Immediate brace weaning maintains similar outcomes to gradual weaning in adolescent idiopathic scoliosis

A randomized clinical trial (RCT) conducted by researchers from the University of Hong Kong (HKU) demonstrated a very similar maintenance of outcomes and health-related quality of life (HRQoL) with immediate or gradual brace weaning in adolescent idiopathic scoliosis (AIS).

Bracing is the most common treatment modality for controlling curve progression in AIS. [N Engl J Med 2013;369:1512-1521] It is completed at the end of skeletal growth, as curve progression risk considerably decreases thereafter. [Pediatr Rehabil 2003;6:201-207] Prolonged bracing can reduce spinal mobility, leading to muscle weakness, osteoporosis, and poor body appearance and HRQoL. [Stud Health Technol Inform 2006:123:352-356] Despite having accurate parameters for determining when patients reach skeletal maturity and no longer require further bracing, there is a lack of consensus and evidence-based guidelines regarding brace weaning.

The main rationale for gradual weaning is to allow the spine to adapt to the unloaded environment while still maintaining corrective posture. On the other hand, immediate weaning allows earlier return to normality, meaning resumption of exercise, muscle training, and activity level. The aims of this trial were to compare the degree of Cobb angle and truncal balance maintenance between immediate and gradual brace weaning protocols. [JAMA Pediatr 2024;178:657-668]

AIS patients (mean age, 14.9 years; girls, 83.4 percent) who were ready to discontinue brace wear were randomized to gradual weaning protocol (n=176), which required an additional 6 months of nighttime brace wear, or immediate weaning protocol (n=193), where the brace was removed completely at recruitment. A total of 284 patients completed the 24-month longitudinal follow-up. The brace was worn for a mean of 3.5 hours per day in the gradual weaning group.

In both the intention-to-treat (ITT) and per-protocol (PP) populations, primary analyses found no significant difference in changes of major and minor Cobb angles between the two protocols, except for only minor Cobb angle change at 6 months postweaning. Secondary analyses similarly found no significant intergroup differences in major and minor Cobb angle changes with covariate adjustment. “The magnitude of Cobb angle changes from baseline for each weaning protocol was within the measurement error range of 5°, while the intergroup difference in change of Cobb angle was within the equivalence margin of 2°,” noted the researchers.

In both the ITT and PP populations, changes in truncal balance were not significantly different between groups at 6, 12 and 24 months postweaning – both with and without covariate adjustment. Intergroup differences of other radiological parameters were also insignificant.

The researchers hypothesized that gradual weaning may help minimize muscle discomfort from the sudden strain of not wearing a brace, while immediate weaning could lead to more back pain. However, the two protocols demonstrated comparable overall HRQoL scores as well as similar scores in Scoliosis Research Society questionnaire pain domain and EuroQoL pain/discomfort dimension.

“This largest RCT on AIS brace weaning … provides compelling evidence that gradual weaning is not superior to immediate weaning, as was commonly believed,” said Professor Jason Cheung of the Department of Orthopaedics and Traumatology, HKU. “Appropriate cases should now be considered for immediate weaning, which allows earlier resumption of higher levels of physical activity and exercise. This approach will help avoid brace overuse and facilitate a quicker return to normal life, helping patients regain their confidence.”