European Vertebral  Deviation Center - Clinique du Parc - Lyon (France)    3D correction

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3D correction
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Torsion
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Prospective study
Scoliosis > 40°

 

First I'd like to thank you very much for the invitation and the opportunity to come to APOSM 2016 Seoul. I am Jean Claude de Mauroy from Lyon France, and I am very happy to participate in your symposium entitled "New horizons in 3D Correction by Spinal Orthosis."

Lyon has always had a great tradition of Orthopaedic and Charles Gabriel Pravaz was not only the inventor of the syringe, but he also created in Lyon a great Orthopaedic Institute to treat scoliosis 200 years ago. The first Lyon brace in leather and steel was created by Stagnara 70 years ago. It undergoes a first change with the replacement of leather by polymetacrylate. 3 years ago, the use of polycarbonate and asymmetry allowed to avoid the plaster cast which was the characteristic of the Lyon Brace.

 

A tensile stress is a  stress that tends to stretch or lengthen the material. Strain is defined as "deformation of a solid due to stress“ Like the old plaster cast, with an initial full time at least 4 weeks, the structure does not return to its initial size and its original shape after removal of applied loads. It's a plastic permanent behaviour or creep, after exceeding the elastic limit.

 

A plastic deformity of the concavity requires an overcorrection of the curvature during the "full time“

The ARTbrace is currently the most corrective brace with an average in-brace correction of 70%

Here is an example with a thoraco-lumbar curve of 39° totally corrected with the new Lyon ARTbrace published at the beginning of the prospective study. Excellent result at weaning.

The main innovative features are in the acronym of ART

1. A stands for Asymmetry obtained with an overlay of three regional shapes captures

2. R stands for Rigidity (in fact High rigidity) of polycarbonate 

3. T stands for Torsion: the brace performing a Detorsion of the scoliotic Torso Column which is a circled helicoid with horizontal generating circle in opposite direction of the spiral column while fixing the sagittal plane in a physiological position.

In 2013, a new version of the software facilitates the overlapping of volumes. Jean Claude de Mauroy then designs the regional molding in 3 stages, with simultaneous correction in the frontal plane and the sagittal plane, which will automatically lead correction in the horizontal plane by the coupled movements law. Originally designed to replace the Abbott's plaster cast, the first results show a correction of 40% higher than that of the old plaster cast. Tolerance is also better, then it is decided to make the whole treatment with the new ARTbrace. It's Stefano Negrini who will give it the name which stands for Asymmetric Rigid Torsion brace.

The asymmetry is obtained by the superposition of three regional moldings in postures associating a frontal and sagittal reproducible correction. It is the child himself who ensures the highest possible correction. A specific CAD/CAM device with video control is necessary.

This asymmetry is obtained by a segmental mould that includes 3 stages:

1. Auto-active axial elongation and sagittal positioning of the pelvis

2. Shift and lumbar lordosis

3. Bending and thoracic kyphosis

The first mould is in axial self active elongation with control of the pelvic tilt. A visual antero-posterior and latero-lateral control is essential. The pelvic tilt is corrected with data of the sagittalmeter.

The basic use of sagittalmeter is the calculation of the pelvic incidence. Pelvic incidence is a constitutional factor and does not vary during the movements in the sagittal plane. The eventual recovery of curvatures in the sagittal plane will be facilitated.

Mould n° 2 made with lumbar frontal shift and lumbar physiological lordosis under visual control

The imbalance can be corrected when making moulding. On the video control, the head is on the gravity line.

Theoretically, the axillary and trochanteric clamps are located on the same vertical.

Moulding 3 is performed in thoracic kyphosis and frontal bending.

It is impossible to make the thoracic bending without specific positioning of the upper limb of the concave side. Spontaneously, the child tilts his head to the convexity.

The translation in the frontal plane is facilitated by the positioning of the concave upper limb

As for the lumbar region, the axillary and trochanteric clamps are on the same vertical.

Then we begin if necessary the kyphotisation which will be guided by the hands of the operator.

The second step is the superposition of the three shapes. It is this superposition that performs overall untwisting of the spine in the opposite direction of the scoliosis.

