THE USE OF HETEROLOGOUS BONE REPLACEMENT TOGETHER WITH PLATELET GROWTH FACTOR DURING VERTEBRAL SURGERY: CRITICAL ANALYSIS AND PRELIMINARY RESULTS

The authors present case histories relating to experience gained over 18 months of using deantigenic osseous grafts together with platelet growth factor for posterior spine arthrodesis.

The spinal column was the last section of the skeleton to recover from the use of this kind of bone graft to promote spinal fusion. This is due to the negative experience encountered during the proposals bought forward during the 1960s and 1970s by French orthopaedic surgeons who used heterologous lyophilised bone for long vertebral arthrodesis. The high incidence of pseudoarthrosis developed as a result of difficulties in absorption of the skeletal implant, which, in order to ensure sufficient mechanical resistance, should have been thicker (8 mm). Therefore it could not be assimilated. This then resulted in relying only on external protection (plastered brace) to provide the necessary rigidity during the process of fusion. The beginning of stable synthesis obtained with transpeduncular fixation and double instrumentation as used in the Cotrel Doubousset technique and methods derived from it made it possible to maintain primary stability over time, therefore positively influencing the process of consolidation. This is why the practice of exclusively using osseous derivations has grown only in the past few years in vertebral surgery, preferring to implant small chips which can be assimilated much easier and to avoid having to search for mechanically resistant areas for bone replacement. In conclusion, the use of heterologous bone grafts in the vertebral column represents a situation similar to that in other mobile osseous areas, in which the immobilisation depends on the use of a mechanical instrument (when it concerns short arthrodesis 2–3 segments). In the case of long spinal fusion such as in correcting vertebral deformity (scoliosis and kyphosis), the problem is more complicated, even though today’s new biological tools (large extension of the bed of arthrodesis) make this possible and offer the advantages of the lack of problems at the donor site. In these cases it is particularly suitable to routinely combine heterologous bone replacement with growth factors (osteoinductive bone proteins) for treatment, which according to our preliminary results should notably shorten the period of assimilation and the fusion healing.