Traction versus supine side bending. Which technique best determines curve flexibility?

Abstract

Study design: A prospective study performed in two institutions where patients scheduled for surgical management of scoliosis were evaluated with traction and supine side bending radiographs to determine curve flexibility.

Objective: To determine if there is a difference in the flexibility of curves as determined by side bending or traction films.

Methods: Fifty-eight patients scheduled for surgery underwent preoperative radiographic evaluation using supine side bending and traction radiographs. The surgeons were free to use the information as they saw fit in determining levels of fusion. All curves were measured using the method of Cobb. Curves were analyzed in three groups: > 60 degrees, 50-60 degrees, and < 50 degrees. A comparison then was made between the traction and side bend films to determine which method demonstrated greater flexibility. Measurement error was assumed to be +/- 5 degrees. If the measurements were within 5 degrees, then the two methods were considered to be equivalent.

Results: In curves > 60 degrees, greater flexibility was seen on traction films. In curves < 50 degrees, side bending showed greater flexibility. In curves between 50 degrees and 60 degrees, side bending showed greater flexibility in the thoracic spine, whereas in the lumbar spine both films showed equivalent flexibility.

Conclusions: Traction shows greater curve flexibility in curves > 50 degrees, whereas in curves < 50 degrees, side bending shows greater flexibility.