A procedure for the manufacture of a structured multilayer membrane, suitable for use in surgical reconstructions of ligament, bone or cartilage tissue, the membrane being made of collagen I freed from telopeptides (partly at least) and containing a minimum of one barrier-structure layer closed to cell ingrowth and one sponge-like structure layer open to cell ingrowth, the procedure consisting of steps where a collagen suspension is frozen in a flat bed into plates which are then vacuum-dried at a temperature below their thawing temperature, the sponge-like membranes are wetted by a controlled procedure in which a limited amount of water, smaller than as sufficient for hydration of the whole membrane thickness, is applied to them, the wetted membrane is conveniently allowed to rest at a reduced temperature of 0°C to 10°C for the moisture to equilibrate inside the structure, the thickness is modified as appropriate by applying mechanical pressure, one side is conveniently discriminated from the other by applying a tread pattern or dye, the membrane is re-frozen and dried at a reduced pressure, controlled heating being applied during a later stage of the drying procedure for the moisture temperature to rise to above the thawing temperature. The invention also covers the membrane so obtained and its use.Linvention concerne un procédé de fabrication de membrane multicouche structurée pouvant être utilisée dans des reconstructions chirurgicales de ligament, dos ou de tissu cartilagineux. La membrane est faite de collagène I débarrassé de télopeptides (au moins en partie) et contient au moins une couche à structure barrière fermée à lintégration de cellules et une couche à structure de type éponge ouverte à lintégration de cellules. Ce procédé consiste : à congeler une suspension de collagène dans un lit plat pour obtenir des plaques qui sont ensuite séchées sous vide à une température inférieure à leur température de décongélation à mouiller les membranes de type éponge
