Organ transplantation has become very successful in the United States. Researchers are working in labs to bring this same success to the spine. Once again, monkeys are the volunteers. Their low back is similar in shape to the human spine. Their upright posture is more human-like than animals who walk on all fours.
Scientists at the University of Hong Kong took disc material from the spine of one monkey and grafted it into the spines of 12 other monkeys. This is called an allograft transplant. Disc material was frozen after removal from the donor. Freezing helps preserve the cells and reduce rejection of the transplant.
Three groups of monkeys were studied. Motion was measured using a three-dimensional motion analysis system. One group was followed for up to eight weeks. The second group was tested again at six months. Repeat measurements were taken for the third group for up to 24 months.
In all cases, the transplanted discs survived. There was even ongoing life and activity at the cellular level two years later. However, by the end of two years, the discs were breaking down quickly.
The authors conclude that using fresh, frozen intervertebral discs from a donor is possible in animal models. It will be some time before this concept can be used in humans. In the future, disc transplantation may help delay spinal fusion. This would be especially helpful for young patients.