Radiographic analysis of the progression of congenital scoliosis with rib anomalies during the growth period

Abstract

Retrospective study. To evaluate progression of various types of congenital scoliosis (CS) with rib anomalies (RA) during the various stages of the growth period, and to assess severity of progression in order to make a strategic planning of expansion thoracoplasty. VEPTR is approved for the treatment of patients with TIS in more than 30 countries. However, there is no consensus on the surgical indications, or the age or time when VEPTR surgery should be performed. Furthermore, there is no study related to natural history of congenital scoliosis with rib anomalies except two reports that are not sufficient to indicate risk factors of progression during the growth period. Based on a survey of CS and RA via questionnaires, 70 patients (32 males and 38 females with an average age of 2.6 years at the first visit.) matched the inclusion criteria: CS with RA, no procedures that could influence natural history during follow-up periods, repeated plain X-ray check-ups with at least two years interval during growth periods. Average follow-up (F/U) time was 5.4 years (2–14). Plain X-ray images of 70 patients were divided into three age groups: infantile (0–5,6), juvenile (5–10,11), and adolescent (11,12-). Each X-ray image was evaluated in terms of laterality, range and type of RA, severity of scoliosis, type of CS, thoracic height ratio, SAL, and associated anomalies. 54 of the 70 patients had unilateral rib anomalies. Rib anomalies included rib fusion in 52, mixed type (fusion and defect) in 8, rib proximity in 6, and rib defect in 4. Vertebral anomalies included formation failure in 1, segmentation failure in 16 and mixed type in 53. The magnitude of scoliosis was 46.9° at the first visit and 65.7° at the final F/U. Scoliosis progressed at the rate of 4.6°/year in 70, 3.6°/year in bilateral RA involvement and 4.9°/year in unilateral. Scoliosis progressed with the rate of 4.6°/year in 70, 3.6°/year in bilateral RA involvement and 4.9°/year in unilateral. Scoliosis progressed most severely during infantile period with the rate of 5.0°/year, followed by adolescent of 3.8°/year and juvenile of 2.3°/year. Patients with rib defect or unilateral unsegmented bar showed higher progression rates (10.7°/year and 7.0°/year) during infantile period. According to the relationship between SAL and scoliosis, four grades in severity of progression (most severe, severe, moderate, mild) were set up with the cut-off value of 70%, 85% of SAL and 45°, 85° of scoliosis for making the strategic planning of ET. Those grades were significantly related with types and location of RA and types of vertebral anomalies. Progression of scoliosis was analysed in 70 patients with CS & RA. Congenital scoliosis with rib anomalies progressed most rapidly during the early infantile period (7.8°/year), followed by the late infantile period (5.0°/year), and the adolescent period (3.8°/year). Progression of scoliosis in patients with CS and RA occurred in early phase of growth periods and significantly related with types and location of RA as well as type of vertebral anomalies. The results of this study surely suggest the timing of ET for the patients with CS and RA.