In the conservative management of scoliosis through orthotic treatment, it is the orthotist’s responsibility to provide an optimally fitting and functioning scoliosis brace and to achieve the orthotic intervention’s objectives to reduce or hold the Cobb angle and improve the patient’s clinical presentation at the end of skeletal growth. There are many factors that can influence curve patterns during the course of treatment, including good brace correction. For brace correction to be effective, the orthotist must identify changes in curve pattern that arise both predictably and unpredictably during the patient’s growth and adjust the brace to those changes.
With all types of scoliosis treatment, proximal structural curves, also referred to as upper structural curves, are among the most difficult curve patterns to treat. The prognosis is often poor, and there is a high risk of brace failure, especially with poor brace-wearing compliance. These proximal structural curves can be primary, secondary, minor, major, or true double-major curves. The most challenging of these curves is a true primary thoracic double major. These proximal structural curves are also known by the King classification as a King V1, or using the Rigo classification as a D modifier.2
When the patient also has a lumbar curve, it is called a triple structural curve pattern, which presents an even higher risk of curve progression. Two other signs of high curve progression risk and poor response to conservative scoliosis treatment are structural rigidity of the proximal structural curve compared with the main thoracic curve, and the specific rotation of the curve. The curve rotation is defined as the difference in rotation of the two vertebrae of the lower end of the upper curve, and the upper curve and the upper end of the main thoracic curve in the transitional region.3
These proximal structural curves were traditionally treated with a Milwaukee brace. However, due to their unattractive appearance, these braces are now seldom used. Some thoracolumbo-sacral orthosis (TLSO) options, in the order of least cosmetic and most functional to most cosmetic and least functional, are: hemi-ring, lateral neck strap, and D modifier (Figure 1). The effectiveness of the D modifier in such scoliosis cases is still unknown, but improvements in some patients with proximal structural curves have been documented. However, it is difficult to identify whether the improvements are due to the D modifier and prepectoral pad, or due to good correction of the main thoracic curve and consequent correction of the upper thoracic curve, which may have been a secondary curve with no intrinsic risk for progression. Therefore, perhaps the prepectoral pad holds the minor upper thoracic curve, and is not as effective as other bracing options for primary thoracic double-major curves.
One reason these curves are so difficult to treat is that they are outside of the levels at which TLSO bracing can provide optimal three-point pressure systems.
A five-year-old girl was diagnosed in 2009 with juvenile idiopathic scoliosis (JIS) with a right major thoracic curve (T6 to L1 with apex at T9) of 24 degrees Cobb angle with a proximal structural curve. This proximal curve was minor in comparison with the main thoracic curve. No treatment was prescribed at that time, and it was advised that she be monitored for curve progression. At the age of eight, the scoliosis had progressed to 41 degrees Cobb angle.
Figure 2a, 2b, 2c
In 2010 and 2011 the patient had follow-up x-rays that showed the curve pattern had not changed and the Cobb angles had not progressed. However, the follow-up x-ray in 2012, when the patient was eight years old, showed that the scoliosis had progressed, with the main thoracic curve at 41 degrees Cobb angle and the proximal structural curve at 30 degrees Cobb angle (Figure 2a). As a result, a TLSO scoliosis brace was prescribed, and an A1-type scoliosis brace following the Rigo classification of scoliosis was fabricated for the patient. The initial in-brace x-ray showed that the main thoracic curve was 20 degrees Cobb angle with this new brace.
Figure 3a, 3b
After 14 months of full-time brace treatment, the patient had more than 50 percent out-of-brace Cobb angle major thoracic curve correction as well as an improved clinical presentation.
In July 2013, at the age of nine, the patient had an x-ray taken when she had been out of brace for one hour. The one-hour out-of-brace x-ray showed that the main thoracic curve was 19.5 degrees Cobb angle and the proximal structure curve was 30 degrees Cobb angle. Subsequently, another scoliosis professional suggested that the x-ray should have been taken while out of brace for the duration of 24 hours. As a result, one month later the patient had a second out-of-brace x-ray. This time the patient had not worn the brace for 36 hours. The x-ray showed that after 36 hours out of brace, the main thoracic curve was 20 degrees Cobb angle, nearly the same correction as shown on the one-hour out-of- brace x-ray, and the proximal structural curve had decreased to 20 degrees Cobb angle (Figure 2b).
