Background: The progression of scoliosis has been observed in skeletally mature patients with cerebral palsy (CP). The aims of this systematic review were to determine the incidence of curve progression of untreated scoliosis after skeletal maturity, to estimate the average annual increase and to identify factors that influence the progression. Methods: A systematic literature search was performed in PubMed, Embase and the Cochrane Library for original research articles published between 1968 and May 2024 with a retrospective, prospective or cross-sectional design, investigating CP patients that were followed up beyond the age of 15 years. The search was limited to articles in English, French, German and Dutch. Articles were excluded if the study population concerned neuromuscular diseases other than CP. After an assessment of the methodological quality of each study, estimates of annual curve progression and the effect of the investigated risk factors for progression were recorded systematically and synthetized. Results: Fifteen studies met the inclusion criteria, resulting in a total sample size of 2569 participants. The study populations of the included original research articles were small and heterogeneous in terms of patient age and the type and severity of CP. Curve progression after skeletal maturity occurred in all included studies. A greater curve magnitude at the end of adolescence and a severe motor deficit (an inability to walk or GMFCS IV-V) were identified as significant risk factors for the progression of scoliosis after skeletal maturity. If at least one of these risk factors was present, scoliotic curves progressed after skeletal maturity in up to 74% of patients, with an average annual increase of 1.4 to 3.5 degrees per year. No significant association was found between curve progression and the physiologic type of CP, the type of scoliotic curve, previous hip surgery, positioning and gravity, weight and length, sex, epilepsy, or pelvic obliquity. Findings on the effect of hip instability were inconsistent: a positive correlation was found with the progression of scoliosis overall, but not after skeletal maturity in particular. A significant selection bias should be considered in the calculation of average annual curve progression, as patients that received interventions to halt curve progression were excluded from follow-up. Conclusions: The identification of risk factors in patients with CP and scoliosis can aid in predicting curve progression and managing follow-ups in clinical practice. Based on the findings in this review a radiographic follow-up once every 3 years is recommended for skeletally mature CP patients with at least one risk factor, and once every 5 years if no risk factors are present.

BACKGROUND: Prior reviews investigating the impact of pregnancy on adolescent idiopathic scoliosis (AIS) have reached different conclusions and a meta-analysis of curve progression among pregnant females with AIS and its effects on clinical outcomes has not previously been performed.
METHODS: A comprehensive search of major bibliographic databases (PubMed, Embase, and Scopus) was conducted for articles pertaining to spinal curve progression during pregnancy among patients with AIS. Patient demographics, scoliotic curve outcomes, and patient-reported quality of life measures were extracted.
RESULTS: Ten studies, including 857 patients with a mean age of 28.7 years, were included. Before pregnancy, 42.1% had undergone spinal fusion and 59.0% had a thoracic curve. Based on pre-pregnancy and post-pregnancy radiographs, the curve increased from 33.9° to 38.5° and meta-analysis revealed a curve progression of 3.6° (range=-5.85--1.25, p=0.003), primarily arising from loss of correction in the unfused group (Unfused=-5.0, p=0.040; Fused=-3.0, p=0.070). At the same time, 45.9% patients reported increased low back pain and many reported a negative body self-image and limitations in sexual function. However, five studies noted that pregnancy and number of pregnancies were not associated with curve progression, and multiple studies identified similar quality of life-related changes in non-pregnant patients with AIS.
CONCLUSIONS: Among unfused pregnant females with AIS, the spinal curvature increased significantly by 5.0° from before to after pregnancy. However, these changes may be independent of pregnancy status and occur with time. Such curve progression can contribute to a negative body self-image, low back pain, and functional limitations irrespective of pregnancy state.

The diagnosis of adolescent idiopathic scoliosis requires clinical and radiographic evaluation; the management options vary depending on the severity of the curve and potential for progression. Identifying predictors of scoliosis progression is crucial to avoid incorrect management; clinical and radiographic factors have been studied as potential predictors. The present study aims to review the literature on radiological indexes for the peak height velocity or curve acceleration phase to help clinicians manage treatment of patients with adolescent idiopathic scoliosis.
This systematic review was carried out in accordance with Preferential Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. The search was carried out including only peer-reviewed articles written in English that described the radiological indexes assessing skeletal maturity in patients with adolescent idiopathic scoliosis and evaluated their correlation with curve progression, expressed as peak height velocity and/or curve acceleartion phase.
Thirteen studies were included and showed promising results in terms of reliable radiological indexes. Risser staging gives a general measure of skeletal maturity, but it cannot be used as a primary index for driving the treatment of patients with adolescent idiopathic scoliosis since more reliable indexes are available.
Skeletal maturity quantification for adolescent idiopathic scoliosis has the potential to significantly modify disease management. However, idiopathic scoliosis is a complex and multifactorial disease: therefore, it is unlikely that a single index will ever be sufficient to predict its evolution. Therefore, as more adolescent idiopathic scoliosis progression-associated indexes are identified, a collective scientific effort should be made to develop a therapeutic strategy based on reliable and reproducible algorithms.

