A bioactive and bioresorbable porous cubic composite scaffold loaded with bone marrow aspirate: a potential alternative to autogenous bone grafting.
METHODS
Experimental animal study.


OBJECTIVE
To investigate the osteogenic properties of a particulate uncalcined, unsintered hydroxyapatite/polydllactide (u-HA/PdlLA) composite scaffold loaded with bone marrow aspirate (BMA).


BACKGROUND
Because of the high morbidity associated with bone graft harvesting, current research in spine surgery has largely focused on bone graft alternatives involving a combination of scaffolds and osteogenic substances. BMA is obtained by a simple and relatively noninvasive method and can easily be clinically applied as an osteogenic material. However, few studies have reported successful posterolateral spinal fusion (PLF) with BMA-loaded synthetic materials.


METHODS
Porous u-HA/PdlLA composites loaded with BMA were used as bone graft substitutes. In experiment 1, porous u-HA/PdlLA cylinders containing or lacking BMA were implanted in rabbit muscles. They were retrieved 4, 8, and 12 weeks after implantation, and ectopic bone formation was histologically evaluated. In experiment 2, 48 rabbits underwent PLF with 1 of 4 bone grafts: autogenous bone (group 1); single-strip u-HA/PdlLA alone (group 2); morselized u-HA/PdlLA + BMA (group 3); or single-strip u-HA/PdlLA + BMA (group 4). After 12 weeks, fusion was assessed by manual palpation, microcomputed tomography, mechanical tests, and histologic examination.


RESULTS
In experiment 1, ectopic bone formation was observed in BMA-loaded u-HA/PdlLA, and the new bone area increased until 12 weeks after implantation. In experiment 2, the fusion rates in groups 1, 2, 3, and 4 were 58.3%, 16.7%, 66.7%, and 91.7%, respectively, as determined by manual palpation, and 66.7%, 16.7%, 75.0%, and 91.7%, respectively, as determined by microcomputed tomography. The mechanical strength was significantly greater in group 4 than in the other groups (P < 0.05).


CONCLUSIONS
Conclusion. Our results indicate that BMA-loaded porous μ-HA/PdlLA is an effective alternative to autogenous bone grafts. The structure and composition of porous u-HA/PdlLA render it an effective scaffold for BMA.
Department of Orthopaedic Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan. tkojiro23@gmail.com
Kojiro
K
Tanaka
Mitsuru
M
Takemoto
Shunsuke
S
Fujibayashi
Masashi
M
Neo
Yasuo
Y
Shikinami
Takashi
T
Nakamura
D020341:Absorbable Implants; D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry / Q000627:therapeutic use*; D001696:Biomechanical Phenomena; D016026:Bone Marrow Transplantation / Q000379:methods*; D018786:Bone Substitutes / Q000737:chemistry / Q000627:therapeutic use*; D016025:Bone Transplantation / Q000379:methods*; D017886:Durapatite / Q000737:chemistry; D007403:Intervertebral Disc / Q000502:physiology / Q000601:surgery; D008159:Lumbar Vertebrae / Q000502:physiology / Q000601:surgery; D008297:Male; D010012:Osteogenesis / Q000502:physiology; D011091:Polyesters / Q000737:chemistry; D016062:Porosity; D011817:Rabbits; D054457:Tissue Scaffolds / Q000737:chemistry; D014182:Transplantation, Autologous
D001672:Biocompatible Materials; D018786:Bone Substitutes; D011091:Polyesters; C033616:poly(lactide); D017886:Durapatite