Allograft versus no graft with a posterior multisegmented hook system for the treatment of idiopathic scoliosis

Study Design. A prospective, randomized study. Objective. To compare the clinical results of posterior spinal fusion (PSF) with allograft augmentation versus no graft for patients with adolescent idiopathic scoliosis (AIS). Summary of Background Data. The use of allograft has become a standard means of augmenting a PSF. Many studies have shown equal rates of fusion when comparing allograft with autogenous iliac crest. There have been no studies to directly compare the results obtained with allograft with those achieved without the use of any bone graft at all. Methods. Ninety-one patients with AIS were randomized into two treatment groups. Seventy-six patients had greater than 2-year follow-up and are included in this review. The Allograft Group consisted of 37 patients who underwent a standard PSF using a multisegmented hook-screw and rod system with the use of corticocancellous allograft for augmentation. The No Graft Group included 39 patients with AIS who underwent the same procedure without any bone graft. All autogenous bone resulting from a thoracoplasty and any local bone ( for example, that removed from spinous processes) was discarded in both groups. Patients with at least 2 years of radiographic and clinical follow-up were evaluated using established criteria for possible or definite pseudarthrosis. Treatment groups were similar with respect to age, preoperative deformity, and correction obtained. Results. The overall definitive pseudarthrosis rate for this study was 1.3% ( 1 of 76 patients). The 1 patient with pseudarthrosis was in the Allograft Group ( 1 of 37, or 2.7%, P = 0.98 as defined by our criteria), versus none of 39 in the No Graft Group. Two patients in each group (5.4% in the Allograft Group and 5.1% in the No Graft Group) met the radiographic criteria for possible pseudarthrosis. This establishes a P value of 0.65 comparing risk of possible pseudarthrosis in the two groups. Conclusion. Our results suggest that a PSF using newer-generation multisegmented hook-screw and rod systems can be successful with allograft and/or local bone graft without the use of supplemental autogenous bone graft ( from the iliac crest or ribs) in patients with AIS.