TRACTION RADIOGRAPHY PERFORMED UNDER GENERAL ANAESTHETIC FOR ASSESSING SCOLIOSIS CURVES, DETERMINING THE SURGICAL APPROACH AND PREDICTING POSTOPERATIVE CORRECTION

Abstract

Objective The hypothesis of this study is that the flexibility of idiopathic scoliosis curves as measured by traction radiography performed under general anaesthetic (TUA) will be superior to supine bending radiography. Subsequently, this may aid in determining the surgical approach, sparing patients anterior release surgery, and show greater correlation with the postoperative result. This is a new technique, not previously reported in the literature.

Design A prospective comparison between TUA and supine bending radiography to determine curve flexibility, and examine their relationship with anterior release surgery and postoperative correction.

Subjects This study was based on 21 patients with a diagnosis of idiopathic scoliosis, admitted for corrective surgery at our unit.

Outcome measures The amount of correction achieved by each of the two methods on the preoperative curve was examined using a paired t-test. The influence of the TUA on the decision for anterior release surgery was noted, along with the correlation of each method with postoperative correction.

Results On statistical analysis with a paired t-test, TUA showed significantly greater curve flexibility than that shown by supine bending radiographs (p< 0.001) irrespective of curve classification or magnitude. Of the 11 patients planned for anterior release surgery with posterior fusion, the use of TUA obviated this in 9 (82%) by demonstrating greater preoperative curve flexibility. Excluding thoracolumbar curves, TUA showed significantly greater postoperative correlation than supine bending radiography (R=0.79, R=0.61 respectively).

Conclusion In our unit, traction radiography performed under general anaesthetic is superior to supine bending radiography in assessing curve mobility prior to surgery. Performing TUA has significant benefits to patients in avoiding unnecessary anterior release surgery, and has greater correlation with postoperative correction. In studying fulcrum bending radiographs, Cheung1 showed similar benefits in avoiding anterior release and we therefore recommend the use of these methods by other institutions.