Scoliosis and Prognosis—a systematic review regarding patient-specific and radiological predictive factors for curve progression

Abstract

Introduction 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. Methods 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. Results 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). Discussion 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.

The Utility of a Novel Proximal Femur Maturity Index for Staging Skeletal Growth in Patients with Idiopathic Scoliosis

“…As chronological age is not accurate in indicating the timing of pubertal growth landmarks such as PHV 6 , skeletal bone age is an essential measure along with secondary sexual characteristics 7 . Skeletal maturity status can be a crucial factor for treatment prognosis and an indicator for the risk of curve progression [7][8][9][10] .…”

Supine correction index as a predictor for brace outcome in adolescent idiopathic scoliosis

“…It is established that a less mature patient and poor brace compliance predict curve progression, 4 , 5 , 7 as patients are required to wear the brace longer and are more prone to non-compliance and risk of curve progression. The major unanswered questions for bracing revolve around identifying other morphological factors to prognosticate and improve brace outcomes in cases unexplained by maturity indicators and compliance.…”

“…The factors commonly used to predict brace outcome are related to age and skeletal maturity, [4][5][6][7] as immaturity implies potential for growth and, therefore, curve progression. However, as bracing alters the natural history of AIS, metrics for measuring the effect of bracing, such as in-brace correction of Cobb angle, may play an important role in predicting the outcome of bracing.…”

A Decade in Review after Idiopathic Scoliosis Was First Called a Complex Trait—A Tribute to the Late Dr. Yves Cotrel for His Support in Studies of Etiology of Scoliosis

“…The effect on curve progression due to anthropometric, environmental, and lifestyle factors are reviewed in these publications [33][34][35].…”

“…Many factors are involved in curve progression, such as basic demographics (age of onset, sex), growth velocity, bone mineral density [ 30 ], mobility, and morphology of the scoliosis spine on imaging [ 31 , 32 ]. The effect on curve progression due to anthropometric, environmental, and lifestyle factors are reviewed in these publications [ 33 , 34 , 35 ].…”