# Left-sided thoracic curves in adolescent idiopathic scoliosis: are the outcomes different?

## TL;DR

This study finds no major differences in surgical outcomes for adolescent scoliosis patients with left or right thoracic curves.

## Contribution

The study provides empirical evidence that left thoracic curves in scoliosis do not lead to worse surgical outcomes than right thoracic curves.

## Key findings

- Curve direction does not affect surgical time, blood loss, or reoperation rates.
- Left curves show greater T2-T12 kyphosis and differences in radiographic parameters post-surgery.
- Correction rates and patient-reported outcomes like SRS 22 scores are similar between left and right curves.

## Abstract

The purpose was to compare outcomes in adolescent idiopathic scoliosis (AIS) patients with left vs. right main thoracic curves. A secondary purpose was to elucidate surgeon opinions between these two curve types and differences in surgical approach via a survey.

A multicenter database was utilized to identify AIS patients with left thoracic curves without significant MRI abnormalities from 1996 to 2018 receiving posterior spinal fusion. A 1:1 propensity match was performed to right thoracic curves. Differences between the curve groups were analyzed.

Fifty patients had left thoracic curves. Curve direction had no impact on levels fused, surgical time, length of hospitalization, estimated blood loss, cell saver transfused, death, pain, pseudoarthrosis, reoperation, or infection rates. At two-years postoperatively, left curves had greater T2-T12 kyphosis (37 vs. 31°, p = .02), and variations in T1 tilt angle direction (30 vs. 39 left tilt, p = .04), EIV angulation (-2 vs. 5°, p < .01), EIV translation (0.6 vs. -0.2 cm, p = .03), and left shoulder elevation (12 in left curves vs. 25 in right curves, p = .01). There were no differences in correction rate, Cobb angle, lumbar curve, T12-S1 lordosis, shoulder height difference, or SRS 22 scores.

In AIS, there are no significant differences in surgical characteristics or outcomes between left and right-thoracic curves. Notably, curve direction does not influence correction rate, surgical time, levels fused, length of hospitalization, blood loss, pain, SRS 22 scores, or rates of reoperation, infection, or pseudoarthrosis. There are some variations in radiographic parameters postoperatively that are unlikely to be clinically significant.