[Large-displacement spondylolisthesis in children and adolescents. Results of reduction-arthrodesis with front plates].

Twenty seven children and adolescents with severe lombo-sacral spondylolisthesis (degre III and IV) were operated using an original procedure of reduction and fixation. It is a two stages procedure, in the same session. Through a posterior approach, the sciatic roots are released and two long screws are set through the sacrum. An anterior approach allows a progressive reduction using a bended plate fixed with the protruded long screws, and an anterior arthrodesis. Results were evaluated with a three years mean follow-up. Clinical results were excellent on pain and on the morphological aspect of the trunk. There were four cases of residual weakness in the L5 motor distribution. This complication can be avoided by a good preparation before the procedure and precise post-operative care. The anterior displacement was improved from 77 per cent to 11 per cent. The angular lombosacral kyphosis from -23 degrees (kyphosis) to + 11 degrees (lordosis). The initial fears in the early experience, about the risks of kyphosis or slipping of the L4-L5 level have not been proved.