**2. Design and methods**

The WCR brace evolved from the original Chêneau brace (1995), which was subsequently refined using the Rigo classification of scoliosis, and hand modifications aimed at addressing

The WCR brace incorporated the best of modern CAD CAM and "old school" hand modifications. Generally speaking, technical advances in brace design and production have increased productivity, albeit at the cost of individualization to each patient's anatomy, curve pattern, and preferences, the lack of which can degrade the brace's fit and function. For this reason, the WCR brace has, since its inception in 1995, applied the most critical patient modifications by hand. The differences between the original Chêneau brace and the author's Chêneau-Rigo hand-

**1.** The brace was designed using the Rigo classification of scoliosis and brace design, incorpo-

**2.** The new Chêneau brace follows the current design shapes taught by MR. Thus, it is a Chêneau-Rigo modern CAD CAM design brace in combination with handmade modifications.

**3.** The Wood Chêneau Rigo (WCR) brace is the author's personal version of the Chêneau-Rigo brace, and it represents the natural evolution of the original Chêneau brace.

In 2017, due to the multiplicity of versions and variations in the quality of the Rigo Chêneau type brace, Dr. Rigo, Grant Wood and Luke Stikeleather founded the Association of Rigo-Chêneau specialists (ARCS), which has the goal of maintaining and providing a standard of

The Rigo Chêneau type brace is a corrective orthotic device which must be individualized to

It is not an orthopedic product but rather a corrective concept for the specific use in the con-

A 3D scan or handmade cast is used to capture the patients exact body shape and anatomy. The scan or cast then produces a positive mold that is rectified to provide a 3D corrected positive mold, which in turn is used to adapt the thermoplastic to provide the finished brace. Using the handmade original tech, a 3D corrected positive mold is created to provide specific pressure areas or pads of contact, and expansion areas or rooms. These pressure areas or pads have specific levels, orientations, depths and shapes. The pressure areas are generally located on the convexities and prominences of the scoliosis body. Contacts or pads are individually

The expansion areas, or rooms, are not windows where a simple hole is cut out of the plastic, but instead, actual buildups of significant space created in the original positive mold. They are generally located in the concavities and prominences of the scoliotic body. Expansion rooms are for tissue migration, growth and breathing movements, thus converting a rigid

rating many significant changes from the original Chêneau brace.

quality and education for orthotists who have practiced these principles.

each patient's specific curve pattern and other unique body characteristics.

oriented in space and shaped to provide 3D correction (**Figure 3**).

the complexities of the original design.

172 Innovations in Spinal Deformities and Postural Disorders

made type brace are the following:

servative treatment of scoliosis.

brace into a dynamic brace [5].

This chapter reviews the biomechanics and breathomechanics of all three planes of the body. The transverse thoracic section demonstrates improvement of the thoracic hypokyphosis. The diagram of patient elongation describes how specific pressure points simultaneously provide for elongation, derotation and lateral curve correction. The pelvis and trunk translations are described, and shown to outline how the Rigo Chêneau brace overcorrects body posture to allow an improved clinical presentation for A-type, B-type, C-type and E-type Rigo classification brace types (**Figure 4**).

#### **2.1. In-brace correction**

There is a perception that the in-brace Cobb angle correction must be 50% to be considered acceptable. This is often true and it is also true that the Cobb angle, which is easily assessed, has been the gold standard of measurement for brace quality. However, not all patients can and/or should be corrected to 50% in-brace correction. In some cases, a 25% in-brace correction coupled with good 3D correction is acceptable and sufficient to prevent scoliosis progression, when greater Cobb angle correction would cause negative compensations. Overall, some patients are best served by targeting a low in-brace correction, whereas for others an 80% in-brace correction is both achievable and desirable (**Figure 5**).

**Figure 4.** In-brace correction of the Cobb angle has been the gold standard for the measurement of successful bracing. This patient's curvature was reduced from pre-brace 21° Cobb angle to an in-brace Cobb angle of less than 5° in a Rigo Chêneau type brace. The pre-brace X-ray shows the pelvis translated to the left and the trunk to the right. The in-brace X-ray shows the pelvis corrected to the right and the trunk balance to the left.

These high and low targets for in-brace corrections depend on several factors, including the Rigo classification brace type, curve pattern, skeletal maturity, flexibility, and the structural component of the scoliosis, which limits correctability. This last factor is particularly important to the effectiveness of the Rigo Chêneau brace which is supposed to work through the detorsional forces and the amount of the mechanical torsion.

3D correction is defined.


The expansion is noticeable and the volume depends on the body morphology. Expansion areas or rooms are not just to be there to be filled at the time but to define the orientation and shape of the contacts. An essential function of the brace design is to produce the right body reaction during breathing (**Figures 6** and **7**).

The orientation of the dorsal and ventral pads is different. The ventral pad is a little more frontally oriented compared with the dorsal pad which is a little more sagittal orientated. The two main forces can be combined into one main force vector. These vectors act as a pair of forces for derotation. The ventral component is always the major one, and the dorsal is the minor one. That way, the ribs and coupled spine will derotate and translate backwards (**Figure 8**).

**Figure 5.** The transverse view of a Rigo Chêneau type brace, which was made for right thoracic and left lumbar curves. The light-colored line represents the thoracic expansion areas and the darker line represents the lumbar expansion areas.
