"Brace Technology" Thematic Series - The ScoliOlogiC® Chêneau light™ brace in the treatment of scoliosis

Abstract

Background: Bracing concepts in use today for the treatment of scoliosis include symmetric and asymmetric hard braces usually made of polyethylene (PE) and soft braces. The plaster cast method worldwide seems to be the most practiced technique for the construction of hard braces at the moment. CAD (Computer Aided Design) systems are available which allow brace adjustments without plaster. Another possibility is the use of the ScoliOlogiC™ off the shelf system enabling the Certified Prosthetist and Orthotist (CPO) to construct a light brace for scoliosis correction from a variety of pattern specific shells to be connected to an anterior and a posterior upright. This Chêneau light™ brace, developed according to the Chêneau principles, promises a reduced impediment of quality of life in the brace. The correction effects of the first 81 patients (main diagnosis Adolescent Idiopathic Scoliosis (AIS) [n = 64] or Early Onset Scoliosis (EOS) [n = 15]), treated according to the principles of the Chêneau light™ brace have shown a satisfactory in-brace correction exceeding 50% of the initial Cobb angle.

Brace description: The ScoliOlogiC® off the shelf bracing system enables the CPO to construct a light brace for scoliosis correction from a variety of pattern specific shells to be connected to an anterior and a posterior upright. This brace, when finally adjusted is called Chêneau light™ brace. The advantage of this new bracing system is that the brace is available immediately, is easily adjustable and that it can also be easily modified. This avoids construction periods of sometimes more than 6 weeks, where the curve may drastically increase during periods of fast growth. The disadvantage of this bracing system is that there is a wide variability of possibilities to arrange the different shells during adjustment.

Results: The Cobb angle in the whole group was reduced by an average of 16,4°, which corresponds to a correction effect of 51%. The differences were highly significant in the T-test (T = 17,4; p < 0,001). The best correction effects achieved with Chêneau braces reported in literature so far are about 40% in two different studies. The correction effect was highest in lumbar and thoracolumbar curve patterns (62%; n = 18). In thoracic scoliosis the correction effect was 36% (n = 41) and in double major curve patterns 50% (n = 22). The correction effect was affected in a slightly negative way due to age (r = -0,24; p = 0,014), negatively with the Risser stage (-0,29; p = 0,0096) and correlated negatively with the Cobb angle measured before treatment (r = -0,43; p < 0,0001).

Conclusions: The use of the Chêneau light™ brace leads to correction effects above average when compared to correction effects of other braces described in literature. The reduction of material seems to increase patient's comfort and reduces the stress patients may suffer from whilst in the brace.80% of the adolescent population of scoliosis patients can be braced with the Chêneau light™ brace. In certain patterns of curvature and in the younger population with an age of less than 11 years, other approaches have to be used, such as plaster based bracing or the application of CAD/CAM based orthoses.

Figure 1

Overcorrection of a curve coming from 37° to -16° in a custom plaster based Chêneau brace from the 90's. In this case, not only progression has been stopped. At weaning off the curve is at 14°, two years after weaning off - final result: 16°. No further treatment necessary. (Weiss 2010).

Figure 2

Clinical follow-up with a significant improvement two years after weaning off. On the left initially a decompensated right thoracic scoliosis is visible, two years after weaning off (right) the trunk is more balanced and the patient copes well with scoliosis. In between the first Chêneau brace of the patient (Standard 1997) and one intermediate result is visible.

Figure 3

13-year old girl with AIS (39° thoracic). In the previous brace she had 22° high thoracic, 12° low thoracic and 5° lumbar, while in the Chêneau light^® brace she has 22° high thoracic, 8° low thoracic and 11° lumbar. The lumbar correction has not been improved after this x-ray in order to achieve a better balance of curves after treatment and a better cosmetic result. The reduction of material in the Chêneau light^® brace compared to the previous brace is clearly visible. Brace change was necessary due to severe pains in the previous brace [2].

Figure 4

13-year old girl with 50° Cobb corrected to 16° in the brace. This is only possible when the brace is adjusted well and the voids (in this case a void ventral on the rib hump side and a void lateral to the concavity) are clearly visible. In order to achieve maximum possible 3D-correction the concavity must be opened in order to allow a corrective rib movement.

