Radiological Findings and Curve Progression Twenty Two Years After Treatment for Adolescent Idiopathic Scoliosis: Comparison of Brace and Surgical Treatment and with a Matching Control Group of Straight Individuals

Aina J. Danielsson, MD,
Alf L. Nachemson, MD, PhD
Sahlgrenska University Hospital, Göteborg, Sweden

INTRODUCTION:
A consecutive series of patients with adolescent idiopathic scoliosis, treated between 1968 and 1977, either with distraction and fusion using Harrington rods (ST, n=156) or with brace (BT, n=127) were followed at least twenty years after completion of the treatment.

PURPOSE:
To determine the long–term outcome with regard to radiological findings and curve progression.

METHODS:
Two hundred and fifty–two patients attended a clinical and radiological follow–up by an unbiased observer (91% of ST and 87% of BT). This included chart reviews, validated questionnaires, clinical examination and full standing frontal and lateral roentgenographs. Curve size (Cobb method), occurrence of any degenerative changes and other complications were noted. Repeat lateral radiographs, independently measured by two observers, were taken to evaluate lateral curvatures and sagittal balance. An age and sex matched control group of 100 individuals was randomly selected and subjected to the same examinations.

RESULTS:
The mean follow–up time was 23 years for ST group and 22 years for the BT group. Curve increase was 3.5 degrees for all ST curves and 7.9 degrees for all BT curves (p<0.001). The overall complication rate after surgery was low. Nine of the patients treated with fusion (5.7%) had undergone some additional curve–related surgical procedure. Both ST and BT patients had more degenerative disc changes in the lumbar region (p<0.001) than the control group. There was no statistically significant difference in terms of degenerative changes between those who were fused below L3 or those fused to L3 and above (p=0.22). The study on intra– and interobserver measurements of kyphosis, lordosis and sagittal vertical axis on two films on each patient, demonstrated that the repeatability of measuring sagittal plumbline on two different lateral radiographs, with patients moving in between, was unreliable.

DISCUSSION AND CONCLUSION:
Although over twenty years have passed since completion of the treatment, the majority of the curves did not increase much. The surgical complication rate was low. Unexpectedly, lumbar degenerative disc changes were equally common in both patient groups and significantly more than in the control group. The earlier shown increased incidence of degenerative changes below fusion extending to L4 or L5 was not seen. The low repeatability on lateral radiography for sagittal balance measurements makes evaluation of single examinations questionable.