SILICATE SUBSTITUTED CALCIUM PHOSPHATE SYNTHETIC BONE GRAFT IN ANTERIOR CERVICAL DISCECTOMY AND FUSION WITH CERVICAL CAGE.

Abstract

Aim: To determine the clinical improvement and the radiological time to fusion as well as correction of the lordosis angle in patients undergoing anterior cervical interbody fusion with the use of a silicate substituted calcium phosphate ceramic (Si-CaP) (Actifuse™ Synthetic Bone Graft, ApaTech, Ltd., Elstree, UK) as the bone graft substitute in the cage.

Design: We conducted a prospective clinical and radiological study to evaluate the use of Si-CaP as bone graft substitute in anterior cervical fusion for degenerative cervical spondylosis.

Materials and methods: Thirty patients were selected prospectively by preoperative and postoperative clinical and radiological assessments. All patients were operated on by a single surgeon (D.A.J.). Neck disability index and visual analogue score were used for the clinical assessment. Radiological assessment included improvement in the lordosis angle and time to fusion. Patients were evaluated at three months, six months and one year post-surgery.

Results: At present 14 patients with a total of 19 levels have completed their one year follow-up. The patients had an average of 50.4 years (range 34–69), with ratio of male to female of 6:7. Lordosis angle improved significantly from a mean lordosis angle of 0.31 preoperatively to 4.75 degree postoperatively (p< 0.05). All the levels had fused at the 1 year follow up and there was no radiological evidence of sinkage of the cage.

Conclusion: Substitution of silicate ions into calcium phosphate ceramics has been shown to impart a negative surface charge, leading to greater protein absorption, increased osteoblast proliferation, and higher production of extracellular matrix. Our results show that Si-CaP has excellent clinical performance as a synthetic bone graft in anterior cervical discectomy and fusion. Postoperatively, patients demonstrate a good fusion with an excellent correction and maintenance of the lordosis angle.