The Canadian Scoliosis Screening Coalition

Links to Publications (including research) on Curve Progression in AIS

The following is a curated list. Spine Deformity experts (surgeons) and many researchers primary focus is on preventing and treating severe curve progression in adolescents. However, Health professionals need to acknowledge that AIS is a complex genetic disease (polygenetic multifactorial disease), that is not just confined to adolescence. That curves over 25° COBB angle, continue to progress long-term, albeit slowly. .70-1% a year, after skeletal maturity is reached. And later in life can cause back pain and other signifcant health quality of life problems.

1. Nam Y, Patel U, Chang DG, Lee YB, Lim J, Yang JH, Suh SW. Curve Progression in Adolescent Idiopathic Scoliosis with Cobb Angles Between 40 and 50 Degrees at the Late Stage of Skeletal Growth: A Minimum 5-Year Follow-Up Study. J Clin Med. 2025 Jul 25;14(15):5272. doi: 10.3390/jcm14155272. PMID: 40806894; PMCID: PMC12347580."...Conclusions In this study, significant curve progression was observed in 39.2% of the AIS patients even at the late stage of skeletal growth. A younger age and Risser stage IV were significantly associated with this progression. In addition, a larger baseline curve magnitude and Risser stage IV were associated with a final Cobb angle ≥ 50 degrees. Understanding these risk factors may aid clinicians in developing more appropriate management strategies for AIS patients at the late stage of skeletal growth. Given that curve progression may continue even after skeletal maturity, especially in patients with residual growth or a larger baseline curve magnitude, extended follow-up and timely clinical decision-making may help prevent progression beyond the surgical threshold."
2. Grivas TB, Vasiliadis E, Soultanis K, Lykissas M, Katzouraki G, Sekouris N, Lykouris D, Mazioti C, Mamzeri A, Papagianni D, Potamiti E, Kastrinis A, Theodosopoulos E. Idiopathic Scoliosis Progression: Presenting Rib and Segmental Rib Index as Predictors-A Literature Review. Med Sci (Basel). 2025 May 21;13(2):62. doi: 10.3390/medsci13020062. PMID: 40407557; PMCID: PMC12101284. "...The present paper summarizes the current knowledge of factors that are involved in curve progression in idiopathic scoliosis and cites the numerous models that have been developed for prediction of IS progression. It also highlights the importance of the thorax in scoliotic deformity and introduces, for the first time, two factors that describe the deformity of the rib cage, namely, the Rib Index and the Segmental Rib Index, as predictors of IS progression."
3. Khodaei, M., Parent, E., Le, L. et al. Identifying and validating prognostic parameters to predict curve progression in adolescents with idiopathic scoliosis. Eur Spine J (2025). https://doi.org/10.1007/s00586-025-08922-w "...Conclusions The results indicated that participants with lower RC (weaker bone, RC ≤ 0.06), larger US Cobb change (≥ 5°), and multiple curvatures (NOC > 1) were at a higher risk of curve progression..."
4. Ogata Y, Kotani T, Asada T, Ohyama S, Okuwaki S, Iijima Y, Sakuma T, Ohtori S, Yamazaki M.Timeline of curve progression around menarche in small adolescent idiopathic scoliosis curves without influence of braces: a single-center longitudinal cohort study of 1,090 patients Spine J. 2025 Jan 31:S1529-9430(25)00062-2. doi: 10.1016/j.spinee.2025.01.022. Epub ahead of print. PMID: 39894277. "...RESULTS Overall, 1,090 female patients were included, with a mean initial visit age of 12.9 years (standard deviation [SD]: 1.5) and a mean coronal Cobb angle of 17.5° (SD: 4.3). Curve progression was significantly decreased between 0–1 and 1–2 years post-menarche (0–1 year post-menarche: 2.9°/year vs. 1–2 years post-menarche: 1.3°/year; p=.03). After 2 years from menarche, the mean curve progression was less than 0.4°/year. The cut-off value of the curve magnitude for the final initiation of brace treatment at the timing of menarche was 20.5° (area under the curve: 0.89, p<.001, 95% confidence interval: 0.86–0.91). CONCLUSIONS This study highlights that in small AIS curves under 25°, minimal curve progression was observed after 2 years post-menarche, aiding follow-up strategies for AIS conservative treatment."
5. Negrini, S., Yaskina, M., Donzelli, S. et al. Puberty changes the natural history of idiopathic scoliosis: three prediction models for future radiographic curve severity from 1563 consecutive patients. Eur Spine J 33, 3767–3775 (2024). https://doi.org/10.1007/s00586-024-08487-0 "...We developed a retrospective model with the largest available sample in the literature and we aimed to investigate if using three peri-pubertal growth periods provides better prediction than a unique model... Three groups: BEFORE (age 6–10), AT (age 11-Risser 2) and AFTER (from Risser 3) the pubertal growth spurt. Available predictors: Cobb angle, curve type, sex, observation time, and Risser score...Curves increased over time mostly in AT, importantly in BEFORE, but also in AFTER...IS curve severities increase differently during growth with puberty stages. Model accuracy increases when tailored by growth spurt periods. Our models may help patients and clinicians share decisions, identify the risk of progression and inform treatment planning."
