Lonstein's 1984 retrospective cohort of 727 skeletally immature patients with idiopathic scoliosis (curves 5-29°) asked which clinical and radiographic factors at first presentation predict curve worsening during growth. The study produced the Lonstein progression factor nomogram, the first quantitative tool for counseling families about progression likelihood.
A child referred from school screening with a 15° curve and Risser 3 has a 1.6% chance of progression — that family needs reassurance, not anxiety-inducing frequent imaging. The same curve in a Risser 0 child carries 22% risk, and a 25° curve in a Risser 0 child carries 68% risk: those patients warrant close follow-up every 3-4 months.
This paper is why we anchor scoliosis surveillance to Risser sign and curve magnitude rather than age alone or curve pattern alone. When counseling families, calculate the progression factor. (Cobb angle − 3 × Risser sign) ÷ chronological age. And use the nomogram to give a specific probability, not vague reassurance.
One important nuance: the nomogram cannot be applied to curves ≤19°, and it was designed for counseling, not to trigger bracing. Treatment decisions still require integrating curve location, sex, and menarchal status.
Lonstein's 1984 retrospective cohort of 727 skeletally immature patients with idiopathic scoliosis (curves 5-29°) asked which clinical and radiographic factors at first presentation predict curve worsening during growth. The study produced the Lonstein progression factor nomogram, the first quantitative tool for counseling families about progression likelihood.
A child referred from school screening with a 15° curve and Risser 3 has a 1.6% chance of progression — that family needs reassurance, not anxiety-inducing frequent imaging. The same curve in a Risser 0 child carries 22% risk, and a 25° curve in a Risser 0 child carries 68% risk: those patients warrant close follow-up every 3-4 months.
This paper is why we anchor scoliosis surveillance to Risser sign and curve magnitude rather than age alone or curve pattern alone. When counseling families, calculate the progression factor. (Cobb angle − 3 × Risser sign) ÷ chronological age. And use the nomogram to give a specific probability, not vague reassurance.
One important nuance: the nomogram cannot be applied to curves ≤19°, and it was designed for counseling, not to trigger bracing. Treatment decisions still require integrating curve location, sex, and menarchal status.