Brace treatment is the most common nonoperative treatment to prevent curve progression in adolescent idiopathic scoliosis (AIS). The goal of this review and analysis is to characterize curve behavior after completion of brace treatment and to identify factors that may facilitate the estimation of long-term curve progression.
A review of the English language literature was completed using the MEDLINE (PUBMED) database of publications after 1990 until September 2020. Studies were included if they detailed a minimum of 1 year post-brace removal follow-up of AIS patients. Data retrieved from the articles included Cobb angle measurements of the major curves at \"in-brace,\" weaning, and follow-up visit(s) for all patients described and for subset populations.
From 75 articles, 18 relevant studies describing a follow-up period of 1-25 years following brace removal were included in the analyses. The reviewed literature demonstrates that curves continue to progress after brace treatment is completed with three main phases of progression: (i) immediate (upon brace removal) where a mean curve progression of 7° occurs; (ii) short term (within five years of brace removal) where a relatively high progression rate is evident (0.8°/year); and (iii) long term (more than five years after brace removal) where the progression rate slows (0.2°/year). 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.
Curves continue to progress after brace removal and the rate and magnitude of progression are associated with the curve size at weaning, with larger curves typically exhibiting more rapid and severe progression. This analysis provides physicians and patients the ability to estimate long-term curve size based on the curve size at the time of weaning.
IV.

To create an updated and comprehensive overview of the modeling studies that have been done to understand the mechanics underlying deformities of adolescent idiopathic scoliosis (AIS), to predict the risk of curve progression and thereby substantiate etiopathogenetic theories.
In this systematic review, an online search in Scopus and PubMed together with an analysis in secondary references was done, which yielded 86 studies. The modeling types were extracted and the studies were categorized accordingly.
Animal modeling, together with machine learning modeling, forms the category of black box models. This category is perceived as the most clinically relevant. While animal models provide a tangible idea of the biomechanical effects in scoliotic deformities, machine learning modeling was found to be the best curve-progression predictor. The second category, that of artificial models, has, just as animal modeling, a tangible model as a result, but focusses more on the biomechanical process of the scoliotic deformity. The third category is formed by computational models, which are very popular in etiopathogenetic parameter-based studies. They are also the best in calculating stresses and strains on vertebrae, intervertebral discs, and other surrounding tissues.
This study presents a comprehensive overview of the current modeling techniques to understand the mechanics of the scoliotic deformities, predict the risk of curve progression in AIS and thereby substantiate etiopathogenetic theories. Although AIS remains to be seen as a complex and multifactorial problem, the progression of its deformity can be predicted with good accuracy. Modeling of AIS develops rapidly and may lead to the identification of risk factors and mitigation strategies in the near future. The overview presented provides a basis to follow this development.

Adolescent idiopathic scoliosis (AIS) is a progressive deformity of the spine. Scoliotic curves progress until skeletal maturity leading, in rare cases, to a severe deformity. While the Cobb angle is a straightforward tool in initial curve magnitude measurement, assessing the risk of curve progression at the time of diagnosis may be more challenging. Epigenetic and genetic markers are potential prognostic tools to predict curve progression. The aim of this study is to review the available literature regarding the epigenetic and genetic factors associated with the risk of AIS curve progression. This review was carried out in accordance with Preferential Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. The search was carried out in January 2022. Only peer-reviewed articles were considered for inclusion. Forty studies were included; fifteen genes were reported as having SNPs with significant association with progressive AIS, but none showed sufficient power to sustain clinical applications. In contrast, nine studies reporting epigenetic modifications showed promising results in terms of reliable markers. Prognostic testing for AIS has the potential to significantly modify disease management. Most recent evidence suggests epigenetics as a more promising field for the identification of factors associated with AIS progression, offering a rationale for further investigation in this field.

OBJECTIVE: The aim of this study was to review the current evidence surrounding curve type and morphology on curve progression risk in adolescent idiopathic scoliosis (AIS).
METHODS: A comprehensive search was conducted by two independent reviewers on PubMed, Embase, Medline, and Web of Science to obtain all published information on morphological predictors of AIS progression. Search items included \'adolescent idiopathic scoliosis\', \'progression\', and \'imaging\'. The inclusion and exclusion criteria were carefully defined. Risk of bias of studies was assessed with the Quality in Prognostic Studies tool, and level of evidence for each predictor was rated with the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) approach. In all, 6,286 publications were identified with 3,598 being subjected to secondary scrutiny. Ultimately, 26 publications (25 datasets) were included in this review.
RESULTS: For unbraced patients, high and moderate evidence was found for Cobb angle and curve type as predictors, respectively. Initial Cobb angle > 25° and thoracic curves were predictive of curve progression. For braced patients, flexibility < 28% and limited in-brace correction were factors predictive of progression with high and moderate evidence, respectively. Thoracic curves, high apical vertebral rotation, large rib vertebra angle difference, small rib vertebra angle on the convex side, and low pelvic tilt had weak evidence as predictors of curve progression.
CONCLUSIONS: For curve progression, strong and consistent evidence is found for Cobb angle, curve type, flexibility, and correction rate. Cobb angle > 25° and flexibility < 28% are found to be important thresholds to guide clinical prognostication. Despite the low evidence, apical vertebral rotation, rib morphology, and pelvic tilt may be promising factors. Cite this article: Bone Joint J 2022;104-B(4):424-432.

