A new type of distractor for the surgical correction of scoliosis and spondylolisthesis.

A distractor for the surgical correction of scoliosis is described. It comprises a threaded rod that runs inside a cannula. The distraction is achieved with special distraction forceps. Fixation is then secured by screwing a nut along the rod until it is in contact with the opening of the cannula. This distractor is not as simple as the Harrington device but it has a number of advantages. It is easier to apply in difficult surgical situations. The fixation mechanism is infallible. The lengthening is achieved more gradually. Slackening and removal are simple and always possible, and it is never necessary to section the rod with cutting shears.