'Brace Technology' Thematic Series - The Lyon approach to the conservative treatment of scoliosis

摘要

The Lyon Brace, or adjustable multi-shell brace, has been used for more than 60 years.The use and function of the Lyon Brace includes: – The utilization of one or two corrective plaster casts, which enables a true lengthening of the concave ligaments.– An oriented CAD-CAM moulding in 3D auto correction after the removal of the plaster cast.A blueprint adapted to Lenke's classification.– A specific physiotherapy program.Background Pierre Stagnara created the Lyon Brace in 1947. The brace has the following characteristics: – It adjusts to allow for a child's growth of up to seven centimetres and for an increase in weight of up to seven kilograms.– It is 'active' in that the rigidity of the PMM (polymetacrylate of methyl) structure stimulates the user to auto-correct. The active axial auto-correction decreases the pressures of the brace on the trunk. – It is decompressive in that the effect of extension between the two pelvic and scapular girdles decreases the pressure on the intervertebral disc allowing for more effective pushes in the other planes. – It is symmetrical making it both more aesthetically pleasing and easier to build.– It is stable at both shoulders and pelvic girdle, facilitating the intermediate 3D corrections.– It is transparent. The pressure of the shells on the skin can be directly controlled so "pads" are usually not necessary.Brace description Two metal bars are fixed vertically, one anterior the other posterior and all shells are attached from the bottom to the top in this order: – Two pelvic shells ensure an optimal stability of the brace.– One lumbar shell T12-L4, which can be either independent or extending, at the abdominal chondrocostal level.– One thoracic shell at the level of the thoracic convexity.– One opposite thoracic shell used as a counter push.– One shoulder balance shell on the side of the thoracic convexity.Long term follow up results This is a retrospective study of 1,338 completed treatments checked a minimum of two years after weaning from the brace.Only 5% of the curves progressed more than 5° from the initial magnitudes. This translates to an effectiveness index of 0.95.A subset of 174 subjects who started treatment at Risser 0 was isolated. The global progressive angular mean curve was superimposed on the statistic general curve and the effectiveness index was calculated at 0.80. The Surgery rate was just 2% of the patients presenting with an initial curve below 45°.Conclusion The Lyon Brace is the historical reference of bracing AIS. To be fully effective, it requires the patient to wear a plaster cast for at least one month and receive specific physiotherapy training. Although this is a retrospective study, the results are very positive, and clearly indicate a need for a prospective study.