REVISION OF FAILED LUMBAR FUSIONS - A COMPARISON OF ANTERIOR AUTOGRAFT AND ALLOGRAFT

Study Design. The radiographic and clinical results of two different a nterior structural grafts were compared in 38 patients who had combine d anterior-posterior revision surgery for failed lumbar fusion. Object ives. Failed lumbar fusion surgery, such as pseudarthrosis or flatback deformity, may result in disabling pain. The optimum revision techniq ue has yet to be defined. The authors of the current study sought to d etermine which of two different types of anterior graft yields the bes t results. Summary of Background Data. Posterior procedures for revisi on of a failed lumbar fusion have not yielded reliably successful resu lts. A combined anterior-posterior approach may be effective in restor ing sagittal balance and enhancing fusion rates. Recent studies have s hown femoral ring allografts to be effective in lumbar fusion revision , but no studies have compared these with other types of structural gr afts. Methods. Thirty-eight patients with pseudarthrosis were treated with combined anterior-posterior lumbar spine fusion using either femo ral ring allografts (26 patients) or tricortical iliac autografts (12 patients). Radiographic follow-up examination and retrospective patien t self-assessment questionnaires were used to evaluate outcomes. Resul ts were assessed by independent reviewers after a mean follow-up perio d of 35 months. Results. Radiographic follow-up examination revealed a cceptably low pseudarthrosis rates for structural autografts (0%) and allografts (6%). The questionnaires revealed significant improvement i n pain for both groups. Allograft patients showed greater improvement in function, less pain medication usage, and higher overall success ra tes (83%) than autograft patients (64%). Conclusions. Femoral ring all ografts are as effective, clinically and radiographically, as tricorti cal iliac autografts when used as an anterior structural element in re vision lumbar spine fusion in patients who have undergone multiple sur gical procedures for pseudarthrosis or flatback deformity. The slightl y greater improvement for the allograft group needs to be confirmed in a larger study.