Response to letter to editor regarding “Night time bracing with the Providence thoracolumbosacral orthosis for treatment of adolescent idiopathic scoliosis: a retrospective consecutive clinical series” by Davis L et al.

Response to letter

My coauthors and I thank the author(s) for their inquiry and remarks regarding our recent study reporting the use of the Providence night-time thoracolumbosacral orthosis (TLSO) for adolescent idiopathic scoliosis (AIS) to prevent curve progression. ¹ Your comments highlight several important points and misconceptions that exist in practice regarding brace treatment for scoliosis that warrant clarification.

As stated, the BRAIST multi-center study serves as a landmark for the effectiveness of brace treatment to prevent curve progression in AIS. ² In the randomized arm, the success rate for bracing was 75% in comparison with the 42% success rate in the observational group. ² This success rate significantly improved when the average daily wear time was included into their analysis, reaching 90%–93% when worn for at least 12.9 h per day, as detailed in Figure 2 of their study. The lowest quartile of wear (mean 0–6.0 h per day) was associated with a success rate of 41%, comparable to the observational group. ² Therefore, our description of the BRAIST study results is correct.

In addition, the BRAIST study was not isolated to Boston-type TLSO braces, but included any rigid TLSO, prescribed according to the standard practice at each location, as detailed in their methods, and did include the Providence TLSO. ² The Providence TLSO has been shown to have comparable success rates to Boston-type TLSO and even superior for certain patient characterisitics. ³ The mentioned meta-analysis by Rowe et al. ⁴ looked at Charleston part-time bracing compared to full-time bracing with either Boston or Milwaukee brace results and are not representative of the Providence TLSO.

The author(s) note that most of the patients in our study, with an average age of 12.4 ± 1.45 years (range: 11.6–13.3 years) as stated in the results, had minor curvatures, <35°, and that the best results were achieved in more mature patients. We agree, and as we demonstrated, the Providence TLSO appears to be best suited for patients at lower risk of curve progression, specifically curves <35°, with an apex at T10 or below, and Risser 1 or greater.

Regarding high correction, asymmetric braces for AIS treatment, it is important to note that the available data are limited and not conclusive. The cited article by Aulisa et al. ⁵ has promising results, with an average curve improvement of 13°, but the article by Weiss et al. ⁶ is an interim analysis of children still undergoing treatment. A recent study by Minsk et al. ⁷ on the Rigo-Cheneau Brace has also shown promising preliminary results, but includes only 13 patients treated with the Rigo, clearly lacking sufficient numbers to draw a meaningful conclusion.

The vital aspects of bracing for AIS that are largely avoided by the author(s) are skeletal maturity, brace compliance, and daily brace wear. As Karol et al. ⁸ have eloquently demonstrated, children who are Risser 0, and especially with open tri-radiate cartilage, experience curve progression to surgical threshold despite bracing, regardless of the amount of time in a brace. In other words, the more growth remaining, the less likely bracing will be successful. Regarding brace compliance and daily wear, we did not include any objective measures in this study. Brace wear time was based upon hours prescribed by the treating physician, not actual wear time, resulting in a likely over-estimated compliance rate.

In conclusion, the authors of the letter have provided us with an opportunity to reinforce the indications of the use of the Providence TLSO. Through continued rigorous scientific investigation and in-depth and valid evaluation of the literature, we, as a community caring for AIS patients, will continue to better understand this deformity and how best to treat it.