The differences between the original Cheneau brace and the author’s Cheneau-Rigo handmade type brace are the following:
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The brace was designed using the Rigo Classification of scoliosis and brace design.
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The new Cheneau brace follows the current design shapes taught by Manuel Rigo, MD. Thus, it is a Cheneau-Rigo handmade type brace.
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The brace was handmade by the author and it is the author’s personal version of the Cheneau-Rigo brace, thus the name follows the evolution of the brace, Wood Cheneau Rigo (WCR) brace.
Good fit and function today does not guarantee a good fitting and functioning brace in 6 or 12 months. This has to be considered and checked by close control and follow-up with the patient.
A scoliosis brace has many pads, pressures, reliefs, expansions, opening in many planes and orientations, and it is beyond the scope of this paper to discuss the optimal situation for each. Rather, it is to discuss how brace design and pad placements were changed in this particular case to improve curve correction of IS.
A finished TLSO scoliosis brace, of all names and brands, should be designed and finished with some basic standards which are imperative to having a more successful result for the patient for the next 9 to 12 months, and not only for the initial in-brace X-ray. For example, the thoracic pad that is one or two vertebra below the apex may produce a good initial in-brace correction but could cause progression later on if not monitored closely.
Thus, for most cases it is preferable to have the thoracic trimline (posterior right side of brace for a right curve) at the apex of the thoracic curve or, in the case of single curves, above the apex of the curve. This must be carefully fit by the orthotist to allow maximum pressures below the apex of the thoracic curve (but not too low), while leaving the actual brace or superior thoracic trimline above the center of thoracic pressure. Optimum thoracic curve correction is achieved when the maximum pressure is below the apex of the thoracic curve. The ribs below the apex actually push the curve above that point, therefore a brace pad placed below the apex pushes on the ribs that push and correct the curve at the apex[4]. However, the fixation of having the pad below the apex should be considered only if realistically possible. For example, this is not always possible if the thoracic apex is low and or in short thoracic curves with high lumbar curves. It must be considered that a pad 2 vertebra below the apex could cause the pad to block correction of that curve and of the lumbar curve. The 2 vertebra below the apex in this situation would have a pad that not only pushes the thoracic curve but would also push against the lumbar correction. The soft tissue below the apex will compress and the forces are not always totally transferred to the vertebra connected to those ribs, but rather to the spine at the level of the pressure. As a result, the low thoracic pad can block correction of the thoracic and lumbar curves if not placed correctly.
Scoliosis braces are fit to growing children who experience significant growth spurts that can make the brace too short relatively soon after that fitting. Therefore, the patient’s potential growth is considered when deciding on the level of pad placement.
Poor trunk decompensation was also observed in some patients, and although it does not directly cause curve progression, it presents the patient with a poor clinical presentation that should be addressed. However this issue is beyond to scope of this paper.
The typical course of bracing intervention for scoliosis is 2-4 years (depending on maturity of each patient), often spanning the child’s growth spurt. Several braces are typically needed to accommodate this growth and also to take advantage of the opportunity to augment the corrective forces after an initial break-in phase. The number and spacing of these braces depend also on scoliosis correction, patient acceptance and economic factors. The important point here is that whenever it is determined that the patient will remain in a single brace for a year or so, especially during the growth-spurt years, care must be taken to ensure that the thoracic pad does not end up applying forces too low on the spine toward the end of that bracing period.
Figures 1 and2 show the correct thoracic and axilla forces required for thoracic Cobb angle correction in the coronal plane. If the brace is fit with a low thoracic trimline, it could produce negative effects subsequent to a significant and normal growth spurt (Figures 3 and4).
Pad placements that could cause scoliosis curve progression are presented in Figures 5a to6b:
Some common causes of curve progression are listed below.
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Thoracic pad and trimlines are left too low below the curve apex at the initial fitting of the scoliosis brace. This often presents with good in-brace correction. However, lack of follow up and/or brace replacement during the growth spurt eventually leaves a brace that is much too short for the patient, and thus causes progression, or at least less than optimal in-brace correction.
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Axilla extension is low and therefore once the patient grows, it does not provide an optimal 3-point pressure system. This, in turn, may lead to a buckling or collapse into the concave side of the curve.
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The thoracic pad is too low and blocks lumbar correction.
A scoliosis brace should be replaced prior to it actually being too short for the patient (i.e. at 11 to 12 months of treatment; in some cases before that). A short-fitting brace will most likely cause curve progression.
Some ways to provide an optimally-functioning brace that would last at least 9 months to 12 months, in most cases, are the following:
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For standard TLSO type braces, the thoracic trimline is left to be at the level of the apex, but the pad is placed below the thoracic apex. This way, the brace is positioned such that as the patient grows, the thoracic pad can be placed higher.
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In cases where there might not be good patient follow-up, the pad could be placed at the apex of the thoracic curve, thereby establishing optimal correction after approximately 3 or 4 months of brace wear (after the patient grows taller).
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In other TLSOs that do not have pads, the thoracic pressure is applied from the brace itself. In these cases it would be desirable to leave the trimline high at the apex (some curve patterns should go above the apex). For optimal Cobb angle correction, the brace should be flared out at the apex and slightly below it, keeping the main pressures below the apex of the thoracic curve.
Independent of the brace type, the levels of vertebral pressures have to be correct to allow 3-point pressure systems to effect optimal lateral translation of each section of the spine. These pressures must be designed to open the concave side of the lateral curves as demonstrated in Figures 7 and8.