1. The sagittal plane is fixed. The posterior bar reproduces exactly the lordo-kyphosis we wish to give to the patient.

2. The frontal plane reproduces the correction obtained by the shift. Polycarbonate is undeformable. The only motion will take place towards the expansions of the concavity

3. The only mobility alone lies in the horizontal plane with untwisting, it is related to the elasticity of the posterior bar and metal articulation with polycarbonate.

These modifications are made using the software OrtenShape.

1.In gray molding 1 and in red moulding 2
2.In gray partial reconstruction and in red moulding 2
3.In grey final reconstruction with superposition in red of moulding 3

On the left we see here the partial reconstruction with moulding 2 in grey and moulding 3 in red. On the right in gray the final design after complete reconstruction.

In the frontal plane, the only mobility occurs in the expansions. In the sagittal plane, there is no mobility. By against shear and derotation are possible depending on the deformation of the metal bar and hinges with the polycarbonate

Even if the old Lyon brace in polymetacrylate was very rigid, the credit for VERY HIGH RIGIDITY goes to the Italian team of ISICO with the Sforzesco brace, which has proven to be effective by avoiding plaster casts for scoliosis over 45°. The merit of the ART brace is the addition of overcorrection to the high rigidity with a global detorsion. It is this overcorrection for small curvatures which explains the average improvement of the in-brace correction.

Polycarbonate characteristics are:

• Transparency

• Unbreakable (25 stronger than Polymetacrylate)

• Lightweight (3 or 4 mm sheet)

• No bisphenol A

• Glass transition 147°-155°

• Bending brake till 120°

• Insulation Rvalue 1.43

The Soft Contact concept is that of the squeeze attachment for cylindrical hay bales. Pressures are spread over the entire cylinder surface; this is contrary to the principle of the push and counter-push of the historical Lyon brace or other three point braces with limited contact areas or internal pads. In the ART brace the shape of the brace is not a straight spine like the Sforzesco or the old Lyon brace, but an overcorrected spine with reverse scoliosis.

In the Horizontal plane, given the multiplicity of planes, the corrections by the 3 points system only operate in a limited number of planes. The local derotation of the apical vertebra in plane geometry is replaced by a global volume Detorsion. of solid geometry. This is why the ARTbrace works in an overall untwisting or detorsion.

The mathematical basis of the torso column is the circled helicoid with horizontal generating circle described by the French mathematician Robert Ferréol. The aim is to get not only a straight spine, but a reverse torso moulding opposite to scoliosis i.e. overcorrection of the scoliosis curvature. This overcorrection is possible only if the vertebral bodies are not distorted. Otherwise, we favor the correction accentuating the asymmetry of pressure on the vertebral body.

In solid geometry, we do no longer speak of rotation (in a plane), but of TORSION. It is the high rigidity of the polycarbonate which allows the Detorsion or untwisting (geometrical and mechanical). The Global detorsion is performed with a fixed sagittal plane. Axial elongation brings the vertebral bodies near the central axis in the frontal plane, and by untwisting the scoliotic spine between the pelvis and the shoulder the horizontal plane is corrected. So both geometrical detorsion and mechanical detorsion of the cylinder are working together.

The feature of the ARTbrace is an untwisting that occurs between the axillary clamp, like when wearing a child, and the pelvis.

The first mechanism of the geometric detorsion is the translation along the vertical axis by elongating the two ends of the torso column

The Moulding of a brace is always performed in elongation along the vertical axis of the spine. In this posture, we don’t’ have any change of rotation.

The means of achieving this elongation, were improved with braces: from the first Sayre’s plaster cast, with head suspension and body weight realizing a bipolar overall elongation, to the new Lyon brace. The axial elongation like “mayonnaise tube” is achieved by the simultaneous clamp of the two hemi polycarbonate pieces. there is a real extrusion by bringing together the two pieces

The biomechanical basis according to Panjabi is the coupled motion behavior of the spine. The moulding is 2D but the correction is 3D.

The direction of rotation may differ depending on the flexion of the spine in the sagittal plane. When there is a flat back, the initial scoliotic rotation may be increased by the correction in the frontal plane. Restitution of physiological curves in the sagittal plane seems to decrease the scoliosis rotation (Harrison Fryette’s laws)

For example during the moulding 2 of the lumbar region, the shift is made in lordosis and one can see the automatic untwisting or detorsion of the spine on this thoraco-lumbar curve.

