An Osteoblast Differentiation Promoting Compound, TAK-778, combined with β-Tricalcium Phosphate used for Packing Interbody Fusion Cages

A synthetic 3-benzothiepin derivative, TAK-778, promotes osteoblast differentiation. If a mixture of TAK-778 and fi -tricalcium phosphate ( 6 -TCP) can be a substitute for autografts used for packing interbody fusion cages, donor-site related complications should be avoided. The lumbar vertebrae from Ll to L5 were exposed in 8 dogs using a posterolateral approach, and discectomy and interbody cage fusion were perfbrrned in three disc spaces. In group A, the cage was fiILed with autograft bone, in group B with fi -TCP, and in group C with fi -TCP and TAK-778. The Lumbar spine was excised at 16 weeks post-surgery, and mechanical, microradiographical and histological evaluations were made. The microradiographical and histological examinations revealed four fusions in eight operations in group A (50.0%), three in group B (37.5%), and five in group C (62.5%). The mean percentage of trabecular bone area in the cages was 53.4% in group A, 45.6% in group B and 64.4% in group C. Although the effect was not significant, addition of TAK-778 to 6 -TCP had some beneficial influence and there was a trend toward an improved fusion status in cages filled with fi -TCP and TAK-778. 6-TCP combined with TAK-778 could be used as a substitute for autografts in clinical spine surgery, especially for those patients who are anticipated to have a poor graft bone status, Key word: TAK-778, Tricalcium Phosphate, Cervical lnterbody Fusion Cage Spinal Surgery 17 (3):183N194, 2003, Autograft, Osteoinduction