Anterior fresh frozen structural allografts in the thoracic and lumbar spine. Do they work if combined with posterior fusion and instrumentation in adult patients with kyphosis or anterior column defects?

This was a prospective study of 24 adult patients with kyphosis or anterior column spinal defects treated with anterior fresh frozen allograft for anterior column defects and posterior instrumentation and autogenous grafting.The objectives of the study were to assess the effectiveness of the anterior allograft in maintaining sagittal correction and to assess anterior incorporation.Twenty-four patients were followed for a minimum of 2 years (range, 2 + 0-5 + 4 years).Upright radiographs were analyzed before surgery, immediately after surgery, and at the final follow-up examination to assess success of anterior fusion and maintenance of correction. A strict four-point grading system was used. Two independent observers analyzed the radiographic results.Only two patients showed some collapse of their anterior allograft. The other 22 patients maintained correction, attaining a Grade I or Grade II fusion. Semiconstrained instrumentation ws used posteriorly in the two patients who had graft collapse.Anterior structural allograft worked effectively to maintain correction of kyphosis if combined with posterior instrumentation and autogenous grafting. Rigid forms of posterior instrumentation were preferred.