Figure 5

The augmented classification according to Lehnert-Schroth. Curvatures decompensated to the thoracic convex side have to be regarded as functional 3-curve type curvatures, when balanced or decompensated to the thoracic concave side (lumbar curves as big as thoracic ones or even bigger) per definition they are functional 4-curve types. As can be seen, the 3-curve lumbar is a 3-curve pattern, but treated like 4-curve with reduced correction in the lumbar curve.

Figure 6

A brace to address the functional 3-curve patterns for right thoracic curves from all four sides. The static overcorrection to the concave side is already visible in this "try-on" brace not yet cut and finalized. The dorsal upright is bent physiologically which can be seen from the side. A final 3-curve brace can be seen on Fig. 4. There are no shells available for left thoracic and right lumbar curvatures.

Figure 7

A brace to address functional 4-curve patterns for right thoracic and left lumbar curves from all four sides. The static re-compensation of the trunk segments is already visible in this "try-on" brace not yet cut and finalized. The dorsal upright is bent physiologically which can be seen from the side. A functional 4-curve pattern brace in its final form can be seen on Fig. 13. There are no shells available for left thoracic and right lumbar curvatures.

Figure 8

A short brace cut from a functional 4-curve pattern brace.

Figure 9

Chêneau light out of the box!" The individual parts can be seen before they are adjusted for a "try-on" brace.

Figure 10

Step by step construction of a "try-on" brace. First the lumbar shell is attached with rivets (in the "try-on" braces the shells might be attached with screws first) at the lordosis apex of the pre-bent dorsal upright. After that the pelvic shell is attached, then the thoracic and finally the axillary shell. Because the individual shells might be tilted, the strap attachment is fitted finally after the shells are in their final position before the shell edges are cut in order to finalize and minimize the brace.

Figure 11

Controlling the voids. Ventrally to the rib hump a void is designated in order to allow a corrective movement of the trunk. On the concave side a void is designated as well for the correction in the frontal plane. The voids are tested with the fingers as can be seen on this Fig.

Figure 12

In-brace x-ray with pad markers visible. The markers are attached to the apical zones of the pressure areas. In this case an artificial decompensation, caused by the brace is clearly visible. In Double Major curvatures compression effects may arise in the middle of the trunk when the lower ribs are very long inhibiting thoracic realignment, when pushed by the lumbar pad. In this case, the brace has to be reassembled, because the correction effect is not sufficient. Without in-brace x-ray this imbalance would have remained undetected.

Figure 13

13-year old girl with double major curvature and with an in-brace correction exceeding 60% in both of the curves.

Figure 14

Patient with overcorrection from 41° to - 12 after 6 weeks and clinical improvement at that stage already (right).

Figure 15

Mature patient with good clinical correction. This brace has been adjusted for cosmetic reasons in a mature patient at the age of 15. No significant correction of the Cobb angle has been achieved, however a significant improvement of clinical appearance, as can be seen comparing the surface scans at the start of treatment and at weaning off at the age of 17.

Figure 16

Example of a patient with an initial overcorrection in a Chêneau light brace. Overcorrection of a thoracic curve from 33° to -12° in a 3CL „Chêneau light" model in an 11-year old boy. The boy had been corrected to 12° without the brace on, however the boy did not comply in the end. This is why the end-result was 26°, still better than at the start of treatment.

Figure 17

Example of a patient with an initial overcorrection in a Chêneau light brace. Overcorrection of a thoracic curve from 38° to -14° in a 3C „Chêneau light" model in an 11-year old premenstrual girl with Tanner II as can be seen on the left three pictures. After two years of treatment the curve without the brace on had been corrected to 19°.

Figure 18

Example of a patient with an initial overcorrection in a Chêneau light brace. Patient from Fig. 17 with the whole documentation left (2005) at the start with 38°, middle (2007) compensated appearance with 18° and finally right (2010) after weaning off (at 16 years of age) with a balanced clinical appearance the curve was 12° (right).