Treatment of adolescent idiopathic scoliosis with quantified trunk rotational strength training: a pilot study

Prospective clinical trial.

To test the hypothesis that quantified trunk rotational strength training will equalize any strength asymmetry, increase strength overall, and stabilize adolescent idiopathic scoliosis.

Bracing, the only generally accepted form of adolescent idiopathic scoliosis nonoperative therapy, has many shortcomings. Paraspinal muscle abnormalities, which have been extensively documented in these patients, are generally considered to be secondary. A normal female's trunk strength in flexion and extension decreases from her juvenile to adolescent years, whereas a male's increases.

Patients received a 4-month supervised followed by a 4-month home trunk rotational strength training program. Trunk rotational strength was measured in both directions at 5 positions at baseline, 4 months, and 8 months. The patients were followed clinically.

Fifteen patients (12 females and 3 males), with an average age of 13.9 years and an average main Cobb of 33 degrees were enrolled. At baseline there was no significant asymmetry. After 4 months of supervised strength training, involving an average of 32 training sessions, each lasting about 25 minutes, their strength had significantly increased by 28% to 50% (P<0.005 to P<0.001). After 4 months of unsupervised home strength training their strengths were unchanged. The 3 patients with baseline curves of 50 to 60 degrees all had main or compensatory curve progression and 2 had surgery. For patients with 20 to 40-degree curves, survivorship from main curve progression of >or=6 degrees was 100% at 8 months, but decreased to 64% at 24 months.

Quantified trunk rotational strength training significantly increased strength. It was not effective for curves measuring 50 to 60 degrees. It appeared to help stabilize curves in the 20 to 40-degree ranges for 8 months, but not for 24 months. Periodic additional supervised strength training may help the technique to remain effective, although additional experimentation will be necessary to determine this.