Abstract
Purpose
To correlate the initial brace correction with quantity and quality of brace wear within the first 6 months for the treatment of adolescent idiopathic scoliosis (AIS).
Method
Brace treatment for AIS has been debated for years. Prediction of treatment outcomes is difficult as the actual brace usage is generally unknown. As technology became more advanced, electronic devices were able to measure adherence in both quantity (how much time the brace has been worn) and quality (how tightly the brace has been worn) of brace usage without need for patient interaction. The developed adherence monitor consisted of a force sensor and a data acquisition unit. Subjects were monitored within the first 6 months of brace wear. The data sample rate was set to be one sample per minute. Data was downloaded at the patients routine clinical visits. The prescription, first in-brace and first follow-up out-of-brace Cobb angles were measured. Twelve AIS subjects (10F, 2M), age between 9.8 and 14.7 years, average 11.9 1.5 years, who were prescribed a new TLSO and full-time brace wear (23 hours/day) participated. All braces were made by the same orthotist. The force value at the major pressure pad at the prescribed tightness level was recorded as the individualized reference value. The normalized force value (measured force magnitude relative to the individualized reference value) was used for the quality factor. The time of brace usage relative to the prescribed time was used as the quantity factor.
Results
The first in-brace follow-up visit was approximately 2 months after the brace fitting session and the first out-of-brace follow-up visit was scheduled after 4 months. The Cobb angle of the major curve prior to bracing, in-brace and at the first follow-up out-of-brace were 31.3 6.2, 16.5 8.7 and 31.8 7.1 degrees, respectively. The mean reference force value was 1.1 0.23N. The average quantity and quality of the brace usage were 61.2 12.2% and 63.4 8.8%, respectively. A relationship was found between wear time with a change in Cobb angle (pre brace – the first follow-up out-of-brace) (r = 0.77). The more time that the brace was worn resulted in a better treatment result. A moderate correlation was found between the force value at the major pressure pad and the in-brace correction (r = 0.40). Also, a moderate relationship was found between wear quality during daytime with a change in Cobb angle (r = 0.67). The more time that the brace was worn close to the prescribed tightness level during the daytime resulted in a better outcome.
Conclusion
This study showed the brace effectiveness is dependent on both the quantity and quality of brace usage.
