Study design: An in vivo study of material from a potential disc prosthesis.
Objective: To examine the histopathologic effect of particulate debris on the dura and neural tissue in sheep.
Summary of background data: Disc prostheses are emerging as alternatives to spinal fusion for the treatment of symptomatic degenerative lumbar disc disease. Preclinical biocompatibility trials must be conducted before any device is considered for general use.
Methods: Artificially generated wear particles of a material known as Sinux (DePuy Spine, Raynham, MA) were implanted directly onto the lumbosacral dura and nerve roots of 18 sheep that were randomly allocated to 3 groups to survive between 1 and 6 months. Tissue sections from T12 to the sacrum were examined for histopathological evidence of inflammation and wound healing in response to the particles and for the effects on the neural elements.
Results: There was no significant evidence of inflammation, macrophage accumulation, or other tissue response. Other observations included some minor tissue pigmentation due to microhemorrhage, occasional but minimal lymphocyte infiltration, and crystalline Sinux in the fibroadipose connective tissue external to the dura.
Conclusion: Artificially generated particles of Sinux placed directly onto the dura and nerve roots did not induce any significant biologic response in a sheep model.