Intervertebral Disc Transplantation: From Animal Study to Pilot Human Trial

Background: Spinal fusion is one of the most commonly performed procedures on the spine. However there are known long term effects on the juxta-fusion segments. Many non-fusion strategies have been attempted in the past 2 decades aiming at preserving the stability, mobility of the spinal segment while relieving the clinical symptoms of neural compression. The authors have over the past 12 years performed a series of experiments in primates and have recently conducted a pilot trial in the human.

Objectives: This is a report on the history of the development in the experimental model and the early clinical results of a pilot series of disc allograft transplantation in the human.

Methods: Eight patients, 6 with degenerative and 2 with traumatic cervical disc protrusions, underwent fresh frozen disc allograft transplantation. The longest follow up was 54 months.

Results: The average operating time was 1.8 hours and blood loss was 93 mls. There was no clinical evidence of rejection of the allograft and no immunosuppressive agent was used. All patients had relief of the preoperative neurological symptoms. The mean JOA score improved from 8 preoperatively to 13.2 at the final follow up. None of them had significant neck pain requiring analgesics. Bony union of the endplate interfaces was seen at 2 months postoperatively. Radiological examination revealed moderate loss of disc height but the segments remained mobile on dynamic radiographs even at 52 months postoperatively.

Conclusions: Intervertebral disc allograft transplantation appeared to be a viable alternative to spinal fusion or artificial disc replacement.