spine surgeons using a detailed 3-point classification system (Appendix 1). 18 – 20 To gain further insight into the contribution of the grafts, intertransverse fusion (lateral to the rod) and facet/lamina fusion (at/medial to the rod) were scored separately. Any disagreements between the reviewers were resolved by re-assessment and consensus.…”

Use of Therapeutic Pathogen Recognition Receptor Ligands for Osteo-Immunomodulation

“…Various off-the-shelf synthetic bone substitutes, such as biodegradable ceramics and polymers, are readily available in the clinic for use in orthopedic interventions [ 1 , 2 , 3 ]. Although the performance of certain synthetic replacements are even reported to be non-inferior to autograft in applications such as spinal fusion, the success rate is not optimal [ 4 , 5 ]. A challenge remains in their limited osteoinductive capacity, namely the ability to induce the differentiation of bone progenitor cells, during the critical early weeks following implantation [ 3 , 6 , 7 ].…”