Could a rigo cheneau brace work on scoliosis and spondylolisthesis ?

Not really : Rigid braces are used in scoliosis in growing children and can be used to lessen the progression of a curve , thereby reducing the likelihood of surgery. They really don't have benefit in a adult. They don't improve the curve and to cover the whole curve means they are cumbersome and can lead to stiffness and atrophy. A lumbar corset may be helpful to with the symptoms of a spondylolisthesis.