Prospective study and new concepts based on scoliosis detorsion of the first 225 early in-brace radiological results with the new Lyon brace: ARTbrace

Abstract

Background: The symmetrical Lyon brace is a brace, usually used to maintain correction after a plaster cast reduction in the Cotrel's EDF (Elongation-Derotation-Flexion) frame. The new Lyon brace or ARTbrace is an immediate corrective brace based on some of the principles of the plaster cast which are improved due to advances in CAD/CAM technology. The aim of this paper is to describe concepts of this new brace to be not only a replacement of the plaster cast, but also a definitive brace.

Methods: Instead of a plaster cast, three segmental CAD/CAM moulds are made with the instantaneous full 3D raster stereography digitizer (Orten):In self axial elongationIn shift and lumbar lordosisIn shift and thoracic kyphosis A specific software (OrtenShape) makes up the overlay of the three moulds. Mould 1 is used for the pelvis and the shoulders mould 2 for the lumbar segment and mould 3 for the thoracic segment. The mathematical basis of the ARTbrace is the torso column which is a circled helicoid with horizontal circle generator. A torso column is reproduced in the opposite direction of the scoliosis. Like the plaster cast, the ARTbrace is worn for a "total time" of 24 hours 7 days a week without modifying the standard protocol of the Lyon brace reduction. The prospective controlled cohort observational study of the 225 first patients treated since May 2013 is reported below.

Results: The in-brace immediate reduction is: 0.7, i.e. 40% better with the ARTbrace than with a plaster cast. The correction of flat back is 9° (from 18°.4 to 28°.5 kyphosis Cobb angle). The improved aesthetic appearance is equal for rib hump and ATR.

Conclusion: This first paper is an introduction with very short results and does not prejudge the final outcome. The ARTbrace can be used not only to replace the plaster cast, but also as a definitive brace. The new segmental moulding with final detorsion is even more efficient and to this day the ARTbrace is the most effective to reduce the Cobb angle of scoliosis.

Keywords: Brace; Cad/Cam; Concepts; Early results; In-brace correction; Lyon brace; Moulding; Scoliosis; Torsion.

Figure 1

Reduction of a scoliosis by Lewis Albert Sayre.

Figure 2

EDF Cotrel’s frame for 3D scoliosis correction in supine position.

Figure 3

Full 3D instantaneous raster stereography Orten.

Figure 4

Circled Helicoid (a) and its mathematical basis (b).

Figure 5

Squeeze attachment for cylindric bales principle.

Figure 6

The wrench and bolt principle.

Figure 7

Theoretical detorsion of the ARTbrace for one single curve and two curves. with both (a) geometrical and (b) mechanical detorsion.

Figure 8

ARTbrace: posterior (a) and anterior (b) view.

Figure 9

Thoracic and lumbar expansion during breathing.

Figure 10

Moulding 1 in axial self active elongation.

Figure 11

Moulding 2 in lumbar shift and physiological lordosis.

Figure 12

Moulding 3 in thoracic shift and physiological kyphosis.

Figure 13

Superposition in the frontal plane.

Figure 14

Superposition in the sagittal plane.

Figure 15

Global helical detorsion after overlapping in the frontal and the sagittal plane.

Figure 16

4D Action of the ARTbrace.

Figure 17

Reference horizontal plane where muscular chains are crossing.

Figure 18

First dimension; internal geometrical detorsion of helix.

Figure 19

Second dimension; restoration of physiological curvatures in the sagittal plane.

Figure 20

Third dimension; external mechanical torsion of cylinder for a double curve.

Figure 21

Fourth dimension; Shift in the frontal plane.

Figure 22

Third dimension; external mechanical torsion of cylinder for a thoracolumbar curve.

Figure 23

Fourth dimension; frontal plane shift for a thoracolumbar curve.

Figure 24

Writing sitting posture.

Figure 25

First short time results of a single thoraco-lumbar curve.

Figure 26

Sagittal in-brace correction of Flat back.

Figure 27

Average Flat back improvement in ARTbrace.

Figure 28

Inversion of the curve without changing rotation.

Figure 29

Immediate in-brace Percent correction with ARTbrace.