Novel Calcium Phosphate Promotes Interbody Bony Fusion in a Porcine Anterior Cervical Discectomy and Fusion Model.

STUDY DESIGN

Experimental porcine anterior cervical discectomy and fusion (ACDF) model: a proof-of-concept study.

OBJECTIVE

The effect of monetite synthetic bone graft containing calcium pyrophosphate (Ca-PP) and β-tricalcium phosphate (β-TCP) on cervical spinal fusion in a non-instrumented two-level large animal model.

SUMMARY OF BACKGROUND DATA

ACDF is the gold standard surgical technique for the treatment of degenerative cervical spinal diseases. However, pseudarthrosis associated with increased patient morbidity occurs in approximately 2,6% of the surgeries. Synthetic bone graft (SBG) may enhance bony fusion and subsequently decrease the risk of pseudarthrosis. Recent studies on monetite-based synthetic bone grafts for use in large cranial defects in humans have shown promising bone healing results, necessitating further investigation of their use in cervical spinal fusion.

METHODS

Four adult female Danish Göttingen mini-pigs received partial cervical anterior discectomy and intervertebral defects at an upper and lower level. One defect was filled with SBG and the other was left empty. Bony fusion was evaluated using computed tomography (CT) at three-month intervals for 12 months. Fifteen months post-surgery, the animals were euthanized for further ex vivo qualitative histopathological and micro-CT evaluations. Fusion rates were compared using Fisher´s exact test at each time point.

RESULTS

Increased interbody bony fusion rates were observed at synthetic bone graft levels (4/4) compared with control levels (0/4) evaluated by CT at 6- and 9-months post-surgery (P= 0.029). Fusion was observed at all synthetic bone graft levels 12 months post-surgery and at only one control level. Histopathological evaluation confirmed high-quality interbody bony fusion at all synthetic bone graft levels, and fusion by spondylosis at one control level.

CONCLUSION

This proof-of-concept study provides preliminary evidence of a novel, Ca-PP -and β-TCP-containing monetite SBG that promotes bony fusion compared to a negative control in a clinically relevant porcine model of ACDF.

LEVEL OF EVIDENCE

N/A.

Informations de copyright

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Déclaration de conflit d'intérêts

Conflicts of Interest and Sources of funding: HE is a co-inventor of patents related to the ceramic material used in the present study. None of the remaining authors declare any conflict of interest. This study was supported by faculty funds (SLU, Swedish University of Agricultural Sciences, Uppsala, Sweden, and a U-Share grant provided by SLU and Uppsala University, Sweden) and Stiftelsen Sällskapsdjurens forskningsfond Ingeborg Ögrens fond, Sweden.