Selection of fusion levels using the fulcrum bending radiograph for the management of adolescent idiopathic scoliosis patients with alternate level pedicle screw strategy: clinical decision-making and outcomes

Abstract

Introduction: Selecting fusion levels based on the Luk et al criteria for operative management of thoracic adolescent idiopathic scoliosis (AIS) with hook and hybrid systems yields acceptable curve correction and balance parameters; however, it is unknown whether utilizing a purely pedicle screw strategy is effective. This study aims to assess the efficacy of pedicle screw fixation with alternate level screw strategy (ALSS) for thoracic AIS. Methods: A prospective radiographic and clinical analyses of 28 operative thoracic AIS patients undergoing ALSS was performed. Fusion level selection was based on the Luk et al criteria and compared to conventional techniques. Results: In the primary curve, the mean preoperative and postoperative 1 week and 2 years follow-up standing coronal Cobb angles were 59.9º, 17.2º and 20.0º, respectively. Eighteen patients (64%) had distal levels saved (mean: 1.6 levels) in comparison to conventional techniques. Fulcum bending correction index were 122.6% at 1 week and 115.0% at 2 years. Trunkal shift was decreased from preoperative to last follow-up (p=0.003). No statistically significant difference from preoperative to last follow-up was noted in sagittal alignment, radiographic shoulder height and list (p>0.05). Successful fusion was achieved in all cases. No 'add-on' of other vertebra or decompensation was noted. Conclusion: This is the “first report” to note that using the FBR for decision-making in selecting fusion levels in thoracic AIS patients undergoing management with pedicle screw constructs, in this case ALSS, is a cost-effective strategy that can achieve clinically-relevant deformity correction that is maintained and without compromising fusion levels.