Risk of Scoliosis Progression in Nonoperatively Treated Adolescent Idiopathic Scoliosis Based on Skeletal Maturity

Abstract

Background: Hand radiographs for skeletal maturity staging are now frequently used to evaluate remaining growth potential for patients with adolescent idiopathic scoliosis (AIS). Our objective was to create a model predicting a patient's risk of curve progression based on modern treatment standards. Methods: We retrospectively reviewed all AIS patients presenting with a major curve <50 degrees, available hand radiographs, and complete follow up through skeletal maturity at our institution over a 3-year period. Patients with growth remaining underwent rigid bracing of curves > 25 degrees, whereas patients between 10 and 25 degrees were observed. Treatment success was defined as reaching skeletal maturity with a major curve <50 degrees. Four risk categories were identified based on likelihood of curve progression.Results: Of 609 AIS patients (75.4% female) presenting with curves over 10 degrees and reaching skeletal maturity at most recent follow up, 503 (82.6%) had major thoracic curves. 16.3% (82/503) of thoracic curves progressed into surgical treatment range. The highest risk group (Sanders 1 to 6 and curve 40 to 49 degrees, Sanders 1 to 2 and curve 30 to 39) demonstrate a 30% success rate with nonoperative treatment. This constitutes an 111.1 times (95% confidence interval: 47.6 to 250.0, P < 0.001) higher risk of progression to surgical range than patients in the lowest risk categories (Sanders 1 to 8 and curve 10 to 19 degrees, Sanders 3 to 8 and curve 20 to 29 degrees, Sanders 5 to 8 and curve 30 to 39 degrees). Conclusions: Skeletal maturity and curve magnitude have strong predictive value for future curve progression. The results presented here represent a valuable resource for orthopaedic providers regarding a patient's risk of progression and ultimate surgical risk.

The Sanders Maturity Scale for skeletal maturity assessment in idiopathic scoliosis

“…By applying the SMS method, Risser 0 patients could be classified into subcategories which may enhance maturity stratification. The SMS together with the Cobb angle have a potential to become a predictive value for the curve progression risk in IS [9,16,17]. A significant difference in progression risk of IS patients with Sanders 1, 2, 3 or 4+ stages was shown by Dolan et al in 2019 [16].…”

Differences in spine growth potential for Sanders maturation stages 7A and 7B have implications for treatment of idiopathic scoliosis

“…The Sanders skeletal maturity staging system has emerged as a more accurate and reliable marker of growth and curve progression [ 7 , 8 ]. The Sanders maturation stage (SMS), derived from the Tanner–Whitehouse III method [ 9 ], simplifies the assessment of bone maturity and is widely adopted in AIS treatment due to its high reliability and ease of use [ 10 – 16 ].…”

The Interrater and Intrarater Reliability of the Humeral Head Ossification System and the Proximal Femur Maturity Index Assessments for Patients with Adolescent Idiopathic Scoliosis

“…Skeletal maturity can evaluate the growth and development potential of children and provide a guide for the treatment of adolescent idiopathic scoliosis (AIS). A convenient and reliable method for assessing skeletal maturity is of great significance for guiding the treatment of spinal curvatures, especially in idiopathic scoliosis ( 1 ). By using skeletal maturity as a predictor, clinicians may determine the likelihood that a scoliosis curve will progress, which helps them decide how long to have their patients wear braces and whether to operate.…”