A method of spinal fusion.

The incidence of failure in spinal fusion is still too high (Barr 1951). It has been stated that if the operation could be undertaken with little or no danger from shock, subsequent thrombosis and embolism, and if it would offer a high prospect of firm union with a short period of bed rest, then a larger proportion of patients would be grafted (Young 1953). Spinal fusion was the subject of an editorial (Scott 1953) in which the need was stressed for a technique in which it would not be necessary to remove bone from other sites or to keep the patients in bed for a long time after operation. King (1948) described internal fixation by the use of screws. Short screws were placed almost transversely across the lateral articulations. A high incidence of failure from this method was reported by Thompson and Ralston (1949). Bosworth (1957) stated that screw fixation did not prove to be of value compared to the difficulties encountered, and he mentioned the adverse psychological effect associated with their use. The principle of internal fixation by screws is sound. Such fixation, however, is only temporary because the screws will loosen (Watson-Jones 1952). Careful preparation of the fusion area and the use of cancellous bone shortens the time needed to obtain fusion. Long, well placed screws give the required stability during this period and make the development of a pseudarthrosis