Biphasic calcium phosphate (BCP) with a characteristic needle-shaped submicron surface topography (MagnetOs) has attracted much attention due to its unique bone-forming ability which is essential for repairing critical-size bone defects such as those found in the posterolateral spine. Previous in vitro and ex-vivo data performed by van Dijk LA and Yuan H demonstrated that these specific surface characteristics drive a favorable response from the innate immune system. This study aimed to evaluate and compare the in vivo performance of three commercially-available synthetic bone grafts, (1) i-FACTOR Putty. ®. , (2) OssDsign. ®. Catalyst Putty and (3) FIBERGRAFT. ®. BG Matrix, with that of a novel synthetic bone graft in a clinically-relevant instrumented sheep posterolateral lumbar spine fusion (PLF) model. The novel synthetic bone graft comprised of BCP granules with a needle-shaped submicron surface topography (MagnetOs) embedded in a highly porous and fibrillar collagen matrix (MagnetOs Flex Matrix). Four synthetic bone grafts were implanted as standalone in an instrumented sheep PLF model for 12 weeks (n=3 bilateral levels per group; levels L2/3 & L4/5), after which spinal fusion was determined by manual palpation, radiograph and µCT imaging (based on the Lenke scale), range-of-motion mechanical testing, and histological and histomorphological evaluation. Radiographic fusion assessment determined bilateral robust bone bridging (Lenke scale A) in 3/3 levels for MagnetOs Flex Matrix compared to 1/3 for all other groups. For µCT, bilateral fusion (Lenke scale A) was found in 2/3 levels for MagnetOs Flex Matrix, compared to 0/3 for i-FACTOR Putty. ®. , 1/3 for OssDsign. ®. Catalyst Putty and 0/3 for FIBERGRAFT. ®. BG Matrix. Fusion assessment for MagnetOs Flex Matrix was further substantiated by histology which revealed significant graft resorption complemented by abundant bone tissue and
Purpose of the study: Titanium cases are used to achieve mechanical stable spinal reconstruction immediately after corpectomy. Bone grafts is often associated to ensure long-term success. Plain x-rays do not allow correct visualization of the graft within the cage, hindering evaluation of the fusion. The objectives of this study were to obtain a precise evaluation of the graft outcome within the cage using computed tomography (CT) and to search for factors affecting bone fusion. Materials and methods: This was a retrospective analysis of a consecutive series of patients undergoing anterior reconstruction of the thoracolumbar spine with a titanium cage and a bone autograft. 3D CT reconstructions were obtained at least three months after reconstruction surgery. Three independent observers (two surgeons and a radiologist) analyzed the images. Standard CT criteria for graft fusion are not described in the literature for this type of arthrodesis so the criteria used were based on a descriptive analysis of the CT slices. A statistical analysis was then conducted to search for factors affecting fusion: epidemiological features, etiology, type of graft, size of the case, number of levels reconstructed, associated posterior arthrodesis. The regional angle was analyzed postoperatively and at last follow-up to determine how the sagittal correction was maintained. Results: Twenty-eight cases were reviewed. Reconstructions had been performed for burst fractures, tumor resection, or deformed callus. CT analysis demonstrated three fusion zones to be examined: the upper, middle and lower part of the cases. Bony bridges were noted at the extremities in all cases. The middle part of the cage generally presented a heterogeneous image which was insufficient to confirm fusion. Loss of correction was not significant. No co-factors could be identified which influenced fusion. Discussion and conclusion: Most of the cases reviewed did not present a
Purpose: A lack of consensus regarding the radiologic criteria to diagnose spinal non-union limits inferences from clinical research. This systematic review aimed to examine the spectrum of radiologic investigations used to assess lumbar spinal fusion and the definitions of successful spine union used in the spine literature. Method: We comprehensively searched three electronic databases from 1950 to 2009 (MEDLINE, Embase and the Cochrane Central Register of Controlled Trials) for clinical studies involving posterolateral fusion of the lumbar spine. English-language studies including adult patients and reporting a definition of successful fusion were included. Studies examining the reliability and validity of radiologic investigations were also identified. Key measures included. radiologic investigations,. definition of successful lumbar fusion and. reliability, sensitivity and specificity of the investigations used to assess the spinal fusion. Results: Among 1165 potentially eligible studies, 91 met our inclusion criteria. Of the studies 78% (n = 71) used plain radiographs to diagnose non-union, 4% (n = 4) used CT scans and 18% (n = 16) used both. Fifty-one studies used both static (xray or CT) and dynamic (flexion-extension xray) images, 35 used only static images and five used only dynamic radiographs. In total, we identified fifty-two different radiographic definitions of successful fusion. More than half of the studies (n = 50, 55%) failed to provide a reference for the definition used. The most common definition of fusion (7 studies) used static radiographs and defined fusion as
