A system to stabilize and guide the growth of the spinal column includes an elongated support member having a width and a length and a guiding connector having a bone connecting portion and a guiding portion. The gyrolaser comprises means of measuring the total optical power circulating in the optical cavity and first means of control of the current delivered by the supply source in such a way as to maintain the total optical power substantially constant in a narrow spectral band centred on the relaxation frequency of the laser. Also disclosed is a method for protecting a composition containing labile biologically active particles which comprises encapsulating at least a portion of the biologically active particles within hydrolyzed polysaccharide particles, thereby protecting said portion of said biologically active particles.