6. Parent EC, Donzelli S, Yaskina M, Negrini A, Rebagliati G, Cordani C, Zaina F, Negrini S. Prediction of future curve angle using prior radiographs in previously untreated idiopathic scoliosis: natural history from age 6 to after the end of growth (SOSORT 2022 award winner). Eur Spine J. 2023 Jun;32(6):2171-2184. doi: 10.1007/s00586-023-07681-w. Epub 2023 Apr 14. PMID: 37059884. "...Treatment selection for idiopathic scoliosis is informed by the risk of curve progression. Previous models predicting curve progression lacked validation, did not include the full growth/severity spectrum or included treated patients....Prediction models were proposed, which can help clinicians predict future curve severity expected in patients not receiving treatment. Our models offer the flexibility to predict at a future timepoints over the full growth period. One model allows such predictions using only simple clinical and radiographic data from an initial specialist consultation, and the other model allows taking advantage of clinical data from prior visits while untreated to improve prediction accuracy. The prediction accuracy of these validated models was very good with 80% or more predicted within 10°. Important predictors varied between models and included: curve severity, documented progression, curve types, skeletal maturity, age at consultation, time to the target prediction, and interactions between time and maturity and time and sex. The nonlinear effects of time in both models account for the rapid increase in curve angle at the beginning of growth and the slowed progression after maturity. Improved prediction ability may help clinicians inform treatment prescription or show families why no treatment is recommended."
7. Luhmann S, Zaaroor-Regev D, Upasani VV, Shufflebarger H. The natural history of curve behavior after brace removal in adolescent idiopathic scoliosis: a literature review. Spine Deform. 2023 May;11(3):567-578. doi: 10.1007/s43390-022-00638-x. Epub 2023 Jan 30. PMID: 36715866; PMCID: PMC10147768."...curves continue to progress after brace treatment is completed... The magnitude and rate of curve progression is mainly dependent on the degree of curve at weaning as curves weaned at < 25° progress substantially less than curves weaned at ≥ 25° at 25 years..."
8. Curve Progression in Untreated Patients with Scoliosis (AIS) from the Scoliosis Research Society Education Resource Center. See table 1. "...Studies have consistently shown the more skeletally immature a patient is, the greater the chance of progression. It also shown the larger the curve at presentation, the higher the probability of progression of the deformity. There is also a greater risk of progression before the onset of menarche in females..."
9. Wong LPK, Cheung PWH, Cheung JPY. Curve type, flexibility, correction, and rotation are predictors of curve progression in patients with adolescent idiopathic scoliosis undergoing conservative treatment : a systematic review. Bone Joint J. 2022 Apr;104-B(4):424-432. doi: 10.1302/0301-620X.104B4.BJJ-2021-1677.R1. PMID: 35360948; PMCID: PMC9020521. "...In summary, this is the first systematic review that assessed radiological prognostic factors for AIS curve progression using the GRADE approach. We found that Cobb angle > 25° and thoracic curves are the major predictors of curve progression in unbraced patients. Thoracic curves, supine flexibility < 28%, and low in-brace correction rate predict poor outcome in braced patients. Vertebral rotation may be a promising factor despite its current low evidence. This review highlighted a few knowledge gaps in the existing literature that will benefit from future research. More prognostic studies with multiva
10. Nault ML, Beauséjour M, Roy-Beaudry M, Mac-Thiong JM, de Guise J, Labelle H, Parent S. A Predictive Model of Progression for Adolescent Idiopathic Scoliosis Based on 3D Spine Parameters at First Visit. Spine (Phila Pa 1976). 2020 May 1;45(9):605-611. doi: 10.1097/BRS.0000000000003316. Erratum in: Spine (Phila Pa 1976). 2020 Jun 15;45(12):E753. doi: 10.1097/BRS.0000000000003555. PMID: 31703055. "...The aim of this prospective cohort study was to improve the prediction of curve progression in AIS. By adding the 3D morphology parameters at first visit, the predictive model explains 65% of the variability...The model will help the treating physician to initiate appropriate treatment at first visit."
11. Sun X, Wu T, Liu Z, Zhu Z, Qian B, Zhu F, Ma W, Yu Y, Wang B, Qiu Y. Osteopenia predicts curve progression of adolescent idiopathic scoliosis in girls treated with brace treatment. J Pediatr Orthop. 2013 Jun;33(4):366-71. doi: 10.1097/BPO.0b013e31827b7b5f. PMID: 23653023."...Conclusions: Osteopenia is identified to serve as a new independent risk factor in the curve progression during the duration of bracing treatment. The evaluation of initial BMD status before bracing may help to predict the outcome of brace treatment." Level of Evidence: Level II.
12. Tan KJ, Moe MM, Vaithinathan R, Wong HK. Curve progression in idiopathic scoliosis: follow-up study to skeletal maturity. Spine (Phila Pa 1976). 2009 Apr 1;34(7):697-700. doi: 10.1097/BRS.0b013e31819c9431. PMID: 19333102. "...Conclusion. Initial Cobb angle magnitude is the most important predictor of long-term curve progression and behavior past skeletal maturity. We suggest an initial Cobb angle of 25° as an important threshold magnitude for long-term curve progression. Initial age, gender, and pubertal status were less important prognostic factors in our study."
13. Lee CF, Fong DY, Cheung KM, Cheng JC, Ng BK, Lam TP, Yip PS, Luk KD. A new risk classification rule for curve progression in adolescent idiopathic scoliosis. Spine J. 2012 Nov;12(11):989-95. doi: 10.1016/j.spinee.2012.05.009. Epub 2012 Jun 21. PMID: 22727318. "...Results The new classification rule identified four risk groups of curve progression. Patients with a curvature of 26° and more and less than 18° constituted the highest and lowest risk groups, respectively. The two intermediate groups were identified by the age (11.3 years), menarcheal status, and body height (154 cm)... Conclusions The risk classification rule only uses information at the first presentation and can aid physicians in deriving an efficient management."