Thanks Mike for your interest and advice.

I had never heard of these Lysate injections but I will certainly look into it. In my case there are several bulging discs ( which is hernia) but the main problem stays the stenosis which is in fact calcination of the nerve channel in the spine. But I can ask my neuro surgon about this treatment.

By the way my experiment with the improvised stool has failed. I have tried it on a very bumpy sea. It appeared that the force-equilibrum which I 'm used to make with my stance hanging on the wire is impossible to do sitting 30 cm above the hull. In fact I have forced my back trying to do so with a very painfull period after that. So wrong idea.