It is the same for the molding No. 3 of the thoracic region. When one combines a frontal bending and a sagittal kyphosis, the untwisting or detorsion is automatic and maximal for this thoraco-lumbar curve

The second mechanism is the mechanical detorsion which is carried by the entire external surface of the thorax. The brace will correct the thoracic and pelvic deformity, but especially move the volumes. The faces of the solid obtained from the cutting planes are called bases of the trunk, and the distance between the two cutting planes is the height of the trunk. The lateral surfaces of this solid are not necessarily planar, but are hyperbolic paraboloids.

The tightening at the thoracic basis is essential. The ratcheting closure allows very precise control. The more the brace is tight, the more the detorsion of the spine will increase.

The EOS 3D system automatically calculates the rotation for each vertebral segment.

The Torsion is the sum of all the segmental rotations. We can calculate the overall in-brace derotation or untwisting. In this case 30 % improvement,

 

More recently the EOS system confirms the accentuation of back flat with all current braces. In all braces, the lengthening of the spine by translation along the vertical axis is accompanied by a decrease in lordosis and an accentuation of the back flat. The EOS system allows to quantify these changes with a loss of 13° of lordosis for the Boston brace and accentuation of the flat back of 3° for the TLSO Chêneau brace.

Here is an example of in-brace correction of the flat back. This correction may improve during treatment.

This is a prospective controlled cohort observational study based on ongoing database including 739 adolescent scoliosis patients treated with ARTbrace from May 2013 to May 2016. Only primary curves were selected and lumbar scoliosis (Lenke 5) are excluded as treated with a short lumbar brace. The weaning protocol is identical to that of the former Lyon brace and compliant with the SOSORT guidelines.

 

The dropout rate calculated for the first 250 patients is 13%.

Ongoing treatment 101 patients (40%), 117 patients (47 % ) finished the treatment with 156 curves

In blue, the stiff thoracic curves. In yellow the more flexible lumbar curves, and in green the average of all the curvatures. The initial angulation is 27,7° Cobb, average in-brace correction 75,9 %  and final correction 38,6 %. It is too early to present the results two years after weaning, but it is possible to compare with the former Lyon brace.

For 76 thoracic curves the reduction percentages in-brace and at the end of treatment were significantly higher

 

It is the same for 80 lumbar curves

78% of the curves were improved by more than 5 °, 22% are stable and one curvature worsened by more than 5 °.

There is a strong positive correlation between in-brace correction rate and end treatment correction rate for thoracic and lumbar curves. The quality of immediate in-brace correction is fundamental to successful outcome.

 

Here is the example of the case 90, with initially thoracic scoliosis of 39° and rib hump of 17° ATR. Excellent in-brace correction with total reduction of the curvature. The sagittal plane is also improved

 

Under EOS 3D, detorsion is excellent

Here is the Clinical picture in brace

At Risser 5, after 2 years of bracing, the angulation is 13°,

Clinical aspect at the end of treatment after 6 months of night time bracing The Bunnel ATR is under 10°.

The ARTbrace with 3 mm polycarbonate can be used to replace the serial casting of early onset scoliosis. In this case, serial casting was a failure.

MD and CPO are doing their best, but, the correction was limited to 60° with a Chêneau brace

For infantile scoliosis, we use the CAD/CAM mirror technique

You can compare the result in Cheneau brace and in ART in the frontal plane,

But also in the sagittal plane with a better balance

The day after fitting the brace, Adele was playing toboggan in the park.

The ARTbrace is also a corrective brace for Adult Scoliosis. In this case, the decompensation occurred at 60 : 28 years after surgery. The night after brace delivery, the pain disappeared.

The patient feels better balanced and there is an improvement in the thoracolumbar kyphosis.

Even if there is nonunion, we note with EOS 3D that the lumbar area underwent a global detorsion of about 25°. This is the proof that ART is a Detorsion brace.

You are welcome in Lyon for the SOSORT meeting 2017


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  The website has been updated for the last time on  November 12, 2017