Rib Regeneration Morphology after Thoracoplasty in Adolescent Idiopathic Scoliosis

Study Design.A retrospective study.Objective.The purpose of this study was to evaluate the morphology of rib regeneration and to analyze the influence of demographics and curve characteristics on regeneration potential after thoracoplasty in the treatment of adolescent idiopathic scoliosis (AIS).Summary of Background Data.Studies on the physiological effects after thoracoplasty have been performed for several decades. However, rib cage anatomical regeneration patterns and reformation have been rarely studied.Methods.A total of 120 AIS patients who underwent thoracoplasty with deformity correction were included. Patients were followed for >12 months and radiographic assessment was done at 3, 6, and 12 months. Conventional or short apical rib resection thoracoplasty was performed and 543 ribs were resected. Demographic and curve parameters were recorded and a rib regeneration classification was used to analyze regeneration. Computed tomography (CT) scan was performed only in selected patients (n=74).Results.At end of 3, 6, and 12 months, 23%, 45%, and 60% of the ribs had fused respectively. On multiple logistic regression analysis, age <10 years (odds ratio [OR]: 3.5, 95% confidence interval [CI]: 0.754-16.982), age 11 to 12 years (OR: 2.7, 95% CI: 2.709-31.595), age 13 to 14 years (OR: 6.2, 95% CI: 2.504-15.391), age 15 to 16 years (OR: 4.8, 95% CI: 2.064-11.571), five or more ribs excision (OR: 2.0, 95% CI: 1.294-3.108) enhance regeneration. Lenke type 2 (OR: 0.5, 95% CI: 0.305-0.898) Lenke type 4 (OR: 2.3, 95% CI: 1.033-5.144), and Risser grade (OR: 0.8, 95% CI: 0.694-0.967) had a negative influence on regeneration.Conclusion.The regeneration potential of the resected ribs after thoracoplasty in AIS patients depends on age, Risser grade, Lenke classification, and number of ribs resected. Age was the single most important factor affecting regeneration.Level of Evidence: 4.