Hydroxyapatite-Based Biomaterials Versus Autologous Bone Graft in Spinal Fusion: An In Vivo Animal Study.
METHODS
An in vivo study was designed to compare the efficacy of biomimetic magnesium-hydroxyapatite (MgHA) and of human demineralized bone matrix (HDBM), both dispersed in a mixture of biomimetic MgHA nanoparticles, with that of an autologous bone graft.


OBJECTIVE
The objective of this study was to evaluate 2 new bone substitutes as alternatives to a bone autograft for spinal fusion, determining their osteoinductive and osteoconductive properties, and their capacity of remodeling, using a large animal model.


BACKGROUND
Spinal fusion is a common surgical procedure and it is performed for different conditions. A successful fusion requires potentially osteogenic, osteoinductive, and osteoconductive biomaterials.


METHODS
A posterolateral spinal fusion model involved 18 sheep, bilaterally implanting test materials between the vertebral transverse processes. The animals were divided into 2 groups: 1 fusion level was treated with MgHA (group 1) or with HDBM-MgHA (group 2). The other fusion level received bone autografts in both groups.


RESULTS
Radiographical, histological, and microtomographic results indicated good osteointegration between the spinous process and the vertebral foramen for both materials. Histomorphometry revealed no significant differences between MgHA and autologous bone for all the parameters examined, whereas significantly lower values of bone volume were observed between HDBM-MgHA and autologous bone. Moreover, the normalization of the histomorphometric data with autologous bone revealed that MgHA showed a significantly higher value of bone volume and a lower value of trabecular number, more similar to autologous bone than HDBM-MgHA.


CONCLUSIONS
The study showed that the use of MgHA in an ovine model of spinal fusion led to the deposition of new bone tissue without qualitative and quantitative differences with respect to new bone formed with autologous bone, whereas the HDBM-MgHA led to a reduced deposition of newly formed bone tissue.


METHODS
N/A.
Department of Oncological and Degenerative Spine Surgery, Rizzoli Orthopaedic Institute, Bologna, Italy.
Giovanni Barbanti
GB
Bròdano
Laboratory of Biocompatibility, Innovative Technologies and Advanced Therapies, Rizzoli Orthopaedic Institute, Bologna, Italy.|Laboratory of Preclinical and Surgical Studies, Rizzoli Orthopaedic Institute, Bologna, Italy.
Gianluca
G
Giavaresi
Department of Deformity Spine Surgery, Rizzoli Orthopaedic Institute, Bologna, Italy.
Francesco
F
Lolli
Laboratory of Biocompatibility, Innovative Technologies and Advanced Therapies, Rizzoli Orthopaedic Institute, Bologna, Italy.
Francesca
F
Salamanna
Laboratory of Biocompatibility, Innovative Technologies and Advanced Therapies, Rizzoli Orthopaedic Institute, Bologna, Italy.
Annapaola
A
Parrilli
Laboratory of Biocompatibility, Innovative Technologies and Advanced Therapies, Rizzoli Orthopaedic Institute, Bologna, Italy.|Laboratory of Preclinical and Surgical Studies, Rizzoli Orthopaedic Institute, Bologna, Italy.
Lucia
L
Martini
Department of Oncological and Degenerative Spine Surgery, Rizzoli Orthopaedic Institute, Bologna, Italy.
Cristiana
C
Griffoni
Department of Deformity Spine Surgery, Rizzoli Orthopaedic Institute, Bologna, Italy.
Tiziana
T
Greggi
Fin-Ceramica Faenza SpA, Faenza (RA), Italy.
Elena
E
Arcangeli
Fin-Ceramica Faenza SpA, Faenza (RA), Italy.
Daniele
D
Pressato
Department of Oncological and Degenerative Spine Surgery, Rizzoli Orthopaedic Institute, Bologna, Italy.
Stefano
S
Boriani
Laboratory of Biocompatibility, Innovative Technologies and Advanced Therapies, Rizzoli Orthopaedic Institute, Bologna, Italy.|Laboratory of Preclinical and Surgical Studies, Rizzoli Orthopaedic Institute, Bologna, Italy.
Milena
M
Fini