Intervertebral disc transplantation: a biological approach to motion preservation.

Intervertebral disc transplantation was developed in a bipedal animal model through the stages of autograft, fresh allograft and fresh frozen allograft. Results showed that the allografts were able to survive through a deep freezing protocol and maintain cell viability after transplantation without significant immunoreaction. Although degeneration of the allograft appeared to be inevitable, it was able to maintain stability and mobility of the functional spinal unit. These findings were similarly reproduced in the human clinical trial with excellent mid-term clinical results at 5 years. The process of evolution and findings were summarized in this review.