Idiopathic scoliosis, defined as a > 10° curvature of the spine in the frontal plane, is one of the most common spinal deformities. Age, initial curve magnitude and other parameters define whether a scoliotic deformity will progress or not. Still, their interactions and amounts of individual contribution are not fully elaborated and were the aim of this systematic review.
A systematic literature search was conducted in the common databases using MESH terms, searching for predictive factors of curve progression in adolescent idiopathic scoliosis (\"adolescent idiopathic scoliosis\" OR \"ais\" OR \"idiopathic scoliosis\") AND (\"predictive factors\" OR \"progression\" OR \"curve progression\" OR \"prediction\" OR \"prognosis\"). The identified and analysed factors of each study were rated to design a top five scale of the most relevant factors.
Twenty-eight investigations with 8255 patients were identified by literature search. Patient-specific risk factors for curve progression from initial curve were age (at diagnosis < 13 years), family history, bone mineral status (< 110 mg/cm3 in quantitative CT) and height velocity (7-8 cm/year, peak 11.6 ± 1.4 years). Relevant radiological criteria indicating curve progression included skeletal maturity, marked by Risser stages (Risser < 1) or Sanders Maturity Scale (SMS < 5), the initial extent of the Cobb angle (> 25° progression) and curve location (thoracic single or double curve).
This systematic review summarised the current state of knowledge as the basis for creation of patient-specific algorithms regarding a risk calculation for a progressive scoliotic deformity. Curve magnitude is the most relevant predictive factor, followed by status of skeletal maturity and curve location.

Brace treatment is the most common nonoperative treatment for the prevention of curve progression in adolescent idiopathic scoliosis. The success reported in level 1 and 2 clinical trials is approximately 75%. The aim of this review was to identify the main risk factors that significantly reduce success rate of brace treatment. A literature search using the MEDLINE and Embase databases was conducted. Studies were included if they identified specific risk factor(s) for curve progression. Studies that looked at nighttime braces, superiority of one type of brace over another, the effect of physical therapy on brace performance, cadaver or nonhuman studies were excluded. A total of 1,022 articles were identified of which 25 met all of the inclusion criteria. Seven risk factors were identified: Poor brace compliance (eight studies), lack of skeletal maturity (six studies), Cobb angle over a certain threshold (six studies), poor in-brace correction (three studies), vertebral rotation (four studies), osteopenia (two studies), and thoracic curve type (two studies). Three risk factors were highly repeated in the literature which identified specific subgroups of patients who have a much higher risk to fail brace treatment and to progress to fusion. This data demonstrates that 60% to 70% of the patients referred to bracing are Risser 0 and 30% to 70% of this group will not wear the brace enough to ensure treatment efficacy. Furthermore, Risser 0 patients who reach the accelerated growth phase with a curve ≥40° are at 70% to 100% risk of curve progression to the fusion surgical threshold despite proper brace wear. Skeletally immature patients with relatively large magnitude scoliosis who are noncompliant are at a higher risk of failing brace treatment.

To identify prognostic factors for curve progression in de novo degenerative lumbar scoliosis (DNDLS) by performing a systematic review of the literature.
Studies were selected for inclusion following a systematic search in the bibliographic databases PubMed and EMBASE prior to September 2015 and hand searches of the reference lists of retrieved articles. Two authors independently assessed methodological quality. Data were extracted and presented according to a best evidence synthesis.
The literature search generated a total of 2696 references. After removing duplicates and articles that did not meet inclusion criteria, 12 studies were included. Due to the lack of statistical analyses, pooling of data was not possible. Strong evidence indicates that increasing intervertebral disk degeneration, lateral vertebral translation ≥6 mm, and an intercrest line through L5 (rather than L4) are associated with DNDLS curve progression. Moderate evidence suggests that apical vertebral rotation Grade II or III is associated with curve progression. For the majority of other prognostic factors, we found limited, conflicting, or inconclusive evidence. Osteoporosis, a coronal Cobb angle <30°, lumbar lordosis, lateral osteophytes difference of ≥5 mm, and degenerative spondylolisthesis have not been shown to be risk factors. Clinical risk factors for progression were not identified.
This review shows strong evidence that increased intervertebral disk degeneration, an intercrest line through L5, and apical lateral vertebral translation ≥6 mm are associated with DNDLS curve progression. Moderate evidence was found for apical vertebral rotation (Grade II/III) as a risk factor for curve progression. These results, however, may not be directly applicable to the individual patient.