The effect of a stiff spinal implant and its loosening on bone mineral content in canines.

摘要: A canine spine surgery model was used to study bone mineral loss induced in vertebrae bypassed by stiff implants. Loosening of implants measured, and a determination made as the effect loosening on degree loss. Sixteen dogs were implanted with rigid screw-rod construct randomized one four groups depending motion segments immobilized. No fusions performed. Bone studied DEXA at baseline, postoperatively 3, 6, 9 months. measurements implant-implant interface implant-bone months postoperatively. Results show that occurred uniformly 3 spanned implants, average density representing 81% baseline. When implant remained secure, persisted 6 but did not worsen. loosened, there recovery baseline level postoperative.