# Early Onset Scoliosis and Casting

> Early onset scoliosis for NEET-PG Orthopaedics: infantile curves, resolving versus progressive, Mehta angle, Mehta casting and growing rod strategies.

- Canonical URL: https://prepelephant.com/topics/neet-pg/orthopaedics/early-onset-scoliosis-and-casting
- Exam / course: NEET-PG · Subject: Orthopaedics
- Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team
- First published: 2026-10-14
- Last updated: 2026-10-14
- Reference basis: Tachdjian's Pediatric Orthopaedics; Apley's System of Orthopaedics and Fractures
- How to cite: "Early Onset Scoliosis and Casting", PrepElephant, https://prepelephant.com/topics/neet-pg/orthopaedics/early-onset-scoliosis-and-casting

## Direct answer

Early onset scoliosis is a spinal curvature that develops before the age of 10, and its course depends on whether an infantile curve is resolving or progressive. Infantile curves are sorted by the Mehta angle, the rib-vertebra angle difference, with a value of 20 degrees or more suggesting progression. Progressive curves are treated with serial Mehta casting, and growing rod systems are reserved for curves that continue to worsen.

## What you must remember

- **Definition:** curve onset before age 10; infantile means the first three years of life and juvenile means ages four to nine.
- **Resolving versus progressive:** many infantile curves resolve spontaneously, particularly those with small Cobb angles and favourable rib-vertebra indices.
- **Mehta angle:** the rib-vertebra angle difference between the concave and convex sides; 20 degrees or more suggests progression, while a smaller value favours resolution.
- **Mehta casting:** serial corrective casts derotate and correct a progressive infantile curve, changed at intervals of several weeks until control is achieved, followed by bracing.
- **Growing rods:** distraction-based systems lengthened at regular intervals, typically every six months, to allow spinal growth while controlling the curve.
- **Thoracic insufficiency:** severe early curves can restrict lung growth, and expansion devices address this thoracic insufficiency syndrome.
- **Definitive treatment:** growing rod systems are eventually followed by spinal fusion once growth is complete.

## An infantile curve, step by step

A 14-month-old boy is found to have a left thoracic curve on clinic examination. The rib-vertebra angle decides whether the curve will resolve on observation or needs active correction.

1. **Confirm the age group:** a curve with onset before age 10, here in the infantile period, establishes early onset scoliosis and a greater tendency to progress.
2. **Measure the Cobb angle:** the radiograph gives a baseline, and the rate of change over serial films determines urgency.
3. **Calculate the rib-vertebra angle difference:** a value under 20 degrees favours resolution, whereas 20 degrees or more favours progression.
4. **Observe the resolving curve:** a curve with favourable indices is followed with serial radiographs at regular intervals.
5. **Cast the progressive curve:** Mehta casting is started, with casts changed serially to derotate and correct the curve, then bracing once it is controlled.
6. **Escalate when casting fails:** curves that continue to progress, or are too large or rigid for casting, move to growing rod systems lengthened every six months.

## Traps in early onset curves

Examiners test whether you can separate resolving from progressive curves before treating them.

- **Trap:** operating on every infantile curve. **Correct:** many infantile curves resolve, so the rib-vertebra angle difference guides the decision before any surgery.
- **Trap:** using a brace for a very young infant. **Correct:** infantile curves are usually managed with casting, since a brace is impractical at that age.
- **Trap:** placing growing rods and forgetting the lengthening schedule. **Correct:** growing rods need regular lengthening to match spinal growth, and definitive fusion follows later.

## Frequently asked questions

### What is the age cut-off for early onset scoliosis?

Early onset scoliosis is a curve that develops before the age of 10 years. Infantile early onset scoliosis covers the first three years of life, and juvenile early onset scoliosis covers ages four to nine.

### How is the Mehta angle used in early onset scoliosis?

The Mehta angle, or rib-vertebra angle difference, is the difference between the rib-vertebra angles on the concave and convex sides of an infantile curve. A difference of 20 degrees or more suggests a progressive curve in early onset scoliosis, while a smaller value favours spontaneous resolution.

### What is Mehta casting in early onset scoliosis?

Mehta casting is serial corrective casting used to treat progressive infantile early onset scoliosis. Casts are applied and changed at intervals of several weeks to derotate and correct the curve, and bracing follows once the curve is controlled.

### When are growing rods used for early onset scoliosis?

Growing rods are used in early onset scoliosis when curves continue to progress despite casting or are too large or rigid for casting. The distraction rods are lengthened at regular intervals to allow spinal growth, followed eventually by definitive fusion.