In August 2013, the patient had physically outgrown the brace, and the 36-hour out-of-brace x-ray indicated that the curve pattern had changed from an A1-type scoliosis to an A2-type scoliosis (Figure 3a). This required the fabrication of a different brace design but of the same brace type—a Wood-Cheneau-Rigo (WCR) brace.
The new WCR brace required a closed right pelvis since the pelvis was now balanced and the L3, L4, and L5 vertebrae were horizontal (Figure 3b). The new WCR brace was an A2-type with a prepectoral pad design using the Rigo classification of scoliosis (Figure 4). The prepectoral pad was used to provide some support and to try to hold the minor upper or proximal structural curve by providing a small and minimal right counter-force to the left axilla extension (Figure 4). An in-brace x-ray was taken the day after the patient had been fitted with the new Figure 2a, 2b, 2c WCR brace (less than 24 hours in brace); the x-ray showed that the main thoracic curve was 16 degrees Cobb angle, the lower lumbar region was -4 degrees Cobb angle, and the proximal structural curve was 22 degrees Cobb angle (Figure 2c). The results showed good in-brace correction of the main curve, and the slight increase in the proximal structural curve was reduced by lowering the left axilla extension 2cm. The author prefers to leave the trim lines long to anticipate patient growth. However, in this case the axilla was too long. (It is particularly important when a D modifier is present not to leave the axilla extension long). The x-ray provided good feedback in that it showed that the left axilla extension was too high and therefore was pushing the proximal structural curve slightly over and causing a slight increase. Lowering the left axilla trim line was a simple solution to this, and once it was lowered, the proximal structural curve was the same as when the patient was out of brace. The goals for treatment of proximal structural curves with a TLSO are to have the upper curve stay the same or slightly increase—an acceptable outcome is some other structural, large, and rigid curves. If good major curve correction is achieved, then an increase of 4 or 5 degrees in brace is acceptable in the structural, large, and rigid curves.
Pre-brace, the patient was decompensated to the right, and in the WCR brace she was overcorrected to the left. However, out of brace she was well balanced. The left pelvis was higher out of brace; therefore, the brace was designed to push on the left pelvis to move it from left to right, which moved the lower right pelvis higher and balanced it better with the left pelvis (Figure 3b).
Figure 5a, 5b
Figure 5b demonstrates the forces and support levels of another patient’s D modifier and prepectoral pad on an in-brace x-ray. It shows the pre-brace x-ray compared with the in-brace x-ray.
The orthotist must be experienced in the particular brace type prescribed by the physician and be diligent in the follow-up care, thus ensuring that the appropriate brace quality-control adjustments are made and changed in the brace design. Although this patient has not started puberty, the risk of progression is lower now that the out-of-brace Cobb angles are less than they were prior to bracing. The true effect of the current D modifier is unknown and uncertain; therefore, future research is needed to find real bracing solutions for proximal structural curves.
Grant Wood, MSc, CO, is the cofounder of Align Clinic, San Mateo, California. He is a specialist in scoliosis bracing with the Cheneau brace, the Rigo-Cheneau brace, and RSC braces, and has trained with Manuel Rigo, MD, and Jacque Cheneau, MD, since 1996.
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- King, H. A., J. H. Moe, D. S. Bradford, and R. B. Winter. 1983. The selection of fusion levels in thoracic idiopathic scoliosis. Journal of Bone and Joint Surgery 65:1302–3.
- Rigo, M. D., M. Villagrasa, and D. Gallo. 2010. A specific scoliosis classification correlating with brace treatment: Description and reliability. Scoliosis 5:1–11.
- Perdriolle, R., and J. Vidal J. 1981. Revue de Chirurgie Orthopédique et Réparatrice de l’Appareil Moteur A study of scoliotic curve. The importance of extension and vertebral rotation (author’s translation; article in French). Revue de Chirurgie Orthopédique et Réparatrice de l’Appareil Moteur 67 (1):25–34.