MagnetOs, Vitoss, and Novabone in a Multi-endpoint Study of Posterolateral Fusion

Abstract

Study Design: This study was a multi-endpoint analysis of bone graft substitutes implanted as a standalone graft in a clinically relevant Ovine model of instrumented posterolateral spinal fusion (PLF). Objective: The objective of this study was to obtain high-quality evidence on the efficacy of commercial bone graft substitutes compared with autograft in instrumented PLF using a state-of-the-art model with a complete range of assessment techniques. Summary of Background Data: Preclinical and clinical data on the quality of spinal fusions obtained with bone graft substitutes are often limited. Calcium phosphates with submicron topography have shown promising results in PLF, as these are able to induce bone formation in tissues distant from the host bone, which facilitates bony union. Methods: Nine female, skeletally mature sheep (4–5 y) underwent posterior pedicle screw/rods instrumented PLF at L2–L3 and L4–L5 using the following bone graft materials as a standalone graft per spinal segment: (1) biphasic calcium phosphate with submicron topography (BCP <µm ), (2) 45S5 Bioglass (BG), and (3) collagen-β-tricalcium phosphate with a 45S5 Bioglass adjunct (TCP/BG). Autograft bone (AB) was used as a positive control treatment. Twelve weeks after implantation, the spinal segments were evaluated by fusion assessment (manual palpation, x-ray, micro-computed tomography, and histology), fusion mass volume quantification (micro-computed tomography), range of motion (ROM) testing, histologic evaluation, and histomorphometry. Results: Fusion assessment revealed equivalence between AB and BCP <µm by all fusion assessment methods, whereas BG and TCP/BG led to significantly inferior results. Fusion mass volume was highest for BCP <µm , followed by AB, BG, and TCP/BG. ROM testing determined equivalence for spinal levels treated with AB and BCP <µm , while BG and TCP/BG exhibited higher ROM. Histologic evaluation revealed substantial bone formation in the intertransverse regions for AB and BCP <µm , whereas BG and TCP/BG grafts contained fibrous tissue and minimal bone formation. Histologic observations were supported by the histomorphometry data. Conclusions: This study reveals clear differences in efficacy between commercially available bone graft substitutes, emphasizing the importance of clinically relevant animal models with multiendpoint analyses for the evaluation of bone graft materials. The results corroborate the efficacy of calcium phosphate with submicron topography, as this was the only material that showed equivalent performance to autograft in achieving spinal fusion.

Chitosan Based Biocomposites for Hard Tissue Engineering

“…They are osteoinductive. The osteoinduction is trigged either by the addition of chemical elements such silicates ions (Actifuse bone graft, by Baxter) or by tailored sub-micron surface topography and porosity [47] that has the capability to induce bone formation in ectopic or heterotopic location such in muscle or under skin. (Figures 5 and 6).…”

“…AB: Autograft bone; BCP < μm, biphasic calcium phosphate with submicron topography; BG, bioglass; TCP, tricalcium phosphate. [47]. An injectable bone graft formulation and hardening injectable bone cements.…”

“…(P < 0.005) and TCP/BG. AB: Autograft bone; BCP < μm, biphasic calcium phosphate with submicron topography; BG, bioglass; TCP, tricalcium phosphate [47]…”

Physico-Chemical Characteristics and Posterolateral Fusion Performance of Biphasic Calcium Phosphate with Submicron Needle-Shaped Surface Topography Combined with a Novel Polymer Binder

“…The biphasic calcium phosphate with submicron needle-shaped surface topography (BCP) investigated in this study has previously been demonstrated to be a promising solution for predictable spine fusion, circumventing the disadvantages of the gold standard autologous bone graft (ABG), i.e., limited availability, donor site morbidity, patient complications such as pain, secondary site infections, and subsequent risks of revision surgery [1][2][3][4]. In skeletally mature rabbit and sheep posterolateral fusion models, BCP showed fusion rates equivalent to ABG [5,6], and head-to-head comparison studies have shown an accelerated bone formation and superior fusion rate with needle-shaped surface topography compared to conventional grain-shaped surface topographies in dog muscle and sheep spine studies [7,8]. Recently, the first clinical case series reported successful fusion rates 12 months post-surgery near 97% (94 out of 97 levels) in the lumbar fusion cohort of 52 patients, and 93.8% (75 out of 80 levels) in the cervical fusion cohort of 25 patients [9].…”

Endochondral bone regeneration: Stepping stones towards clinical translation

“…In addition, their resorption rate is challenging to tailor and a foreign body reaction is occasionally observed as a consequence of their implantation [31,37,38]. Thus, the use of these bone substitutes as a stand-alone treatment is limited and currently they are mainly used as autologous graft extenders [33,39,40]. The drawbacks of autologous and allogeneic bone transplantation together with the lack of satisfactory bone substitutes represent the major driving force behind the search for alternatives.…”