European Vertebral  Deviations Center - Clinique du Parc - Lyon (France)    Plaster Cast

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Lyon Exercises
Plaster Cast
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History

Webmaster's note:

Since 2013, the plaster cast is replaced by a digital cast with direct realization of the polycarbonate ARTbrace


 

Nicolas Andry, born in Lyon, creates the term “Orthopédie” in 1741 from two Greek words meaning "straight" and "child". In a book describing the different methods to prevent and correct deformities in children, we find the torso tree which is the symbol of many orthopedic societies in the world.

Less than 100 years later, Gabriel Pravaz, the inventor of the syringe, created in Lyon one of the first scoliosis treatment institute.

The Lyon Method has many exercises that were later used in other methods, such as Schroth.

At the beginning of the 20th century another Lyon physician, Claude Bernard invented Experimental Medicine which gradually replaced empirical medicine. He publishes a book proving the good results obtained by the Lyon method.

At the beginning of the 20th century another Lyon physician, Claude Bernard invented Experimental Medicine which gradually replaced empirical medicine. He publishes a book proving the good results obtained by the Lyon method.

To better understand the Lyon brace, the 4 main objectives of the braces are recalled to mind:

1 - Guiding growth at night.

2 - Reducing load during the day.

3 - Plastic deformation of musculotendinous paraspinal structures.

4 - Remodeling by inversion of the apical load. (which needs more than 48% in-brace correction).

All braces are guiding growth during the night. This objective is sometimes sufficient to stabilize the scoliosis, but the deformation occurring during the day, daytime port is usually necessary.

The second objective of the brace is to reduce load during the day.

In fact, the more the apical vertebra moves away from the gravity line, the more the deforming load will be high at the concavity level. It is the result of a first-class lever.

The brace acts as a composite beam with a very rigid outer shell strongly reducing the load at the vertebral axis. All symmetrical or slightly asymmetrical braces worn during the day are stopping the deformation of the apical vertebral body.

The third objective is the Plastic deformation of musculotendinous paraspinal structures.

The elastic deformation is well known: after 2 hours without brace the radiological correction is lost with return to the initial angulation.

To obtain a plastic deformation knowing that it is impossible to increase the load the only solution is to maintain the load in the time.

This is the role of the original plaster cast in the Lyon method. with maintenance of the correction from 1 to 4 months to obtain a creep.

The visco-elasticity observed in all connective tissues allows a histologically visible tissue realignment after 3 weeks.

By maintaining a vertebral bending in rats for 5 weeks we can create structural scoliosis.

Plastic deformation requires stretching of the concavity obtained only by a hyper-corrective plaster cast.

Currently the plaster cast is replaced by a digital cast with transposition of 40 years of experience of plaster cast in a precise protocol of digital cast. For didactic purposes, we will take the main steps of the plaster cast and visualize their equivalent in digital cast.

The Cotrel frame is replaced by a 4 columns digitizer with 8 sensors allowing a scanner in 4 seconds and a precision of 1 mm necessary for the high rigidity.

The first step is the axial translation. The chin and pelvic traction are replaced by an active axial self-elongation which is the basis of the Lyon Method in the "grand porter”

The second step is the translation or "shift" of the lumbar curve, according to the protocol of Min Mehta. In the frontal plane, it is a translation to open the ilio-lumbar angle when there is a tilt of L4. In the sagittal plane, lumbar lordosis is easily achieved by the lumbar tape.

It is more precise and easy during the digital cast.

The third step is the thoracic bending performed by a 3-point system.

In digital cast thoracic bending is facilitated by positioning the concave hand on the patient's head. Sagittal kyphotisation is easier to obtain than with a conventional plaster cast.

The ARTbrace obtained from digital cast is asymmetrical like the plaster cast while the Lyon Stagnara brace is symmetrical.

The Lyon method has completed the integration of new digital technologies in Orthopedic Medicine.  The in-brace correction of 70% in ARTbrace will allow to achieve the 4th objective which is the remodeling by inversion of the apical load as we will see in the next chapter devoted to the ARTbrace.


First presentation:ESPRM Brugge 2008

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  The website has been updated for the last time on  May 26, 2018